Potential Climate Impact of Large-Scale Deployment of Renewable Energy...
Transcript of Potential Climate Impact of Large-Scale Deployment of Renewable Energy...
Potential Climate Impact of
Large-Scale Deployment of Renewable Energy Technologies
Chien Wang (MIT)
�Desired Energy Output:
supply 10% of the estimated world energy demand in 2100
(1400 EJ/yr; Reilly and Paltsev, 2007)
�Installation Scale:
~4.4 millions 1-MW devices (operating continuously! actual
output varies with wind speed) that would occupy a very
large area!
�Interesting Science Issue:
What are the possible climatic impacts of such a large-scale
installation of windmills?
1. A large-scale installation of windmills
Simulating the Climate Effects of Large-scale
Installation of Windmills
• NCAR CCM3 GCM+slab ocean, T42 (~2.8 degree, 18 layers) resolution
• Simulate windmills based on changes in surface roughness that convert kinetic energy to targeted power outputs
• Land Installation: all grass and shrub regions (~58 M km2)
• Ocean Installation: ocean depth < 200 m(~10 M km2)
• 60-year model runs with and without “windmills”
• Use the last 20-year mean of differences between the 2 runs to isolate the effects of windmills
Red Color: Change of surface momentum Drag (10-3);
known ranges of real windfarms: 5 - 13
Blue Color: Location of oceanic “installation sites”
Wang and Prinn (2010)
What a windmill would do to the atmosphere:
Energy cascade in the planetary boundary layer
Kinetic Energy Turbulent
Kinetic Energy
Molecular and
surface
mechanic
dissipation
Heat and matter
mixing- dKE/dt = dTKE/dt
Windmill =
Converting KE to
Electric Energy
- dKE/dt = dTKE/dt + dCEE/dt
Temperature
Change in the
Lowest Model
Layer
Wang and Prinn (2010)
Not the same story as GHG-caused warming
Wang and Prinn (2010)
Significant changes in
precipitation caused
by the windmills
reflect a substantial
alteration to the
pattern of
atmospheric general
circulation
Precipitation
Changes
Wang and Prinn (2010)
The
Reliability
Issue
NA = North America
SA = South America
AF = Africa
AU = Australia
EA = East Asia
Wang and Prinn (2010)
Mysterious Ocean Deployment Story
Wang and Prinn (2010)
Ocean drag
configured in
the model
might be too
large?
Wang and Prinn (2010)
Major Climate Effects of Modeled
Large-Scale Installation of Windmills
• Using land-based wind turbines to meet 10% or more of global energy demand in 2100 could cause surface warming exceeding 1oC over land installations
• Surface cooling exceeding 1oC is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study
• Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributionsof rainfall and clouds
• Intermittency of wind power on various time scales poses a demand for one or more options to ensure reliability
• High-resolution climate modeling, process modeling, and field observations are needed
2. Large-Scale Deployment of Solar Panel
� NCAR CCM3 +slab ocean,
T42 (~2.8 degree, 18 layers)
resolution
� Assume solar panels reduce
grid albedo by 0.02, 10%
conversion efficiency
� Solar panel arrays
“installed” in Sahara and
Mideast deserts (~10 M
km2)
� 60-year model runs with
and without “solar panels”
� Use the last 20-year mean
of differences between the
2 runs to isolate the effects
of solar panels
Large-Scale Deployment of Solar Panel
3. Two Stories about Indirect Effects of Biofuels:
Ecosystem GHG implication
Year
2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
mill
ion k
m2
0
15
30
45
60
75
90
105
120
135
Food Crop
Pasture
Managed Forest
Biofuel
Grasslands
Shrublands
Natural Forests
Other
Year
2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
mill
ion k
m2
0
15
30
45
60
75
90
105
120
135
Food Crop
Pasture
Managed Forests
Biofuels
Grasslands
Shrublands
Natural Forests
Other
Land Use Evolutions Land Use Evolutions
Deforestation Scenario:convert nature areas to meet
the demand as far as profitable
Intensification Scenario:more intense use of existing
managed land
Melillo et al., (2009)
Two Stories about Indirect Effects of Biofuels:
Ecosystem GHG implication
Year
2000 2020 2040 2060 2080 2100
Carb
on F
lux ( P
g C
O2-e
q )
-180
-150
-120
-90
-60
-30
0
30
60
90Direct
Indirect
Net Land Carbon Flux
Year
2000 2020 2040 2060 2080 2100
Carb
on F
lux ( P
g C
O2-e
q )
-180
-150
-120
-90
-60
-30
0
30
60
90
Direct
Indirect
Net Land Carbon Flux
Year
2000 2020 2040 2060 2080 2100
Net Bala
nce ( P
g C
O2-e
q )
-600
-400
-200
0
200
400
600
800
1000Fossil Fuel Abatement
Net Land Carbon Flux
Fertilizer N2O Emissions
Net Abatement
Net Land Carbon Flux (Negative = Emissions)
Net Carbon Balance
Melillo et al., (2009)
Major Climate Effects of Modeled
Large-Scale Installation of Windmills
• Vegetation and soil carbon effects on biofuels land use are mixed
• Indirect greenhouse gases implication associated with intensive biofuel scenario is very likely
• Extensive reliance on biomass for electricity would have ecosystem GHG implications
• In-depth research through modeling on the potential GHG implication of various scenarios associated with biofuel electricity production is needed
Ecosystem GHG implication of BiofuelsWhat have we learned and what type of research is need
• High-resolution GCM for both wind and solar simulations
• More detailed energy (heat) partitioning, updated conversion rates
• Detailed process modeling (LES, mesoscale models) to support GCM parameterization
• In-depth economic analyses and modeling on the potential GHG implication of various scenarios associated with biofuel electricity production
• Large-scale deployment of renewable technologies in a changing climate
Needed Research