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Green Building News

N.C. Newspaper Links Solar Energy to Increased Air Pollution

An application from Duke Energy stirs a debate over emissions from gas-fired peaker plants

A North Carolina newspaper has rekindled a debate on whether more solar on the grid actually increases air pollution. Photo: Alan Stark / CC / Flickr

Does the addition of solar capacity on the grid cause an increase in air pollution? A North Carolina newspaper argues that it does.

Earlier this month, the North State Journal pointed to an air pollution application from Duke Energy for gas-fired power plants it operates in Goldsboro, North Carolina, as evidence that solar energy causes an increase in nitrogen oxide (NOx) emissions.

The Raleigh newspaper quoted Duke spokeswoman Kim Crawford as saying that reductions in carbon dioxide emissions also could be reversed if solar energy policies aren’t changed. Emissions go up, the article says, because solar energy is intermittent. When solar output drops, inefficient peaker plants fired by fossil fuels must be brought on line, but starting and stopping the plants reduces efficiency and thwarts emission control devices.

In fact, the article continues, more NOx is released into the atmosphere than would be the case if natural gas were used exclusively and solar energy was eliminated. It quotes Steve Gorham of the Heartland Institute, which does not accept climate science, as saying there’s “very little measured data” showing that renewables lead to lower greenhouse gas emissions.

According to an article detailing the dispute posted at E&E News, Duke Energy acknowledges that ramping power plants up and down does lead to more emissions. But a spokesman said conclusions reached by the newspaper were wrong.

“We just need to note that in our air permits for the units,” spokesman Randy Wheeless said of the utility’s March application to North Carolina authorities, “To take that and stay, ‘Renewable energy causes more pollution,’ that’s faulty. That’s like saying an [electric vehicle] is bad because your electric costs go up, not noting that you saved money on gas.”

Costra Samaras, an associate professor of civil and environmental engineering at Carnegie Mellon, also rebutted the newspaper’s argument. He told E&E News, “Increased cycling for many types of fossil generators will affect the pollutant emissions. Is that more emissions than just turning off solar and running gas all of the time? I doubt it.”

The connection between more solar deployment and increased greenhouse gas emissions have been raised before. But a 2013 study from the National Renewable Energy Laboratory found that carbon emissions caused by more frequent cycling of power plants running on fossil fuels are “negligible.”

North Carolina is second only to California in the amount of solar capacity currently online. In California, greenhouse gas emissions have been falling for the past 15 years, due to modern natural gas plants and a flexible, real-time market system for energy. Older, less efficient plants have been retired because they cost too much to operate. In North Carolina, where monopolies rather than an independent agency operate the grid, older power plants are kept online until they are paid off.

-Scott Gibson is a contributing writer at Green Building Advisor and Fine Homebuilding magazine.

7 Comments

  1. John Clark | | #1

    The only issue NC has to worry about is the release of heavy metals via solar panels which were damaged/destroyed by storm events such as hurricanes.

    The solar industry in the US has for the most part has taken a bit of a "head in the sand approach" with regards to recycling/disposal of panels.

  2. User avater
    Jon R | | #2

    It doesn't surprise me that some people can't grasp that both of these can be true: "more emissions per kWh from fossil fuel plants" and "less total emissions". Metrics matter and even "experts" often use the wrong ones.

    I think there is an important issue of the model necessary to address technical issues. Most voters aren't interested in (or capable of) anything more more complex than a sound-bite. Politicians are increasingly corrupt and regulators are increasingly lax. The shift in news sources makes news increasingly unreliable. So what will make the right things happen?

    1. Tyler Keniston | | #7

      Jon,
      Your second paragraph is sort of why I feel the erosion of trust in our institutions and in 'experts' is a major concern.
      No-one is smart enough to be expert on everything, and a huge percentage of people aren't capable of investing enough to be expert on anything. This is why trust in institutions and experts, who are supposed to be responsible and capable of the necessary in-depth analyses, is essential. Unfortunately, this trust is eroding, and often time for good reason.
      Dunno, maybe it's always been this way, but it seems like we need to seek a system that encourages trust-worthy behavior instead of a system that encourages deceit, manipulation, and selfishness. If everyone had good intentions, it wouldn't be a problem.

  3. But Why? | | #4

    "Costra Samaras, an associate professor of civil and environmental engineering at Carnegie Mellon, also rebutted the newspaper’s argument. He told E&E News, “Increased cycling for many types of fossil generators will affect the pollutant emissions. Is that more emissions than just turning off solar and running gas all of the time? I doubt it.”"

    "I Doubt it." is NOT a rebuttal and to print it as such is what some would call "fake news"

  4. Andy Kosick | | #5

    Dana can chime in with his seemingly encyclopedic knowledge of this subject but my casual reading at UtilityDive has me undersatnding that solar-plus-storage is already penciling out to a cheaper and more effective way to manage peak loads than gas plants. Combined with the evidence from the NREL study cited in the article it feels like they're grasping straws. Even though most of the public hasn't noticed yet, as someone keeping a general eye on utility generation, it seems like the tables have started to turn.

    1. User avater
      Dana Dorsett | | #6

      >"...solar-plus-storage is already penciling out to a cheaper and more effective way to manage peak loads than gas plants."

      That's the long and short of it. Solar + 4 hours of storage is already a lower-risk bet than a peaking gas plant in much of the US. I would expect in sunny NC that to be more true than some dimmer locations. Overbuilding solar and curtailment (without storage) can even be a winner in some locations.

      The bigger picture on renewables also has to factor in wind power's effect on reducing the capacity factors of peakers, not merely buffering solar power with storage. While NC doesn't have a lot of wind power this week (and plenty of opposition to on-shore wind), wind is likely to become a major player in the local market once the offshore wind ball gets rolling. The offshore wind developer Avangrid has already thrown down a marker for first-dibs on NC's offshore wind:

      https://energynews.us/2019/02/18/southeast/after-moratorium-north-carolina-looks-offshore-for-wind-energy-potential/

      https://www.greentechmedia.com/articles/read/avangrid-jones-act-workarounds-hold-promise-for-other-offshore-markets#gs.0p9q07

      Offshore wind has far a superior capacity factor and lower volatility than ridgetop wind in NC. Wind (and to some extent solar) has fast enough ramp rates when operated at a few percent lower than the current max-available to provide many of the frequency and other ancillary services previously supplied by peakers, at the cost of some curtailment (but compensated for financially for those services.) This too can become a filler/stabilizer for the diuranal swings of local PV relative to the grid load.

      At some low capacity factor the emissions/Mwh of a gas peaker hardly matter, since the total Mwh number continues to sink. The financial cost per Mwh of low capacity factor gas peakers can be quite high- high enough to make some curtailment of renewables cost-competitive even without storage. But some amount of storage still has a financial rationale, and probably will well into the future.

      There are lots of moving parts to the grid- reducing it to a binary X-amount of Solar needs Y-amount of gas peaker is pure BS.

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