Wind turbines: are they sustainable?

  • Evidence that some wind turbines receive up to 39 times as much energy back than is put in
  • Coal fired power stations produce up to 100 times the life-time greenhouse gas production of wind turbines
  • Benefits of turbines depend on careful research and planning

29 December 2014

By Bill Butterworth

photo (3)

There is something comfortable about windmills. However, not everyone feels so good about wind turbines. In this blog, I really do like to question commonly held views. I like to question my own, too.

Are you in the “wind turbines are green” camp or just think they are a bit of a silly fashion because they will never pay back the energy put in? Would you have one on your property if they make money? Do you think that the politicians are wrong to spend so much taxpayers’ money subsidising them? Do we really know if wind turbines are genuinely “sustainable” and does it matter anyway?

It is commonly said that one should never believe anything until a government minister has denied it. Probably the converse is true in this case; as government wants us to believe that wind turbines are “green”, environmentally friendly and “sustainable, they probably aren’t. So what really is the truth?

Craig and Neal Birch farm at Sproxton, near Melton Mowbray in Leicestershire. The brothers joined Land Network, the farmer-owned group, nearly a decade ago with the objective of reducing mineral fertiliser use by recycling urban wastes; thus saving indirect energy inputs in their farming. Their long term strategy is to change energy inputs and move into 21st century technology then move attention to direct energy production. They decided to put a wind turbine in a couple of years ago and did their homework carefully, including a year of wind recording on the proposed site. Their operation is computerised, so Craig can sit in the farm office and monitor exactly what is happening up the mast. While I phoned him about this article, he switched over to the turbine monitor on his computer and observed that in the last hour the turbine had produced 37kWhrs and earned £10. Their best day was 1700 kWh (£459) and the worst was nil, of course. When queried about whether the facility was producing as expected, he observed that the manufacturer (Opus Energy) and the installer (Aeloar) had given a prediction which had actually, in practice, been consistently exceeded by between 10 and 20 %. The payback has allowed the Birches to buy some more land and they are likely to put in another wind turbine – but larger.

There is a lot of research on this subject. Some of it looks biased in that what it does not say is significant. There is, however, one bit of research which looks good and trustable. The University of Wisconsin, USA, which looked at the available research and calculated the “Energy Payback Ratio” of a wide range of turbines in the published research reports as being between 17 and 39, which means that the minimum payback is 17 times the energy cost of the set up, maintenance and operation of turbine installation and, at best, output was 39 times inputs. That sounds pretty conclusive – but was it? Well, the University researchers looked at research from several countries across the world and calculated the total inputs using the following equation;

Energy Payback Ratio = Energy produced in the turbine’s full operational life
Total energy invested in manufacture of materials used in lifetime
+ construction of whole installation
+ operation of the facility in its lifetime
+ decommissioning

All of that sounds thorough and definitely in favour of the turbines. By the way, that research was for on-land turbines. The energy cost of set up for turbines out at sea is at least 3 times that of land and the risk of catastrophic failure risk is very much higher.

The other part of “sustainable” is whether there is a gain in Carbon dioxide from the production of energy to manufacture and to install? Again, it depends on what the comparison is. That same research from Wisconsin concluded that a wind turbine does, for all those factors listed in the equation above, produce some greenhouse gases; principally Carbon dioxide. However, averaged over its life, it really is quite small and a coal-fired power station would produce 50 to 100 times as much per unit of energy. This, then, becomes fairly believable. However, does this mean that we can put these facilities anywhere and it will produce these sorts of payback? The answer is most certainly not. If a facility is placed where there is little or no wind, where there is turbulence in the lea of a sheltered area, and/or not maintained and operated properly, then the figures will change downwards and may become negative. The only thing that is common to failures is poor maintenance. However, there are many other causes of failure and a common one is lightning strike.

Success with wind turbines, as anywhere and everywhere in business, depends on professional management. Initially, it is formulating an outline plan where an economic connection to the national grid is critical. Doing wind monitoring at a range of heights for 12 months is likely to appear a bore but very likely to allow the design of a better business. Part of that initial homework is consultation with the local planning authority and with neighbours. It is a good idea to talk to your accountant, too, and look at tax planning. When it comes to design of the equipment and the detail of installation, relevant technology (not all turbines are the same) and commitment to a professional maintenance programme are both part of delivering profit.

That phrase “delivering profit” raises the question and why anyone might do this. There is little doubt that some wind turbines really are good for the environment compared with burning fossilised fuels. However, it is equally true that a smaller percentage are not so good and a minor percentage are a disaster. This is not a game for amateurs. You might find it instructive to put into your search engine; “wind turbines lubrication fires”. To balanced view, if motor cars were invented now, the EU regulators would stifle them at birth; they are dangerous. Wind turbines, like so many other things, are potentially dangerous but that does not mean all are under all circumstances. Read the safety research and check the small print in your insurance policy very carefully.

It may be sensible to put good environmental intent on one side and look at the other reasons for developing wind power. First, will it make money sounds a reasonable enough business question. There is also a longer term issue; might we need our own sources of power, to isolate ourselves from imports if need be? This applies at national level, at local level and for the individual. A strategic view of self-reliance is sometimes a good investment.