[daverich]

Is Woking the future?

Regards
Dave

http://www.iht.com/articles/2007/04/19/ ... wbgrid.php

[WatchfulEye]

It's an interesting idea.

The co-generation concept is one of the advancements we are seeing in electricity generation. Conventional large generators are too far away from population centres for their heat to be useful - as a result it is simply dump to the environment as waste.

'Embedded', or municipal, generation has the advantage that the heat may be usefully distributed - turning a waste product that you had to pay to get rid of, into a valuable commodity. The overall efficiency of this scheme can easily reach 80%, and potentially more. If used for municipal refuse incineration, then it turns yet another costly waste into a valuable fuel.

However, distributed generation is not without its problems. First think back to why power generation has been centralised, almost since its inception. The reason, is because it's more efficient and cheaper that way. The more people/businesses that share an electricity supply, the smoother the overall demand becomes. Dips and troughs are smoothed over, and overall variation can be relatively small. Peak load on a large grid is about (often slightly less) than double the average. Whereas in an individual town, or city block the variation is much higher (peaks may be 10x the average, or even more in residential areas).

The other problem is that small scale generation is not as efficient as large centralised plants - even when distribution losses are taken into account. It's a lot easier to control losses in a mega project than in a small one. This is offsetable if you are able to use the waste heat. However, you then have to balance your electricity demand against heat demand. If heat demand is low, then it's pointless running co-gen plants and dumping the heat (far better to just use the grid). Similarly, if heat demand peaks, how do you supply it if demand exceeds supply? Do you have to burn fuel just for heat, without the offset cost of the electricity?

There's now growing interest in large-scale industrial co-generation. We've already seen some projects - e.g. LNG regasification plants need massive amounts of heat. Traditionally this comes from an ocean or river - but there are concerns that these plants can chill the water excessively. There have been a few built next to large power stations - the waste heat from the power plant is used to warm the gas. Projects under consideration include co-locating desalination plants with power plants, as desalination requires monstrous amounts of low-grade heat, which is exactly what the power plants need to dispose of.

[SILENTTODD]

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