Monday, 22 August 2011

Solar power. UK v Portugal

The European Union has mandated that 20% of its energy consumption come from renewables by 2020 (with the goal of also slashing carbon emissions by 20 percent by the same deadline), a small country on the Iberian Peninsula has already eclipsed that goal.
With no domestic supply of oil, gas or coal, Portugal’s ambitious pursuit of alternative energy has left the nation on track to generate 45% of its electricity this year from renewable sources, an increase from 17% just five years ago.
We’ve just returned from the sunny Eastern Algarve in Portugal. You would assume that with the amount of sunshine they get, and the longer season with daylight, that most homes would have PV panels. Not a bit of it. We looked every day for the distinctive rooftop patterns with no success. It’s strange that the domestic take-up for solar power is so low.

  • In the UK the maximum domestic installation qualifying for the FiT is 4.0kw. In Portugal it’s a very similar 4.3kw.  
  • The FiT rate in the UK is currently 43.3p. In Portugal its .38€.
  • The Fit is guaranteed in the UK for 25 years, with the added benefit of an index linked inflationary boost to the rate each year. Disappointingly, in Portugal the .38€.payment is guaranteed for 8 years, after this there's another 7 years at .22€ kw/h.
  • The UK and Portugal both have an agreement with the electricity suppliers, who guarantee the payments to the domestic installer.

I met a Portuguese national who had decided to install PV panels on his property for much the same reason as myself; it’s a great return on capital. Like me he had 14 PV panels. On the plus side he was generating in August on average 22kw/h each day, over double the output I achieve. On the negative side his installation cost him €23,000 compared to my £10,000.

The one element of his system (and most domestic Portuguese installations) which I envied was the solar tracking array which his panels were mounted on. I suspect that it would be impractical in the UK as we don’t have the room, but in Portugal many families have large tracts of unused land around their houses which allows them to have their PV panels mounted on a computer controlled array which tracks the suns movement throughout the day. None of this South facing rooftops will provide the best results as in the UK; their panels are at the optimum angle and direction 24/7.
The output is increased for a tracking array compared to a static rooftop system by 30%. Well worth thinking about if you have the spare land.

Interestingly, the payback periods for the two systems were almost identical despite my lower output as the Portuguese system installation costs are significantly higher. It seems strange that two European countries with similar standards of living and wage costs should have such a huge difference in installation costs. Perhaps siesta breaks need to be factored in? I certainly wouldn’t want to be out in the midday sun unless it was under an umbrella with a cold beer at my side…


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