A recent UKH Opinion piece dealing with the ecological cost of the forthcoming Glen Etive micro hydro, and micro hydro in general, includes this statement: ‘[we can] produce large amounts of truly “clean and green” energy ... through solar, offshore ... and tidal energy solutions’. I have come across permutations of this argument before, and it strikes me that our assessment of the environmental cost of renewables, and our understanding of renewables in general, is somewhat simplistic, glossing over what it is renewables actually do.
Power plants, like the rest of our world, are subject to the law of conservation of energy. They don’t make energy, they convert energy from one form into another, so that it could be transported and released elsewhere. Renewables differ in one important respect: their source energy is being extracted directly from the ecosystems of their installation. In other words, renewables are principally mining operations of a resource that is an intrinsic part of active ecological processes; the fact that we cannot see the thing being mined by the naked eye doesn’t make it any less so.
Thus, renewables have a built-in ecological cost, for it is not possible to extract a significant amounts of energy from an ecosystem without affecting a material change in it -- there are no ‘truly clean and green’ renewables. This is something that is not talked about, I suspect not least because the renewables industry is more about the source energy being ‘free’ than ‘clean’. Yet, we cannot afford to assume this to be inconsequential.
The scale of the problem is easier to grasp when viewed from the other end of the transaction, so let’s talk wind. A typical wind turbine today is rated a bit over 2MW, so a large farm of 150 turbines, such as the Clyde Wind Farm alongside the M74, generates around 350MW. We know that when the 300,000 homes this represents consume this energy, it radically alters the ecosystem around them, changing ambient temperature, humidity, light and noise levels, etc. It is unreasonable to expect that the ecosystems from which this energy was extracted to start with will not experience a transformation of a comparable magnitude.
Sticking with wind, it’s been known for some time that wind farms create their own micro-climates, with one of the easily measurable effects being an increase in temperature at ground level. A study by Harvard researchers Miller and Keith published last year concluded that if all US power generation was switched to wind, this would lead to an overall continental US temperature increase of 0.24C.
The above study has been misrepresented by the popular press as ‘wind turbines cause global warming’, which is, obviously, not what it says; what it does show is that renewables have their own, significant, ecological impact. As Keith summarised it,
If your perspective is the next 10 years, wind power actually has—in some respects—more climate impact than coal or gas, if your perspective is the next thousand years, then wind power is enormously cleaner than coal or gas.
The problem is that the 1,000 year perspective currently focuses strictly on combating (the easily commercialised) effects of warming, while glossing over more subtle questions of ecological integrity. This needs to change.
There is an additional issue with renewables. Since no engineering processes is, or can be, 100% efficient, not all of the source energy extracted is converted to electricity. Some of it leaks back into the ecosystem in other forms. The classic example of this is noise. We know that people living in proximity to wind turbine installations report health issues, but the effect is far wider. We are aware of major effect on birds, bats, and, moving off shore, marine mammals; and, of course, these ecosystems are home to myriad of other tightly interconnected species.
This is not meant to be a diatribe against renewables. Given that the public opinion is firmly against nuclear energy, renewables are all we have in combating Climate Change, for Climate Change does change everything, if we don’t get it under control, nothing else is of consequence. Nor is this a diatribe against wind power; I have used wind as a convenient example, these problems are I believe intrinsic to the whole class of renewable energy, and I expect we will be hearing increasingly more on this subject in the future.
What I want to do here is simply to draw an attention to the fact that all renewables come with intrinsic ecological costs that go beyond the obvious and visible things like loss of habitat. I draw two conclusions from these observations:
The single most important thing in addressing Climate Change is not switching to renewables but a radical cut to our energy consumption. Renewables might allow us to keep the planet cooler, but they do not necessarily preserve its ecosystems.
I find the ‘renewable X bad, renewable Y good’ line of reasoning a form of NIMBY-ism, missing the big picture. We can’t afford to exclude any form of renewables en masse, because when it comes to renewables too much of any one thing is going to be bad news for something somewhere. And in Scotland our renewables portfolio is too heavily weighted toward wind, it needs to be more balanced.