Hydrogen and Oxygen production via electrolysis powered by

2010 - 2012
www.life-greenlysis.eu
Layman’s Report
Hydrogen and Oxygen production via electrolysis
powered by renewable energies to reduce
environmental footprint of a WWTP
With the contribution of the
Life financial instrument of
the European Commission
Hydrogen and
oxygen production
via electrolysis powered
by renewable energies to
reduce the environmental
footprint of a WWTP
The Life+ GREENLYISIS project (2010 - 2012) has developed the
production of hydrogen by using the effluent of a wastewater
treatment plant (WWTP). During the three years of duration of the project, a
pilot plant was designed, implemented and operated in order to study its
working conditions and applicability. Its implementation was set in the WWTP of
Montornès del Vallès (Barcelona, SPAIN).
The project scheme comprises a water treatment step of the WWTP effluent to be conditioned
before entering the electrolyser and the electrolysis of this pre-treated wastewater.
Through this process H2 with a purity higher than 99% is obtained and therefore it can be
used in a vehicle powered with a combustion engine. In addition, in order to minimize the
greenhouse gases (GHG) emissions, all this system is powered by renewable energies.
The support provided by the WWTP of Montornès del Vallès and El Consorci per
la Defensa de la Conca del riu Besòs, as well as and the collaboration between
the project partners (Cetaqua, SAFT Baterías and CIRSEE) has allowed
the execution of this innovative and successful process. The results of
Life+ GREENLYSIS project will contribute to transform WWTP
into greener installations as well as broaden the usage of
renewable energy sources.
STAKEHOLDERS
COLLABORATORS
Contents
www.life-greenlysis.eu
1. Context and Background ..................................................................................04
2. The idea: Electrolysis for H2 production ..........................................................05
3. The GREENLYSIS project
3.1 The objectives...........................................................................................06
3.2 The process scheme ................................................................................07
4. The process outcomes
4.1 Water treatment .......................................................................................08
4.2 Energy supply .......................................................................................... 09
4.3 Electrolyser ..............................................................................................10
4.4 Hydrogen ..................................................................................................11
4.5 Oxygen......................................................................................................11
5. Communication activities
5.1 Workshop and visits .................................................................................12
5.2 Publications ..............................................................................................12
5.3 Events .......................................................................................................13
5.4 Digital dissemination ................................................................................13
6. Environmental assessment ..............................................................................14
7. Conclusions: future challenges ........................................................................15
3
1
Context and background
The GREENLYSIS project was conceived in the context of the EU policy which stated the need of
dealing with the global warming and energy market. Its aim is to transform Europe into a high
energy-efficient and low greenhouse gas (GHG) emitting economy.
In this way several laws and roadmaps have been published in the last few years, the most
remarkable ones are:
Action plan on
energy efficiency.
APR. 2000
NOV. 1997
White paper on
renewable energies
(6% → 12% of renewable
energies by 2010).
Communication on
alternative fuels
(hydrogen: 5% of
road transport fuel
by 2020).
NOV. 2001
OCT. 2001
White paper on EU
transport policy
(20% substitution of
diesel and gasoline
for alternative fuels
by 2020).
European Strategic
Energy Technology
Plan.
JUN. 2008
SEPT. 2003
Communication
on an European
partnership for
the sustainable
hydrogen
economy.
The European Roadmap “Action plan on energy efficiency” published in 2000 was established for the
evolution of our fuel-based economy into a hydrogen-oriented economy by 2050, which would
lead to a reduction of the GHG emissions by 60-80%.
Currently, the majority of hydrogen (~95%) is produced from fossil fuels by steam reforming or partial
oxidation of methane and coal gasification. However, several processes or routes can be found to
produce hydrogen from water.
• Electrolysis
• Thermolysis
HYDROGEN
PRODUCTION
FROM WATER
• Photobiological water splitting
• Photocatalytic water splitting
• Sulfur-iodine cycle
• Biohydrogen routes
• Fermentative hydrogen production
4
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2
The idea: Electrolysis for H2 production
The Life+ GREENLYISIS project has main its basis on the production of hydrogen by
electrolyzing water. The electrolysis of water is the decomposition of water (H2O) into
oxygen (O2) and hydrogen gas (H2) due to an electric current passing through the water
(see Figure 1).
WATER
ENERGY
Figure 1: Water electrolysis
This procedure needs two important elements: water and energy. Water can be found in huge
quantities in WWTPs. Regarding the energy needs, they have been covered by renewable energies.
In addition, WWTPs are perfect emplacements for the GREENLYSIS pilot plant implementation due to the
following reasons:
• Availability of space to install an aerogenerator, and several photovoltaic and thermal panels.
• Plenty of water to produce hydrogen and oxygen via electrolysis.
• Strategic geographical distribution to become hydrogen suppliers.
• Possibility to reuse the oxygen generated.
The GREENLYSIS pilot plant was finally set in
the WWTP of Montornès del Vallès (Barcelona,
SPAIN), which has a treatment capacity of
40.000 m3 (see Figure 2).
Montornès del
Vallès (Barcelona)
Figure 2: WWTP located in Montornès del Vallès
5
3
The GREENLYSIS project
Project: GREENLYSIS: Hydrogen and oxygen production via electrolysis powered by renewable
energies to reduce the environmental footprint of a WWTP
Budget: 1,3 M€
Duration: 01/01/2010 – 31/12/2012
Partners: Cetaqua (Coordinator), SAFT, CIRSEE
SAFT is
a worldwide leader
designer and manufacturer of
high technology industrial batteries;
already established in 19 countries
Cetaqua is
an organisation part of
AGBAR, devoted to research
and development in technologies
linked to the integral water cycle,
promoting synergies between
business, research
and with 16 production centres
CIRSEE (Centre
International de Recherche
Sur l’Eau et l’Environnement)
is SUEZ ENVIRONNEMENT’s
international centre for
research on water and the
and education
environment
3.1 The objectives
• To produce hydrogen via electrolysis from the effluent of a WWTP.
• To use the hydrogen obtained as a fuel to power a vehicle. Therefore, the use of other
carbon fuels can be reduced, as well as GHG emissions.
• To avoid GHG emissions, renewable energy sources were used (thermal and photovoltaic
solar power and wind power).
• To obtain deionized water, required for the electrolysis. This pure water was obtained by
a pre-treatment (UF and UV) and a purification system (membrane distillation powered
by thermal solar energy) of the wastewater effluent.
• To use the oxygen obtained by water electrolysis to replace or enhance the current
aeration system of the WWTP.
6
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3.2 The process scheme
The GREENLYSIS pilot plant takes profit of the effluent from a WWTP. However, this water must be conditioned
first in order to be introduced into the electrolyser. The conditioning process consists of three water treatment
steps (see Figure 3): an ultrafiltration (UF) process, an ultraviolet (UV) disinfection and a membrane distillation
(MD) process. Afterwards, water is introduced into the electrolyser. Hydrogen produced is stored to be
used afterwards to power a combustion engine and oxygen can be used in the biological process of
the WWTP.
The pilot plant electricity supply is covered by renewable sources: solar and wind energy. In order to
optimize the utilization of both renewable sources, several batteries and an energy manager have also
been included in the system.
ELECTROLYSER
(Splits water into
H2 and O2 )
WATER TREATMENT
(Suits water conditions
for the electrolyser)
ENERGY SUPPLY
(Provides the process with
power supply)
Figure 3: Diagram of the Greenlysis pilot plant
7
4
The process outcomes
4.1 Water treatment
The water treatment step was designed to adapt the WWTP effluent conditions in order to make them
suitable for the subsequent electrolysis process.
ULTRAFILTRATION (UF)
It improves water quality by decreasing the
turbidity and the amount of suspended matter
contained in the WWTP effluent.
UF parameters
Feed Water
Permeate Reduction [%]
Suspended matter [mg/L]
8,4
1,3
84,8
Turbidity [NTU]
3,7
0,5
87,0
Table 1: Operational results obtained with the UF
Ultrafiltration (UF)
ULTRAVIOLET LAMP (UV)
Ultraviolet lamp (UV)
This device is installed after
the UF step and it is essential
in order to limit distillation
membrane biofouling. MEMBRANE DISTILLATION (MD)
Membrane distillation (MD)
To the Electrolyser
8
MD removes dissolved ionic species from water,
in this way, a conductivity under 1 µS/cm in order
to feed the electrolysis is obtained. The optimal
working temperature for this MD process has
been proved to be 70 ºC (heated only with solar
collectors).
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4.2 Energy supply
The GREENLYSIS energy grid is entirely based on renewable sources. In particular, it is an off-grid system
and can be divided into different blocks.
GENERATION
Generation
Composed by an aerogenerator and several photovoltaic
solar panels, which can produce electricity using wind
energy and solar irradiation, respectively.
126 photovoltaic panels
Power: 28,35 kW
Energy Manager
ENERGY MANAGER (EM)
It controls the energy grid and decides
either the direct use of the electricity
generated to power the pilot plant’s
loads at the same time it is being
produced, or its storage in batteries
for future needs.
1 aerogenerator
Power: 3,5 kW
Storage
STORAGE
Composed by several batteries which
can store the electricity generated
and guarantee an autonomy of 1 day
of operation whenever the electricity
generated is not enough to power the
system.
Batteries capacity: 56 kWh
To loads
(UF + UV + MD + Electrolyser
+ Pilot biological reactor)
Estimated consumption: 56 kWh/day
9
4.3 Electrolyser
The electrolyser is the module in charge of generating hydrogen and oxygen from water. In the
GREENLYSIS pilot plant this function was covered by a proton exchange membrane (PEM) electrolyser
(see Figure 4), where electrolysis is based on the use of a solid conducting polymer that conduces
protons from anode to cathode.
DC
e
This type of electrolyser was chosen for the
following advantages:
e
-
-
H2O
H2
+
O2 , H2O
H , H2O
High purity of the generated gases
( > 99 % for hydrogen).
Polymer
Electrolyte
Membrane
(PEM)
Production of pressurised gases (15 bar)
for its direct storage.
Anode
+
H2O → 2 H + 0,5 O2 + 2 e-
Cathode
+
2 H + 2 e- → H2
Figure 4: Electrolyser diagram
The following table specifies the real working conditions of the electrolyser. During its operation in the
project, an energy efficiency of 62% and a production of 0,7 Nm3/h have been demonstrated.
Electrolyser working conditions
H2
O2
H2O
Production
0,7 Nm3/h
Quality
> 99 %
Production
0,35 Nm3/h
Quality
> 95 %
Consumption
0,6 - 1 L/h
Energy efficiency
62 %
Table 2: Working conditions of the electrolyser
Figure 5: Electrolyser
10
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4.4 Hydrogen
The hydrogen generated at the GREENLYSIS pilot
plant was tested for its usage as fuel in a vehicle.
In the project, a bicycle that was equipped with a
combustion engine (see Figure 6) was used for this
purpose.
Assuming an operation of 6 hours per working day,
the GREENLYSIS pilot plant has lead to an annual
production of hydrogen that corresponds to:
Figure 6: Combustion vehicle
8.767 km travelled in a fuel-cell production hydrogen car
1.841 kg CO2/year of avoided emissions*
*(compared with the emissions generated when travelling in a gasoline-powered car)
4.5 Oxygen
The O2 generated in the process has been tested in a biological pilot reactor to compare its treatment
performance versus air (see Figure 7). It has been demonstrated that similar removal efficiencies
can be obtained, and therefore the use of pure oxygen could potentially reduce the energy
consumption associated to air compression.
Effluent characteristics [mg/L]
FEEDING
Air
Oxygen
+
DQO
DBO5
SS
N-NH4
NTK
83
<5
37
< 0,5
5,5
74
6
36
< 0,5
5
Removal efficiencies [%]
FEEDING
Air
Oxygen
+
DQO
DBO5
SS
N-NH4
NTK
62
87
60
98
88
74
82
64
99
91
Tables 3, 4: Comparison of the reactor’s performance
varying the nature of feeding (one day operation)
Figure 7: Biological pilot reactor
11
5
Communication activities
5.1 Workshop and visits
On November 29th of 2012, the GREENLYSIS final
workshop was held in Cornellà de Llobregat. The
event started with a set of talks and presentations
by Cetaqua, was followed by a roundtable with the
project partners and stakeholders, and ended with
a visit to the pilot plant in Montornès del Vallès. The
40 water and energy professionals who attended the
workshop were very satisfied with the content of the
presentations and the quality of the debate. The visit
to the WWTP in Montornès del Vallès had already
been done several times throughout the project, with
students, professionals and other people interested in
the project.
5.2 Publications
Different news on the final workshop have been
disseminated. In addition, a press release was sent and
published by local and regional media of Vallès Oriental,
who were interested in the project development and
its impact in the area.The magazine InfoAGBAR also
published an interview to Lorenzo Cañas, Cetaqua’s
researcher specialized on water and energy, who
talked about the GREENLYSIS project. Besides, some
articles were published in different technical media, for
example, the Newsletter of the European Membrane
House and the Newsletter of the STREAM project.
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www.life-greenlysis.eu
5.3 Events
The GREENLYSIS project has been presented in many
different occasions, in internal and external events. The most
important presentations are the ones made for ACA (Water
Catalan Agency), for the Team Energy of Suez Environnement,
and the one given in the LIFE+ 20th Anniversary event, which
took place in Cetaqua headquarters in May 2012. In parallel,
project’s materials (brochures and posters, for example) have
been distributed in Euromembranes congress (London, UK),
Smart Cities congress (Barcelona, Spain) and IWA World
Congress (Busan, Korea).
5.4 Digital dissemination
The dissemination of the project by means of digital communication has been very important. A website was
created and updated with events, photos and news. It received more than 1.000 visits per month. In addition,
Cetaqua’s corporate dissemination channels were used; the project’s latest news were published on Cetaqua’s
Twitter (@Cetaqua), which has more than 460 followers, as well as the GREENLYSIS video, which is a good visual
summary of the methodology used and the results achieved.
13
6
Environmental assessment
Energy
(renewable)
The evaluation of the environmental benefits of the GREENLYSIS project is based on its carbon footprint
(CF). The CF of a certain process or technology is defined as the amount of greenhouse gas (GHG),
expressed in CO2 equivalent units, emitted to the atmosphere as a consequence of its construction,
operation and dismantling processes.
H2
WATER TREATMENT
(UF + UV + MD)
+
ELECTROLYSER
ts
O2
or
sp
Tra
n
at
He
Ch
em
ica
ls
WWTP effluent
Used to power
a vehicle
•
Data used: annual consumptions of the pilot plant
•
GHGs included: CO2, CH4, N20
Figure 8: Reduced emissions contribution
Reduced emissions = 1.862 kg CO2 / year (due to the auto-consumption of renewable energies)*
Avoided emissions = 1.841 kg CO2 / year (related to the hydrogen utilisation)
GREENLYSIS CF = 22 kg CO2 / year**
*(CF calculated according to the Spanish electricity mix)
** (Considering only the operation phase)
Overall, results show the benefits of hydrogen production in terms of a carbon footprint reduction due
to the important amount of avoided emissions when using hydrogen to substitute fossil fuel in vehicles.
In addition, thanks to the use of renewable energies to power the GREENLYSIS pilot plant, its CF is
very low (almost negligible).
14
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7
Conclusions: future challenges
For some years now, several European communications on energy issues have been developed; a
remarkable example is the Energy Roadmap 2050, which stated several strategies in order to reduce
GHG emissions while ensuring energy supply and competitiveness. In the Communication “Energy
2020”, several guidelines were given aiming to develop a strategy for achieving a more competitive,
sustainable and secure energy policy.
In this context, the GREENLYSIS project was started aiming to produce hydrogen from an effluent of a
WWTP powered entirely by renewable energy sources. The research developed during three years has
led to the following conclusions:
The H2 produced can be deployed
in the powering of a combustion
engine: The Hydrogen generated in
the GREENLYSIS process has been
used as fuel in the combustion engine
of a vehicle.
Hydrogen production has been successfully achieved
by only using renewable energy sources (solar and wind
energy): A generation and a storage units have been working
together with the supervision of an energy manager providing
all the process loads with power supply regardless of weather
conditions.
The O2 produced reduces the WWTP’s energy costs
as it can be used in its biological treatment: The
oxygen obtained from the electrolysis was used in a
biological pilot reactor to treat wastewater. It has been
demonstrated that O2 can be used to partially substitute
the air used in the WWTP biological treatment, therefore
reducing the amount of electricity needed for aeration.
WWTP effluents are perfectly suitable for
H2 production: It has been demonstrated
that hydrogen can be produced from
wastewater electrolysis. Nevertheless, an
appropriate water treatment of the effluent
must be performed in order to make water
suitable for the process.
Overall, the reproduction of the GREENLYSIS process in other WWTPs does not only promote the
partial reutilisation of the plants’ effluents, but it also pursuits the substitution of carbon-based fuels by
a cleaner source (hydrogen), and consequently, GHG emissions can be substantially reduced.
15
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www.life-greenlysis.eu
CETaqua, Centro Tecnológico del Agua
Carretera d’Esplugues, 75
08940 Cornellà de Llobregat (Barcelona)
www.cetaqua.com
GREENLYSIS LIFE08ENV/E/000118