The country has been debating renewable energy for decades—how much we should support it, what place it should have in our energy policy, how big an impact it actually has.
Yet many of the things we think we know about renewable energy go back to the earliest arguments. Many of the debating points we hear today are based on outdated facts and assumptions that don't hold up anymore.
So, we set out to look at a few persistent myths or beliefs held by both supporters and critics of renewable energy. We've focused largely on wind and solar power, in part because they've shown explosive growth in recent years but also because they are at the center of political debates over energy.
MYTH NO. 1: Renewables Are an Insignificant Source of Power
One of the most persistent criticisms of renewables is that they account for a fraction of the U.S. electricity system—despite years of federal subsidies and breakneck growth.
When looking at "newer" renewable energies such as wind and solar power, that's largely true. Wind accounts for about 5% of generation capacity and a little over 4% of U.S. electricity production, or roughly one-tenth what coal provides.
But the criticism overlooks one important point: Conventional hydroelectric power, such as the Hoover Dam, is also renewable energy. Taken together, hydroelectric and other sources—biomass, geothermal, solar and wind—combined to account for 12% of U.S. electricity production last year, and close to 14% so far this year. The entire nuclear fleet provides about 19%.
It's also important to remember the scale of the country's renewable efforts. The U.S. has the second-biggest electricity system in the world, accounting for about 20% of the entire world's generation capacity. Wind power's 5% of that pie is a big slice. The 60-odd gigawatts of wind power installed in the U.S. amounts to more electricity-generation capacity than in the entire country of Australia or Saudi Arabia, and as much as all of Mexico. It's about half as much power as in France or Brazil.
To be sure, the wind doesn't always blow. Wind farms produce only about one-third of their listed capacity, while a nuclear plant produces almost 100%. But even that discounted amount of electricity generated by U.S. wind farms is huge in global terms—54% of all the juice generated by Mexico, 26% of France and Brazil, 62% of Australia, 64% of Turkey and more than twice that of Switzerland.
The seemingly small share of power produced by renewable energy at the national level also reflects the fact that some states have a lot of green power and some have practically none. Texas has the biggest electricity system in the country, and gets 11% of its juice from renewables, nearly all from wind. New York and Georgia both have large power sectors, but get relatively small amounts from renewables.
MYTH NO. 2: Renewables Can Replace All Fossil Fuels
The flip side of critiques of renewable energy is boosterism. A handful of proponents describe a future where 100% of energy needs can be met affordably and reliably by renewables.
Focusing on electricity, researchers at the National Renewable Energy Laboratory tackled this question. They found that, technically, by 2050 the U.S. could get 80% of its electricity from renewable energy and keep the lights on every hour, every day, in every corner of the country. (Their study didn't consider a 100%-renewable scenario.)
Perhaps. But getting there would be a long, tough slog. The study found that the U.S. would need to install about 20,000 megawatts of renewable generating capacity every year for a couple of decades, gradually ramping up to about 40,000 megawatts every year. The study found no reason to doubt the global renewable-energy industry's ability to eventually meet that level of production. What might be trickier, the study found, is finding a place to put all those wind farms, solar arrays and hydroelectric facilities.
Managing the big upfront capital costs of wind and solar power would be another obstacle. And down the road there could be another challenge: Areas with lots of variable power could see wholesale power prices close to zero at times. That would complicate the economic case for fresh investments in generation capacity year after year.
The U.S. would also need to virtually duplicate the entire existing network of transmission lines by 2050 to handle 80% renewable energy. The study notes that the trick would be figuring out where the lines would go, who would pay for them, and which state and local governments would be in charge.
In other words, there's no technical reason renewable energy can't provide 80% of the power in the U.S. by midcentury. But there are a host of challenges that would have to be met first.
MYTH NO. 3: Renewables Are Too Expensive
Forget about problems down the road. Another criticsm of renewables in the here and now: They're expensive ways to generate electricity.
One new, comprehensive comparison of wholesale electricity prices, in the Journal of Environmental Studies and Sciences, concludes that coal-generated power costs 3 cents a kilowatt-hour; new gas plants would produce juice at 6.2 cents; wind power costs 8 cents; and solar photovoltaic, 13.3 cents.
But there are two big issues to bear in mind. First, costs are falling fast—thanks largely to technological advances such as larger wind turbines and cheaper components for solar-power arrays—so in some places, solar and wind power can cost even less.
The latest price data for wind-energy power-purchase agreements, released by the Department of Energy last month, showed that nationwide, the price of wind-generated electricity fell to just over 4 cents per kilowatt-hour nationwide, not counting the 2.2-cent federal tax subsidy. In some regions, well-sited wind farms produce electricity for closer to 2 cents.
Likewise, Lawrence Berkeley National Laboratory just released its latest report on the costs of installing solar power. Costs for small-scale solar residential arrays fell by about 13% in the past year, driven largely by cheaper solar components due to a global supply glut. Utility-scale prices also fell.
There's also the question of hidden costs. Coal-fired electricity, for instance, has nasty side effects, including air pollution, health impacts and carbon-dioxide emissions that contribute to global warming (all of which factored into the Obama administration's proposal Friday for new limits on coal emissions)—and those don't show up in coal's price tag. If coal and other fossil fuels had to tally the total costs their use imposed on society, coal wouldn't be the cheapest source of electricity, and clean-burning renewables wouldn't look nearly so pricey.
Add all the hidden costs together, and the total cost of different power sources looks quite different, according to that recently published study. At an existing coal-fired plant, the cost goes up by 6 cents per kilowatt-hour, making its true cost 9 cents; at a new coal plant, it would go up by about 4 cents to 13.2 cents. New natural-gas-fired electricity would go up by 1.3 cents, bringing its total to 7.5 cents. But wind and solar and nuclear energy don't go up—because they don't cause asthma, and they don't emit carbon dioxide.
A few cautions when comparing the cost of different power sources. Gas plants are often used to meet peaking power demand, when they can fetch higher prices. Solar power also produces during hours of high demand, and its power is more valuable. But wind power produces more at night and less in the daytime, so its electricity is less valuable to the system.
Furthermore, different energy sources have additional costs that muddy direct comparisons. Nuclear plants have decommissioning costs, waste storage and liabilities that aren't always fully priced in. Variable sources such as wind and solar power need extra transmission lines and special efforts to integrate their power into the grid, which isn't included in the cost.