Feedback: your letters

Topics under discussion this fortnight: Britain's nuclear programme; exceptions for historic buildings from Energy Performance Certificates; wind turbines improving with age; belting sounds from your TV; the dawn of sunlight bulbs and more.

Opportunity of a lifetime

Those who seriously consider the UK's energy balance against a background of global warming and security of supply welcome a diversity of energy resources, combined with efficiency measures to reduce consumption across the board. Clearly, security of supply is absolutely key to the British economy and social stability. However, there are major concerns with the situation.

The principal concern is the ageing stock of fossil fuel and nuclear power stations and the grid. After cessation of Britain's nuclear programme and privatisation of the generation and supply industries, our only way forward is to import inspected reactor designs and equipment, provided companies are willing to invest in power plant at a time of extreme turmoil in financial markets.

What action has been taken? As major shareholders in British Energy, the British government has sold out total nuclear generating capacity to EdF (49 per cent owned by the French government) which has had a consistent nuclear strategy since the 1950s.

So we have put our whole economic future in the hands of one company, which may or may not deliver the power stations we need in the timeframe required to stop the lights going out. The forecast costs of electricity from new PWR stations is very low compared to fossil-fuel powered stations and EdF stands to make high profits to recoup its investment. The sale of British Energy should be renegotiated immediately.

There are thousands of tonnes of irradiated fuel in cooling ponds at Sellafield from which only a small fraction of the potential energy has been extracted, basically the Uranium 235 isotope, leaving the bulk of the Uranium 238 isotope. Uranium 238 is fissile in fast reactors and there is potentially many hundred-fold more energy to be won from this waste material. Releasing this energy was the vision of Sir John Cockcroft and the reason for the construction of the fast breeder reactor at Dounreay that was successfully generating electric power when the whole nuclear programme was abandoned.

Britain now urgently needs a nuclear strategy to secure electricity supplies in the medium-term, independent of imports and possibly participating in the supply of nuclear plant such as fast reactors as a future business opportunity arising from the global problem of climate change. This could be in partnership within Europe or with another country such as India.

The opportunity of a lifetime has to be taken during the lifetime of the opportunity. Consideration of the benefits of fast reactor technology needs to be given now.

Mark Rogers, Huntington, Chester

TV screen sizes

I was surprised by the description throughout 'Moving Pictures'(Vol 3 #18) of screen sizes by diagonal measurement in inches. This trade practice seems to date back to pre-war days when tubes were circular and the raster was framed by a mask. In the 1980s, with the introduction of the flatter squarer tube, there was a move to express screen size as actual viewable diagonal in centimetres, but this has lapsed.

When I replace a 4 x 3 TV, I want the visible height of the new 16 x 9 screen to be at least the visible height of the old screen. I am not interested in the diagonal. Neither was I interested in overall tube dimension; I have neither the time nor the inclination to open up the TV to check this out.

Paper has two dimensions; A4 is 210 x 297cm, not 15in. Now that LCD and plasma screens are taking over, is it not time to describe these similarly?

Denis McMahon MIET, Basingstoke, Hampshire

Insulating historic buildings

In her 'If You Ask Me' column on zero carbon buildings (Vol 3, #19), Brenda Boardman concentrates on future housing stock that will not call on power utilities and add to the world's warming. She also makes it clear how tough it will be to reduce the carbon requirements of the UK's other 25 million houses.

Insulation advice is normally: cavity wall insulate, loft insulate and double glaze. For people living in older houses, this advice is of little use. There is no cavity in the wall and the roof is often the attic and cannot have fibre-glass or equivalent laid in the loft. The most contentious is double glazing, which is banned for listed buildings and even for the non-historic glass in more recent extensions.

When the task of reducing the carbon requirements is tackled, could some reference be made to listed buildings and some help and guidance offered to the current custodians? Otherwise, those houses that could never achieve a high grade Energy Performance Certificate should either be given exemption or, logically, removed from the housing stock. What sort of country would ban heritage homes?

Michael Etherington CEng FIET, Winchester

Wind matters

Dr R Barnes (Letters, Vol 3, #19) describes seeing wind turbines standing idle and requests comment on downtime. As a 'wind person', I've recently been involved in a performance assessment of over 14,000MW of operational wind farms reported in the paper, 'Availability Trends Observed at Operational Wind Farms' at this year's European Wind Energy Conference.

A database of over a thousand wind farm years of different turbine types around the world has been created to examine the system availability. This excludes any contractual downtime and reflects the actual time that the project is available to generate (independent of the wind resource, which is an entirely different discussion).

The study derived the distribution of availability of the wind farm years,which had a mean of 96.4 per cent, which is a little lower than the industry standard long-term assumption of 97 per cent. The distribution is skewed: 90 per cent of wind farm years had an availability above 92.5 per cent and only 1 per cent of the dataset had an availability below 80 per cent.

Plotting the availability as a function of time since project commissioning shows how initial teething issues reduce availability for the first couple of quarters, but they soon achieve a stable level. Some projects have suffered specific problems with gearboxes, etc that have led to higher than average downtimes, but as the technology matures this will become less significant.

For a relatively new technology that has really taken off over the past few years, wind turbines are doing pretty well.

Michael Wilkinson MIET, Bristol

Bill Hyde (Letters, Vol 3 #20) is quite right to point out the deficiencies in wind turbines. A further point is the question of standby generation. When wind fails to supply the demand, power must come from (carbon dioxide emitting) fossil-fuel generators which are running idle as 'spinning reserve'.

Germany is often pointed out as a model for wind-power generation. However, it is able to import power from nine adjacent countries. The need for standby generation within the country is thereby reduced. We have one (2GW) cross-channel cable, so most standby power must be available within Britain.

Charles Hughes FREng FIET, Felixstowe,Suffolk

As someone responsible for educating the next generation of senior engineers (through the MBA/MSc in Technology Management at the Open University), I am pleased that "answer comes there none" to Bill Hyde's questions about how renewables could supply the UK's 60,000MW maximum electricity demand.

What is required is to keep the lights on and the home dialysis machines running, not to supply 60,000 MW maximum demand. How do we replace a system which has a one-dimensional approach to meeting demand, increasing centralised generating facilities and increasing negative externalities, with one that provides adequate power to meet our needs at all times while reducing negative externalities.

Suddenly answers come there many, indeed an incredible plethora of ideas. A good strategy is to provide direct and indirect subsidies to encourage the development and testing of these ideas. The successful will develop to be self-supporting and the unsuccessful will leave an infrastructure for the future.

I guess the final solution will be a renewable grid and a mix of renewable and traditional micro-generation alongside intelligent grid-linked devices that reduce their load when power availability is limited.

Another element will be feel good factors and emotive issues, alongside the economics. What a bleak view of engineering if we don't consider such parameters; no wonder young people prefer to study finance or media.

Jon Fanning MIET, The York Management School, University of York

Dangers of brute force

Stuart Bridgeman (Letters, Vol 3 #18) describes a method of listening to television that is potentially dangerous. There are TVs still in use that exploit the 'live chassis' technique, where one side of the mains supply is connected direct to the chassis with no isolating transformer as used in most stereos, computers and other more modern designs.

Live chassis design was still common in 1990s-era TVs and was universal "a few decades ago". The danger is that connecting a cable directly to the speaker connections makes that cable potentially at high voltage. Therefore, the entire cable, mounting, switching components, construction, and installation must be rated for high-voltage operation.

Modern TVs with headphone sockets are probably safe for speaker connections, though it would be wise to check that the entire circuit is mains-isolated.

Clive Woods, Baton Rouge, Louisiana, USA

Seeing the light

I am surprised that the use of 'daylight' fluorescent tubes is hailed as a new discovery (Vol 3 #20). I knew about this in 1964, and persuaded the management at ITT Consumer Products (formerly Kolster-Brandes) to deal with complaints from the design draughtsmen that "We can't see in the new drawing office" by changing the Warm White tubes to Daylight.

Lighting amateur dramatics, using coloured filters to convert the 3,500K colour temperature of incandescent lamps to nearer the 5,500K of British daylight, prompted me to acquire a Daylight tube. The improvement seems to be in visual acuity, although the subjective reaction is that the light level is too low. The unwanted effect is most marked with Warm White, although it is still present with some more modern phosphors.

I wish I could get CFLs with a 'daylight' phosphor, as a lower lamp power would be usable.

John Woodgate, Rayleigh, Essex


The report on the 2008 IET Innovation Awards in issue 20 of E&T listed the winner of the asset management category as Three Valleys Water. The project to optimise capital maintenance planning processes was done jointly with Asset Management Consulting Ltd, and the award was made to both companies.

What they're talking about on the Internet

A recent discussion in the manufacturing forum on the IET website was prompted by the question: "The government has a detailed manufacturing strategy but is it delivering improvements? With manufacturers reporting shortages of qualified engineers and problems with the perception of manufacturing continuing, will manufacturing in the UK just consist of small, high-tech, niche manufacturers by 2050, or will the world have gone 'full circle' and the UK be a low cost economy?"

It's fairly safe to say that technology transfer from the UK probably won't help.

Once the developing countries have stronger unions, calling for holiday pay and better wages, then the work lost to those countries at present will probably return to the UK, but not in my lifetime.

It is worth putting effort into reducing the cost of production in the UK. Appropriate automation of assembly can help to reduce UK labour costs. For example, a pick and place machine is cost effective if skill and effort is applied to designing an assembly to make best use of one.

I think that CEng requirements should include a sufficient experience of making - as opposed to designing - things and servicing them. You learn what can and cannot be done.

I was listening to a minister discussing the fact that this is the same slump that manufacturing had seen in the 1980s and 1990s now being replicated in the service sector and that manufacturing had survived it. Manufacturing has only just survived the slump of the 1990s and had to rebrand itself and create new industries. To say they have survived the slump and imply that this slump may not affect them seems unlikely.

Join the debate, or start one of your own, at [new window].

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