Monday, 7 January 2013

Can we ignore wind and just use solar?

A frequent response from those opposing onshore wind is that we should use more solar energy as it has a lower impact. While I agree there is a huge potential for solar energy (PV and thermal), particularly in the South West, it is not a perfect solution. We live fairly far North, which means that in the winter months, when are energy use peaks, the energy from the sun is very low. We also use more energy at night - when there is no generation from solar.
There is also variability from cloud cover that can have an impact, which can be easily seen at the Civic hall and Leatside surgery in Totnes, with the live output (kW) shown on the screens.

You could argue that solar PV is much more variable than onshore wind, however it is far more predictable and reliable. I found a report on renewable energy targets for Devon completed by the University of Exeter which states:
" large 3MW wind turbine generates more electricity in a year (at 25% load/ capacity factor) than over 3000 domestic (2kW) PV arrays at a tenth of the capital cost" 
(NB. as the report is a year old, the price of the PV panels has come down since). 
This remains a staggering statistic, that should needs to be taken into account when analysing the different options. It also shows the difference between micro-generation of renewable electricity and that of large scale production. It is far more efficient to do it at a larger scale, but then you have to also take into account the larger impacts. This was also mentioned in my last post - 92 small turbines needed to produce as much as the two large turbines proposed in Totnes Community wind farm.

If we look at the renewable production of energy in 2011 from the 2012 DUKES report, there was an interesting change - wind and hydro performing much better than previous years (windier and wetter). There has also been a lot of media attention on the extreme weather observed in 2012 in recent reports. Given these developments it is surely better to use a diverse set of generation technologies, including onshore wind, so we can weather the 'perfect storm' of resource scarcity, extreme climatic events, retiring power stations and increased demand. All communities should be responsible for generating some of their energy and conserving their use. The scale of the challenge and the lack of time means we cannot afford to ignore any low carbon technology.

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