Potential Climate Impact of Large-Scale Deployment of Renewable Energy Technologies Chien Wang (MIT)
1. A large-scale installation of windmills 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?
Simulating the Climate Effects oflarge-scale Installation of Windmills NCAR CCM3 GCM+slabocean, T42 (~2.8 degree, 18 layers) resolution Simulate windmills based onchanges in surface roughness that convert kinetic energy to targeted power outputs Land Installation: all grass and shrub regions (~58 M km 2 ) Ocean Installation: ocean depth < 200 m (~10 M km 2 ) 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 ofsurface 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 -dke/dt = dtke/dt Heat and matter mixing Kinetic Energy Turbulent Kinetic Energy -dke/dt = dtke/dt + dcee/dt Molecular and surface mechanic dissipation Windmill = Converting KE to Electric Energy
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 Precipitation caused by the windmills reflect Changes a substantial alteration to the pattern of atmospheric general circulation 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 1 o C over land installations Surface cooling exceeding 1 o C 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 distributions of 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 km 2 ) 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 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 135 135 120 120 million km 2 105 90 75 60 45 million km 2 105 Food Crop Pasture 90 Managed Forest Biofuel 75 Grasslands Shrublands Natural Forests 60 Other 45 Food Crop Pasture Managed Forests Biofuels Grasslands Shrublands Natural Forests Other 30 30 15 15 0 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 0 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year Year Melillo et al., (2009)
Two Stories about Indirect Effects of Biofuels: Ecosystem GHG implication Net Land Carbon Flux (Negative = Emissions) Carbon Flux ( Pg CO 2 -eq ) 90 60 30 0-30 -60-90 -120-150 Direct Indirect Net Land Carbon Flux -180 2000 2020 2040 2060 2080 2100 Year Carbon Flux ( Pg CO 2 -eq ) 90 60 30 0-30 -60-90 -120-150 Net Carbon Balance Direct Indirect Net Land Carbon Flux -180 2000 2020 2040 2060 2080 2100 Year Net Balance ( Pg CO 2 -eq ) 1000 800 600 400 200 0-200 -400 Fossil Fuel Abatement Net Land Carbon Flux Fertilizer N2O Emissions Net Abatement -600 2000 2020 2040 2060 2080 2100 Year Melillo et al., (2009)
Major Climate Effects of Modeled Ecosystem GHG implication of Biofuels Large-Scale Installation of Windmills What have we learned and what type of research is need Vegetation and soil carbon effects on biofuelsland 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
Needed Research 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