Environmental impacts of PV electricity generation A critical comparison of energy supply options
Erik Alsema (Utrecht University) Mariska de Wild-Scholten (ECN) Vasilis Fthenakis (Brookhaven Nat. Lab.) Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Outline Crystalline silicon technology Thin film technologies Competition of other low-carbon energy options; Strong and weak points PV Recommendations for industry and research Summary Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Important issues for PV technology • • • • •
Energy Pay-Back Time GHG mitigation Toxic emissions Resource supply Health & Safety risks
Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
EPBT silicon present
Energy Pay-Back Time for Silicon PV
Energy Pay-Back Time (yr)
(rooftop system, irrad. 1700 resp. 1000 kWh/m2/yr) 4.0
to be updated !!
3.5 3.0
inverter support+cable frame module ass. cell prod. ingot+wafer Si feedstock
2.5 2.0 1.5 1.0 0.5 0.0 ribbon 11.5% S-Eur.
ribbon 11.5% M-Eur.
multi 13.2% S-Eur.
multi 13.2% M-Eur.
Copernicus Institute Research Institute for Sustainable Development and Innovation
mono 14% S-Eur.
mono 14% S-Eur.
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Silicon technology improvements Energy input for silicon modules (MJ-prim per m2 module area)
-Thinner wafers (285→150 um)
3500 3000 2500
module ass.
2000
cell prod.
1500
ingot+wafer
1000
Si feedstock
500 0 present multi 13.2%
future multi 17%
Copernicus Institute Research Institute for Sustainable Development and Innovation
-Silicon produced by Fluidized Bed Reactor; -Reduced energy input for ingot growing (best techn. 2004) -Efficiency →17%
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
EPBT Silicon future
Energy Pay-Back Time for Future Silicon PV Energy Pay-Back Time (yr)
(rooftop system, S.-Europe) 2.5 2.0 1.5
BOS frame Laminate
1.0 0.5 0.0 present ribbon 11.5%
present multi 13.2%
present mono 14%
Copernicus Institute Research Institute for Sustainable Development and Innovation
future ribbon 15%
future multi 17%
future mono 19%
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Energy Pay-Back Time (yr)
Energy Thin Pay-Backfilm Thin-Film Systems EPBT present (rooftop system, S.-Europe) 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0
BOS module
a-Si 5.5%
CdTe 10%
CIGS 11.5%
Results generated by SENSE project. Courtesy: M. Shibasaki, Univ. Stuttgart Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
CdTe Energy Pay-Back and GHG emission (USA) Energy Pay-Back Time (Ground-mount system; irradiation 1700 kWh/m2/yr)
GHG emission (ground-mount system, irradiation 1700 kWh//m2/yr)
1.2
30
1
BOS
25
BOS laminate
Laminate CO2-eq (g/kWh)
Y e a rs
0.8 0.6 0.4
20
15
10
0.2
5
0
0
CdTe 9% ground-mount, U.S. production
Copernicus Institute Research Institute for Sustainable Development and Innovation
CdTe 9% ground-mount, U.S. production
Fthenakis and4-9Kim, 2006Dresden 21st Eur. PVSEC, Sept 2006,
Cd emissions Comparison between energy supply options 50
43.3
30
0.9
0.3
mc-Si
mono-Si
CdTe
6.2
4.1 0.2
0.5
0.03
Hydro
0.9
3.1
Nuclear
0.8
ribbon-Si
10
Lignite
20
Hard coal
g/GWh
40
Copernicus Institute Research Institute for Sustainable Development and Innovation
UCTE avg.
Oil
Natural Gas
0
Fthenakis and4-9Kim, 2006Dresden 21st Eur. PVSEC, Sept 2006,
Comparison of BOS options for roof- and ground-based systems 12 10 (g CO2-eq/kWh)
Life Cycle CO 2 emissions
(system with 165 Wp c-Si modules, located in S-Europe)
8
frame
6
cable+connectors
4
mounting structure
2
inverter
0 -2
S-Eur.
S-Eur.
S-Eur.
S-Eur.
S-Eur.
S-Eur.
on-roof
on-roof
in-roof
in-roof
ground
ground
Phonix
Schletter Schletter Schw eizer Phonix Springerville
multi
multi
multi
multi
multi
multi
See Poster 7 DV 5.15
Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
250
200
New gas: 400
Fossil + CO2 capture
g/kWh
200 150
25 biomass CHP
Nuclear USA
nuclear Europe
Coal Gasif.+ CO2
CCGT+ CO2
Copernicus Institute Research Institute for Sustainable Development and Innovation
wind
11
6 0
32
PV future
25
15
15 future CdTe
45
50
PV now
future multi
Renewables
CdTe
Nuclear
multi-Si
120
100
Comb. Cycle Gas Turbine
Life-cycle GHG emissions (g CO2-eq/kWh)
Life-Cycle Greenhouse Gas Emissions
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Strong points PV technology • Large installation potential • GHG emissions reasonably low • Zero or near-zero emissions of toxic substances (direct emissions); • Potential for further improvement in GHG/EPBT Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Issues which need attention • Reduce energy consumption (and GHG emission) in solar cell production; • Reduce dependency on scarce metals (In, Te, Ag); • Close the material cycles (recycling); • Zero-emission production facilities. Copernicus Institute Research Institute for Sustainable Development and Innovation
21st Eur. PVSEC, 4-9 Sept 2006, Dresden
Summary EPBT • now 1-2 years (S.-Europe); •
