On-gridders have plenty of reason to be concerned about where their electricity comes from these days. But exactly how much of it comes from miner-killing and mountaintop-removing coal; aquifer-polluting and fracked “natural” gas; radiation-producing nuclear; war-causing oil; or fish-killing dams? How much comes from carbon-free renewables—and just how “green” are they?
The Environmental Protection Agency’s Power Profiler (1.usa.gov/EPAPowerProfiler) is an online database that shows the fuel mix of the electricity you buy from the grid. By plugging in your ZIP code and electric utility’s name, you can find the fuel mix and pollution emissions of the electricity in your subregional grid (one of 26 generally independently functioning electrical grids in the United States) and compare it to the national average.
The 2009 data comes from the EPA’s Emissions & Generation Resource Integrated Database (eGRID, bit.ly/EPAeGrid). The eGRID summary tables are a great way to see how your subregional grid stacks up against the others.
You can also get EPA data on generation sources by state, but since electric energy is consumed on grids—which can be a subset or a superset of states (or parts thereof)—it’s most accurate to assess your electricity sources by including the entire subregional grid.
And, when it comes to being green, there are several important, but different, metrics—climate-friendly, earth-friendly, and human-friendly. By any measure, fossil fuel (coal, oil, natural gas, etc.) is not “green.”
Biomass, typically burned to produce electricity, produces emissions and causes air-quality issues. And carbon emissions from biomass-produced electricity is not much of a short-term winner for the climate.
Hydropower is renewable as long as the rain falls, but large dams have large environmental impacts, including decimating or eliminating wild runs of salmon and other fish, and destroy entire canyons and river runs.
Nuclear power generation doesn’t emit carbon dioxide into the atmosphere, but uranium mining, plant construction and decommissioning, and the manufacturing of their highly specialized equipment releases a lot of CO2. Plus there are the matters of catastrophic failures and storing radioactive waste.
Geothermal steam that is tapped to turn turbines to make electricity is fairly climate-friendly, but depending upon the rates of extraction, it may not be sustainable. Depending upon where it is located and the size of the facility, it may or may not have significant environmental impact.
Only a few generation sources come out tops in all categories. Photovoltaic (solar) electricity is tops for the climate and for earthlings, but it’s even more planet-friendly if distributed over thousands of roofs rather than having tens of thousands of PV modules clustered in one spot. Wind power, although also pollution-free, can be bad for birds if poorly sited.
In 2009, the most solar electricity as a percentage of a subregional grid (0.30%) was generated in California, with Hawaii following at 0.046%. (The Paradise State produces more than two-thirds of its electricity from burning oil.) Due to a boom in PV installations, however, the percentage of solar-generated electricity has increased dramatically.