by Dr. Donald R. van der Vaart
Former Secretary, North Carolina Department of Environmental Quality
Note: Click the links for Part 1, Part 2, and Part 4.
Governor Cooper’s “Clean Energy Plan” seeks to install more renewable energy including solar power in North Carolina. NC already has more installed solar energy than any other state except California. NC has more than double the solar power of 45 other states. NC’s solar plants operate at only 21% of their stated capacity, however, which is below the nation’s average. Are other states crazy, or are we? It turns out we are.
Solar plants generate power only when the sun is shining, and only when the sun is shining directly overhead do they generate a significant amount of electricity. Here are some actual electricity generating curves for a solar facility:
Source: Dan Way, “Solar energy output ratings misleading if not deceptive, critics say,” Carolina Journal article, May 20, 2019
When not generating electricity, some other electricity generator must step in to fill the gap. Due to an unusual interpretation of federal law in NC, almost all of the power solar plants generate must be purchased by the utility company for delivery to the customers. This means that the dispatchable plants that step in to fill the gaps must idle when solar plants are generating electricity. This causes those plants to operate inefficiently, and means that customers are actually paying for twice the generating capacity during those periods.
The grid must also accommodate large fluctuations in electricity generation. When the sun shines, solar plants throughout the area send electricity across the grid for distribution to our homes. When clouds pass over, or at about 3:00 when that power evaporates, a number of large gas combustion turbines and coal plants must quickly ramp up to fill the gap. These large fluctuations strain the grid. As more and more solar plants are being installed, NC electricity customers will be made to pay billions of dollars to upgrade our grid to maintain its reliability.
Nuclear plants could fit into our current grid seamlessly. But even without including grid modifications, solar power is more expensive than even new nuclear power.
Solar power requires the use of fossil fuels. Solar requires fossil fuel–fired combustion turbines and coal plants to provide 79% of the load. It turns out that when fossil fuel backup generators operate in this fluctuating mode, their efficiencies drop, necessitating more fuel. So in terms of reducing greenhouse gases (GHG), the overall benefit of solar and wind is diminished. It also increases non-GHG pollution. To the extent manmade GHGs are impacting global warming, then, solar power cannot compete with nuclear power.
While the Cooper plan does not compare intermittent sources plus their backup generators with nuclear plants, the plan discusses using battery storage as a way that could potentially extend solar power’s capacity and reduce the need to provide backup. The idea would be to store excess solar or wind energy when the sun is shining or the wind is blowing for release to the grid when sun and wind are absent. For this scheme to work, of course, a very large amount of batteries would need to be installed.
How large? The plan does not consider this obvious question, for obvious reasons. Other researchers have. It turns out that such a deployment of batteries would be absurd for the following reasons:
Neither solar nor wind energy will ever deliver the needed energy for our country without the significant use of fossil fuel as backup. Battery storage is not the answer for extended storage of large amounts of electricity. If Gov. Cooper is serious about cleaning up our energy sector, he needs to push for more nuclear plants and stop wasting billions of dollars on expensive, dirty, and ecologically harmful alternatives.
Other posts in this series: