The intermittency of fossil fuels

This article by Simon Mahan was cross-posted from Footprints on the Path to Clean Energy, the blog of the Southern Alliance for Clean Energy.

You’ve likely heard this argument before: “The wind doesn’t always blow and the sun doesn’t always shine, so we can’t rely on renewable energy.” However, a series of recent events undermine the false dichotomy that renewable energies are unreliable and that coal, nuclear and natural gas are reliable.

There are too many reasons to list in a single blogpost why depending on fossil and nuclear energies is dangerous, but one emerging trend is that coal, natural gas and even nuclear energy are not as reliable as they are touted to be. Take for instance the nuclear disaster still unfolding in Japan. On March 11, that country experienced a massive earthquake and the resulting tsunami knocked out several nuclear reactors on the coast. Three days later, an operator of a nearby wind farm in Japan restarted its wind turbines – turbines that were intentionally turned off immediately after the earthquake. Several countries, including France and Germany, are now considering complete phase-outs of nuclear energy in favor of offshore wind energy in the aftermath of the Japanese disaster. Even China has suspended its nuclear reactor plans while more offshore wind farms are being planned off that country’s coast.

In another example much closer to home, here in the Southeast, some of TVA’s nuclear fleet is operating at lower levels due to extreme temperatures. When the water temperatures in the Tennessee River reach more than 90 degrees, the TVA Browns Ferry nuclear reactors cannot discharge the already-heated power plant water into the river. If water temperatures become too high in a natural body of water, like a river, the ecosystem can be damaged and fish kills may occur. This problem isn’t limited to nuclear power plants either.

Texas has been experiencing a terrible heat wave this summer – along with much of the rest of the country. According to the Dallas Morning News, this heat wave has caused more than 20 power plants to shut down, including coal and natural gas plants. On the other hand, Texan wind farms have been providing a steady, significant supply of electricity during the heat wave, in part because wind turbines require no water to generate electricity. The American Wind Energy Association (AWEA) noted on their blog: “Wind plants are keeping the lights on and the air conditioners running for hundreds of thousands of homes in Texas.”

This near-threat of a blackout is not a one-time or seasonal ordeal for Texans. Earlier this year, when winter storms were hammering the Lone Star State, rolling blackouts occurred due to faltering fossil fuel plants. In February, 50 power plants failed and wind power helped pick up the slack.

Although far from the steady winds of the Great Plains, Cape Wind Associates noted that if their offshore wind farm was already operational, the turbines would have been able to harness the power of the heat wave oppressing the Northeast, mostly at full capacity. Cape Wind, vying to be the nation’s first offshore wind farm, has a meteorological tower stationed off Nantucket Sound in Massachusetts. If Cape Wind farm had been built, it could have been using these oppressive heat waves to operate New England’s cooling air conditioners.

These three examples would suggest that the reliability of fossil fuels and nuclear reactors has been overstated, as has the variability of wind power.

So just how much electricity can wind energy realistically supply as a portion of the nation’s energy? A very thorough report completed by the U.S. Department of Energy in 2008 (completed during President George W. Bush’s tenure) presents one scenario where wind energy could provide 20% of the U.S.’s electrical power by 2030. To achieve this level, the U.S. Department of Energy estimates energy costs would increase only 50 cents per month per household.

A more recent study, the Eastern Wind Integration and Transmission Study (EWITS), shows that wind could supply 30% of the Eastern Interconnect’s service area (all of the Eastern U.S. from Nebraska eastward) with the proper transmission upgrades. As wind farms become more spread out across the country, and are better connected to each other via transmission lines, the variability of wind energy further decreases. If the wind isn’t blowing in Nebraska, it may be blowing in North Carolina, or off the coast of Georgia and the electricity generated in any state can then be transported across the continent. A plan has been hatched in the European Union to acquire 50% of those member states’ electricity from wind energy by 2050 – mostly from offshore wind farms, spread around the continent and heavily connected with transmission lines.

With a significant amount of wind energy providing electricity in the U.S., what would happen if the wind ever stops blowing? Nothing really – the lights will stay on, refrigerators will keep running and air conditions will keep working. As it so happens, wind energy has made the U.S. electrical supply more diversified and protects us against periodic shut downs from those pesky, sometimes-unreliable fossil fuel power plants and nuclear reactors.