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MAKING THE SWITCH

TECHNICAL & PRACTICE

Some weeks ago (AJ 22.09.05) I reported on the BRE's microgeneration conference and the government's commitment to local, small-scale, renewable energy generation. Not only are renewables the only game in town but 'localism' has now become an essential part of the government's agenda - from local sustainable communities, to David Miliband's speech at the British Urban Regeneration Association's annual conference last month praising devolving funding 'to neighbourhood level' and 'communities bound by shared values'. Not to mention the New Deal for Communities' 'commitment to locality', or the Local Government Association's whole-hearted support for 'democratic localism'.

When the trajectory in energy policy is away from state provision to individual generation, we ought to at least question the motives and benefits of such a move. It does, after all, undermine the notion of universal supply - the national grid - and a broader collective vision of community.

Of course, there's nothing wrong with efficiency, but some of the most efficient power-generation plants are centralised. That's what marks the implementation of the National Grid as a benchmark in progressive universalistic social provision - as opposed to the moralistic, self-serving, ungracious, fatalism propounded in books like Sue Roaf's (et al's) publication, Adapting Buildings and Cities for Climate Change: A 21st Century Survival Guide.

While the 'I-told-you-so' school of modern millenarians ask: 'What will I do when the lights go out?' at least there are some rational voices that want to improve things for society as a whole. One such voice is Joe Short of Dynamic Demand, who recognises the benefits of 'mains supply' and has devised a way of making it better, as well as saving energy and money. This is an example of the use of technology to iron out problems with old technology - in the same way that scientific theory develops from, and adjusts, the previously accepted best ways of understanding things.

Because power supplied from the grid services so many people, fluctuations in demand - the classic surge in tea-making during half-time on Match of the Day, for example - generate variable frequencies in the supply. Sometimes these are barely discernable but are balanced to some degree by adjustments at source. However, these balances are reputed to cause 0.6MtC emissions over and above the normal emission rates because the generator has to work at a less than maximum output in order to have sufficient back-up capacity to compensate for frequency troughs.

Short's device works at the customer end. It is fixed to appliances that operate on a 'duty cycle' - ie airconditioning plants, water heaters, refrigeration coils, etc - and alters the timing of electricity consumption of that appliance to best suit and correct imbalances in the grid.

What at first looks like minor tinkering actually addresses a UK electricity demand of 1,900MW from domestic fridges alone.

The microcontroller installed in the appliance measures the grid's nominal 50Hz supply frequency and detects variations. It overrides the simple thermostatic response switch in a fridge, for example, and allows the controller to alter the timing at which the appliance comes on, to coincide with a peak. This serves to reduce the peak and even out supply. With much doubt expressed about the ability of wind power generation to overcome its seasonal and natural fluctuations, this universalising switchgear could, ironically, come to the rescue.

Contact: joeshort@dynamic demand. co. uk

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