Troublesome truths behind quest for universally agreeable energy sources

Whilst nuclear provides around 78 per cent of France's electricity, it only provides 18 per cent of total energy consumed (Business, 17 April). The country still consumes more oil per capita than the UK. If Britain replaces its nuclear fleet this would only save around 4 per cent of our carbon emissions. We could easily make up for this with extra, cheaper, energy efficiency measures.

Recent more rigorous estimates of carbon emissions from the nuclear cycle are ten times higher than a industry estimates – around 66 g/kWh – worse than all renewable alternatives. This number is likely to increase as the industry is forced to use poorer quality uranium ores.

France has the same problems with radioactive waste as everyone else. It has no operating high-level waste repository. In the UK, problems in the 1990s with the scientific basis for calculating the rate waste would leak halted the programme. It is imperative this is resolved before further waste is produced.

If there are concerns about whether new non-wind renewable energy can contribute in time to Scotland's energy supplies, then we should look at combined heat and power (CHP). Pyry Energy has shown that industrial CHP across Britain could generate as much electricity as ten nuclear stations and halve gas imports. Two of the nine sites examined are in Scotland, at Grangemouth and Peterhead. Together these would be almost enough to replace Scotland's nuclear capacity.

CLLR EUAN McLEOD

Chair, Scottish Nuclear Free Local Authorities

City Chambers

Glasgow

Scottish and Southern Energy (SSE) intends to appeal against the unanimous decision of local Highland councillors who threw out their plans for building a massive "electrical converter sub-station" near Beauly. SSE claimed, in the report presented to the councillors, that the development was needed to transfer electricity from the proposed Lewis windfarms to the mainland network. There are no windfarms on Lewis.

Stirlingshire groups fighting another SSE proposal, the contentious Beauly-Denny pylon line, took their case to the EU to win support for putting parts of the line underground. The vociferous opposition to the pylon line is well documented, with over 17,000 objections lodged with the government against this SSE project. What is perhaps less well documented is the equally vociferous opposition to the "proposed windfarms" on Lewis, including yet another SSE project, this time for 26 giant 500ft turbines, which has already generated over 3,000 official objections and only three letters of support.

Over 19,000 letters of opposition have already been lodged against the three large wind farms planned for Lewis, with only 165 letters of support.

When the controversial Amec/British Energy Windfarm project was finally laid to rest last year, the energy minister, Jim Mather, went on record as saying that no Lewis windfarm would progress without community support. In that case, there is no large windfarm project on Lewis that should be consented, as the third proposal (the Eisgein windfarm, which is the subject of a public local inquiry) generated nearly 3,400 objections and just 85 letters of support.

Clearly, to consent any of those projects, in the face of such unprecedented public opposition, would require some explanation from a Scottish government that could owe its slender one-seat majority to the voters of the Western Isles, who elected the SNP candidate largely on the back of the huge public backlash against the sitting Labour MSP's support for the Amec Windfarm.

DINA MURRAY

North Galson

Isle of Lewis

In her report, "Two men, two very different views of future" (16 April), Jenny Haworth makes two mistakes in claiming that renewable energy provides electricity "only 30 per cent of the time".

William Oxenham (Letters, 18 April) makes a similar error in claiming that wind farms "output their full power for only 30 per cent of the time".

Different renewable systems generate for different periods of time. The percentage Jenny Haworth quotes is one that applies only to windfarms, and then only to their load factor: that is the total amount of electricity energy generated over time aggregated as a proportion of the amount that could have been generated if the plant operated 24/7. In fact, windfarms generate some electricity for about 85 per cent of the time, at varying power rates depending on the wind strength and only generate at full power at high wind speeds.

It is important to distinguish between these two ratios.

STEUART CAMPBELL

Dovecot Loan

Edinburgh