The CEO of a former employer once asked me whether I thought it possible for the United States to operate its electric grid solely on renewables. The question startled me. Was it meant in jest? No, I was assured, it was a serious question. I respected the CEO both as an engineer and a business person. It was difficult for me to believe that he was seriously in doubt of the answer from either perspective.
Certainly, one can theoretically operate the electric grid on renewables, just as one can theoretically operate the grid using generators powered by stationary bicycles. The real question isn’t whether we can do it; it’s whether we can afford it.
Like many others who work in and around the energy sector, I very much doubt it.
Some of the moving parts of renewables messaging are lubricated with liberal doses of snake oil. One of the most popular is for a company or organization to claim that it’s operating this building or that facility on 100 percent renewable energy. Pay attention, green energy advocates will say, you might learn something. If they can do it, we all can do it! And it won’t cost a penny more.
However, the claim of operating on 100 percent renewable energy is almost never true. It relies on a bit of verbal sleight of hand that’s only possible because most people don’t understand how our electric distribution grid actually works. Actually, an electrical engineer working for one of the big independent system operators that manage distribution once told me that nobody running things really understands how the grid works, only how their bit is supposed to behave. He appeared to be only half joking.
In any case, consider when a new store or distribution center opens and the owner happily announces that his or her organization is doing its part to fight climate change because this place is powered by 100 percent renewable energy. Mainstream media outlets, whose grasp of power distribution rarely extends beyond knowing that sticking one’s finger in a live electrical socket isn’t a smart idea, dutifully parrot the 100 percent renewable claim, not knowing or caring what it means.
In any electrical power distribution system, power isn’t pushed out from the generator but is pulled through the system by the electrical demand. Turn on your blow dryer, and the grid pulls a little harder, causing a generator to work a bit harder in proportion to meet the demand. But in a grid full of hundreds of generators, where does the electricity you use actually come from? Except for some exceptional circumstances, the answer to that question is the generator located nearest to the source of demand.
Think of electricity in a wire like water flowing downhill in a channel. If a hole appears in a part of the channel, the water will flow down into the hole until such time as the hole fills up and remaining water can carry on down the channel. In the same way, if the nearest generator is a coal plant 30 miles away, then the actual electricity you use comes from that coal plant, not from a wind farm located 300 miles away with whom you have signed a contract.
When you purchase green electricity, you’re not buying actual electricity. You pay for maintenance and upkeep associated with a particular generation asset on the grid that you may like, but that doesn’t mean that you’re getting any significant portion of electricity generated at the wind farm with whom you contracted. You’re paying for capacity to generate energy, not the energy itself.
In the broadest sense, there are two types of generation involved in maintaining an electrical grid. There are base load assets and there are peak load assets. Base load refers to that part of demand that’s more or less constant regardless of the time of day. Peak load refers to relatively short stretches of time when demand exceeds base load. Summer days, for example, typically generate a great deal of peak load demand.
Traditionally, base load power has been provided by nuclear plants and coal-fired plants. Today, more and more base load generation is fueled by natural gas, which is less objectionable to most environmental activists than nukes or coal. Peak load power, on the other hand, comes mostly from natural gas-fired assets and to a lesser extent diesel-fired assets. Peak load power has to be available in a very short period of time, something a modern gas turbine can do but renewables can’t.
Wind and solar don’t provide a good fit to meet either base load or peak load demand. Neither is reliable enough to provide consistent base load power without hugely over-constructing capacity. Neither wind nor solar can provide the quick start capacity needed to meet peak load demand.
The windmill is either turning or it’s not, depending on weather conditions. A solar panel is either collecting photons or it’s not, depending on the time of day and cloud cover. One could build a wind farm with the capacity to generate 100 megawatts, but there’s no way to guarantee it can generate 20 megawatts whenever it’s badly needed.
Fulfilling that job is easy for petroleum-fired turbines and internal combustion engines. Most peaking plants using this technology will be on the grid meeting demand within 20 or so minutes of getting the dispatch call.
Wind and solar could never do that, so how does the renewable fantasy deal with this obvious flaw? Mostly by making batteries. Lots and lots and lots of batteries. Batteries with massive capacities and unrivaled efficiencies, which, for the most part, haven’t been invented yet, if they ever will.
Theoretically, enough battery storage could make up for wind and solar’s inherent unreliability. That would allow them to provide base load capacity without shutting down the grid every time the wind died down. Even more batteries with more power would be needed to fulfill peak load duty. People have done calculations on how much battery storage a renewables-only grid would require. The numbers and the cost, as you might imagine, are astronomical.
One can’t wish one’s way into an environmentally pristine power generation system, although some in blue states appear more than willing to do so. They don’t understand the problem outlined by “Star Trek’s” Commander Montgomery Scott to Captain Kirk on more than one occasion: You cannae change the laws of physics.
