Energy researcher and author Tom Blees exposes a dirty little secret behind wind and solar energy.
Dear Melina,
I’m glad things are going so well for you at college. I’m sure you’ll make Mom and me proud.
Unfortunately I have some sad news. Your little hamster Steve died last week. So little Peve is now all alone. She spends more time on her treadmill now that she doesn’t get exercise tussling about with Steve anymore. As I was watching her the other day I got to thinking that it might be a neat idea to tap all the energy she’s putting out, so I hooked a little generator to the treadmill and then spliced the output into our rooftop solar panel output line. Now when we’re feeding power into the grid and Peve happens to be on her treadmill, Peve’s power is running the neighbourhood. I just thought you’d like to know.
Much love,
Dad
This farcical letter is meant to illustrate my real pet peeve: the ridiculous claims about the output of renewable energy systems that are a staple of nearly every article on new solar and wind projects. Anyone who pays attention to this field has repeatedly read the phrase that such-and-such project is “enough to power XXX,000 homes” or, in more egregious cases, “X million homes.”
But rarely is any indication of the actual amount of electricity expected to be produced expressed in meaningful terms like kilowatt-hours. Usually all we get is a number of megawatts describing the system and the enthusiastic description of the number of homes it will supply with electricity. And this obscures the truth behind solar and wind projects.
In the interest of translating this into realistic measurements, it should be pointed out that the number of megawatts cited is virtually always its nameplate rating. This is the maximum amount of power that can be produced under optimal conditions. For a solar panel that’s going to be about high noon on a perfectly clear day. For a wind turbine it’ll be when the wind is blowing just below the speed at which the turbine would have to shut down to avoid damage due to high wind speeds.
As you may well imagine, these maximums are rarely achieved. For solar farms in good locations (like Arizona), you’ll only get about 19 to 23 percent of that maximum, because of course, the peak power is only produced for a very short time every day. For modern wind systems you might get about 30 percent in a good spot, though in some very good spots in California the effective capacity of slightly older turbines is only about 22 percent of the theoretical maximum. This is called the capacity factor. In contrast, nuclear power plants in the USA run at a capacity factor exceeding 90 percent.
So when you read about a 4,000MW solar project, right off the bat you should divide that number by four or five, or even more in a location farther from the equator and/or one that experiences lots of cloudy weather. For wind projects, you’re unlikely to go wrong dividing by three or four.
Now to the matter of the number of homes supplied by these projects. How much electricity does a typical home use? I’m going to use USA figures here, which is where I’ve seen the most articles making such claims. Based on US census figures the average American home requires about 40 MWh annually, or .040 GWh. Meanwhile, for every 100MW of solar/wind plant capacity running 24-7, you’re getting – in theory – generation of 876 GWh/year (24 hours x 365.25 days x 100MW), enough for 22,000 homes.
This, of course, assumes that it’s running at a 100 percent capacity factor, and as we’ve established, they can’t and don’t. So a 100MW solar farm will – in reality – only provide enough power for about 4,400 homes (20 percent of its maximum potential). Your mileage may vary depending on location, but that’s in the ballpark.
It is highly misleading to use nameplate capacity when citing any wind or solar project, then comparing that cost across different systems as if their capacity factors were the same. Wind or solar projects are often compared on a cost/MW basis with nuclear plants, for instance, despite the fact that a nuclear plant will not only provide the energy when it is needed, but will also provide three to five times more electricity per rated megawatt. Nor is the cost of the absolutely necessary backup power for wind and solar systems ever factored into the price, which would go a long way to exposing the true costs of such intermittent systems.
At energy conferences I’ve often elicited substantial ire from wind and solar proponents when I simply cite actual power production data from existing wind and solar installations, or the costs of the actual energy produced. If you go to almost any website describing such renewable energy projects you could bet that one of the figures you won’t find will be the number of megawatt-hours of energy the project produced last year.
Having read countless articles about renewable energy projects in the course of my research, I’ve found that most of them describing the number of homes that can be powered by wind and solar systems exaggerate by anywhere from about fourteen to twenty-five times. The numbers simply have no basis in fact. That’s the dirty little secret usually kept well hidden. The next time you see an article extolling the merits of a power project and you see its output expressed in the number of homes it will power, remember my pet Peve, the widowed hamster.
Tom Blees is a member of the international selection committee for the Global Energy Prize. He is the president of The Science Council for Global Initiatives and the author of Prescription for the Planet – The Painless Remedy For Our Energy & Environmental Crises.
He is also one of the panellists for Eco-Business’ interactive “ask the energy experts” event being held in partnership with the Global Energy Prize. To post your tough questions to Tom and the other panelists, click here.
About the Global Energy Prize
The Global Energy Prize was established in 2002 by a group of Russian scientists, with the support of major energy corporations. This international award is granted for outstanding scientific achievements in the field of energy which have proved of benefit to the entire human race. Since its inception, the award has been granted to 22 scientists from Great Britain, Iceland, Canada, Russia, the USA, Ukraine, France, Germany and Japan. Awarded annually, the prize fund amounts to 30 million roubles (approximately $1m USD) and is divided among the Laureates. The President of the Russian Federation participates in the awards ceremony held in St Petersburg each year, which is accompanied by a Laureates’ Week celebrating the work of the winning scientists.
About Tom Blees
Tom Blees is author of “Prescription for the Planet”, which explains how a trio of revolutionary technologies could springboard humanity to an era beyond energy scarcity, with a particular focus on properly regulated nuclear power provided by Integral Fast Reactors. He co-founded a charitable organisation to provide safe water supplies to villagers in Central America, and it was during the course of fundraising for this project that Mr Blees came across the technologies examined in his book.
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