|Table 4.6. Capacity Additions, Retirements and Changes by Energy Source, 2011 (Count, Megawatts)|
||Generator Additions||Generator Retirements|
|Energy Source||Number of Generators||
Generator Nameplate Capacity
|Net Summer Capacity||Net Winter Capacity||Number of Generators||Generator Nameplate Capacity||Net Summer Capacity||Net Winter Capacity|
|Solar Thermal and Photovoltaic||133||637||639||622||1||2||2||2|
|Wood and Wood-Derived Fuels||5||126||124||124||8||63||54||44|
|Hydroelectric Pumped Storage||--||--||--||--||--||--||--||--|
|Other Energy Sources||4||140||120||120||1||22||20||20|
||Net Changes to Existing Capacity|
Generator Nameplate Capacity
|Net Summer Capacity||Net Winter Capacity|
|Solar Thermal and Photovoltaic||17||20||20|
|Wood and Wood-Derived Fuels||2||-31||-23|
|Hydroelectric Pumped Storage||277||94||204|
|Other Energy Sources||-1,643||-1,480||-1,599|
|Notes: Coal includes anthracite, bituminous, subbituminous, lignite, and waste coal; coal synfuel and refined coal; and beginning in 2011, coal-derived synthesis gas. Prior to 2011, coal-derived synthesis gas was included in Other Gases.
Petroleum includes distillate fuel oil (all diesel and No. 1, No. 2, and No. 4 fuel oils), residual fuel oil (No. 5 and No. 6 fuel oils and bunker C fuel oil), jet fuel, kerosene, petroleum coke (converted to liquid petroleum, see Technical Notes for conversion methodology), waste oil, and beginning in 2011, synthetic gas and propane. Prior to 2011, synthetic gas and propane were included in Other Gases.
Other Gases also includes blast furnace gas and other manufactured and waste gases derived from fossil fuels. Prior to 2011, waste heat was included in Natural Gas.
Hydroelectric Conventional capacity includes conventional hydroelectric power excluding pumped storage facilities.
Wood and wood-derived fuels include wood/wood waste solids (including paper pellets, railroad ties, utility poles, wood chips, bark, and wood waste solids), wood waste liquids (red liquor, sludge wood, spent sulfite liquor, and other wood-based liquids), and black liquor.
Other Biomass include municipal solid waste, landfill gas, sludge waste, agricultural byproducts, other biomass solids, other biomass liquids, and other biomass gases (including digester gases, methane, and other biomass gases).
Other Energy Sources include batteries, hydrogen, purchased steam, sulfur, tire-derived fuels and other miscellaneous energy sources.
Capacity by energy source is based on the capacity associated with the energy source reported as the most predominant (primary) one, where more than one energy source is associated with a generator.
In the case of some wind, solar and wave energy sites, the capacity for multiple generators is reported in a single generator record and is presented as a single generator in the generator count.
Net Changes to Existing Capacity reflect generator additions, generator retirements, and changes to previosuly reported generator capacity.
Source: U.S. Energy Information Administration, Form EIA-860, 'Annual Electric Generator Report.'