The Sixth Form Purvis Society was delighted to welcome Mr Ben Stafford to talk about alternative sources of energy, mostIMAG2150 especially, wind. With a background in physics and now working with a firm of investors, Mr Stafford was well placed to deliver a well-argued presentation in favour of wind turbines and their likely impact on the energy supply to this country over the next few years. “Why do we care about energy?” he began. “Because, in the UK, we don’t have to.” Citing Nigeria as an example, he pointed out that, whilst there is plenty of fuel, there is also a major lack of infrastructure in that country so this energy cannot effectively and reliably be delivered to the consumers. In the UK we are blessed with a security of supply and a predictability of demand (millions turn on their kettles when “EastEnders” finishes, for example) so we are equipped to cope.

It was about 15 years ago that security of supply came under the microscope and three alternative sources of energy were identified as being realistic propositions: hydro-electric, solar and wind. Fossil fuels were increasingly being condemned as dirty and not terribly economic so renewable sources of energy gradually became responsible for 17.8% of power deliveredIMAG2155 to the grid (statistic for 2014). The target is 20% by 2020. There had been significant problems and, in the early days, the smaller turbines simply didn’t work and, as one could not predict the wind, their performance was sporadic to say the least. Since then the technology has advanced and one is now looking at turbines whose blades are the size of football pitches (a rotating diameter in excess of 125m) and larger ones are in development; costing as much as £10M each! Of course no one really wants these things in their back yard, and the wind is still intermittent (but our ability to forecast is steadily improving), and they are space-expensive as well, so off-shore is an obvious alternative as we have virtually run out of space to build them on land. We now have the biggest off-shore wind-farm in Europe and it is off-shore wind that provides one of the cheapest sources of power there is. Government tariffs have helped (although the nuclear industry gets a lot more) and although the engineering is proving challenging, and installation and maintenance are especially difficult, these enormous structures may well last for at least 25 years, having possibly paid for themselves in six.

The discussion shifted away from what we have achieved to one of the major remaining problems: the intermittence of supply. There are ways of coping with this and one of the most obvious is that, ideally, consumers switch things off when they are not using them… Easier said than enforced (consider Central London in the dead of night, positively ablaze with lights). Diesel generators that join in when demand exceeds production seem to be an option, but these are hardly ideal and we already have a variety of sources so are not totally reliant, thankfully, on one technology. The main difficulty is therefore storage. It is proving incredibly difficult to store energy that is being produced during periods of low consumption. Pumping water back up the hill to be re-used to drive a turbine is one option but, as yet, battery technology does not exist.

Dr Christopher Mann