I AM appalled at some of the media coverage following the announcement of the seven-year operating extension being sought by the owners of Torness nuclear power station (“Extended life for Torness is predicted to keep bills down”, The Herald, February 17).

I failed to see any media attempt to secure the contribution of qualified power systems engineers to advise on the technical problems that the ever-increasing levels of renewables generation into our network are causing. Once again, professional engineering was swept aside as irrelevant compared to the posturing of politicians and self-interest groups on the future of our energy system in Scotland. Equally the politicians largely kept their heads down, but then 2030 is three political lifetimes away after all.

Ultimately it will be electrical engineering science that tackles the issues to try to keep the lights on.

Yes, Torness is needed for base load in the foreseeable future in Scotland, as wind frequently collapses, but will only offset some of the technical problems. Wind generation rises and falls rapidly but the output of nuclear power stations cannot be varied to match as Xenon poisoning of the fuel rods would result, probably within a very few hours and take days to resume normal levels.

Gas and coal (and large wood chip burning stations) on the other hand do have the capability to closely match and compensate wind variation.

These, plus large nuclear, critically provide inertia within the system that helps keep frequency stable whilst wind generation does not and their big generators are also able to meet the demands that vary constantly from our industry users and from network fluctuations for reactive (wattless) power to resist system voltage collapse. As these generators are replaced with wind turbines we create a hugely increased risk of voltage collapse.

So it is a question of managing transition and balance.

We cannot introduce 100 per cent renewables before we have solutions to these problems and major studies are in progress in many areas of the profession to address them – some assisted by work in universities in Glasgow. At present we do not have working solutions and if we ultimately do establish technically robust options it is likely to take years and involve huge financial investment.

Converting coal stations to run on woodchips is promoted as giving an average CO2 saving of around 80 per cent; however huge amounts of energy are required before trees arrive as wood chips at a power station (much in UK coming from the United States) and generates its own CO2 elsewhere in the chain. This “embodied energy” subtracted from the energy generated makes the process much less efficient. Nonetheless these stations qualify for renewables subsidies and are classed by the renewables bodies as such – skewing the picture.

Closing of Longannet will increase all of these problems and more, much more.

National Grid, Ofgem and several of the leading professional engineering institutions in the UK are now becoming increasingly preoccupied with the increasing risks that renewables have introduced to our electrical system. It is a shame for the bill and subsidy-paying public in Scotland that our media chose to largely ignore our engineering profession this week as it was the ideal opportunity to summarise the reality.

DB Watson,

Saviskaill, Langdales Avenue, Cumbernauld.

IT is welcome news that Torness is having its licence extended until 2030. With a bit of luck Hunterston will receive a similar extension however it is a much older station and the inspection criteria will be heavily weighted in this regard.

My concern is the absence of any clear commitment by the SNP to build a new base load facility. What are its reasons for not building nuclear? After all Longannet is thankfully to be no more and the local environment in that location will be greatly improved by the absence of heavy lorry traffic, coal trains and the reeking lum. Does it really believe that coal is an evironmentally friendly solution to polution?

It is time that a coherent Scottish Government electrical energy future supply policy is produced with a new nuclear facility at Hunterston providing continued base load support as it has done since 1963.

The knowledge base is here so don't let it fritter away.

Archie Burleigh,

Meigle, Skelmorlie.