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Secret Scotland If it’s secret, and in Scotland, it should be here.

One of the many things the dewy-eyed lovers of green/renewable energy (as opposed to the sane folk who actually have to deliver the stuff) suffer selective blindness over is the intermittency of their favoured energy source.

In the real world, as opposed to their idealised land of plenty, wind farms generate only about one third of their capacity over a given time period, hydro-electric schemes depend on full reservoirs, and pumped storage depends on the store being full. These are simple facts, I’m not kicking these symptoms, just pointing out that they are as imperfect as their fossil-fuel burning brethren.

As we move towards more use of such system, there is real danger that the supply will not match demand, and the result will be power outages – brownouts or blackouts – as the system either fails to provide enough power, or produces too much and has to be tripped. At the moment, sources such as coal and nuclear provide base load stations that provide the minimum requirement and run 24/7 for maximum efficiency, while sources such as gas and hydro can be switched in at short notice, seconds if necessary, in order to ensure that sufficient capacity is always on line to meet demand.

However, wind and wave power can’t do the same trick. They produce when the wind and waves are present, and don’t when they’re not. solar power also suffers from a lack of ability to generate power in the dark, at night. These are limitations that need to be addressed, and undoubtedly will, as we are only at the start of bringing these systems into use, and gaining anything like the knowledge and experience gained from operating their non-renewable predecessors.

According to a recent article in New Scientist, one option is to create networks of virtual power plants.

This doesn’t involve building or creating anything tangible, but would create virtual power generation systems made up of hundreds, or even thousands, of smaller generating system, creating units which generated their total output from a wide mix and variety of sources. Although they don’t give much detail, it would make sense to have the virtual system be aware of the best operating criteria, current operating performance, and capacity of each element within each virtual power plant, and have software analysing this and matching to the current and predicted demand in the area served by such virtual plants. This would allow the best mix to be called on at any given time, with the aim of matching supply to demand, using the generators that were most appropriate for the forthcoming demand and its duration.

Such systems are yet to be fully developed, tested and proven, but some trials have taken place in the UK, and a larger test will be carried out in Spain in the last quarter of 2009. Although the test will not involve the actual control of any generators, the exercise will allow the the behaviour of the system to be evaluated using live data, and determine how effective it would be in operation.

This notable, as it shows that despite the moans of those who beat their chests and complain about nothing ever being done, and that no-one is doing anything worthwhile as long as there are fossil fuels to be had, back in the real world, those who actually have to not only keep the lights on today, but develop new thinking, are actually doing so.

http://secretscotland.wordpress.com/2009/06/12/virtual-power-plants-could-help-renewables/