The UK Energy Research Centre has published a report entitled "The Costs and Impacts of Intermittency: An Assessment of the Evidence on the Costs and Impacts of Intermittent Generation on the British Electricity Network". The report focuses on existing renewable energy targets and changes that might be required in the period to 2020.

Most of the report’s findings are predicated on penetrations of intermittent renewables of up to 20% of British electricity supply. At those penetrations, the aggregate costs of intermittency are of the order of £5‑£8 per MWh of intermittent generation. These comprise:

  • the costs of maintaining associated required system balancing reserves (£2‑£3 per MWh), being about 5‑10% of the installed wind capacity
  • the costs of maintaining system reliability (£3‑£5 per MWh), calculated as the fixed cost of energy-equivalent thermal plant minus the avoided fixed cost of thermal plant displaced by the ‘capacity credit’ (see below) of intermittent plant.

The report also makes a number of other findings, including that:

  • the effects of requiring extra system balancing reserves from fossil fuel plant are smaller than the savings in fuel and emissions from renewables (at high levels of penetration)
  • approximately 20‑30% of installed intermittent capacity can make a contribution to reliability (referred to in the report as ‘capacity credit’)
  • the costs of intermittent power can vary greatly between different countries and caution therefore needs to be exercised when looking at data from other countries. The following factors can have a significant impact:
    • the nature of the intermittent power generation and the nature of a country’s energy industry
    • national regulatory and operating practices (e.g. gate closure periods)
    • accuracy of forecasting of intermittent output
    • the geographical dispersal of intermittent generators.

The report, which has been favourably received by Malcolm Wicks, the Energy Minister, and the British Wind Energy Association (BWEA), supports the conclusions of two recent reports commissioned by the BWEA ("Onshore Wind: Powering Ahead" and "Offshore Wind: At a Crossroads") which argue that both onshore and offshore wind power can contribute to a significant percentage of the UK’s electricity generation at a reasonable cost if given appropriate funding by the Government. It could be anticipated that others will have different views.

To read the full report, please click here.

This article was written for Law-Now, CMS Cameron McKenna's free online information service. To register for Law-Now, please go to www.law-now.com/law-now/mondaq

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The original publication date for this article was 10/04/2006.