Impact of Solar panels on global climate

Transcription

1 DOE/UCAR Cooperative Agreement Regional and Global Climate Modeling Program Impact of Solar panels on global climate Aixue Hu, Samuel Levis, Gerald A. Meehl, Weiqing Han, Warren M. Washington, Keith W. Oleson, Bas J. van Ruijven, Mingqiong He, Warren G. Strand Hu, et al., 2016, Impact of Solar Panels on global climate. Nature Climate Change, 6, , doi: /nclimate2843.

2 Energy sources Joules Fossil fuel Global mean T in RCP8.5: 4 o C by o C by 2300

3 World renewable energy 18 Total energy used in the word: 567X10 18 J (2012) 18 TW (population 7.0B) So if we could harvest small amount of the available solar energy, it would be enough.

4 Model and Experiments: Model: CCSM4, with 1 degree horizontal resolution for all components Forcing: RCP2.6 ( ) Experiments: 1. Control standard RCP2.6 simulation and no solar panels; 2. SPDU Solar panels are installed in cities and major desert areas; 3. SPDU+UH Same as in 2, but energy is consumed in urban regions; 4. SPDLess Solar panels are installed in a limited area. Assumptions: Solar panels reflect 10% of incoming solar radiation(albedo= 0.1), then convert 30% of the absorbed solar radiation to electricity and this electricity is transported elsewhere (90%*30%=27%). The rest (63%) heats the ground. Solar panel efficiency can reach ~40% for Concentrated PV, Thermophotovoltaic (TPV), Concentrated solar power (CSP)

5 Regions where solar panels are artificially installed Green stippling is for reduced solar panel installation experiment Four experiments: 1. Control 2. SPDU 3. SPDU+UH 4. SPDLess %

6 All scenarios Low scenarios Energy demand based on the IPCC AR5 If all final energy were solar-electricity If all final energy were solar-electricity TW Solar Panel Power Production Power production (TW) Power production urban only (TW) SPDU SPDU+UH SPDLess 739±5 740±5 59±1 48±1 48±1 0

7 Global and regional mean temperature CCSM4 CMIP5

8 Power consumed 110 TW 0.84±0.21

9 Albedo Changes The Effective albedo in regions where solar panels are installed in SPDU, SPDU+UH and SPDLess experiments is actually larger than that in the Control since part of the solar radiation reaching the solar panels is converted to electricity and consumed elsewhere.

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12 DOE/UCAR Cooperative Agreement Regional and Global Climate Modeling Program Summary 1. It is unavoidable for human beings to convert the major energy sources from fossil fuel to renewable energy. Solar energy could be the major energy source in the future. 2. Large scale application of the solar panels could significantly affect the regional and global climate such as a local cooling. 3. Consuming the solar energy can produce a compensating effect on the surface temperature, leading to an insignificant change of the global mean T, but regionally, especially in urban areas, T still can increase significantly.

13 DOE/UCAR Cooperative Agreement Regional and Global Climate Modeling Program Thank You This work is funded by the Office of Science (BER), US Department of Energy, Cooperative Agreement No. DE-FC02-97ER NCAR is sponsored by the National Science Foundation

14 Changes of Temperature and Precipitation Global mean temperature ( o C) Land mean temperature ( o C) Urban mean temperature ( o C) Global mean Precipitation (m/yr) Land mean precipitation (m/yr) Control Changes from Control SPDU SPDU+UH 15.08± ± ± ± ± ± ± ± ± ± ± ± ± ± ±0.026

15 Global mean temperature anomaly relative to Control Results shown later is the 90-yr mean ( )

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17 Changes in global incident and absorbed solar radiation Units: TW (10 12 W) Control Changes SPDU SPDU+UH Global incident solar 97394± ± ±166 radiation (ISR) (0.24%) Land ISR 31709± ± ±125 Ocean ISR 65685± ±151 67±144 Global absorbed solar 84801± ± ±143 radiation (ASR) (-0.3%) Land ASR 23936±92-320±88-315±96 Ocean ASR 60865±113 46±97 31±109

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19 Changes of Surface Temperature and Precipitation in RCP4.5, RCP6.0 and RCP8.5 relative to RCP2.6 in CCSM4

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21 Changes of climate variables in solar panel installed desert areas Control Changes from Control SPDU area SPDU SPDU+UH SPD incident direct solar radiation (TW) 2703±13 35±19 (1.3%) 49±18 (1.8%) SPD total cloud cover (%) 21.5±1-1.1±1.3 (-5%) -1.5±1.3 (-7%) SPD absorbed direct solar 1955±9-374±3 (-19%) -367±3 (-19%) radiation (TW) SPD reflected direct solar radiation (TW) 748±5-330±3 (-44%) -330±3 (-44%) SPD T in desert solar panel region ( o C) 16.24± ± ±0.38 SPD P in desert solar panel region (mm/yr) 271±47-41±47 (-15%) -63±40 (-23%) SPD Albedo 0.295± ± ±0.003

22 Solar Panels: Three major types of solar panels: 1. Photovoltaic (PV) panels that convert light directly to electricity 2. Thermophotovoltaic (TPV) panels that convert radiant heat differentials to electricity via photons 3. Concentrated solar power (CSP) using mirrors or lenses to concentrate sunlight to heat a fluid in order to drive a turbine and generate power Efficiency of the solar panels 1. PV ~ 10-20% 2. TPV ~ 40% up to 80% 3. CSP ~ 40% 4. Concentrated PV ~ 40%

23 Solar Panel Power Production Power production (TW) Power production urban only (TW) SPDU SPDU+UH SPDLess 739±5 740±5 59±1 48±1 48±1 0 Achievable solar power in the world range from ~400 to 8800 TW, given the current system performance, topographic limitations, environmental, and land-use constraints (Rogner, H.-H. et al., 2012) Roof area ~40%; if 50% installation PP ~10TW desert area ~40%; PP ~296TW/~24TW

24 Changes of global and regional mean precipitation

25 Solar Panels: Three major types of solar panels: 1. Photovoltaic (PV) panels or Concentrated PV 2. Thermophotovoltaic (TPV) panels 3. Concentrated solar power (CSP) Efficiency of these solar panels can all reach ~40%