Arnhem - Rijnstate - RES

Transcription

RES-HOSPITALS
Towards Zero Carbon Hospitals with Renewable Energy Systems
Final Technical Implementation Report
Rijnstate - Arnhem (NL)
Update: 20 November 2013
Authors
TNO
Necdet Cankoy
Roberto Traversari
Project Coordinator
Agenzia Sanitaria Locale ASL AT
Prof. Arch. Simona Ganassi Agger
Kampweg 5
NL-3769 DE Soesterberg
NETHERLANDS
Email: [email protected]
[email protected]
Via del Conte Verde 125
14100 ASTI
ITALY
Email: [email protected]
Project website: www.res-hospitals.eu
Table of Contents
Table of Contents ......................................................................................................................... 2
A.
Brief description of the hospital ............................................................................................ 3
B.
Description of Measurement, Monitoring and Reporting System ........................................... 3
C.
Current energy situation ....................................................................................................... 4
a. Energy use ....................................................................................................................................... 4
b. RES share......................................................................................................................................... 6
D.
CO2 emissions ....................................................................................................................... 7
E.
Description of energy efficiency measures ............................................................................. 9
a. Already implemented measures ..................................................................................................... 9
b. Possibilities for further energy savings ......................................................................................... 10
F.
Description of renewable energy measures ......................................................................... 13
a.
Already implemented ............................................................................................................... 13
b.
Planned RES investments .......................................................................................................... 13
G.
Potential Impact of the Pilot Project.................................................................................... 17
a. Energy Saving Measures ............................................................................................................... 17
b. Energy Generation via RES ............................................................................................................ 17
H.
Zero Carbon Roadmap ........................................................................................................ 19
I.
Recommended actions towards 2020 .................................................................................. 21
a.
Decision chart for the hospital .................................................................................................. 21
b.
Timeline for the geothermal project......................................................................................... 28
J.
Commitment for the project ............................................................................................... 29
K.
New developments in the context of the RES project ........................................................... 30
L.
Conclusions ........................................................................................................................ 31
Appendix ................................................................................................................................... 34
Wind Turbines ................................................................................................................................... 34
Solar Energy ...................................................................................................................................... 36
Heat pumps ....................................................................................................................................... 39
Geothermal Energy (deep underground) ........................................................................................ 41
Biomass boilers/Stoves ..................................................................................................................... 45
Biomass / Energy from waste digestion........................................................................................... 46
2
A.
Brief description of the hospital
The Foundation of Rijnstate is a private healthcare organization that operates two hospitals and a
few polyclinics in the central part of the Netherlands. Besides the main location, a small hospital is
situated in Zevenaar (80 beds). The locations in Velp, Arnhem-Zuid and Dieren only provide poly
clinical care.
The main location is situated in Arnhem. This hospital was built in 1995 and is the largest hospital in
the area providing top clinical care. This study is focused on the main location Arnhem. This top
clinical hospital with 720 beds and 2,600 FTE staff members has a gross floor area (GFA) of 81,953
m2, which extends to 85,672 m2 when the parking area is taken into account. This hospital can be
described as two cross-shaped buildings connected by a central hall and it is built of 8 floors. The
Rijnstate Hospital is located at the edge of the city.
Rijnstate is participating in the RES project because sustainability and low operational costs on the
short and long term are very important to them.
Figure 1. Map of the Rijnstate Hospital, Arnhem.
B.
Description of Measurement, Monitoring and Reporting
System
Rijnstate has a general and conventional monitoring system for its energy consumption. The energy
provider collects information from the main meters and delivers data to the hospital. However,
currently there is not enough structure for the interpretation of the monitored data. The hospital is
planning to install intermediate meters and a dashboard in order to obtain more insight of the
energy streams and to manage the energy consumption better.
3
C.
Current energy situation
a. Energy use
The hospital has a central power plant with two CHP units (gas driven engines) and a total electric
output of 2 * 600 kW. The thermal capacity is 2 * 1,050 kW. For cooling purposes there is a
absorption cooler installed with a total output of 800 kW cold water (6-12°C). In addition
compression systems are used consisting of two screw compressors (1,175 kW each, COP in the
range of 3-4).
For steam production, two gas fired boilers are used with a total output of 3,489 kW and an
efficiency of 80%. A third boiler with a output of 3,489 kW is placed on a lower temperature. This
boiler has an efficiency of 90% .
Three emergency generators (Diesel) with an electric output of 3 * 850 kVA are installed for
situations.
The heat and cold is distributed through the building via the air handling units on the third floor.
These air handling units are fitted with heat recovery systems (regenerative heat wheels) and speed
controlled ventilators. Further heat distribution is supplied by hydronic systems (radiators).
The energy in and outflows of the Rijnstate Hospital are given in Table 1. The energy flows are
presented in Figure 2.
The energy consumption of Rijnstate per m², GPA, FTE, GPE or bed, is low in comparison with some
other hospitals, Gelre for instance. The lower consumption can be attributed to a possible lower
level of climatisation (ventilation) and to the compact design of the building.
Table 1. Energy inflows and outflows for Rijnstate
In & outflows
Natural gas (boiler)
Natural gas (CHP)
Green electricity
Diesel fuel
Total
Unit
3
m /year
m3/year
MWh/year
kg/year
Amount
GJ
904,658
1,982,553
7,767
13,600
34,377
75,337
27,958
612
138,284
2
GJ per m , FTE, GPE*, beds
2
Floor area
m
85,672
1.61
Staff
FTE
2,600
53.19
GPE*
749,000
0.18
Beds
720
192.06
*GPE (gewogen patienten eenheid, weighted unit patients) is a term used by hospitals to compare
their environmental performance. GPE is a weighted sum of patient admissions (10), nursing days
(0.49), day-care days (3.4), first clinic visits (1.22). The weight factors are indicated in parentheses.
4
Figure 2. Energy flows of the Rijnstate Hospital
Especially for the heating purposes, final consumption numbers have to be classified with the
needed temperatures. With this method, RES options which have the technical potential to supply
those demands can be discussed in the following chapters. The temperatures corresponding to the
consumption items and the proportions of the demand are estimated based on the available
information given in Figure 2. These final consumption numbers are tabulated in Table 2.
5
Table 2. Final consumption classified under specific needs and temperatures, all numbers in GJ.
End-use
LTH
(~60°C)
MTH
(~90°C)
HTH
(~150°C)
Electricity
Cooling
Absorption cooling
8,272
Sterilization and kitchen
6,894
Heating
20,000
11,022
Humidification
22,749
Electricity
53,033
Total
20,000
19,294
29,643
53,033
LTH: Low Temperature Heating; MTH: Medium Temperature Heating; HTH: High Temperature
Heating
b. RES share
The only current (at the start of the project in 2011) RES option in use is the green electricity
purchased from the grid, which supplies 27,958 GJ. As a result, the RES share of the final energy
consumption amounts to 23% (Figure 3).
Figure 3. RES share in the total final consumption (at the start of the project in 2011)
6
D.
CO2 emissions
The CO2 footprint of hospitals are evaluated under 3 categories:
Scope 1 – All direct GHG emissions
Scope 2 – Indirect GHG emissions from consumption of purchased electricity & heat
Scope 3 – Other indirect emissions such as those arising from the material supply chain, transport,
etc.
The CO2 footprint of Rijnstate (scope 1 and 2), based on the key figures presented in Table 1 are
summarized in Table 3.
The total building related emission (scope 1 and 2) in 2011 amounts 5,487 tonnes. Scope 3 emissions
were not taken into account in this report. For the combustion of natural gas and diesel fuel, the
effects of CH4 and N2O emissions were also taken into account with the CO2 equivalent emission
method.
Table 3. The CO2 emissions classified per purpose and scope.
In & outflows
Unit
GJ
CO2-eq (ton)
%
Scope
3
Natural gas (boiler)
m /year
34,377
1,705
31%
1
3
Natural gas (CHP)
m /year
75,337
3,738
68%
1
Green electricity
MWh/year
27,958
0%
Diesel fuel
kg/year
612
44
1%
1
Total
138,284
5,487
2
Floor area
m
1.61
0.06
Staff
FTE
53.19
2.11
GPE*
0.18
0.01
Beds
192.06
7.62
*GPE (gewogen patienten eenheid, weighted unit patients) is a term used by hospitals to compare
their environmental performance. GPE is a weighted sum of patient admissions (10), nursing days
(0.49), day-care days (3.4), first clinic visits (1.22). The weight factors are indicated in parentheses.
7
Figure 4. The comparison of CO2 emission sources.
The largest component of the CO2 emissions of the Rijnstate Hospital is the CHP unit, amounting to
68% of the total CO2 emissions. The emissions from the gas boiler are responsible for 31% of the
total. As the hospital is contracted to a “green electricity” tariff, no Scope 2 emissions arise in the
energy flows of Rijnstate. All emissions come about via the on-site combustion of fuels such as
natural gas (99%) and diesel (1%).
8
E.
Description of energy efficiency measures
a. Already implemented measures
In this section, the energy efficiency measures which are already implemented in the Rijnstate
Hospital are described. To begin with, the quantification of these measures on the energy
consumption and the identification of the energy efficiency level of the hospital are not
straightforward. In this respect, it is necessary to define a reference situation for a fair comparison of
the current situation of the hospitals. This reference situation will help in determining the level of
energy efficiency of the investigated hospital.
The reference situation is based on the building standards published in the year 1990. Characteristics
of the reference situation are given in Table 4.
Table 4. Reference situation of the Dutch hospitals
Techniques applied
Heat generation: 50% with high efficiency (90%) and 50% with improved efficiency (80%)
Heat recovery ventilation (80%)
50% of the cooling demand by conventional compression cooling (COPcooling = 3,0)
50% of the cooling demand by absorption cooling, tri-generation (COPcooling = 0,7)
Conventional TL lighting (fluorescent lamps)
Building measures (insulation, facades (including insulating glass) and roofs, R= 2,5 m2.K/W)
CHP (Ƞe = 39%, Ƞth = 45%,(without economizer). CHP optional, not standard!
District heating (few cases)
In comparison with the reference situation described above, the Rijnstate Hospital has a better
energy efficiency. In order to quantify this comparison, the influence of each different element from
Table 4 was calculated.
In comparison with the reference situation, Rijnstate consumes 10% less final energy thanks to its
efficient energy delivery systems and consumes 18% less gas and electricity thanks to its efficient
CHP plant. In addition the green electricity tariff helps in reducing the CO2 emissions to 45% of the
reference situation. Rijnstate has already achieved a reduction of 4,483 tonnes CO2 emission thanks
to the measures mentioned in Table 5.
9
Table 5. CO2 reduction per applied energy efficiency measure
Energy efficiency / green
solutions
Heat recovery (ventilation)
Note
10% saving on the heating and cooling demand
CO2 reduction in
tonnes
256
Energy efficient lighting
Efficient design and building
management
Efficient use of CHP
Green electricity
Total
HF lamps (30% saving on electricity for lightning)
5% saving on all other consumptions
538
257
10% improved gas-to-heat efficiency
Instead of normal tariff
830
2,600
4,483
Figure 5. Share of CO2 reduction per applied energy saving measure.
b. Possibilities for further energy savings
Having described the current energy efficiency level of Rijnstate, the next step is to list potential
energy saving measures to reduce the energy consumption even more. There are 3 important
benefits of further energy savings: reducing the energy consumption and the energy expenses,
reducing the emissions and lowering the requirements from the renewable sources to be
implemented.
Within the RES project a quick scan of the situation by two Energy Service Companies (ESCo) was
organised. The aim of the quick scans was to find possibilities for energy reduction. These companies
provide hospitals a service whereby the yields of energy measures are guaranteed. They design,
implement, maintain installations and take care of the periodic reports. In this sense, the hospitals
invest in measures which have guaranteed returns and therefore it is more appealing to invest.
10
One of the companies mentioned several improvement possibilities as listed in Table 6 leading to a
total of 6% final energy reduction, corresponding to roughly 6,900 GJ per year. With the
improvement in the boilers and the CHP plant, the total energy inflow (purchase of gas and
electricity) will decline by 10% which means savings of 13,800 GJ. The related estimation of
cumulative investments is given in Figure 6.
Table 6. Possible energy saving measures
Basic common measures
The use of economizers, to make use of the
combustion gases from boilers and CHP
Heat recovery ventilation
Optimized steam-systems
Optimal control installations / BMS
Applied in
Rijnstate
Yes
Yes
Partly
Partly
Efficient (optimal) use of CHP (use of heat by
tri-generation)
The use of high frequency lighting and LED
Yes
Building measures (insulation, facades, glass
and roofs, R > 2,5 m2*K/W)
Yes
Suggestions by the ESCO
Further improvement is possible
Improvement is possible (also in boiler
room)
Optimize steam pressure
Can be further improved (energy
management system) action already
started
Optimize use of ventilation
Further optimisation/ maximisation is
possible
Yes
Figure 6. Estimated cumulative investments and savings
11
Conclusions
The quick scan demonstrates that Rijnstate is already energy efficient compared to the reference
situation. The final energy consumption of the hospital is 121,970 GJ and it produces 5,486 tonnes
CO2 each year. Compared with the reference situation, this means that a 10% reduction on final
energy consumption and a 45% reduction on CO2 emissions has already been achieved.
But further improvements are possible resulting in 6% energy reduction. Thanks to these measures,
the CO2 emissions can be reduced further by 550 tonnes.
12
F.
Description of renewable energy measures
a. Already implemented
Rijnstate has a rather conventional energy system. There are no renewable energy systems
implemented, besides the purchase of sustainable electricity.
b. Planned RES investments
In 2013, 600 solar panels were installed on the roof of the hospital as part of on-going sustainability
plans. Geothermal heat and solar collectors are considered as future possibilities. The hospital will
be enlarged and renovated in the coming years and Rijnstate is willing to implement RES-options in
the building program.
In this chapter the RES-options are described, considering their suitability for the Rijnstate Hospital.
For this purpose we analysed both technical and non-technical barriers. Table 7 gives an overview of
the different RES options. The purchase of sustainable electricity or sustainable gas are additional
options besides this table.
Further elaboration on each renewable source can be found in the Appendix.
Table 7. Overview of the different RES options and limitations RES option
4) Other
limitation [Y/N]
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
No
Yes
Yes
Yes
No
No
3) Financial
limitation [Y/N]
Wind Turbines
Solar Thermal Collectors (heat)
Solar Thermal Collectors (electric power, CSP)
Photovoltaic Panels
Air Source Heat pumps
Ground Source Heat pumps
Water Source Heat pumps
Geothermal (deep underground, depth > 0,5 km)
Geothermal (deep underground, depth > 4,0 km)
Geothermal (Heat and cold storage)
Hydropower Systems
Wave Power systems
Tide Power Systems energy
Biomass boilers/Stoves
Biomass from (waste) digestion
2) Limitations by
legislation
[Y/N]
1) Technical
limitation [Y/N]
Steps to analyse the possibilities
Yes
No
No
No
No
No
No
Yes/no
Yes/no
Yes
No
Yes
Yes
Yes
Yes/no
Yes/no
Yes/no
Yes/no
Yes
Yes/no
Yes
No
Yes
Yes
No
No
Yes
No
Yes
No
Unknown
Yes
Yes
No
No
Yes
Yes
Source: This list of renewable energy sources is compiled by selecting from the pool of options mentioned in the
European Renewable Energy Council [1] and the EU Directive of promoting the use of energy from renewable
sources [2].
13
Wind energy is less interesting for Rijnstate because of the less windy conditions compared with
other locations in the Netherlands. Biomass will not be considered mainly because of the logistics
issues. Solar energy is still part of the possibilities but may only prove a small help due to the limited
available area for solar panels.
For Rijnstate, geothermal heat is a worthwhile option as it can supply year-round heating and
cooling demands of the hospital and neighbour areas if needed.
Initial Economic Study
A geothermal energy project can be designed for different sizes and applications. It is important to
decide beforehand which energy demands will be addressed by the geothermal source. Another
question to answer is whether the Rijnstate Hospital plans to use the geothermal heat only to supply
energy for its own energy demand or if energy can be sold to neighbouring customers via district
heating.
We had classified the final consumption of the Rijnstate Hospital according to the supply
temperatures of the systems and tabulated the categories in Table 2. There are two distinct large
heat demands corresponding to temperatures of 60°C and 90°C. According to this distinction of
different heat demands and the possibility of selling energy to other parties, 4 different options are
devised and listed in Table 8.
Option 1 describes a small sized and relatively shallow geothermal source. The main goal of this
design is to supply the hospital’s low temperature heat demand. Figure 7 shows a design which
involves an all-air heating system which has a supply temperature of 60°C. This temperature is
obtained thanks to a heat exchanger which extracts heat from a geothermal source with production
and reinjection temperatures of 65°C and 35°C, respectively. To reach a temperature of 65°C, a
depth of 1800 m is necessary and this will lead to investment costs of more than 7 M€. The main
revenue, which is the avoided purchase of natural gas is not enough to make this option financially
viable even with the support of SDE+ grant. Without the subsidy, the investment does not pay back
within the lifetime of the geothermal plant (30 years).
Figure 7. Illustration of Option 1: a small size system for low temperature heat demand.
14
Table 8. Technical and economical parameters for different geothermal options. *
Unit
Name
Option 1
Option 2
Option 3
Option 4
Own small
size
Own large
size
Small heat
producer
Large heat
producer
Outlet temperature
°C
65.8
96.8
96.8
96.8
Reinjection temperature
°C
35
35
35
40
Depth
m
1800
2800
2800
2800
Flowrate
L/s
7.1
9.8
18.0
30.0
Heat power
MWth
1
3
5
8
Own Heat Consumption
GJ
20,000
55,202
55,202
55,202
Heat production
GJ
19,837
54,940
100,910
154,576
Drilling costs
€
6,474,000
11,334,000
11,334,000
11,334,000
Pump investment
€
600,000
600,000
600,000
600,000
Total subsurface investment
€
7,074,000
11,934,000
11,934,000
11,934,000
Heat plant costs
€
150,282
416,211
764,469
1,171,031
Total investment
€
7,224,282
12,350,211
12,698,469
13,105,031
Pump electricity costs
€/year
30,307
83,936
154,168
236,158
Heat plant O&M
€/year
4,969
38,111
128,571
301,689
Total O&M
€/year
35,276
122,047
282,739
537,847
Avoided gas purchase
€/year
287,290
795,658
836,863
836,863
Income from sold heat
€/year
0
0
624,550
1,401,764
SDE+ income
€/year
121,007
390,073
716,460
1,097,491
Net revenue after tax
€/year
339,308
897,422
1,519,812
2,196,104
Payback time
years
28.05
14.35
8.50
6.07
Net Present Value
€
2,689,370
7,585,667
13,010,139
18,868,604
Payback time (without SDE+)
years
21.83
13.33
9.80
NPV (without SDE+)
€
5,375,307
8,950,295
12,649,641
n.a.
2,003,678
*The method proposed by ECN and TNO was used in the economical calculations. Additional
assumptions in the calculations behind this table are as follows:
A. Energy tariffs for the hospital: purchase of electricity – 0.0011 €/kWh; purchase of gas – 12.31 €/GJ;
sale of heat (district heating) 14.48 €/GJ.
B. Utilization of the geothermal energy during the year: 5500 load hours
C. Eligibility for the subsidies: EIA – No; SDE+ - Yes
D. For the excess heat generated, there is a customer who is willing to buy energy from the hospital.
E. Discount rate: 10% (for the Net Present Value Calculation)
F. All the investment was assumed to be from the hospital’s own resources.
G. The existing energy situation of the hospital, given in Figure 2 is adopted for these calculations.
15
Option 2 depicts a medium sized and deep geothermal source. Here, it is aimed to supply both the
low and medium temperature heat demand of the hospital. A source depth of 2800 m would mean
an outlet temperature of 96°C. As expected, the investment costs increase compared to Option 1
with a deeper source but revenues rise as well thanks to a larger amount of avoided gas purchase.
Nevertheless, with a payback period of 14 years, this investment is not promising enough as the heat
flow is too small to compensate for the drilling costs.
Options 3 and 4 both describe cases where the Rijnstate hospital is a heat supplier to neighbouring
customers, with heat generation of 100,000 and 150,000 GJ respectively. As can be seen from the
figures, the larger the heat extracted from the geothermal source from the same depth, the more
profitable the investment. If the hospital can be an energy supplier to a hub which has a yearly heat
demand of around 150,000 GJ, the payback period goes down to 6 years and the NPV of the
investment is nearly 19 M€.
For Options 2, 3 and 4, all cooling demand is supplied through absorption cooling in order to
increase the utilization of the geothermal heat.
It should be noted that this calculation is a simplified financial analysis of the geothermal investment
using standard and average values made available by ECN and TNO in order to provide indications of
feasibility. Conditions may differ in reality. The investment costs don’t include costs for laying
pipelines connecting the heat plant to customers nor project costs related to the time invested in
finding partners and starting up the project (see Chapter I).
16
G.
Potential Impact of the Pilot Project
a. Energy Saving Measures
As described in Section E, possible energy saving measures can reduce the final energy consumption
by 6% if implemented. As a result following reductions are estimated:
Table 9. Estimated gains as a result of the energy saving measures.
Reduction
10,982 GJ
2,837 GJ
544 tonnes
Savings
€ 135,194
€ 86,707
Gas
Electricity
CO2
Total
€ 221,901
Considering that the investment costs of the energy saving measures were estimated as € 1,290,000
the payback period is around 6 years.
b. Energy Generation via RES
Out of the options presented in Table 8, investing in a larger geothermal source supplying medium
temperature heat is more profitable and suitable for the goals of the hospital. The absolute energy
generation from the geothermal source will depend on the actual size of the project and on the
availability of a customer for the excess heat, such as a district heating network. The hospital’s own
demand will be around 55,000 GJ/year for medium temperature heat (see Table 10).
After adding the contribution of geothermal heat to the existing RES contribution from the purchase
of sustainable electricity from the grid, the RES share increases to 78%. Table 10 shows that the only
consumption element not supplied by a renewable source is high temperature heat required for
sterilization, kitchen and humidification purposes. This investment on geothermal energy will
decrease the CO2 emissions further by 3,500 tonnes a year to 1,400 tonnes. Therefore, the energy
saving measures and the implementation of a geothermal heat plant will reduce the emissions by
75% compared to the values in 2011, the start of the RES project.
Table 10. Share of RES in the final energy consumption in 2020 per application, all values in GJ
End-use
Absorption cooling
Sterilization and kitchen
Heating
Humidication
Electricity
Total
Green
Gray
LTH
(~60 °C)
MTH
(~90 °C)
22,972
HTH
(~150 °C)
Electricity
6,549
18,000
10,850
21,612
18,000
18,000
33,822
33,822
28,161
46,669
46,669
46,669
28,161
17
Figure 8. The impact of the project expressed in terms of the RES share in the total final
consumption: (a) the situation in 2011 at the start of the project, b) potential in 2020 if geothermal
heat is implemented
18
H.
Zero Carbon Roadmap
The Rijnstate Hospital has decided to investigate the option of investing in geothermal energy as
RES. This investment will help the hospital reach the goal of 50% RES generation by 2020. In the long
term, there are other options to consider to make the hospital a zero carbon entity. Those options
were presented in Section F and in the Appendix with their corresponding barriers.
With the implementation of the geothermal energy, low and medium temperature heat demands
will be satisfied. The remaining demand item will be high temperature heat. The electricity demand
is covered with a RES option thanks to the purchase of sustainable electricity.
Here, some conclusions from Section F and the Appendix will be repeated on the potential use of the
RES options for the zero carbon roadmap:
 The solar thermal collectors are financially not profitable, in particular when high
temperatures are required
 The lack of land area, know-how and experience for the Concentrated Solar Power is a big
barrier against its implementation in a hospital.
 Electricity generated by Photovoltaics cannot satisfy the entire electricity demand due to
limited roof area of the hospital letting alone the economical disadvantages. Therefore this
option can be considered as additional tool especially in the future when investment costs
decline.
 Heat pumps become inefficient when high temperature heat is needed.
 Hydropower, wave power and tide power are not considered due to their technical
limitations in the Dutch conditions.
 Generating heat and/or electricity from biomass is a valid option for the hospital but logistics
is the main issue to solve. This barrier can be overcome if the consumption is not too large.
 Supplying the electricity demand of the hospital with wind turbines is both technically and
economically questionable due to the low wind profile of the Arnhem region. Other big
issues are the lack of needed land area and the legislative difficulties for investing on a wind
turbine elsewhere.
 Purchasing sustainable gas and sustainable electricity are the easiest options if they are
available. Considering their compatibility with the existing infrastructure in the hospital, no
effort is needed for this option.
According to the above conclusions and assuming a constant energy consumption along the years,
the following scenario can be sketched for the zero carbon roadmap:
2013: 600 solar panels were installed on the roof of the hospital producing ~530 GJ of electricity per
year.
2018: The recommended energy saving measures are incorporated leading to 6% reduction in
energy consumption.
2020: The geothermal heat source is in operation and supplies an important share of the heat
demand excluding the high temperature heat consumption. The CHP plant is disconnected which
means that the high-temperature heat demand is covered by the gas boiler and all required
electricity is purchased from the grid via a green tariff.
19
2030: Gas boilers are fed with sustainable gas (which may become available in the future). With this
action, the entire energy consumption of Gelre is covered with renewable energy sources.
2040: Rijnstate continues investing in solar panels gradually along the years, the useable roof area of
the hospital is covered with solar panels in 2040 producing ~7,000 GJ of electricity per year.
Figure 9 is an illustration of this scenario as a function of the timeline. According to this scenario, the
Rijnstate Hospital reaches the long-term zero-carbon target in 2030 after starting burning
sustainable gas in their boilers.
Figure 9. The zero carbon roadmap of the Rijnstate Hospital.
20
I.
Recommended actions towards 2020
An initial economic study for the application of geothermal heat for Rijnstate was presented in Table
8. Following this, challenges and potential solutions for an investment on geothermal energy were
discussed with Rijnstate. This chapter has the aim of providing a guideline for Rijnstate and
generalizing the conclusions to other hospitals in the Netherlands.
a. Decision chart for the hospital
Figure 10 displays a flowchart of steps and choices to be considered by a hospital interested in a
geothermal energy investment. The following is an elaboration of each step including a reference to
Rijnstate’s situation.
1. Requirements
Knowing the magnitude of the (relevant) heat consumption is an important initial step to assess
further possibilities for the hospital. In this context, the relevant heat consumption means the heat
demand at temperatures which can be supplied by a geothermal source as described in Deliverable
3.3.
Rijnstate: 59,425 GJ (Temperature<90oC). This is almost equivalent to 1/3 of the required size for a
profitable geothermal investment, see Table 8.
2. Governmental Support
Usually the municipalities or provinces have long-term goals of reaching carbon neutral or energy
neutral conditions. They may already have programs or roadmaps in collaboration with energy
providers or investors. In this respect, they may have two distinct contributions: (1) act as contact
point for the stakeholders, (2) facilitate participation and legal arrangements, and (2) supply financial
stimulus through subsidies or tax discounts. It is important to involve those public bodies from the
beginning in order to manage the expectations regarding their support. The following summarizes
the situation for the partner hospitals.
Rijnstate: The province Gelderland is actively stimulating geothermal energy and district
heating as well as other renewable energy options. This is done by bringing parties together
in workshops such as Duurzaam benutten van Warmte (Sustainable use of heat) which was
held on 12 June 2013 where opportunities concerning the district heating, geothermal heat
and heat storage were discussed. The province Gelderland has a program on Energy
Transition which considers the global developments on energy production, economical value
and social responsibilities1. Subsidies are also available for the business case studies and
master-plans for geothermal energy. This is particularly of interest for Rijnstate if they are
willing to perform a feasibility study for a geothermal installation.
1
http://www.gelderland.nl/eCache/DEF/20/270.html
21
Figure 10. Decision flow chart for geothermal energy for a hospital in the Netherlands
22
3. Existing district heating
One of the critical points for the hospital is the connection to a heating network. Unless the heat
consumption of the hospital alone is very large (>150,000 GJ), a business case on geothermal heat
without a connection to other users will not be financially profitable as calculated in Deliverable 3.3.
If the hospital is connected to a district heating network, the hospital can engage in discussions with
the energy provider of the network to request a supply of geothermal (or another form of green)
heat. A hospital has significant negotiation power in this respect thanks to the size of its heat
consumption and its long-term stability as customer. Compared with an average dwelling in the
Netherlands which has a heat demand of ~30 GJ, the heat demand of the hospital is considerably
high. The heat consumption of the partner hospitals almost equals 2000 dwellings. In addition, the
hospital has a steady and predictable heat consumption pattern. In many cases, the hospital can
guarantee a constant heat purchase over a long term. All these make the hospital a very valuable
customer for the energy provider. Therefore, by expressing a demand in renewable energy sources,
a hospital can stimulate their supply by the energy provider.
Rijnstate: The hospital is not connected to a heat network.
4. Large consumers
If the hospital is not connected to a district heating network or if the energy provider of the network
is unwilling to supply green heat, the next option is to form a collective of customers for the
geothermal heat supply. In many cases, other large consumers are located in the vicinity of a
hospital. Critical factors are the size of their energy demand, their potential for long-term purchase,
their distance to the hospital and to a smaller extent, their demand pattern.
The total size of the collective of consumers need to be above 150,000 GJ to make the investment in
deep geothermal heat financially feasible (see the financial calculations in Deliverable 3.3).
Therefore a knowledge of the energy demand of these potential partners is essential for the
business case.
Another crucial aspect is the ability of one consumer to guarantee the purchase of heat in the longterm. In this respect, public institutes or companies with a stable long-term existence are favorable.
One of the inevitable criteria is the distance between the hospital and the other large consumer in
consideration. Taking into account the costs for the necessary pipelines, which may go up to 300.000
€/km23, the closer the consumers the higher the benefits will be.
The demand pattern is related to the technical efficiency of the installation. A hospital has a very
steady demand pattern over the year, which is favorable for the continuous heat production leading
to high efficiencies (the higher the operating hours of the plant, the higher the financial benefits).
Other consumers may have different demand patterns with fluctuations which would be worthwhile
to take into account.
2
Operating figures, quality parameters and investment costs for district heating systems. Ehrig, R. et al.
Bioenergy2020+.
3
Investment models for district heating in areas with detached houses. C. Reidhav, S. Werner, 2006. 10
International Symposium on District Heating and Cooling.
th
23
Rijnstate: One interesting partner for Rijnstate may be the Burger’s Zoo. Their energy consumption
was estimated as 30,000 GJ. This is a significantly large contribution but the total consumption of
Rijnstate and Burger’s Zoo together will not be enough for a profitable business case. Therefore
Rijnstate needs to find other large consumer(s) to form a large enough group. Another relatively
large consumer is the Nederlands Openlucht Museum which is situated right next to the Burger’s
Zoo and their estimated heat demand is 15,000 GJ a year.
Figure 11. The locations of large energy consumers in the vicinity of Rijnstate.
5. New district heating
In some cities, small or large district heating networks exist although they don’t cover the entire area
of the city. Thanks to the large energy demand of the hospital and possible other nearby consumers,
a hospital is a very attractive customer for the district heating operator. In this case, the hospital can
engage in discussions with the operator of the district heating to install necessary pipeline
connections and supply green heat.
Rijnstate: Nuon operates the district heating network in Arnhem, Westervoort and Duiven. The
network is fed by two plants: 1 CHP in Kleefswaard and 1 waste incineration plant in Duiven. In 2012,
the size of the customers reached 8300 dwelling-equivalents with a total heat consumption of
245,000 GJ. Nuon has the plans to extend these small groups of heat networks and link them
together4. However due to the relatively high distance (2,5km) to the existing network, the
difference in ground levels and the necessity to cross the city center with the pipelines, the expected
costs for extending the existing network towards Rijnstate are significantly high. Therefore a such
connection is only foreseen in the long term and depends on the support of the municipality.
4
http://nieuws.nuon.nl/wp-content/uploads/2013/07/CO2-prestatieverslag-Arnhem-Duiven-Westervoort2012_LR.pdf
24
6. Partnership
When the size of the guaranteed heat consumption is large enough for a geothermal heat
investment, the parties need to form a partnership and appoint a lead party which can act on the
business case. The leading party may be one of the consumers or an external party such as the
contractor of the installation, an investor or a new company that is found together by the group of
consumers. The need for a lead party is brought about by two reasons: (1) a single representative for
the entire group is desired in the possible discussions with banks, investors, contractors etc. and (2)
most of the consumers may be willing to invest little effort in the design of the business case and its
application. A lead party will need to invest time for all the actions including the formalities such as
applying for subsidies.
7. Development
A contractor company is needed for all the operational aspects such as drilling, installing pipelines
and equipment etc. The contractor can also act as the lead party for the partnership of consumers
described in Section 6. A suitable contractor with experience in the geothermal heat business is
favored. Below is a small (and incomplete) list of companies in the geothermal energy business in
the Netherlands.





Hortimax
If Technology
Transmark Renewables
Hydreco
T&A Energy
8. Investment
There are several options for financing the project: (1) bank loans, (2) investors and (3) own
resources. For a hospital the last option is unlikely because of limited resources. In addition, an
investment on energy is not a priority for the hospital since energy is not their main business.
Possible other investors are stakeholders of the investment, which can be energy providers, or
district heating operators.
When bank loans are to be used, an investment on geothermal energy has the advantage of
benefiting from green funds (groenfonds in Dutch) which have a ~1% lower interest rate than other
bank loans. To benefit from this, a bank which owns green funds5 needs to be approached and a
permit (groenverklaring)6 from AgentschapNL is necessary. The lower interest rate of green funds is
achieved thanks to a tax discount from the government for investments on sustainability.
For the bank, the reliability of their investment is crucial. Investments on deep geothermal energy
and giving loans to hospitals for energy investments are both new cases for a bank which bring
about a higher risk perception. For example greenhouses are rather well-known partners compared
to hospitals. A large energy consumer with a stable future outlook and credible financial history is a
5
http://www.agentschapnl.nl/subsidies-regelingen/groen-beleggen/deelnemen/aanvragen/banken-eninstellingen
6
http://www.agentschapnl.nl/subsidies-regelingen/groen-beleggen/deelnemen/aanvragen/stappenplangroenverklaring
25
prerequisite from a bank’s perspective. A direct application is only appreciated when a hospital
consumes enough energy (150,000 GJ) to justify the geothermal investment alone. If the
consumption is significantly less, the hospital should connect to other large consumers and find a
technology developer as the lead of the group and then apply for a loan. Guaranteed purchase
amount and price is also necessary. 10 years is a standard duration for the investment term from the
bank’s perspective.
In many cases banks prefer to involve other banks to share the risk.
9. Feasibility study
Before engaging in a large geothermal project, a go/no go decision has to be taken after a feasibility
study performed by the contractor or a consultancy firm. The study should include estimations on
the heat production from the actual location. A typical feasibility study may address some or all of
the below topics: geologic properties, rock properties (geomechanics, porosity), fault systems,
fracturing, reservoir properties, design of the well and the heat plant. From the financial perspective,
it should include a business case.
10. Subsidies and insurance
In the Netherlands currently some financial tools are offered to support the application of renewable
sources including geothermal energy. These tools are: (1) the SDE+ subsidy, (2) the EIA tax benefit
and (3) the SEI drilling insurance.
SDE+ (Stimulering Duurzame Energieproductie): The SDE+ stimulates the production of renewable
energy by compensating the difference between the production costs of “gray” and “green” energy
in order to make green and sustainable energy profitable. As the current economics of each
renewable energy technology is different (some being more profitable than others), the subsidy
rates and their validity (5, 12 or 15 years) depend on the applied technology. The costs of the green
energy are determined at the start of the subsidy period and is valid for the whole period of 5,12 or
15 years. The cost of the gray energy, and thus the actual SDE+ contribution is calculated each year.
The SDE+ contribution is valid up to a certain full load hours.
However, the total budget for SDE+ and the applicable rates are published each year and it is not
certain whether the SDE+ subsidy will remain as powerful as it is now in the next years. In 2013, a
total of 3 Billion € was available, compared to 1.7 Billion € in 2012 and 1.5 Billion € in 2011. It is
expected that the budget will continue increasing in 2014.
For each category there is a maximum budget allocated for each year and the subsidy is granted in 6
phases to reward cost-effective installations. When the yearly budget is reached, no more grants are
given that year.
The compensation is supplied even if the generated energy is consumed in the same organization,
without feeding it to the network, excluding the energy consumption of the plant itself.
In 2013, SDE+ is offered for electricity, gas and heat produced with biomass, geothermal energy,
water, wind or solar energy. Deep geothermal heat (>2700 m depth) is included in the program in
2013.
For geothermal heat the following information is valid for SDE+ in 2013:
26

Maximum subsidized energy production per installation: 245,520 GJ (depth<2700m), or
356,400 GJ (depth>2700 m).
 SDE+ contribution per generated energy: 6.1 €/GJ (depth<2700m), or 7.1 €/GJ (depth>2700
m)
 SDE+ is valid for 15 years
 Maximum subsidized full load hours: 5500 hours (additional hours do not benefit from SDE+)
 The installation must start producing energy within 4 years after being granted with SDE+
In order to apply for SDE+ a candidate must possess an exploration license (opsporingsvergunning)
and an environmental permit for construction (omgevingsvergunning/wabo). The performance
analysis of the subsurface of interest. The approval of applications are done on the first come first
serve basis. Therefore the timing of the application matters with respect to the maximum yearly
budget.
EIA (Energie Investeringsaftrek): The companies investing in energy efficient techniques and
renewable energy can obtain fiscal benefits via this rule. 41.5% of the investment costs can be
deducted from the fiscal profit which corresponds to 10% tax benefits on average. A total budget of
151 M€ is available for EIA in 2013. Hospitals are not eligible to apply for EIA because of the
corporate tax regulations. However the situation may be different if they are part of a larger group
of applicants lead by a commercial party.
SEI: The SEI support is offered by the Ministry of Economic Affairs to stimulate the use of geothermal
energy by covering the risks of misdrilling. Risks such as not being able to generate the expected
temperature or the expected amount of heat are hindering the investments on geothermal energy.
SEI works as insurance rather than a subsidy. For a geothermal project two wells (also called a
doublet: a production well and an injection well) are needed. The SEI covers the risk of generating
less than expected stream or temperature but doesn’t cover the risks of obtaining oil and gas or
seismicity.
In order to apply for SEI several conditions are required: (1) a location-specific geologic study
performed by a certified organization which states the expected the heat production from the
subsurface, (2) an exploration/production license, (3) a detailed financial plan. If the application is
granted the applicant needs to pay a premium equal to 7% of the requested insurance.
The available budget per project is 7,2 M€ or 12.75 M€ for deeper (>3.5km) drillings. The total
available budget is 43.3 M€ and is distributed on a first come first serve basis.
The insurance covers the risks in steps. When the first well is drilled there are some options: if the
well produces >75% of the expected power, the project continues with the second well and the SEI
insurance does not give away payments. If the well produces <50% of the expected power, the
project must stop and the insurance pays 0.85x(actual costs-remaining value of the installation).
11. Other options
If the total size of the guaranteed heat consumption is not above 150,000 GJ, the financial
investment on geothermal energy is not feasible. Consequently the hospital needs to consider other
options described in Section F to use sustainable energy such as purchasing green electricity and
green gas through contracts with energy providers.
27
b. Timeline for the geothermal project
Figure 12 is a proposed timeline for the geothermal project based on the recommendations
provided by the SodM (Staatstoezicht op de mijnen), Ministry of Economic Affairs mostly for the
greenhouses. This timeline is only indicative, some steps can take shorter, or additional steps may be
needed for other situations. The geothermal project developer can take the lead in most of these
steps.
If all the steps provided in the above timeline need to be taken, Rijnstate needs to start exploring its
options outlined in Figure 10 in order to complete the whole process and have an operating
geothermal energy plant by the end of 2019.
1 2 3
Exploring
options
Year 0
2014
4 5 6 7
Forming
partnership
8
9 10 11 12
1
2
3
1
2
3
4
8
8
Preparing Evaluation
application
WABO
9 10 11 12
1
2
3
Evaluation opsporingsvergunning
4
Year 3
2017
5 6 7
Preparing Evaluation
application
SDE+
8
1
2
3
4
8
Design
9 10 11 12
Preparing
license
Drilling
9 10 11 12
Preparing Evaluat
application ion SEI
Geological study
Year 4
2018
5 6 7
9 10 11 12
Business case
Preparing
application
Year 2
2016
5 6 7
4
Year 1
2015
5 6 7
1
2
3
4
Year 5
2019
5 6 7
8
9 10 11 12
Evaluation
winningsvergunning
Plant construction
Plant operational
Figure 12. A proposed timeline for the geothermal plant installation.
28
J. Commitment for the project
At the end of the RES project, Rijnstate is aware of the possibilities and willing to continue
investigating geothermal heat as renewable source. However, as explained in this document, their
actual commitment depends on the conditions.
Rijnstate is not connected to an existing heat network. However, other large consumers exist in their
vicinity to form a group of consumers to make an investment on geothermal heat profitable.
Rijnstate is keen to initiate discussions with the local public bodies and neighbouring large
consumers to form a partnership.
Besides the RES project, Rijnstate has already developed its own plans to increase its sustainability
with the following measures:
Goals
Implemented measures
Planned measures







2% annual reduction in
energy consumption
10% reduction in transport
distance in 2020
2% annual CO2 reduction
via garbage processing
10% reduction in drinking
water consumption
Increase the reputation of
Sustainable Rijnstate








LED lighting in the parking
garage
Heat and Cold Storage
600 Solar panels installed
on the roof
Purchasing green electricity
from the grid
Energy-efficient measures
against Legionella
Charging
stations
for
electric cars
Energy monitoring
Heat recovery units
Shuttle bus working with
green gas









Feasibility of geothermal
energy investigated
Green roofs
Monitoring sustainability
Electric bike and scooters
Daylight arrangements
Sun shading
Solar collectors
Energy saving
requirements in planning
new construction
Sustainable lease cars
Purchase
of
regional
materials
to
lower
transport emissions
29
K. New developments in the context of the RES project
The Energy Agreement for Sustainable Growth (het Energieakkoord)
More than forty organizations including central, regional and local government, employers’
associations and unions, nature conservation and environmental organizations, and other civilsociety organizations and financial institutions agreed in 2013 on an energy and climate policy for
the Netherlands.
The purpose of the Energy Agreement is achieving a wholly sustainable energy supply system by
2050. The parties to the Energy Agreement will strive to achieve the following objectives:
• savings in final energy consumption averaging 1.5% annually;
• in this context, a 100 petajoule (PJ) saving in the country’s final energy consumption by
2020;
• an increase in the proportion of energy generated from renewable sources from 4.4%
currently to 14% in 2020, in accordance with EU arrangements and a further increase in that
proportion to 16% in 2023;
• at least 15,000 full-time jobs, a large proportion of which will be created in the next few
years
The following measures underlined in the energy agreement are also relevant to the scope of this
project:
• A revolving fund of 600 M€ will be made available already in 2013 for awareness raising,
reducing the burden of investors and funding support with regard to energy savings in the built
environment. Energy companies will be given the opportunity to offer customers more financing
options, with loans being repaid via the energy bill.
• Implementation and enforcement of the Environmental Management Act [Wet
milieubeheer] – with an obligation to implement energy-saving measures with a cost-recovery
period of five years or less – will be substantially improved, for example by providing lists of
specific approved measures.
• The possibilities of a regional heat infrastructure will be investigated for various parts of the
country, based on and comparable with the proposals already made by the Rotterdam region.
• The budget for the SDE+ subsidy will increase gradually to EUR 3.8bn in 2020.
• Decentralized energy generation will be supported where necessary and possible – by
municipalities, provinces, and central government.
• With effect from 1 January 2014, a tax relief of 7.5 eurocents per kWh will be introduced for
renewable energy generated locally.
30
L. Conclusions
The RES project was performed with 3 partner hospitals in the Netherlands and it proved very useful
not only to help these hospitals increase their awareness on energy management but also to draw
some important conclusions on the opportunities and challenges for the sustainable future of the
healthcare sector in the Netherlands.
Large Consumers
Hospitals are large energy consumers. In the example of the
partner hospitals, the total energy consumption is between
80,000 GJ and 150,000 GJ, which is roughly equivalent to
1,000-2,000 houses in comparison. The estimated total
energy consumption in the healthcare sector 7 in the
Netherlands is even more dramatic. Hospitals consume
around 8,300,000 GJ of gas and 2,670,000 GJ of electricity.
Including other healthcare organizations, the entire sector
consumes 31,500,000 GJ of gas and 8,500,000 GJ of
electricity. The energy costs are estimated around
567 M€/year.
Opportunities in the energy management of the healthcare sector
Due to the size and some characteristics of the hospitals, many opportunities are present regarding
a sustainable and green future in the healthcare sector. Currently, many hospitals are not aware of
their energy situation and possibilities for improvement. Accurate and detailed monitoring of energy
consumption is not standard practice in the Dutch hospitals. Consequently, hospitals do not operate
at the most energy-efficient conditions, significant energy savings can be achieved with simple
measures.
Thanks to their large and steady energy consumption patterns, hospitals are suitable for the
application of renewable energy sources. In addition, most of them are willing to become more
sustainable and to reflect this in their public image.
Technologies
Significant energy savings can be achievable with simple measures such as heat recovery in
ventilation and in boilers, improved insulation, energy saving lamps and optimization of processes.
For the partner hospitals, these simple measures can mean 5-10% reduction in consumption on
average. Many of these measures have a payback period of less than 5 years.
Although many RES options are technically feasible, most of them fail due to economic or legislative
concerns. In the current circumstances, purchasing geothermal heat from heat networks and
7
Energy savings in healthcare (in Dutch):
http://www.agentschapnl.nl/sites/default/files/bijlagen/Energie%20besparen%20in%20de%20Zorg%20%20beurskrant%20SEN%20DOW%20101007.pdf
31
purchasing green electricity from the energy providers seem to be the most suitable options. In case
the right conditions arise, hospitals can also form partnerships with other large consumers to
produce their own geothermal heat.
Challenges
Although many opportunities are present to improve the sustainability in the healthcare sector,
important challenges are still to be tackled.
Energy vs. health
Even though this project and similar campaigns help in
raising the awareness in energy consumption for
hospitals, safety and health of the patients remain in
the center of their focus. The management of energy
is not the core business of a hospital. This has some
consequences on their commitment towards energy
and sustainability. For example, a hospital can’t afford
large energy investments, the priority will remain on
the investments for medical equipment. In addition,
the time capacity to follow the technological developments and the expertise needed to assess the
opportunities may lack in these organizations. Therefore they may need an external party to lead the
process, bring parties together and take action. Naturally, hospitals want to avoid innovative and
risky energy investments as much as possible, safe and reliable sources are always preferred.
Considering all these aspects, commitment of a hospital for an energy investment requires the right
conditions such as: a profitable business case, reliable technology partners and developers,
availability of investors or bank loans.
Uncertain future
Although hospitals are considered to be solid and permanent organization, the policies in the
Netherlands are evolving. The number of hospitals in the country may fall significantly in the longterm future. Therefore long-term sustainability roadmaps may prove unrealistic for some hospitals.
Likewise, the future of support tools to stimulate RES offered by the government is also perceived
uncertain by the market.
Lack of experience
Application of some renewable sources such as deep geothermal energy is only beginning in the
country and carries large risks and uncertainties. So far, the greenhouses were able to demonstrate
the potential of this technology. But the extension to other markets was not always successful. The
large failure of the new district heating network supplied by geothermal heat in Den Haag raised
concerns over the business case of this technology.
Positive Outlook
Having mentioned the challenges ahead of the sustainable ambitions of the hospitals, many positive
signs are also worth considering.
32
RES environment
The government and local public bodies have set long-term sustainability goals. The Netherlands as
country aims to increase their share of renewable energy generation to 14% by 2020. Some
municipalities target energy neutral cities by 2050.
In the current situation, financial and knowledge-based support is made available to stimulate
investments on renewable sources. SDE+, EIA, and SEI are examples of financial tools and the energy
agreement (energieakkoord) promises increasing financial support in the future. Both central and
local bodies provide knowledge sharing workshops or meetings to raise awareness. Bank loans for
sustainable energy investments are also available. In addition, energy providers are increasingly
offering optional green energy contracts for affordable prices.
Another positive outcome of this project is that, the partner hospitals can supply a very large part
(>80%) of their energy demand with renewable sources if the recommended changes are made.
Global perspective
Naturally, the conclusions of this study can be extended to other healthcare organizations in the
country. If simple but right measures are taken, they can become more energy efficient and
sustainable in a profitable way with high returns on investment. Experiences can be shared to
multiply the benefits for the country and the global society. In this context, the policy makers have
an important role in making the support tools easier to reach and more applicable.
33
Appendix
Wind Turbines
Technical limitations and energy output
Technical limitations for the on-site application of wind turbines can consist of the availability of
wind, available space, the lay-out of the public net, and the connection to the hospitals electric
infrastructure.
Figure 13 reveals that location Apeldoorn belongs to a less windy area of 6 m/s average wind speed
at 100 m height.
Figure 13. Average wind speed at 100 m in the Netherlands [3].
A wind turbine with a height of 100 meter and a rotor of 82 meter in diameter has power output of
2.3 MW. At limited wind conditions (average wind speed of 6 m/s at 100 m height) experienced in
Arnhem, this turbine can produce 4,370 MWh/year (15,730 GJ/year) [4]. This is about 56% of the
purchased amount of electricity. By producing this amount of electricity in a sustainable way (no
emissions), this windmill can help achieve a CO2 reduction of 1,490 tonnes a year (compared with
purchasing “gray” electricity from the grid).
On the other hand there is not enough land area to install a wind turbine at the Rijnstate Hospital
campus, see Figure 1. As the hospital is located at the edge of the city, land area is available around
the hospital campus.
34
Limitation caused by legislation
Building a wind turbine in the Netherlands requires permits. The legislation regarding larger wind
turbines is often seen as very restrictive and time taking. Especially in the urban environment
concerns of local residents should be considered.
Due to a compulsory minimum distance of 400m towards the nearest residential buildings (patient
wards in this case), large wind turbines can’t be constructed on-site.
Laws that apply to wind turbines are:





Spatial Planning Act (WRO), wind turbine projects have a spatial impact. They must therefore
fit into the regulations in the field of spatial planning. The zoning of the integration plan
must allow wind.
Environmental Management Act, this Act contains general rules for activities that are
detrimental to the environment. In some cases, a license to exist even for wind farms. That
authorization is part of the environmental permit.
Environmental impact assessment (EIA), it is mandatory for activities that may have
significant environmental impacts. Wind farms larger than 15 megawatts or more than ten
turbines EIA assessment requirement. The competent authority then determines whether an
environmental impact assessment is necessary. For wind farms up to 15 MW wind turbines
but with 3 or more there is a so-called “vergewisplicht”. The competent authority then
determines whether there is still cause an environmental impact assessment to be drawn
up.
Other laws and regulations, for example in connection with aircraft and radar stations.
In case the hospital wants to invest in a wind turbine to be built elsewhere, the hospital
becomes an energy supplier according to the current laws and becomes subject to different
tax rulings.
Financial limitations
The investments for a wind turbine of 2.3 MW are around 3,000,000 Euro (1,100 - 1,500 Euro/kW)
excluding the fees, investigations and the maintenance costs. The electricity delivered by the wind
turbine saves maximum 480,000 Euro/year (0.11 Euro/kWh). Taking into account the cost of
maintenance, fees, taxes etc. the payback time of this wind turbine can go above 13 years.
SDE+ subsidy
There is a possibility of applying for the SDE+ support from the government although it is not
guaranteed that the subsidy will be granted because the total budget is limited. A maximum amount
of 0.064 €/kWh subsidy can be received per produced wind energy. With this help taken into
account, the payback period can potentially go down to 7 years.
Another financial help for the investors on renewable energy sources is the EIA tax reduction, which
concerns making 42% of the total investment tax free. However hospitals are not eligible to receive
this help.
35
Other limitations
Wind energy is more efficient in areas with high wind speeds as shown in Figure 13. The wind speed
reduces landward. Besides the geographical situation wind speed is also determined by local
obstacles (nearby housing, industry and forests). On shore windmills are also dealing with an
increasing public and political resistance, mainly concerning the noise, appearance and the effects
on the lifes of birds.
Conclusion
Although wind turbines are financially attractive options in particular in the presence of the SDE+
subsidy, other limitations complicate the application of wind energy for hospitals. The main concern
is the legislative limit of 400 m distance to the nearest residential place and the financial difficulty of
investing on a wind turbine somewhere else. Further, the location of the Rijnstate Hospital is not
favorable in terms of wind speed, limiting the yearly energy output and the economical profits.
Solar Energy
Technical limitations for the use of solar energy by photovoltaic (PV) panels or solar thermal
collectors consist of the solar irradiation on the area, the direction of the building and the available
area for placing the panels or collectors. The climate strongly affects the output. Monthly and annual
energy production varies substantially from year to year (by +/-40% monthly and +/-20% annually).
Area
The Rijnstate Hospital has a total gross roof area of roughly 20,000 m2 as estimated on the map. The
usable roof area would be much smaller than this depending on the practical facility needs on the
roof and the positioning of solar panels or collectors. If the hospital decides to utilize the parking
areas for this purpose in the future, another 7,000 m2 gross area may become available. However, in
our current analysis we will stick to the boundaries of the roof area of the hospital only.
Thermal Collectors
Solar thermal energy (STE) is a technology for harnessing solar energy in the form of thermal energy
(heat). Two main types of solar heat collectors are: flat plate collectors and evacuated tube
collectors.
Conventional flat plate collectors have a low output and a short life span due to moisture problems.
As the needed output temperature of the solar collector increases to above 65°C corresponding to
the space heating purpose, the efficiency of the flat plate collectors drop to 40% based on absorber
surface area and 30% based on the gross collector area. Taking the example of the Apricus FPC-A32
collector, following information can be found: 2.99 m2 gross area, 2.8 m2 aperture area and 2098 Wth
peak output. This collector can produce an annual output of 986 kWhth (3.5 GJ/year) [5]. If Rijnstate
can manage to install about 15,000 m² of these collectors on the roof, the annual energy output
would be approximately (17,800 GJ/year).
Evacuated tube collectors are more efficient and last longer. An evacuated tube collector of 4.4 m²
gross area, with a corresponding aperture area of 2.83 m² and 30 vacuum tubes, has a peak output
36
of 1,944Wth. This collector can produce an annual energy output of 1,440 kWhth (5.2 GJ/year). If
Rijnstate can manage to install about 15,000 m² of these collectors on the roof, the annual energy
output would be approximately (17,600 GJ/year). In both cases, the potential CO2 emission
reduction is 873 tonnes a year.
Concentrated Solar Power
High-temperature collectors concentrate sunlight using mirrors or lenses (Concentrated Solar Power
or CSP) and are generally used for electric power production using subsequent process to convert
heat into electricity. Electricity from CSP is already competitive in power markets worldwide, under
the condition that the generation takes place in areas with a constant and high solar radiation
potential (> 2,000 kWh/m2 per year). CSP plants can be very interesting in southern Spain or Italy but
not for the Netherlands (solar radiation energy less than 1,000 kWh/m2 per year). Furthermore, it is
difficult for a hospital to house the necessary land area to place the mirrors and the conversion
units.
Photovoltaics
Photovoltaics are another method of producing electricity from sunlight. One square meter of
current average PV modules has a peak power output of 130-170 Wp under standard test conditions
[sroeco, solar panel comparison]. For most of the Netherlands (including Arnhem) there are
approximately 4-5 peak sun hours in Summer reducing to 1 hour in Winter. The expected annual
energy output of a well sited PV array in Apeldoorn will be about 123-160 kWh per square meter PV
[6]. If Rijnstate can manage to install 15,000 m² of PV panels on the roof, the annual energy output
would be around 2,115 MWh/year (7,610 GJ/year). This is about 27% of the electricity purchased.
The maximal CO2 reduction is about 720 tonnes a year (compared with the normal electricity tariff
from the grid).
In the Netherlands there are some specific criteria in determining whether you need a permit to
apply solar thermal collectors or PV panels. To be allowed to apply these solar energy systems
without a permit, the systems have to meet the following requirements:
1. The thermal collectors or PV panels have to be placed on a roof;
2. The thermal collectors or PV panels must form a single unit with the installation to store hot
water and generate electricity respectively. If not, the installation must be placed inside the
building;
3. If the thermal collectors or PV panels are placed on a sloping roof,
 the collectors or panels must stay within the plane of the roof,
 the collectors or panels must be placed in or directly on the plane of the roof,
 the inclination of the collectors or panels must be the same as the plane of the roof;
4. If the thermal collectors or PV panels are placed on a flat roof, the collectors or panels must
be at least as far from the eaves as the height of the collectors or panels.
5. The collector or panel can’t be placed on a listed building, monument or in a conservation
area.
Taking into account the above requirements, in the case of the Rijnstate hospital much of the flat
roof can be used to install thermal collectors or PV panels without an environmental permit.
37
Thermal Collectors
A solar collector system costs about 350 €/kWth peak. Thus 15,000 m² of these collectors would
require about € 4,500,000 initial investment. The heat delivered by the collectors (17,600 GJ) saves
maximum 196,200 Euro/year. Even in an optimistic scenario the payback time of a heat pipe
collector system is about 35 years at least. Including the taxes, fees and the operating costs, the
solar collectors do not have a payback period within their lifetime.
However, when the SDE+ subsidy can be accessed, a maximum additional income of 19.1 €/GJ can
be obtained which reduces the payback period to around 14 years. Even with the subsidy scheme,
an investment in solar collectors do not seem profitable at the moment.
Concentrated Solar Power
The investments for a high temperature collector (CSP) station for electric power are about 2 to 3
Euro per Watt. Thus about 4,000 m² of CSP collectors with a power output of 1.75 MW would cost
3,500,000 to 5,000,000 Euro to build. The electricity delivered by the CSP collectors saves maximum
321,200 Euro/year (0.11 Euro/kWh). In the most optimum scenario the payback time of the CSP
collectors is about 11 years at least. Taking into account the cost of maintenance, fees, taxes etc. the
payback time of the CSP collectors is estimated about 16 years. In these calculations the use of hot
water that CSP collectors also can produce, is not taken into account.
Photovoltaics
Including the invertor, mounting material and installation costs the initial investment for PV systems
is about 1.90 Euro per Watt Peak (2012). For the above-mentioned system of 15,000 m² area and
2,115 MWh annual output, the capital investment would be around € 4,500,000. The electricity
delivered by 15,000 m² of PV panels can save around € 230,000 each year. Including the taxes,
project costs, operating costs and fees, the payback period for the hospital can be up to 30 years.
If the SDE+ subsidy can be obtained, a maximum additional income of 0.093 €/kWh can be received
which reduces the payback period to around 15 years. Even with the subsidy scheme, an investment
in solar panels do not seem profitable at the moment. However this situation may change in the
future as the prices of solar modules are decreasing at a significant rate (see Figure 14) thanks to the
advances in the photovoltaics technology. Also, taking into account the rise in the electricity prices
an investment in solar panels may become profitable in the future.
Another issue is that hospitals are purchasing electricity at the industrial tariff (0.11 €/kWh) which is
almost half of the residential tariff. If a smart business model can be developed to benefit from the
residential tariffs, solar panels may become financially attractive.
38
Figure 14. The average price development of solar modules in the 21st century [7].
Other limitations
In the Netherlands, there is no experience in the use of CSP collectors so far. Therefore evidence
based figures for the energy output of such an application are missing. It wouldn’t be wise to
experiment with this innovative technology in the premises of a Dutch hospital.
Conclusion
The solar energy options are not feasible for different reasons. Solar collectors are not profitable in
the Dutch climate for space heating purposes. The Dutch industry did not accumulate experience in
the CSP technology, therefore this will be a risky investment. In addition, the required space for the
CSP plant is not available in the hospital’s premises. The PV technology is not profitable for hospitals
at the moment but may compete with the conventional power generation in the coming years.
Heat pumps
The main technical limitation for the use of air source or ground source heat pumps at the Rijnstate
Hospital is the probable inefficiency of those heat pumps at the design temperatures of the heating
system which are estimated to be around 65°C for the all-air heating system. COP is expected to be
around 2 for an air source heat pump and around 2.5 for a ground-source heat pump. Therefore the
heat supplied by the CHP seems to be a better option for heating. Gas driven absorption heat pumps
face the same technical barriers as electric driven heat pumps.
Even if heat pumps are used in this purpose, low temperature heat demand of the Rijnstate Hospital
is less than one third of its total heat demand (see Table 2). Other RES options would still need to be
installed to reach a high RES share in the energy generation.
A heat pump can also be connected to deeper underground sources (aquifers), which is commonly
applied in the Netherlands, as seen in Figure 15. A basic condition/need however is the availability of
an efficient aquifer.
39
At first sight heat pumps can be more suitable for the new building constructions. In these buildings
a low temperature heating system such as floor heating systems (design system temperature < 50°C)
can be used with efficient use of heat pumps.
Figure 15. Existing heat and cold storage systems in the Netherlands as of 2006.
There are no special permits needed for the use of air source heat pumps. For ground source heat
pumps however permits are necessary for the ground heat exchanger or the heat and cold storage in
the ground. In the Netherlands several acts are relevant for the application of heat and cold storage
in the ground. This concerns for “open” systems with a water flow of 10 m3/h or more than 30 meter
in depth:

Acts that deal with the so-called duty of care. This duty means that anyone who acts on or in
the soil, is bound to be careful and accurate to act. Where negligence environmental
damage is inflicted, on the basis of the duty of care that it be punishable even if there is no
specific standard offence.

Pollution Act surface water: For groundwater systems, this act only applies if groundwater is
discharged to surface water. There is a limit for discharges flow set, above which the
discharge of water to surface water require licenses. Is the discharge below the limit then a
notification in necessary. It should be proven that there is an energy balance during the year
so the extracted heat should have the same amount as the injected amount.
The temperatures in the heating system of the hospital are too high for effective application of heat
pumps with a high efficiency. In order to compete financially with the boilers and the CHP
installation, heat pumps need to sustain a minimum COP. Table 11 shows that a minimum COP of
2.11 is required from a compression heat pump to financially compete with the boiler considering
the energy tariffs for the Rijnstate Hospital. This requirement rises to a COP of 3.41 when compared
with a CHP plant.
40
Table 11. Financial comparison between a boiler, a CHP plant and a heat pump.
Boiler
CHP
ηheat
0.85
1.37
€/GJ heat
14.48
8.96
Minimum COP required
2.11
3.41
Assumptions: Electricity tariff: 0.11/kWh; gas tariff: 12.31 €/GJ.
The CHP plant is assumed to consist of a gas turbine with 55% electrical efficiency and a heat plant.
Given the expected COPs of air source and ground source heat pumps (2 and 2.5 respectively), an
investment will not be profitable.
Conclusion
Heat pumps will not be considered for further investigation because of the high temperatures
needed in the hospital which makes this technology inefficient.
Geothermal Energy (deep underground)
The technical limitations about the application of geothermal energy consist of limited experience in
deep underground geothermal applications in the Netherlands and the necessity to make a detailed
feasibility study in order to avoid risks and understand the subsurface structure.
Figure 16 shows the working principle of a geothermal doublet. Two wells are drilled from the
surface into an aquifer layer, one is for extracting hot water and the other is for reinjecting the water
into the aquifer after its heat is absorbed in a heat exchanger. The source temperature depends on
the depth of the source and the layer structure underground. As a rough estimate, the ground
temperature close to the surface can be assumed a constant 10°C. Each additional km of depth will
increase the temperature by 30°C. Hot water is extracted from the aquifers using a production pump
which is situated in the subsurface and it needs to be replaced every 5 years. Usually a second pump
is also deployed at the reinjection side. A heat exchanger is needed to extract the heat from the
underground water and use it for heating purposes.
41
Figure 16. Illustration of a geothermal doublet [8].
In the Netherlands experience with the application of deep geothermal has been gained in about 10
projects, mainly in the horticulture for the heating of greenhouses. The operational sources vary in
depth. The maximum depth, for Green Well Westland in Honselersdijk, is 2,900 meters. At this depth
a water temperature of around 90°C exists. This source provides a heat output of about 10 MWth.
There are also less deep sources at a lower temperature (60°C at a depth of 1,600 meters). The total
production rate (up to 200 m3 per hour) and the temperature difference between supply and return
determine the total heat capacity. The Green Well source in Honselersdijk delivers more than
300,000 GJ/year.
Based on the applied geothermal plants in the Netherlands, we can conclude that this technique can
provide the total heating and cooling demand of the hospital, where the cold generation entirely can
take place by absorption cooling. Due to the year round needs, hospitals (Rijnstate for instance) are
ideal objects for the use of geothermal energy.
Much more potential is expected from geothermal energy from a depth between 4,000 and 7.500
meters (the so called ‘enhanced geothermal systems’ (EGS)), where the existing water temperature
varies from 135 till 230°C, as seen in Figure 17. These temperatures are directly suitable for the
production of steam and electricity. However the investment costs of a such system will increase
dramatically.
According to a recent IF/Ecofys/TNO publication “Diepe geothermie 2050, een visie voor 20%
duurzame energie voor Nederland”, EGS can deliver in 2050 at least 20% of the total Dutch energy
consumption. However, the ‘riskprofile’ of EGS is unfavorable at the moment and forms a barrier for
the implementation of these systems. Knowledge about the deep underground and the practical
experience of extracting energy from deep sources is hardly available and needs to be expanded.
Some case studies have already been performed (e.g. Hoogeveen).
42
Figure 17. Temperature in the Dutch underground at a depth of 2.000m and 5.000m
There is a strong need for further research to overcome that barrier and to build up experience.
Support from the government and energy companies, interested entrepreneurs and pioneers among
the consumers are therefore essential.
The new Mining Act regulates, among other issues, the detection, exploration and extraction of
geothermal energy. For all these activities licenses are needed. Interviews with survey and drilling
companies revealed that the mining act is no barrier.
The biggest financial limitation for an investment on geothermal energy is the required initial
investment for the drilling costs. The drilling costs depend on the application type therefore on the
required drilling depth. Yet the needed investments are at least at the level of 5 M€. This may cause
difficulties to finance the project although it may prove highly profitable in the long-term. In
addition, there will be yearly costs related to the electricity consumption of the pumps and the
maintenance of the system.
ECN has made a calculation for the cost of energy generated with geothermal heat. According to
that calculation the cost of heat produced from a geothermal source (based on use in greenhouses
or heat distribution) is 10.9 Euro/GJ. This number is considerably lower than the cost of energy from
most of the other renewable sources (see Figure 18) and comparable with energy costs from boilers
and CHPs using natural gas. Nonetheless one needs to consider the differences between a
geothermal application for a greenhouse and a hospital. In the case of a hospital, energy needs are
more spread in a year-round pattern and the required heat is at higher temperatures.
43
Figure 18. Comparison of unit energy costs per GJ for renewable sources. (source ECN, 2011)
The investments for enhanced geothermal systems (EGS) are much higher than the above
mentioned. The case study for ‘Hoogeveen’ concludes a total investment of 61,000,000 Euro. Such
an investment seems far beyond the possibilities of a hospital. On the other hand, the final cost for
electricity is not more than 0,073 €/kWh and for heat 2,22 €/GJ, far below normal tariffs. The
average IRR for electricity is 12,3%, for heat 19,5%.
Support and Subsidies
The Sustainable Energy in the Netherlands (DEN) programme helps professional organisations such
as municipalities, businesses, and research organisations with practical blueprints, brochures and
support for realising sustainable energy.
With the Sustainable Energy Production Stimulation funds (SDE+), the Dutch government supports
and stimulates projects which involve investments on sustainable energy. A total of 3 billion euros is
available for applications in 2013. The applications are received in phases depending on the cost
effectiveness of the project. The ones which predict a lower energy cost will have a higher chance of
receiving a SDE+ grant.
Furthermore investors can benefit from a tax reduction called “Energie Investering Aftrek” (EIA)
which is aimed to help investments aiming for energy savings and sustainable energy. With this
financial help, 41.5% of investment costs can be deducted from the profits which is more or less
equal to a 10% tax reduction. However the hospitals are not eligible for this financial help.
The guarantee arrangement SEI covers the risks for Geothermal. A hole for a geothermal project is
very costly. Through the arrangement SEI Geothermal largely covers the risk of ‘misdrills’.
Other limitations
In the Netherlands, there is no experience in the use of enhanced geothermal systems (EGS) so far.
Therefore evidence based figures for the energy output of such an application are missing. It
44
wouldn’t be wise to experiment on this innovative technology with its high technical and financial
risks.
Biomass boilers/Stoves
There are no serious technical limitations for the use of biomass boilers. The combustion of biomass
can be interesting, thanks to innovative techniques. This type of generation is rather common in
other European countries. In the Netherlands there are about 2,000 installations with a capacity of
at least 0,1 MWth heated by wood. About 100 installations have a capacity larger than 1 MW.
In comparison with natural gas, the use of biomass needs more attention, maintenance and logistics.
In wood pellet boilers special wood pellets are burned. It is an easily applicable fuel of more or less
constant quality, which meets the stringent DIN 51731 and Önorm 7135 in terms of calorific value,
water content, ash content, contamination and dust emissions. The small wooden rods have a
diameter of 6-8 mm and a length of 10 - 30 mm. They are produced by compressing sawdust.
The energy content (calorific value) of wood pellets is approximately 18 MJ/kg. The bulk density is
650 kg/m3 with a corresponding combustion value of 11.7 GJ/m3. To equal the gas consumption for
the gas fired boilers the yearly need is about 2010 ton (weight) with a volume of about 3,000 m3
(approximately an average of 2 trucks a week).
The costs for transport and handling are relatively low, so it is often feasible to transport the
wood pellets over long distance. The fuel must be stored in silos or storage bunkers.
Burning wood pellets leads to the production of ashes. The yearly ash production is about 10 tonnes.
Wood pellet boilers are available in capacities from 20 up to 5,000 kWth. Boilers with large capacities
can often burn various types of pellets such as (dry) woodchips. Woodchips are cheaper than pellets
and available in the surroundings of Arnhem. Compared with pellets larger amounts of ashes are
produced and more volume is required to generate the same heat.
Wood pellets and woodchips can be burned in a clean way in advanced boilers supplied with flue gas
purification. The emission of odor, dust, NOx and organic compounds are limited thanks to advanced
techniques. The emissions are significantly higher when the boiler regularly restarts. For that reason
a continuous use of the pellet boiler is preferable. Hospitals, with a constant need for heat, are
therefore suitable users. Biomass boilers can take over the actual heat production of the gas fired
boilers of Rijnstate.
According to the Environmental Management Act, a hospital must have a permit to use a pellet
boiler if the capacity is larger than 20 kWth. The mentioned act is part of the wider ‘WABO’ act that
governs the environmental permit. The environmental permit is an integrated permit for
construction, housing, monuments, space, nature and the environment.
Wood pellets are derived from clean waste wood and therefore fall under the definition of clean
biomass (white list part 1). For a device the Waste Incineration Decree therefore is not applicable.
This means that the local authority is the competent authority.
45
Emission Regulations states that wood pellet boilers with a power output of less than 1 MW are
covered by the special scheme of the Dutch Emission Directive (NeR, F7 - plants for combustion of
clean wood). For installations with a capacity of 1 MW or more, the Decree on emission
requirements medium combustion plants (BEMS) apply.
On boilers up to 1 MWth, no emission requirements are stated to reduce CO, hydrocarbons and
PAHs, but it is possible to avoid emission of these incomplete combustion products through a good
management, allowing complete combustion by




Good dimensioning of the plant (not too big or too small for the amount of
supply heat)
Good adjustment of the fuel and the combustion air supply
Appropriate maintenance regime
Dry wood pellets cause by complete combustion no nuisance due dust or odor. Additional
measures to reduce odor nuisance are therefore not necessary.
The price of wood pellets currently appears to be between 150-180 Euro/ton [9]. This amounts to
8.3 - 10 €/GJ (fuel). If we assume a thermal efficiency of 90%, the cost of the heat produced will be
around 9.3 - 11.1 Euro/GJ. The price of heat produced with natural gas varies from 8.5 to 10.6
Euro/GJ. That’s in the same range as wood pellets.
Biomass / Energy from waste digestion
An important technical limitation of the use of energy from waste digestion is the availability of a
suitable place to locate this installation and to offer good logistics. An example of an ‘onsite’ waste
digestion for hospitals in the Netherlands is the ‘Pharmafilter‘-project in Delft. Although the
treatment of waste and the purification of wastewater is the main aim, this installation produces
also heat and electricity from the processed biogas.
Digestion converts wet biomass by means of an anaerobic (oxygen-free) process into a residue and a
gas mixture of methane and carbon dioxide. This (bio)gas can be used for the cogeneration of
electricity and heat (CHP). Due to the rather small scale of the Pharmafilter installation the energy
production is not even sufficient for its own process.
A digestion installation is much more interesting when there is a stable and large flow of biomass
(manure) from a nearby livestock.
Conclusion
Heat and power generation with biomass can be financially feasible taking into account prices which
are competitive with natural gas boilers. However there are 2 obstacles ahead of this technology for
its use in Rijnstate. Firstly, comparing with the natural gas infrastructure, harnessing energy from
biomass will need an extensive effort in terms of logistics. Secondly, although biomass is accepted as
a renewable source, there are emissions associated with its use. In conclusion, the management of
the hospital decided not to proceed further with the investigation of the biomass option.
46
References
[1] „Renewable Energy,” European Renewable Energy Council. [Online].
[2] „Directive 2009/28/EC of the European Parliament and of the Council,” 2009. [Online].
[3] „Klimaatatlas,” KNMI, [Online]. Available:
http://www.klimaatatlas.nl/klimaatatlas.php?wel=wind&ws=kaart&wom=Gemiddelde%20wind
snelheid%20100%20m.
[4] „Stimuleringsregeling Duurzame Energie 2013,” ECN, [Online]. Available:
http://www.ecn.nl/units/ps/themes/renewable-energy/projects/sde/sde-2013/.
[5] Thermomax, „Solar Collector Efficiency,” 2010.
[6] „PV GIS,” EU Joint Research Center, [Online]. Available:
http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php?lang=en&map=europe.
[7] „Module Pricing,” Solarbuzz, 2012. [Online]. Available: http://www.solarbuzz.com/facts-andfigures/retail-price-environment/module-prices.
[8] J.-D. v. Wees, „Geothermal aquifer performance assessment for direct heat production –
Methodology and application to Rotliegend aquifers,” Netherlands Journal of Geosciences, vol.
91, nr. 4, pp. 651-665, 2012.
[9] „Webshop,” Hout Pellets Direct, [Online]. Available: http://www.houtpelletsdirect.nl/shop.
47

Arnhem - Rijnstate - RES

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