Keeping the lights on with solar and wind energy
I’ve written two posts on nuclear – one on new plants and the other on existing ones – indicating we shouldn’t build new ones and phase out existing ones. Some people with impeccable credentials don’t agree. For example, former Energy Secretary Steven Chu, a Nobel-Prize winning physicist, told the Associated Press that “…when the wind doesn’t blow and the sun doesn’t shine …we will need some power that we can actually turn on and dispatch at will. That leaves two choices: either fossil fuel or nuclear.” He is far from alone. I can say, having studied this specific issue carefully for more than 15 years: they are wrong. Solar and wind can do the job reliably and affordably when complemented by available technology. I’ve done the math.
I’ve also been there before. It is worth recounting that half-a-century-old story because it applies eerily well to the present predicament.
In the years before the world-changing energy crisis of 1973 and the Arab oil embargo, it was the prevailing opinion, also held by people with impeccable credentials, that energy growth and economic growth were tightly coupled. While I pursued my doctorate in nuclear fusion, I concluded, in 1971, that the United States could, by being more efficient in the use of energy, run a much larger economy with the same amount of energy (or the same economy with a lot less) and published a report to that effect with my graduate advisor, Allan Lichtenberg. At the same time, across the country, S. David Freeman, a great leader in US energy policy, was worried about the national insecurity associated with escalating oil imports. He thought energy growth could be reduced by being more efficient; far more boldly than I, he also thought that economic growth could be decoupled from energy growth, a truly radical idea at the time that was vigorously contested even after the 1973 crisis by many, including the President of the Mobil Oil Company. I recounted Dave’s story in the tribute I wrote for him when he passed away in 2020; I worked for him in the 1970s. Suffice it to say he was right. Energy growth and economic growth were decoupled between 1973 and 1985, when the Reagan Administration changed direction, aided by plummeting oil prices.
Back then, the practical toolbox was small. Solar was extremely costly; wind was costly as well, though not as much. Efficiency was the main, huge opportunity, but that did not answer the remaining supply question. Fortunately, we are in a position to reject what Alvin Weinberg, the first scientific director of Oak Ridge National Laboratory, called the “Faustian bargain”: accept nuclear energy (a “magical energy source”) and trust the nuclear establishment to take care of the waste and the plutonium essentially forever.
Today electricity from utility-scale solar and wind is several times cheaper than new nuclear power plants. Batteries for supporting some (though not all) of the gaps in wind and solar supply are already coming into use on a large scale and getting cheaper (in contrast to nuclear, which has become more expensive over time in the United States and France, the poster-country for nuclear). Communications and electronics technologies are extremely advanced; a smart grid is now possible and economically desirable.
Can solar and wind be the mainstays of reliable primary energy supply with available technologies? Will the electricity be affordable? What about equity? What about the good jobs at the coal and nuclear plants?
My colleagues and I posed all these questions in a multi-year study centered on Maryland, funded entirely by the Town Creek Foundation. The Renewable Maryland Project published many reports, assessments, and evaluations addressing all these issues and more. The technical core was hour-by-hour modeling of the electricity sector with actual demand data and site-specific solar and wind data; we included the electrification of space heating and transportation. We assumed that Maryland’s two-reactor nuclear plant, Calvert Cliffs, would close at its license expiry in the mid-2030s. We included a small amount of existing hydro (about two percent). That’s it. The conclusion: such a system would be more resilient and affordable than business as usual even though focusing on a single state rather than a multi-state grid made the system more expensive than it would be in reality. The details are in the final, 300-plus-page report, Prosperous, Renewable Maryland. Here is a brief description of the technical aspects.
Efficiency continues to be a mainstay. There are four other major elements:
- The first, a seasonal balance of solar and wind, which also gives some electricity at night.
- A modest amount of battery storage, designed to fill mainly short-term gaps (about five-and-a-half hours of annual average hourly load).
- A smart-grid “demand response” system in which customers sign up to shift loads like water heating and clothes washing within the day and get paid for it (since, among other things, it greatly reduces the need for storage capacity).
- Making hydrogen from surplus wind and solar that would otherwise be curtailed at the industrial site of use by splitting water, H2O into hydrogen and oxygen; that way the electricity, the largest single cost of making electrolytic hydrogen, is essentially free; there is a cost – a low capacity factor for the electrolyzer. The water can be recovered when the electricity is generated using the hydrogen in a light-duty fuel cell for peaking power supply.
How do the lights stay on 24/7/365?
- For two-thirds of the hours in the year, the load is fully met without the use of storage, etc. Solar and wind balance is a key element here.
- The battery extends that to about 96 percent of the hours of the year.
- Demand response then takes over. Imagine turning on your clothes washing machine. Renewable supply is low at the time. You push the “Start” button; the machine does not turn on at once but a few hours later when renewable supply is better; it is guaranteed to run within 24 hours of your pushing “Start.” You get paid a high price for delaying the wash. You also get paid to sign up in case the grid needs that service. You have an override switch if you really need it but there will be a cost to use it. A smart grid and smart appliances would enable all that automatically. (You don’t have to sign up; not everyone will.) This is where the smart grid brings economic opportunity – it can lower electricity bills. In fact, some colleagues and I, in analyzing how to link energy affordability to the renewable energy future, have recommended that smart grid access (including broadband access) should be among the priorities for low-income households because it would enable them to reduce their bills.
- The remaining load is met by renewable hydrogen produced on the site of peaking plants and used fuel cells to make electricity when needed.
Electric vehicles can also be used in creative ways not included the model described above. Technology for two-way electricity flow to and from the vehicle – called vehicle-to-grid (V2G – video) – already exists; school bus systems are using it. Most vehicles are idle over 90 percent of the time. For example, long-term parking lots can serve as peaking power supply. The total horsepower of light duty vehicles alone outstrips the total installed electrical generation capacity in the United States by roughly 30 times. Long-term parking capacity at a single large airport, like Thurgood Marshall Baltimore-Washington International Airport, full of EVs can provide as much power as a nuclear power plant for peaking, which is what is at issue. You would get paid to park your electric vehicle if you leave it to the grid operator to manage for a few days, with a guarantee of a minimum pre-specified charge on your return.
All this is more than enough to guarantee a resilient, renewable, and economical grid. The main reason other models don’t come to the same conclusion that I did is that they are trying to fit radically new sources of supply, which vary with Nature’s rhythms, into the mold of today’s electricity system. They postulate that a giant battery system would be needed for a 100 percent decarbonized system with solar and wind. This was, for example, assumed in the study referenced by the Nuclear Energy Institute. The model did not consider demand response at all; it did not consider vehicle-to-grid technology; it did not consider making hydrogen with essentially free solar and wind energy that would be otherwise curtailed. Then it concluded that nuclear energy would be better and cheaper. It’s easy to win a battle against a straw man.
We have the technology for the storage, electric vehicles, and machines in homes and businesses to create a smart grid to complement Nature’s solar and wind rhythms. Demand response is now such a mainstream concept that the Federal Energy Regulatory Commission issued a rule in 2020 allowing it to be treated on a par with dispatching power from a coal or nuclear power plant. It’s also much faster and more flexible and can put money in consumers’ pockets instead of draining them, which nuclear plants would do.
The notion that the choice to fill the gaps in solar and wind supply is between fossil and nuclear is based on models that incorporate ossified thinking. The idea of a baseload power plant is, or should be, obsolete in an age of low cost solar and wind energy. I am not alone in thinking that. For example, David Olsen, a member of the Board of Governors of the California Independent System Operator, which runs the electricity grid in that state, pointing to the inflexibility of nuclear power, said: “’Baseload’ refers to an old paradigm that has to go away.”
Trying to decarbonize with nuclear power and solar and wind all being significant parts of the system will make for an inequitable, polluting, costly, and insecure decarbonization. Because of the delays and cost overruns that routinely plague nuclear and the (infrequent) accidents that disrupt it, the approach is also likely to miss the urgent timetable for a 100 percent decarbonized electricity sector (2040 at the latest in my reading of what is needed in wealthy countries). Creating a reliable system with solar and wind as the primary supply sources is feasible, desirable and economical; it is also a necessary element for achieving the globally agreed goal of keeping global average temperature rise to a maximum of 1.5 degrees Celsius (2.7 degrees F).
Opening Photo Credit: by Ely Valdez first appeared in csmonitor.com