How much of our electricity is generated from emission-free energy?

The purpose of this post is to organize US electrical production data for easy access. To impact global warming what matters is the developing world. But the US data is easy to access, so here it is:

 

Most Renewable-Generated Electricity is from Hydropower

Renewable energy sources provided about 12% of total U.S. utility-scale electricity generation in 2012. The largest share of the renewable-generated electricity came from hydroelectric power (56%), followed by: wind (28%), biomass wood (8%), biomass waste (4%), geothermal (3%), and solar (1%).

Electricity generation from renewable resources is primarily a function of generation capacity and the availability of the resource. The history of electricity generation has been different for each renewable source.

  • Nearly all of the hydroelectric capacity was built before the mid-1970s, and much of it is at dams operated by federal government agencies.
  • Biomass waste is mostly municipal solid waste which is burned as fuel to run power plants.
  • Most of the electricity from wood biomass is generated at lumber and paper mills. These mills use their own wood waste to provide much of their own steam and electricity needs.
  • The amount of installed wind generation dramatically increased in the past decade, due in part to Federal financial incentives and State government mandates, especially renewable portfolio standards.
  • Unlike other renewable sources, a significant amount of solar power is generated by small-scale, customer-sited installations like rooftop solar (or, distributed generation). According to the Annual Energy Outlook 2013, these small solar facilities are projected to generate an estimated 14.13 billion kilowatthours of electricity in 2013.1