The subtle but important way energy reporters misinform readers when reporting on wind and solar projects
How many energy reporters does it take to change a light bulb?
When trying to illustrate for readers how much electricity a certain wind or solar project will produce, energy reporters love to use the “will power x number of homes” metric. This metric, while simple and concise, is completely and totally misleading, and it’s furthered energy illiteracy.
A St. Louis NPR affiliate reported Tuesday on a small solar project in East St. Louis:
The more than 3,000-panel facility, located on the north side of town near the Gordon Bush School, will produce nearly 1.4 megawatts of power that can energize 650 homes in the region, according to the company.
CBS News affiliate WCCO in Minnesota reported on a ribbon-cutting event Tuesday for a solar project, which Minnesota Governor and former vice-presidential candidate Tim Walz attended:
In the completion of phase one, there are about 500,000 solar panels at Sherco Solar. By 2026, the number is expected to triple to 1.5 million across 5 acres of land, which will be enough to power 150,000 homes across the Upper Midwest.
The article included this rather amusing sentence, which somehow didn’t give the reporter pause to claim that the project would effectively power homes:
The sun was hard to find, but its power was still harnessed in Clear Lake.
The dedication to the ideology of green energy would be impressive were it not so delusional.
These are just a couple examples from this week, but a Google search will turn up a dozen such claims every month. It is a very common practice to characterize electricity produced by intermittent wind and solar projects by taking the nameplate capacity of the project in watts and dividing it by some average electricity consumption rate of the average home over an unspecified amount of time.
As many of you know, this is completely and totally false. In terms of the scale and inaccuracy of this practice, it is perhaps second only to the claim that wind and solar are the cheapest form of energy.
The total number of homes that can be powered by any wind or solar project regardless of its size is 0.0. It doesn’t matter if the project’s capacity is 2 gigawatts or 1 megawatt, it is always precisely zero.
Well, I shouldn’t say that. It is possible that there are households out there in the developed world that are connected to the grid and will happily shut off their refrigerators when the wind stops blowing. Perhaps there are homes where the residents are happy to sit in a dark house on a hot summer evening and read by candlelight as sweat drips down their face. I don’t know of any such people, but if they do indeed exist, they are exceedingly rare.
Since most readers, as well as many reporters covering the development of wind and solar projects, don’t know what a watt is, it’s important to try to illustrate what it means that an offshore wind project, for example, will produce 2 gigawatts of power when it’s operational and all the whale carcasses have been removed from the beaches.
To be fair, it’s not an easy to explain how much power that is in any clear, concise format. Such is the state of energy reporting today, however, many energy reporters will just parrot the number of homes homes to be powered by these projects – numbers that usually come from government officials or the project developers – without ever scrutinizing them.
As someone who won’t regurgitate information, I’ve tried to find a more accurate means of illustrating megawatts and gigawatts of nameplate capacity without long paragraphs explaining nameplate capacity, watts and watt hours. To get an idea of the challenge, let’s have a look at the math. Say you have a solar project whose nameplate capacity is 100 megawatts, meaning that with a happy sun lighting the panels, the solar farm will produce 100 megawatts of electricity.
According to the U.S. Energy Information Administration, the average U.S. home consumes 899,000 watt hours per month. Using an average per month for the nation is problematic, because the average varies greatly by region. A home in Hawaii averages 6.4 megawatt hours per year, and a home in Louisiana averages 14.4 megawatt hours per year. I’m not sure why Louisianians use so much power, but apparently, they do.
You could use a regional average rate of residential electricity consumption to explain how many homes are powered by a 100 megawatt solar farm to address that issue, but since this solar farm is hypothetical, I’ll use the U.S. average. So you take 100 million watts and divide it by 10.8 megawatt hours, and you get 9.3 households. Right?
Wrong. You’re using two different measurements – watts and watt hours. A 100 megawatt solar farm will produce 100 megawatt hours with one hour of good sunshine.
So, let’s try using the same factors. So, how many megawatt hours per year does the 100 megawatt solar farm produce? Well, it’s not 100 megawatts times 8,760 (24X365) hours, because of course that pesky sun goes down every night. Also, so many things solar panels would have done, but clouds got in their way.
A solar farm typically operates about 20%-25% of the time. So, why not take 22.5% and multiply it by 8,760 hours? That gives you 1,971 hours. So, you then multiply 1,971 hours by 100 million watts, to come to 197.1 gigawatt hours per year. Now, divide that number by 10.8 megawatt hours the average American home consumes, and you get 18,250 homes.
Sounds pretty good, right? Well, not really. You’re still assuming all these homes will just stop using electricity when there’s no sunshine. So, to say, 18,250 homes will be powered by a 100 megawatt solar farm is still highly misleading.
One way I’ve attempted to use the “homes powered by” metric is to say that the wind or solar farm will power x number of homes when the wind is blowing or the sun is shining. But that’s still misleading. Homes use different amounts of electricity at different times of day. Most homes consume the most electricity between 5 p.m and 8 p.m. That happens to correspond with that pesky sunset thing that happens every 24 hours. Surface winds typically are highest at night, when the energy demand is at its lowest.
To provide a truly accurate illustration of what a megawatt or gigawatt of wind and solar energy is, the method I use is to use the Killough-watt Method ®, which illustrates the electricity-generation potential of a wind or solar project with x number of light bulbs powered per hour of sunlight or wind. So, a 100 megawatt solar farm will power 1 million 100-watt light bulbs for one hour when the sun is shining for one hour. A 1 gigawatt offshore wind farm will power 100 million 100-watt light bulbs for one hour and kill 1.3 whales when the wind is blowing is blowing for one hour.
By telling readers that a certain number of homes will be powered by a wind or solar project, energy reporters are obscuring the biggest problem with wind and solar energy — they’re intermittent. Homes, businesses and industries need 24/7 power, without exception. This misleading metric furthers the “100% wind and solar energy is possible” myth. My method may not be a vivid as the “x number of homes” method, but it’s at least accurate.
If you have any suggestions of a better way to concisely illustrate a wind or solar project’s nameplate capacity figures, please leave them in the comments.
First-hand experience: our solar installation has a monitoring thingy that tells us how much electricity we've used from it and the grid. Over the past month (low-sun November) it's 25% from solar 75% from the grid. To me, that's as clear as it gets, even if at certain hours of the sunny days we get 100% powered by the panels. It can only ever be a supplementary source of energy.
Arguably, you could simply divide the number by 2 since you always need the equal amount of on-demand power when solar or wind aren't producing. so, at most, that 100 MW solar farm, which has a 22,5% efficiency really only has half as much on a cost basis since it costs again to have the natgas plant to be there when the sun sets.