Solar Wind Hydroelectric Geothermal Nuclear Natural Gas Coal Biomass
Reliability When sunny When windy When there is water   24/7/365      
Capacity factor                
Space required                
Pollution High life-cycle CO2 &
metals
High life-cycle CO2.
 
      Lots of CO2 Dirtiest  
Waste Difficult to recycle Not recyclable.
Blade disposal in landfill