Outdoor wood boiler pollution

SOLAR THERMALWOOD BOILER
COMBI SYSTEMS
Reducing Pollution,
Increasing Efficiency,
Economically Advantageous
Thank you to the University of Minnesota Central Region Sustainable
Development Partnership for supporting this study
SOLAR – TAXONOMY
RECIRCULATING (GLAZED)
TRANSPIRED
Solar Air Heat
GLAZED FLAT PLATE
UNGLAZED
EVACUATED TUBES
Solar Water Heat
ACTIVE SYSTEMS
Building Design
PASSIVE SYSTEMS
SOLAR ELECTRICITY (PV)
 Makes usable energy from
the sun in the form of
electricity
SOLAR THERMAL
 Makes usable energy
from the sun in the form
of heat
SOLAR – TAXONOMY
GLAZED FLAT PLATE
EVACUATED TUBES
Solar Water Heat
ACTIVE SYSTEMS
SOLAR ELECTRICITY (PV)
 Makes usable energy from
the sun in the form of
electricity
SOLAR THERMAL
 Makes usable energy
from the sun in the form
of heat
SOLAR THERMAL WATER HEAT
“A hydronic heating system harnessing solar energy to heat
fluid in the system, which can then be transferred to building
heat loads.”
Wikipedia
OUTDOOR WOOD BOILER
“A method of wood-based hydronic heating adapted for set-up
outdoors, and transferring the heat generated to building
interiors.”
Wikipedia
SOLAR THERMAL WATER HEATOUTDOOR WOOD BOILER COMBI
A wood and solar thermal energy combination
hydronic heating system harnessing solar energy
and biomass energy, and transferring the heat
generated to building heat loads.
THE PROBLEM
Outdoor wood boilers…
 INEFFICIENT (averaging 30-40% annual efficiency)
 YEAR ROUND OPERATION (summer use for DWH only) - super




inefficient burns
CYCLIC OPERATION – Increases toxic and PM emissions
SHORT STACK HEIGHTS – Smoke does not disperse
OVERSIZED FIREBOX – Simple for users to combust inappropriate material
WOOD CONSUMPTION INCREASING – MPCA 2012 study showed over
half (53%) of MN households burned wood; 9% of the Nation’s space
heating energy needs come from wood
THE PROBLEM
 Burning wood emits highest amount of carbon dioxide per unit energy
Source: Renewable Energy Systems
 Soot is second-greatest contributor to climate change
Source: Black Carbon Second only to CO2 in climate change
 Soot ranks behind carbon dioxide but ahead of methane gas as a cause
of climate change
Source: Black Carbon Second only to CO2 in climate change
 US social cost of carbon dioxide = $40 per ton
New York
Alaska
Ohio
OUTDOOR WOOD
BOILER POLLUTION
Minnesota
OUTDOOR WOOD
BOILER POLLUTION
Emissions from ONE Outdoor Wood Boiler equivalent to:
22 EPA certified wood stoves
205 oil furnaces
8,000 natural gas furnaces
Relative Emissions of Fine Particulate Matter
Source: NESCAUM, 2006
THE QUESTIONS
 Costs/Benefits of solar – OWB combi system?
 Pollution reductions?
 Fuel consumption saved?
 Add’l. Details?
THE METHOD
 Models (flat plate & evacuated tube)
 Case Studies (flat plate & evacuated tube)
THE MODEL
Base case Residential
Base case Commercial
Larger Commercial Case
2169 (Census)
5000 (US DOE)
15000
$12.72
$6.56
$6.56
# persons in HH
2.61 (Census)
Building size (sq ft)
Wood Cost per mmBtus (EIA)
Annual Wood boiler efficiency est.
40%
mmBtus input required based on annual delivered wood boiler efficiency
(NASCAUM)
30%
271
Total annual cost wood
$
40%
361
3,447.12
$
30%
448
4,596.16
$
40%
598
2,940.85
$
30%
1345
3,921.13
$
1793
8,822.54
$
11,763.39
Solar System Design
Solar Fraction (% of load)
25%
40%
25%
40%
25%
40%
25%
40%
25%
40%
25%
40%
mmBtu Annual theoretical potential
27.1
43.36
27.1
43.36
44.83
71.728
44.83
71.728
134.5
215.184
134.5
215.184
mmBtu wood savings, adjusted for boiler efficiency
67.8
108.4
90.3
144.5
112.1
179.32
149.4
239.1
336.2
538.0
448.3
717.3
1.4
2.2
1.8
2.9
2.3
3.6
3.0
4.8
6.8
10.9
9.1
Cord equivalent annual hardwood savings
Annual cost savings
$
862
$
Social benefits of carbon pollution avoided - annual savings
$
341
$
Fine PM emissions reduction - annual minimum kg
Flat Plate System - Solar Skies
System 1
$
546
584.8
Size - collector sq ft
Total Cost est.
1,379
$
1,149
455
935.7
System 2
78.7
$
1,838
$
728
779.8
System 1
143.7
$
735
$
$
565
$
1247.6
System 2
78.7
967.4
System 3
143.7
1,176
$
904
$
1547.9
System 4
130.2
$
1,568
$
2,206
$
3,529
$
2,941
$
4,705
753
$
1,205
$
1,695
$
2,711
$
2,259
$
3,615
1289.9
System 3
237.8
2063.9
System 4
130.2
2902.3
System 5
237.8
4643.7
System 6
390.6
3869.7
System 5
713.3
$
9,838
$
17,968
$
9,838
$
17,968
$
13,019
$
23,778
$
13,019
$
23,778
$
39,057
$
MN State Rebate (through 2024)
$
(2,459)
$
(2,500)
$
(2,459)
$
(2,500)
$
(3,255)
$
(5,945)
$
(3,255)
$
(5,945)
$
(9,764)
Federal tax credit (after rebate)
$
(3,689)
$
(6,140)
$
(3,689)
$
(6,140)
$
(4,882)
$
(8,917)
$
(4,882)
$
(8,917)
$ (14,647)
Federal accelerated depreciation
14.5
980
390.6
713.3
$
39,057
$
$ (17,834)
$
(9,764)
$ (17,834)
$ (26,751)
$ (14,647)
$ (26,751)
5-yr schedule
71,335
6191.6
System 6
71,335
5-yr schedule
Total system cost after incentives
$
3,689
$
9,327
$
3,689
$
9,327
$
4,882
$
8,917
$
4,882
$
8,917
$
14,647
$
26,751
$
14,647
$
26,751
Total O&M (5% every 5 years, est 30 year lifespan)(USDA)
$
2,951
$
5,390
$
2,951
$
5,390
$
3,906
$
7,133
$
3,906
$
7,133
$
11,717
$
21,400
$
11,717
$
21,400
Simple payback after incentives (years)
7.7
Weighted payback including Annual Savings from Avoided Carbon
Pollution and Incentives (years)
Evacuated Tube System - Thermomax
5.5
System 1
Size - collector sq ft
Total Cost est.
10.7
5.8
7.6
System 2
66.1
8.0
4.1
System 1
120.7
12.0
5.7
System 2
66.1
13.6
6.8
System 3
120.7
9.0
7.7
System 4
136.2
10.2
5.1
System 3
248.7
12.0
5.8
System 4
136.2
13.6
6.8
System 5
248.7
7.7
System 6
408.5
5.1
System 5
746.1
408.5
18,098
$
9,909
$
18,098
$
17,020
$
31,086
$
17,020
$
31,086
$
MN State Rebate (through 2024)
$
(2,477)
$
(2,500)
$
(2,477)
$
(2,500)
$
(4,255)
$
(7,771)
$
(4,255)
$
(7,771)
$ (11,744)
$ (21,449)
$ (11,744)
$ (21,449)
Federal tax credit (after rebate)
$
(3,716)
$
(6,179)
$
(3,716)
$
(6,179)
$
(6,382)
$ (11,657)
$
(6,382)
$ (11,657)
$ (17,616)
$ (32,174)
$ (17,616)
$ (32,174)
Federal accelerated depreciation
N/A
Total system cost after incentives
$
3,716
$
9,419
$
3,716
$
9,419
$
6,382
$
11,657
$
6,382
$
11,657
$
17,616
$
32,174
$
17,616
$
32,174
Total O&M (5% every 5 years, est 30 year lifespan)(USDA)
$
2,973
$
5,429
$
2,973
$
5,429
$
5,106
$
9,326
$
5,106
$
9,326
$
14,093
$
25,739
$
14,093
$
25,739
5-yr schedule
$
46,975
746.1
$
N/A
85,796
5.8
System 6
9,909
N/A
$
10.2
$
N/A
46,975
9.0
$
85,796
5-yr schedule
Simple payback after incentives (years)
7.8
10.8
5.8
8.1
15.6
17.8
11.7
13.4
14.4
16.4
10.8
12.3
Weighted payback including Annual Savings from Avoided Carbon
Pollution and Incentives (years)
5.6
7.7
4.2
5.8
8.8
10.1
6.6
7.6
8.1
9.3
6.1
7.0
THE MODEL
Solar System Design
Solar Fraction (% of load)
mmBtu Annual theoretical potential
Base case
Residential
25%
Base case
Commercial
40%
25%
Larger
Commercial Case
40%
27.1
43.36
44.83
71.728
1.8
2.9
3.0
4.8
Cord equivalent annual hardwood savings
$
1,149
$
1,838
$
980
$
1,568
25%
40%
134.5 215.184
9.1
$
2,941
14.5
$
4,705
Annual cost savings
Fine PM emissions reduction - annual minimum
kg
779.8 1247.6 1289.9 2063.9 3869.7 6191.6
Flat Plate System - Solar Skies
System 1 System 2 System 3 System 4 System 5 System 6
Size - collector sq ft
78.7
143.7
130.2
237.8
390.6
713.3
Simple payback after incentives (years)
5.8
8.0
9.0
10.2
9.0
10.2
Weighted payback including Annual Savings
from Avoided Carbon Pollution and Incentives
5.1
5.8
(years)
4.1
5.7
5.1
5.8
Evacuated Tube System - Thermomax
System 1 System 2 System 3 System 4 System 5 System 6
Size - collector sq ft
66.1
120.7
136.2
248.7
408.5
746.1
Simple payback after incentives (years)
5.8
8.1
11.7
13.4
10.8
12.3
Weighted payback including Annual Savings
from Avoided Carbon Pollution and Incentives
6.1
7.0
(years)
4.2
5.8
6.6
7.6
CASE STUDIES – RESIDENTIAL I - NY
CASE STUDIES – RESIDENTIAL II - MN
CASE STUDIES – COMMERCIAL I - MN
CASE STUDIES – COMMERCIAL II - NY
CASE STUDIES – COMMERCIAL/RES - MN
CASE STUDIES
THE SOLUTION
Solar-Wood Boilers Combi Systems…
 PAYBACK in less than 10 years
 REDUCE PM EMISSIONS by 1,000 kg annually
 ELIMINATE OWB SUMMERTIME OPERATION
THE SOLUTION
Deep Portage Solar-Wood Boiler Combi System
FIND OUT MORE…
CLEANENERGYRESOURCETEAMS.ORG
LOOK FOR THE REPORT:
“COSTS AND BENEFITS OF SOLAR THERMAL
AND WOOD BOILER COMBI SYSTEMS”
Thank you to the University of Minnesota Central Region Sustainable
Development Partnership for supporting this study