Thanks to William, who referenced the cave in his recent comment, here, discussion of the practicalities of so-called ‘small wind’ has continued since my original post on November 22nd.

There are two matters to address here. First of all, William’s observations on the government’s latest pronouncement on offshore wind, and the claim that wind power could generate all of the UK’s domestic energy by 2020. He’s right; it is extremely unlikely. You should also be aware that the claimed ‘expansion’ failed to mention that there are several hundred existing applications for planning permission for wind farms already in the pipeline (see the BWEA’s website for details). The delay in getting them going is almost entirely in the planning and public consultation process, which has to date caused about a two-year backlog in the works.

As per usual, then, there is less substance in this proclamation than there first appears. The rapid expansion of wind is already under way, and is being hampered most of all by inefficient processes related to local governance, rather than economics.

I’m not about to advocate that these should be ‘rubber-stamped’; I’m a firm believer in due process and stakeholder involvement, but there are already several well-coordinated and highly vocal ‘anti-wind-farm’ pressure groups, who work together to obstruct the process and restrict development.

Strangely, there are interesting parallels between the ‘climate change debate’ of the past twenty years and the ongoing ‘wind debate’ in local cases in the UK: those who wish to prevent development of wind farms spread well-worn disinformation, dubious attacks on the technology and or the economics, and work in a coordinated and organised manner which makes a very small minority voice punch well above its weight in the relevant decision-making processes.

The Syngellakis report I have previously mentioned, (as well as another paper whose name escapes me), suggest that the cost-per-energy-unit of both onshore and offshore wind-produced energy in the UK by 2020 should be down to around 2.2-2.4 pence per kWh. If this is correct, the government would have to be completely bonkers not to invest heavily in large-scale wind energy facilities. Add to this that, as an industry, wind energy is now reasonably mature (over 25 years of consistent development), and enough experience has been gained for both the engineering and the economics to be quite well understood. The same cannot be said for Solar PV, which is still, to some extent, a developing technology and which, as things currently stand, produces energy at a considerably higher cost than comparably-priced wind facilities. Geothermal is great, but hugely expensive. Those newfangled bio-boiler thingies are good, but work best on a fairly large scale, and are impractical for most medium to small energy users.

Where rapid expansion can be enhanced at little extra cost to government, and involving the public and business on a personal level, is in the ‘small wind’ and ‘medium wind’ sectors. William is correct in saying that small wind cannot produce energy at a cost comparable to large-scale installations, but this is to miss the point, somewhat, because small wind does not have to compete with the energy utilities’ production price, but with their retail price.

The economics can be simplified to a simple bit of arithmetic. At least two energy companies will currently agree a contract with small energy producers (domestic, agricultural and business installations of between 5kW and 50kW rated output), which credits the provider at the going rate for every unit produced which is consumed on-site, and rebates/refunds at 9 pence per kWh for every unit ‘sent back’ into the grid. This places a baseline value of 9p/kWh on energy produced by a small-wind system, or £90 per thousand kWh. If a small turbine generates 10000 kWh in a year (a not unreasonable assumption, wind permitting), it is ‘earning’ £900.

A good small turbine should last twenty years. There is one which has been running non-stop at Corrour Railway Station for the last fourteen, with only routine maintenance, so this life expectancy is reasonable.  Using the earlier example, a turbine will produce £18000-worth of energy at present values in 20 years. Therefore, if the installation costs £18000 or less, the installation will pay for itself over its lifetime. As a good turbine will ‘live’ another five years or more beyond the twenty, the installer will be in net gain after this time. If the price of energy increases faster than the underlying rate of inflation during this period, the payback time is shortened considerably.

At least two small turbine manufacturers use the very reasonable estimate of 0.42-0.43kg of CO2 saved per kWh of energy. For the 10000kWh example, this equates to around 4.3 Tonnes of CO2 per year, 86Tonnes in 20 years, with no economic penalty. That’s a real-world reduction of CO2, as the energy no longer has to be produced by fossil fuels. If only 1000 new ‘small’ turbines with this kind of (very modest) efficiency are installed in the UK each year for the next ten years, that would amount to a total of around 43000T.

In 2006, the AWEA Global small wind energy survey reported the global installation of around 16,500  ‘small wind’ systems; 7,000 in the USA, and the rest spread around the world. The market increased by 34% on previous years. If small wind is to make a meaningful contribution to the CO2 problem, this number has to be increased by orders of magnitude. Even then, it will only be a contributor to the energy mix, not a major reducer.

Which brings me to ‘Medium Wind’. This is something you won’t have heard about, because I have just invented the term. In practical terms, this is probably the most useful way forward in wind energy production. By ‘Medium Wind’, I am referring to turbines which are considerably smaller than the utility-sized units found on large wind farms, but bigger than the standard ‘small wind’ product. These are the sort of things you see in the background as Jeremy Clarkson rumbles around Europe in the latest supercar on ‘Top Gear’. They have rated outputs greater than 50kW, but generally less than 500kW. The masts are 30-50 metres high, the props between 17-30 metres. They rotate at about 60 rpm. They are reasonable quiet, and a few thousand have been installed around the world over the past several years with no known environmental detriment.

This type of turbine produces anything from 100-1000 mW of power per year. Installation does not require the kind of heavy plant and machinery required by a large wind farm. Relatively large numbers can be produced in a relatively short time, as the designs are generally well-tested and efficient. They can be placed in brownfield sites, or in fields (which can still be used for crops or grazing), or along the sides of roads. They are much less intrusive visually than large wind farms (though, TBH, I don’t have a problem with these, either). Finally, they can be ‘processed’ through the planning system much more rapidly, in around 12 months, typically.  At the energy costs used previously (9p per kWh), they generate a return of between 7-15% per annum, pay for themselves in 4-12 years, and reduce CO2 by tens-hundreds of tonnes per installation, per year.

10,000 small wind systems will make a small but useful contribution to emissions reductions in the coming years. A similar number of ‘medium wind’ systems would reduce emissions by megatonnes per year.

Later, I’ll post about the pros and cons of existing small wind systems, based on the research I have done over the past few months (sorry, Adam, you’ll have to wait).