The Intermittency of Fossil Fuels

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.

Japans windy mountain tops look suspiciously similar to Appalachia.

Japan's windy mountain tops look suspiciously similar to Appalachia

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 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 farms 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 energy helped pick up the slack.

Satan called. He wants his weather back.

Satan called. He wants his weather back.

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 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.

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.

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Notwithstanding the fact that, statistically, fossil fuel and nuclear plants are orders of magnitude more reliable than wind or solar plants, what you are describing is the type of balanced and diverse energy portfolio that will be necessary to meet the nation’s energy needs in the future. Solar, wind and other renewables will never completely supplant fossil fuels or nuclear, but will necessarily comprise an increasing percentage of all US (and global) generation output. The most effective energy policy will never be an either-or proposition, but an all-of-the-above. This is one of the more thoughtful posts on this blog and makes some good points. However, don’t undermine an otherwise credible argument by suggesting that fossil fuels and nuclear energy will not continue to be just as essential to our national energy portfolio as they are today, and as renewables will be in the future.

Comment by Frank Talk on August 19, 2011 12:54 pm

Although the article exaggerates the perceived “unreliability” of fossil fuels, it makes a valid point without even mentioning that fuel supply and price variations are reliability issues for fossil fuels as well.

There will be a mix of energies for a long time but wind has proven it can supply a large percentage of power, perhaps 20-30% or more, and with most of the money for windpower being spent locally, it’s becoming more popular.

Comment by Bill Pay on August 20, 2011 12:51 am

The article should also mention the Fort Calhoun flooding, June 2011.

Comment by Rif on August 20, 2011 6:28 am

Thank you for your comments.

@Frank Talk – Thank you for the accolades; however, you overstate the reliability of conventional power plants. Specifically, “orders of magnitude” are on a scale of 10x. With current technology, onshore wind farms in our region could operate at 20% – 30% capacity factors with 98% availability. For conventional power plants to be “orders of magnitude” (more than 1 order) more reliable than this, those power plants would need to be operating at 2,000 – 3,000% with a 9,800% availability, which is impossible. Accuracy is important here.

At some point, this country will be unable to support fossil fuel and nuclear expansion either due to expense, lack of resources or excessive burden on the environment. Here in the South, we’ve been facing a serious drought. With more thermoelectric power plants, we will have to choose between electricity and thirsty citizens, recreational water uses and agriculture. The expanding demand for electricity, with ever continuing restraints on water consumption, will necessitate utilizing large quantities of renewable energy.

@Bill Pay – There is no exaggeration of the reliability of the conventional power plants here. I have noted several significant events, which have happened, that highlight how large conventional power plants can go offline very suddenly. During those events outlined earlier, while conventional power plants were failing, nearby wind farms were doing exceptionally well – highlighting the need for a more diversified energy portfolio.

@Rlf – Thanks for highlighting the Calhoun flooding. Wind farms are usually situated away from low-lying areas like river basins due to lower wind speeds – this may actually help prevent wind farms from being at risk from floods.

Comment by Simon Mahan on August 22, 2011 9:39 am

Duh, that’s why there is a substantial amount of surplus capacity built into the grid. And that’s why wind would have so little impact on fossil and nuclear fuel use: it’s just one more source of load variability that the dispatchable grid has to adjust to.

Comment by Frida on August 24, 2011 9:11 am

@Frida – I recommend you read the DOE’s “20% by 2030″ wind report. It shows that having 20% of the nation’s electricity come from wind power by 2030 would cut carbon emissions by 825 million metric tons and save nearly 4 trillion gallons of water – that goes to show wind can have a huge impact on traditional fuels. All that for just about 50 cents per ratepayer per year.

Comment by Simon Mahan on August 25, 2011 4:53 pm

@Simon Mahan – That is not data. That is wishful thinking. A sales brochure. What effect has wind already had? It’s hard to see that it has had any.

Comment by Frida on August 26, 2011 12:06 pm

@Frida – Re-read the blog post where wind was vital to ensuring grid stability when coal and natural gas plants failed in Texas. 40 gigawatts of wind capacity have been installed in the U.S. already – if it weren’t for that capacity, surely it would have been made up by new coal and new natural gas. If you have actual criticisms of the DOE report, state them with actual data and then we can discuss this further.

Comment by Simon Mahan on August 26, 2011 5:14 pm

@Simon Mahan – As Denise Bode, CEO of AWEA, tells it, there were no actual numbers involved in Texas that week. In fact, the offshore wind generation rose in late afternoon, well after peak demand was falling. Throughout the week, total wind generation averaged about 1,400 MW at peak demand, which was over 67,000 MW for 6 out of 8 days and about 63,000 MW the other 2 days. So wind provided just over 2%, or 14% of its nameplate capacity.

That may well have been helpful in this extreme situation, but it underscore­s the inefficien­cy of wind in that so much has to be built to get (by chance) so little.

Comment by Frida on August 26, 2011 10:02 pm

@Frida – I believe I found the article you mention from Denise Bode.

Some of her highlights include:
“Adding wind power makes a utility system more reliable, not less.”
“No power plant runs 100 percent of the time.”
“Geographic dispersal of wind farms makes their electricity production more dependable.”
“Generation from offshore and coastal land-based wind matches up well with summer demand peaks.”

There are no offshore wind farms in operation the U.S. today. However, offshore wind has the potential to better meet peak demand in the afternoons due to something called the “sea breeze effect”. Bode’s post (and other sources) note that during the Texas heat wave, the coastal Texas wind farms (like the Peñascal Wind Farm in Kenedy, TX) provided nearly 70% of all of the wind energy’s electricity generation during that time. If inland wind farms are coupled with coastal and even offshore wind farms, the electricity supply will be more reliable.

Those figures you quote are from a comment to her blog – not from Denise, and certainly not a reputable source.

And again from Denise’s article:
“As he did after a sudden freeze stressed the Texas system in February, ERCOT CEO Trip Doggett credited wind power with a critical contribution during last week’s power emergency. Doggett said electricity from wind farms recently installed along Texas’ Gulf Coast began flowing at just the right time to help meet peak demand in the late afternoons.”

Comment by Simon Mahan on August 29, 2011 10:14 am

Thanks for correcting: I meant “coastal” not “offshore”. The point remains, however, that wind’s contribution was in fact very small, particularly at peak demand. Doggett’s comment implies that wind came on as demand peaked, but in fact it came on as demand was already going down. Finally, Denise Bode is a trade-group lobbyist, making her perhaps the least reliable (let alone reputable!) source of information about her industry. I have since seen a graph of that week’s demand and wind generation as provided in an article by Robert Bryce in the National Review. It backs up the figures provided by the commenter at Huffington Post. It also shows, even with the geographic diversity of wind in Texas, the high variability (even on the large scale of the graph — who knows what it looked like minute to minute?).

Comment by Frida on August 30, 2011 1:32 pm

A diversified energy portfolio is more secure than the one we have now – and that’s exactly the point Doggett made. If you’d like to disagree with the head of ERCOT (Texas’ grid operator), but instead trust some unknown commenter on the Huffington Post blog, and Robert Bryce (a fossil-fuel funded hack) that’s your prerogative. Pooh-poohing wind because its “contribution was in fact very small” misses a very large point: that wind capacity in this country is very small and should be much higher.

Comment by Simon Mahan on September 8, 2011 10:05 am

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