These days there is a recurring refrain from the greens to the effect that renewable power is cheaper than coal power. This is a half truth at best and the false half is the worst part.
There may well be circumstances where the unit cost of power produced by a wind or solar generator is in fact lower than the unit cost from a coal fired power plant. But the extensive intermittency of renewable power makes this cost saving irrelevant, because the cost to overcome the intermittency is astronomical.
What we are seeing is an endless stream of studies that ignore this fundamental fact, that intermittency makes renewables very expensive when it comes to providing reliable power. The latest such study is “THE COAL COST CROSSOVER: ECONOMIC VIABILITY OF EXISTING COAL COMPARED TO NEW LOCAL WIND AND SOLAR RESOURCES” (all caps in original) from Energy Innovation and Vibrant Clean Energy.
This study is impressive in its way, because it takes a fine chained look at the whole country. In this respect it has a good bit of useful information. But its basic claim that renewable power is now cheaper than coal fired power is so misleading that it is wrong.
The study is largely based on a comparison of independent power contracts, especially for renewables. But these contracts do not provide reliable power, quite the contrary. They just provide wind and solar power when it happens to be available, in many cases even if it is not needed at the time.
When it comes to wind and solar power the facts are starkly simple. A typical wind farm produces little or no power about 25% of the time. It produces full power less than half of the time and those times are unpredictable.
Even worse, the meteorological conditions that create peak need for electricity are often long periods of low to no wind. These are stagnant high pressure systems that cause maximum hot and cold weather.
Fixed array solar power generators only produce good power around four hours a day, while moveable arrays might generate for eight hours, both centered on noon or so. Peak daily power usage is typically before or after this period. In cold weather the peak can even be at night.
What all of this means is that some other way of producing power is required, for most of the day, or even for several days. This is the intermittency problem and it is profound. The fact that when solar and wind power are available, it is relatively cheap, does not address this profound problem. Making intermittent power reliable is a big part of the high cost of wind and solar.
Of course the Energy Innovation and Vibrant Clean Energy people know about this profound problem but they slide right by it. Here is their studiously vague acknowledgement:
“Other resources will be required to complement wind and solar and provide essential reliability services, but the increasingly attractive relative value proposition for the raw energy available from wind and solar versus more expensive coal generation can generate more and more money to directly address grid challenges. Steep declines in costs for resources like battery storage will stretch that money even more.”
At today’s prices the cost of batteries to provide reliable wind and solar power would be well into the trillions of dollars. The fact that wind or solar power, when available, is a bit cheaper than reliable coal fired power in no way makes battery backup affordable.
Thus this study is misleading at best. They then go on to make this totally false claim:
“The data in this report provide an economic rationale for a coal phase-out in the next decade led by wind and solar, happening a lot quicker than most had imagined. It’s time to get on with the coal-to-clean transition.”
It is economically impossible to phase out coal using wind and solar power.