Pylons would be an act of vandalism

• The existing grid, with modifications, provides sufficient capacity for realistic forecasts of renewable generation in the Highlands over the next 15 years and certainly far more than is required to meet the Scottish Executive targets. There is, thus, no technical case for the line.

• The cost far outweighs any financial benefits to the consumer: there is no economic case for the line.

• If increased grid capacity is ever needed, a less costly and less damaging east coast route exists.

Constructing the line would, therefore, be an entirely unnecessary act of vandalism. The structure of the inquiry, in which important evidence that could not have been available by the start of the inquiry last January was excluded by the reporters, is not such as to expose all the facts.

Professor Andrew Bain (former board member, Scottish Enterprise), Sir Donald Miller (former chairman of Scottish-Power) and Colin Gibson (former director, National Grid Group),1 Stafford Street, Helensburgh.

DOROTHY Sinclair (May 23) need not be concerned about the health of the hydro-power industry in Scotland. It remains in fashion, though subject now to the justified attention of the regulators in view of the international obligations which this and all other development sectors have to respect.

The learning curve to which developers and administrators have had to adjust over the past few years, and which has interrupted the arrival of new projects, could well be the reason for Ms Sinclair's suspicion that all is not well. From our experience of designing and developing these nigh-invisible sources of renewable energy I am pleased to be able to confirm that there is an ever-greater appetite in Scotland for hydro, and happily no shortage of suitable development opportunities when these avoid the use of lochs and reservoirs; water storage is not an issue today; witness the success of windfarms.

Dr T L Shaw, Shawater Ltd, Ston Easton, Bath.

Nicol Stephen (May 21) said: "There are enough proposals and applications to replace several new nuclear power stations with windpower." But Mr Stephen knows that wind and nuclear are not alternatives as the wind, being variable and intermittent, needs power-station backup. The average 30% output of windfarms (25% in 2006) is itself a cumulative figure and even this is unpredictable. Mr Stephen is confusing designed capacity with output.

Your leader said: "How sustainable is a renewable energy policy when there is ambivalence towards windfarms?" Well, windfarms only provide "renewable" and emission-free electricity to the extent that they displace fossil fuel generation. Wind-farms introduce instability into the grid and backup can be 100%. The description "renewable" is therefore misleading. The abandonment of the proposed carbon-capture plant at Peterhead is cause for concern and raises questions about the British gov-ernment's energy policy in Scotland.

A R Nelson, 5 Scarletmuir, Lanark.

With regard to Dorothy Sinclair (May 23), I would like to offer some suggestions as to why hydroelectric power is out of fashion.

First, hydro-electric power is not a reliable source of energy. Look in almost any river at this time of year and you are likely to see a dried-up river bed. With climate change bringing longer, hotter and drier summers, this problem is only going to get worse. No water - no energy.

Secondly, hydro electricity does not produce large amounts of energy on the scale of nuclear power stations. A lot of the proposed hydro plants are small-scale "run of river" schemes, which produce a small amount of electricity, even when the river is running at a decent level.

Finally, while it is true that hydro does not have the decommissioning problems associated with nuclear generation, it does have a profound impact on the ecological and environmental wellbeing of the locality around the river on which it is based. A lot of our rivers are beautiful locations to which people escape. We walk by them, kayak in them and fish them. It is for these reasons - damage to ecology and negative impact on leisure - that Sepa can advise against certain highly damaging proposals such as the ridiculous plan to turn one of Scotland's most beautiful rivers, the Braan in Perthshire, into a subsidy-generating scheme for Npower.

Dr Michael Kelleher, Langlee, 217 Balgillo Road, Broughty Ferry, Dundee.

Anyone who thought Alex Salmond would seek to pick fights with London to advance his case for independence need look no further than two items in yesterday's news to see that this is not the case. In a gesture of realpolitik and compromise the SNP announced that the lives of Scottish nuclear plants can be extended by 25 years, and on the same day it was announced (and little reported) that BP had pulled out of the Peterhead carbon-capture project because the government had delayed even looking at the initiative until November. If any of your readers thinks Alex Salmond is jumping on the bandwagon on this issue let me, BP senior management, the UK Labour government and his constituents in Banff and Buchan assure them he has been working extremely hard on bringing this project to fruition since at least July 2006, when I had the pleasure of sharing a train trip from Edinburgh to Aberdeen with him. Not only did he explain the project and its benefits to me in some detail, he took calls on the subject with BP and his team, and agreed to send me some details of the project for my son to give to his physics teacher for use in class.

Until now I have been uncertain about independence but if Labour keeps dragging its feet (and then shooting itself in them) and Mr Salmond continues to conduct affairs in his current astute and visionary way I don't think I'll be the only person who at least wants to vote SNP next time round.

Allan Sutherland, 1 Willow Row, Stonehaven.