Harold M Hallikainen wrote:
>
>         Though they take a certain minimum amount of space (I can't put a
> windmill on my calculator), it seems that windmills take less space per
> kw out and cost less per kw out than PV arrays. So, perhaps we should
> just build wind mills. The "match the source to the load" problem (which
> required a maximum power point controller between the PV panel and the
> motor/generator below) can be handled using a variable pitch prop on the
> windmill. We'd just watch the watts out of the windmill generator and
> tweak the prop pitch to maximize it. If the power goes negative (we have
> a big fan instead of a windmill), drop it off the line. When the open
> circuit speed of the windmill is increases and reaches line synchronous
> speed, drop it on the line.
>         Now if I could get my apartment manager to let me put a windmill on the
> roof...


Yep, windmills are great! I think they are peaceful
and relaxing to watch too, if you have ever had the
chance to watch a REAL big one, like a 300kw+ size.
Magnificent.:o)

I also agree with running the mill on-line directly,
in the past this was only really used with very large
mills. Now with PICs to sync the mill speed to mains
freq and control blade pitch etc this is becoming
practical for smaller installations. That really affects
the economic viability of wind power as a business.

There are two economies of scale with alternative
energy, macro and micro. Everybody "knows" that it is
only economically viable to make BIG power stations.
But is is also possible to make money from very small
stations, through economies of personal labour and
clever sourcing of parts. Like salvaging small
generators from scrapyards and auctions etc.

With semiconductor prices dropping it is also becoming
more attractive to use electronics rather than
mechanical solutions. Although variable pitch blades
are nice you can get good results with a simpler,
cheaper turbine and use electronics to adjust the
power tracking for max efficiency. If this is done
at the same time it is fed into the mains you kill
two birds with one inverter. :o)
-Roman

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