Effects of the solar eclipse that will cross the United States on Monday, Aug. 21 have scientists – and businesses – making plans. Small towns in places like Rabun County, Georgia started preparing for an influx of visitors who want to make the most of the rare opportunity to observe the eclipse in totality.
But more than an opportunity for me to take a day off and enjoy the Moon obscuring the Sun, casting its shadow to turn day into night, it has an impact on some industries. If you think about it, you’ll realize immediately at least one industry that’s affected by the eclipse. Yep, utilities that depend on solar energy to power their electric grid will see a measurable decline in power output.
How much decline varies by location, as not every solar power generation facility will have the same amount of totality. A small portion of the country will get between a few seconds to a little over 2.5 minutes of the total eclipse. The Sun will be partially obscured for longer than that.
But don’t get too worried about sudden brownouts, lights dimming or other catastrophes. The North American Electric Reliability Corporation (NERC) doesn’t expect any reliability issues, based on analysis of the available data. That’s even though the solar eclipse will obscure the sunlight at approximately 1,900 utility-scale solar photovoltaic (PV) power plants in the nation. Very few of those power plants sit in the path of totality, with most of those in eastern Oregon. California has the most solar production, but none of its plants are in the path of totality.
Georgia and North Carolina have most of the plants totaling approximately 4.0 gigawatts of capacity that will be at least 90 percent obscured. Another 2.2 GW of solar capacity will see the Sun obscured by 80 percent, and 3.9 GW of capacity will be at least 70 percent obscured. Though with clouds and rain in the forecast, it might be a moot point.
In Georgia, Green Power EMC provides electricity through its 38 member EMCs (Electric Membership Corporations). The nonprofit corporation uses green resources such as solar, low-impact hydroelectric plants, biomass and landfill gas to generate electricity.
“While the Georgia cooperatives collectively have more solar power than any other group of cooperatives in the country, it is still only around 2% – 3% of the capacity that they get from other sources of energy like coal, nuclear, natural gas, hydro, etc.,” said Jordan Webb, operations coordinator, Green Power EMC. “On an energy basis, it would be more like 1% of the energy that the cooperatives use comes from solar.”
Webb said even if Green Power’s solar facilities produced zero energy during the eclipse, other power facilities have excess capacity to meet any energy needs, which he said is called reserve capacity. “Regulatory bodies usually require producers and transmission facilities to maintain a constant reserve margin of 10-20% of normal capacity as insurance against breakdowns in part of the system or sudden increases in energy demand,” Webb said.
Anyone living entirely “off the grid” and depending on solar energy might need a backup plan, but the eclipse doesn’t last that long.
(Save your eyes if you don’t have solar glasses! You can use a small box like a shoe box to make an eclipse viewer.)
Duke Energy, one of the largest utilities in North Carolina, reports that solar energy production will dramatically drop while a corresponding demand for lighting rises, according to a blog by Jessica Wells in the utility company’s illumination news website. She reported that officials at the utility company expect solar energy output to drop from approximately 2.5 GW to 0.2 GW during the eclipse. Visiting the Carolinas or live there? Don’t worry – system operators will have natural gas plants ready, and they plan to power production by solar and increase natural gas production as the eclipse begins to adjust. If it’s very cloudy they’ll already have made that kind of adjustment.
But in North Carolina, despite being the second largest solar production state, solar only supplied 3.1 percent of the state’s generation in August 2016. So it won’t be as big an adjustment as in California, which has 14 percent of its production coming from solar.
The California ISO and Locus Energy both used weather trends and forecasts to create their own predictions on what the eclipse will mean for power production. Both analyzed available data to determine how much the Moon’s shadow will affect electricity generation.
Because the capacity for solar generated power continues to increase each year, direct comparisons become difficult. For August 2016, California’s utility-scale solar was close to 8.5 GW. Current capacity rose to 10.4 GW. So Locus Energy used data on the hourly change in solar generation from last July to August on a percentage basis. They compared that with solar generation in July.
The results? Locus Energy expects utility-scale solar to decrease at a rate of 51.1 MW per minute as California approaches the peak of the eclipse. Once the peak passes, it should increase at a rate of 62.8 MW.
The overall effect will require California utilities to make up for 7.8 GW of electricity more than they would on a clear day. California ISO plans to generate electricity from natural gas and hydropower plants to replace the drop from solar generation.
Telecom Industry Expects Demand Spikes
The telecom industry also expects to experience the effects of the eclipse. An article by GeekWire’s Alan Boyle said telecom carriers expect the additional demand will resemble music festivals held in less populated areas. They’ll deploy mobile communication towers and portable power generators, and beef-up backhaul connections – to handle the flood of eclipse videos and photos.