YESTERDAY'S announcement by EDF Energy that the operating life of the Hunterston B nuclear power station in Ayrshire is to be extended by a further seven years should be welcomed for several reasons.

The most tangible benefit of prolonging the life of the 36-year-old plant is that it will continue to benefit the local economy by up to £40m a year and secures the futures of more than 700 workers. It will also provide training opportunities for a new generation of Scottish nuclear engineers. As the Scottish Government has set its face against any new nuclear stations, it could be the only source of such experience, unless Scotland's other nuclear station, at Torness in East Lothian, also has its operating life extended, as now seems likely.

For economic and environmental reasons, nuclear power should remain part of Scotland's energy mix until no longer required. The Government's declaration yesterday that it was "perfectly open" to the continued operation of Hunterston suggests a contradiction in its energy policy. If it is against nuclear power and sees no need for it, why are ministers happy to see the life of Hunterston B extended 12 years beyond the original closure date? Is it really possible to argue simultaneously for action to mitigate climate change and against nuclear generation, by far the cheapest way of displacing carbon from energy production?

Failing to invest in nuclear leads to continued reliance on coal and gas. While France benefits from 80% carbon-free power, due to its past investment in nuclear, today George Osborne is set to announce a new generation of gas-fired stations "to keep the lights on".

Meanwhile the charity WWF finds itself in the strange position of favouring the use of coal or gas-fired stations rather than nuclear to provide baseload on windless days. The rationale appears to be that nuclear reactors are either on or off, while fossil-fuelled stations can run at variable capacity; a curious position for a body that has been prominent in addressing climate change. According to EDF, Hunterston B has displaced the emission of 160 million tonnes of carbon dioxide since 1976.

The Holyrood Government has bet the farm on the predominantly intermittent power of renewables and carbon capture and storage, unproven on a commercial scale. This policy depends on onshore and offshore wind farms. Extending the lives of Hunterston B and Torness postpones confronting Scotland's energy challenge. Ultimately they must be decommissioned. What then happens when a lengthy period of cold, clear, still weather covers the country, as has happened in recent winters? Scotland can probably rely on renewables under most weather conditions but at what price to the economy and those struggling to pay mounting energy bills? EDF's decision to continue supplying Scotland with electricity looks like a piece of serendipity.