Renewables: Plug & Pray?

Photo by American Public Power Association on Unsplash

We are made to believe by PR articles and mainstream media pundits that “renewables” are just plug and play. Like computer screens. That all we need to do is to shut down old fossil fuel power plants and replace them with wind and solar. We are constantly bombarded with simplistic statements like “renewables are now cheaper than fossil fuel power plants”, as if such a simple one to one comparison could be made. All this hand waving, however, completely disregards the fact that the real life utilization of solar panels and wind mills are much lower than their nameplate suggests, and that they are a whole lot less useful in maintaining a stable grid than their polluting predecessors. It’s clearly not a plug&play game… Much rather, as it is played today, it’s all plug&pray.

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There is a saying in contemporary German company culture: ‘Zahlen-Fakten-Daten’ — literally meaning: numbers, facts and data. It’s usually uttered during management reviews when someone makes a bold statement or starts to wax lyrical about an idea. It is meant to channel energies back to the task at hand and to request the necessary data to make a sound decision. So let’s see if statements pertaining the relative cheapness and usefulness of “renewables” really stand this test.

The latest report from the Energy Institute titled Statistical Review of World Energy (previously compiled by BP) provides us with just that: a ton of numbers and some rather inconvenient facts. Let’s start with the capacity factor: a ratio of actual electrical energy output over a given period of time to the theoretical maximum electrical energy output over that period. In case of a fossil fuel or nuclear power plant this factor is limited by actual demand and availability. Let’s say your plant provides electricity 24/7 at maximum output for 90 days, but then it is down for maintenance for 10 days. In this case your capacity factor equals your availability of 90%. For gas turbines this availability (and thus their maximum capacity) ranges between 80–99%, which is pretty good by any standard (with most other thermal power plants like nuclear or coal standing somewhere between 70 and 90%).

Renewables, on the other hand, increase / reduce their electricity output according to the weather and the time of day, and not according to demand or planned maintenance schedules. When it’s overcast outside, or when the wind doesn’t blow that hard, they provide much less electricity than their rated (nameplate) capacity. Hospitals, smelters, water treatment facilities or nuclear power plants, however — among many other things — cannot be left without electricity, just because it’s dark outside or the wind isn’t blowing. If we are to believe bold statements regarding the relative cheapness and usefulness of “renewables”, however, we need to treat them as if they were able to provide power 24/7, just like any other fossil fuel power plant they aim to replace. So, in order to see how many solar or wind farms are needed to replace a fossil fuel plant (presuming we have an ample storage of power) we need to take a good hard look on their actual capacity. Time for some Zahlen-Fakten-Daten.

Thanks to the wealth of data provided by the Statistical Review of World Energy, this calculation can be done a whole lot easier than it might seem at first sight. Let’s start with solar panels. By comparing “Renewable energy — Generation by source” (page 47) and “Renewable energy Solar — Installed photovoltaic (PV) power” (page 48) we can gain a candid insight into the real life capacity factor of photovoltaic panels. All we need to do is to divide the actual figures supplied by “renewables” with the total (purely theoretical) nameplate capacity of said technologies for a given year. After performing this calculation (1), the global capacity factor of solar generation turns out to be a mere 14.3%. Let that sink in.

Translated to a real life example, this means that when you buy a hundred kW worth of panels, what you actually get on an annual average is 14.3 kW, whereas if you bought a generator of a similar rated performance you would get 70 to 90 kW. Call that a difference. So, if we were to convert to photovoltaic electricity globally, we would need to install 7x their nameplate capacity in order to match annual power demand. The same ratio for Germany is even worse: 10.4%. This low performance mandates a 9.6x overcapacity to match fossil fuel inputs on an annual basis. The reason is simple: half of the time (during the night) you have a stranded asset. Then comes the “problem” of misalignment. In this regard solar panels are worse than broken clocks: they are “right” only once a day, the rest of the time they stand misaligned to the Sun, greatly reducing their effectiveness. Finally let’s not forget cloud cover — something so prominent in Germany — which just makes things even worse.

And this is just the beginning. We still have fossil fuels to compensate for the downtime, but what shall we do once they are gone? The usual answer is storage, which will be absolutely necessary to iron out intermittencies. But in order to fill that storage up during the day, you would definitely need some overcapacity; this is why you need to calculate with an average demand and supply over 365 days, 24 hours each. And not only that. Storage always comes with additional losses. Batteries, for example, can return 90% of the power needed to charge them at best, the rest being lost during AC-DC or DC-DC conversion, along the cables and in the battery cells themselves as waste heat. Pumped hydro fares similarly, with a round-trip efficiency of 80%. The much touted hydrogen-economy, however, plays in an entirely different ballpark, with a full conversion cycle efficiency of a shoddy 32%. Yes, this means that more than two thirds of your hard earned energy input goes into complete waste when you use it to generate hydrogen. Pumping water, splitting H2O molecules, compression, cooling, transportation and storage — not to mention converting H2 back into electricity — all take precious power to perform, and come with their associated losses. And before you ask: the energy required to perform these steps is bound by physics and chemistry, not something human ingenuity can alter. So if you’ve pinned your hopes on Hydrogen-storage, then you need to multiply the capacity of your power plants needed to cover your annual demand by as much as three, at least. In our example with solar, this means that instead of seven times their nameplate capacity you would need to plan with a 21 times larger theoretical maximum output than your actual annual energy demand. Something to ponder on.

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Here is a simple thought experiment to illustrate all this. Let’s say you need to provide electricity to a mid-size town with thousands of households, a few factories and some other businesses. With a large enough safety margin included, you calculate that your town needs to have an annual 100 GWh of electricity generation capacity. Using power plants with a 10 GWh annual theoretical maximum capacity each, you calculate that you would need 11 units of gas fired power plants (where 1 would always stand by to jump in, when one out of the other ten is down for maintenance).

In case of solar panels, however, you would need to have 78 units, calculating with their average 14.3% capacity factor and an additional 10% loss on battery storage. In a full fledged “hydrogen-economy” with its staggering 68% loss on conversion, though, you would need to have 219 solar farms, 10 GWh annual nameplate capacity each. Calculating with half of the electricity being used up immediately (without going into storage first), you would still need 144 solar farms to cover your annual demand.

Note that this is just a super dumbed-down example. It doesn’t calculate with a necessary base load and surge capacity or grid frequency stability, nor with any difference between summer and winter production / consumption, among many other things. This is just to illustrate how much more “renewable” capacity is needed to cover the same annualized demand currently served by fossil fuels and nuclear.

Real life is not that kind, however. Solar panels tend to lose 12–15% of their theoretical maximum output during their 25 year lifespan, not to mention batteries, inverters and converters, all of which is needed to be replaced at least once (or twice, if not more) during the same timespan. Besides all that, solar panels still need fossil fuels (natural gas, coal and diesel) for their continued production and replacement. Recycling is far from being solved, not to mention the problem of mineral depletion affecting not just solar, but ALL of our technologies.

Wind energy fares a little better with a 26.7% capacity factor, but making turbines and towers takes up even more resources and fossil fuels. Rare earth metals for the magnets, copper for the wiring, cement and steel for the tower and reinforced concrete base — not to mention the immense amounts of resin used in their blades — are all made with (or outright from) fossil fuels and by using finite minerals. Is it any wonder then, that the wind power industry is unable to break even as these input costs spiral out of control?

All in all it shouldn’t come as a surprise then, that CO2 emissions are just keep rising and rising — hitting a record high of 34.4 billion metric tons last year — “despite” an unprecedented increase in wind and solar output. Meanwhile fossil fuels still account for 82% of primary global energy consumption, just like half a century ago. It seems, as the saying goes:

the more things change, the more they stay the same…

This, of course, is not to say that we should keep burning fossil fuels then. These ancient stores of energy are also depleting fast (now requiring more than a barrel worth of energy to produce a barrel of fuel), not to mention their horrific effects on Earth’s climate and the entire biosphere. If you have hoped for a quick-fix “solution”, though, I’m afraid I have to disappoint you: there is none. This is not a problem with one. Energy and mineral depletion, together with climate change is a symptom of overshoot: us humans using more resources and releasing more pollution than what could be regenerated or assimilated. 

Since we seem to be unwilling (or rather, unable) to change course with regards to resources and the biosphere, we have to call this situation we are in a predicament with an outcome, not a problem with a solution.

Hoping that “renewables” will save the day, and will replace fossil fuels is simply an energy- and minerals-blind statement. Neither wind nor solar or hydrogen alleviates the core issue of overusing Earth’s resources — they just make it multiple times worse by expanding the mining of even more minerals and the burning of even more fossil fuels. Remember, you need to build out four to seven times the original fossil fuel generation capacity to start with, then multiply that number with additional losses from energy storage (not to mention all the mining and manufacturing needed to provide those storage solutions). And to top it all off, keep in mind that these technologies are incapable to reproduce themselves, and thus will be gone as soon as we no longer have access to cheap fossil fuels. Why bother then?

The best we can do at the moment is to accept our predicament as a fact of life, and stop pretending that we can turn things around by applying more technology. The sooner we realize that it was precisely that — the overuse of technology — which has brought us to where we are, the sooner we will start mitigating its innumerable side effects and stop trying to sustain the unsustainable. So instead of asking how we transition to renewables, we should ask how we provide basic civilizational services like shelter and fresh water in an era of dwindling resources and falling energy inputs. How do we grow food with less and less (then entirely without) fertilizers and pesticides made from finite minerals and natural gas…? How do we organize ourselves once mass consumption and manufacturing, together with long distance transport becomes a thing of the past…? Many things to ponder, yet we keep wasting our resources on attempting the impossible: trying to replace an inherently unsustainable system with an even less sustainable one… 

Then pray that it will work.

Until next time,

B

Notes

(1) Global generated power by solar in 2022 was 1,322.6 Terawatt-hours, while installed capacity stood at 1,053,115 Megawatts (or 1.053115 Terawatts). First we have to bring these two numbers to an equal basis by calculating the total annual capacity from installed capacity (365 days times 24 hours a day times installed capacity). Our aggregated installed generation capacity for 2022 was 365 x 24h x 1.053115 TW = 9225.3 Terawatt-hours. Calculating the capacity factor is trivial from here: 1,332.6 / 9,225.3 = 14.34%