Thursday, October 28, 2010

ENERCON E-44 (vol 4)


The two essential components of all generators on the power grid are DISPATCHABILITY and RELIABILITY. Wind power, as it is applied today, offers neither.

Dispatchability means that generators can be started when operators need them, any time day or night, regardless of weather conditions. Wind power isn’t completely dispatchable; it can’t be started unless the wind is blowing.

Reliability means that a generator will, virtually every time it’s fired up, produce constant, controllable power exactly as required by the power plant operator.

Wind power also fails the reliability test because, even when the wind is blowing, it rarely blows at a constant speed. Wind tends to blow in gusts with an ebb and flow that makes wind generated power difficult to control. To make it more difficult wind has to blow also between a certain speed range in order to make economic sense and remain safe for the machinery.

I would like to add that generating electricity with current design wind generators is also quite inefficient.

Wind energy has a 'capacity factor' of just 30%. Because the wind does not always blow, a given set of turbines will only, on average, be producing about a third of the electricity that they could in theory produce.

In addition there is an AVAILABILITY issue, meaning that all generators need maintenance and repairs. This also reduces the amount of time of them actually being online and ready to produce electricity.

Of course the electrical grid system works not because every piece of equipment is one hundred percent reliable, but because there are hundreds of components with a large amount of reserve output capability (back-up) that work together to form one, very large, reliable system.

What if you do not have the ability to access substantial reserve output? For instance Estonia does not and therefore would be forced to buy electricity from elsewhere (at the moment mostly from Russia). Again the issue of national security comes up.

The amount of electricity produced from renewable resources in Estonia is mediocre at best. If we choose only wind as our main source of electricity then we would have to sacrifice our whole coastal area for these machines and even then we would still need more to gain our electricity INDEPENDENCE back.

At first glance it would seem that a simple wind generator would be cheap to build. But reality has shown that simple isn’t necessarily cheap. Nor is it carbon-free for that matter.

Money saved because wind turbines don’t need steam or other engines to drive them, boilers or reactors, expensive fuel to operate is still spent on huge, surprisingly high tech, propellers and gearboxes, towers and electronic control systems and they often OCCUPY relatively large landmasses that are paid for with rent payments from every kilowatt generated.

Wind is widely distributed but it is also area specific. There are a large number of areas with economically usable wind sites. But the best wind sites are often located in sparsely populated areas, far away from the population centers they need to SERVE.

The problem with these remote locations is that wind generators placed there will require miles of extra transmission lines and will suffer reduced efficiencies from transmission losses. These problems can be overcome but they add yet more cost to wind power.

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