The debate over how to reduce carbon emissions across the energy sector has increasingly turned on two words: "renewable" versus "clean."
After all, while most renewables are clean, clean isn't necessarily renewable.
It's a small, technical distinction that will have substantial, real-world effects on how the electric grid transforms in the coming decade as states consider upping the amount of electricity that must come from these resources. This year, lawmakers have been particularly active, with close to a dozen states debating and setting targets at or near 100%.
Hawaii--a state that is highly dependent on imported fossil fuels for electric generation--was the first to push the envelope to 100%. The Legislature passed a law in 2015 requiring 100% of its electricity to come from renewable resources by 2045. This includes wind, solar, hydroelectric, geothermal and biomass. Maine and Puerto Rico recently passed 100% renewable power targets for 2050, while the District of Columbia set the same requirement for 2032.
Discussions elsewhere, however, appear to be moving increasingly toward "clean" energy standards. California, New Mexico and Washington all passed bills in the past 12 months that require 100% carbon-free electricity by 2045. New York requires the same by 2040. Nevada established a voluntary 100% carbon-free goal for 2050. And Illinois, Minnesota, New Jersey, North Carolina and Wisconsin debated similar requirements.
Clean energy standards focus primarily on carbon emissions. They tend to aim for "carbon-neutral" or "carbon-free" electric systems. Washington's recently enacted law, for example, sets a 2030 carbon-neutrality target, which would allow utilities to offset remaining carbon emissions by purchasing renewable energy credits or paying a fee through 2045, at which point all electricity would have to come from carbon-free resources.
These policies will determine which resources utilities choose to invest in.
Not all carbon-free resources are defined as renewable under state laws. Hydroelectricity provides a little more than 20% of the nation's...