ATLANTA — Sweltering summer days have traditionally been when electricity generators have had to work the hardest to keep up with demand, but Georgia Power says changes in weather now require it to add generating capacity for winter.
The idea met with head-scratching by the five members of the Public Service Commission during a recent hearing.
Blame it on the brutal winter storm that crippled the South in 2014. After adding the low temperatures from that storm to the 53-year statistics, Georgia Power executives were in for a surprise. Company analysts were preparing for an update to long-term plans to be submitted to the commission. After running 175,000 scenarios, the data showed winter peak demand requires more reserve capacity.
For decades, the utility has aimed for a 15 percent reserve – unused generating power that can be ramped up quickly when needed. The model now called for 17.75 percent for optimum reliability.
The whole issue could be the result of two aspects of climate change.
On one hand, the variation in winter’s coldest temperatures is now 21 degrees while there’s only an 8-degree swing between summer’s average temperature and the hottest day. The greater the fluctuation, the more reserve is needed to adjust.
On the other hand, the Obama administration’s global-warming strategy required power companies to use less coal and more natural gas, solar and wind generation. But since there’s no way to guarantee sunshine or wind, there’s no practical way to store commercial volumes of electricity for when nature isn’t cooperating.
Natural gas must be delivered by pipe, and there is only so much pipeline capacity, so there isn’t enough gas to go around on the coldest days. Coal plants could store reserve fuel on site, but gas reserves are less common.
“On-site storage means the resource can be called upon during severe weather events that may otherwise threaten delivery systems,” said David Gattie, an associate professor of environmental engineering at the University of Georgia. “But for a flow resource (like gas), which can’t be stored on site, its availability is subject to disruption during severe weather.”
To lower the risk of blackouts, Georgia Power wants a higher reserve target to justify using combined-cycle generators that can switch from gas out of the pipeline to on-site fuel oil, which is more expensive. The company estimates it will cost electricity customers $2.5 million annually for the margin increase.
While the Public Service Commission has to decide July 19 on giving the OK, some advocacy groups are speaking out.
Nuclear Watch South argues that the company doesn’t even need to be adding two reactors already under construction at Plant Vogtle. It notes that Georgia Power cited 4 percent annual projected growth in electricity usage back in 2009 as the reason for expanding Vogtle, which was planned to begin operating this year.
“Georgia Power predicted it would need new base load power by 2016,” says Glenn Carroll, a coordinator of Nuclear Watch South. “Now 2016 is here, and Georgia Power’s electricity sales are the same as they were back then.”