Re: Power Supplies, Saving Money, and switching vs. Linear?

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Andrew(N)" <andrew.ward@xxxxxxxxx> wrote in message
news:44207747.4090209@xxxxxxxxxxxx

<stuff snipped>

> The move of this thread to Solar power is VERY interesting... Because
> this is what I am doing.
>
> I now have 28 200+ watt SunPower Solar panels on my roof feeding an
> inverter that will take advantage of California's NetMetering regulation
> which allows me to put power back into the grid. So, during Peak hours
> (M-F Noon - 6 PM) I will be pumping watts back into the grid at the
> elevated Rate. No storage batteriies in this system. System is designed
> to be a 5 KW system. (Contractor is ReGrid Power, BTW). The panels and
> inverter are installed, but these guys haven't gotten back out to make
> the connection to my AC mains yet. This should be this week or next. The
> panels are wired to give about 400V DC into the inverter and 120 V 2
> phase out.

The simple fact that there are contractors to choose from means that solar
is chugging along, maybe at the Altair or TRS80 stage parallel in the PC
world.  The people who are installing now, like you, are creating the
roadmap for the future.  It was interesting to watch the technology jump in
the PC world because it's similar to what's happening in solar.  People take
the plunge and then report on their experiences, good and bad.  That
inspires one or two more people to do it until a critical mass is reached
and some chain reaction starts.  Every time I read about you or someone like
Mr. Baber converting to solar in a big way, it chips away at my fears of
getting into something that may not pay off or work as well as imagined.

> Either way... This is the reason for my huge pursuit of power savings...
> to cut the usage wherever possible, to get my savings up.

Early adopters have to ignore or at least wink at the "business model" that
says the conversion is not cost efficient or at least won't be for X numbers
of years.  I think it's great you've been able to just ignore that "X" years
payback predictions.  From where I sit, those projections are not generally
very valid.  Back in the early days of the IBM PC people assumed that PC's
were limited because the physical size of memory chips (at that time)
prevented PC's from having very much memory.  Predictions can't accurately
factor technological breakthroughs into their equations.  I have 4GB in a
box no bigger than the original IBM PC but more powerful than any computer
on earth 20 years ago.

While we can't say for sure what will happen in solar technology, we *can*
predict their *will* be breakthroughs because there always have been.
People rise to challenges.  The challenge now is to reduce our need for
foreign oil for a number of reasons; some economic, some political, some
humanitarian.

> BTW... people are always curious.  Raw system cost is arouns $47K, after
> California rebates, my cost is ~34K.

Exactly my point!  People always want to know the bottom line!  By posting
here, you've started a little ripple in what some day will be a very big
pond.  There are strong forces opposing solar:  the oil industry, the power
industry and even the government itself (sunlight is not yet taxable but is
litigated far more often than 20 years ago).  Solar power is taxed once when
you buy the equipment, but not thereafter.  Look at your power bill and see
how much the government gets.  They don't want solar, either, but they
grudgingly support it with a few meager task breaks.  California, at least,
has realized that its survival may depend on solar self-sufficiency.

> I might be eligible for one more tax credit totaling ~3000.

How insubstantial a reward for trying to do the right thing.  I wonder how
much solar the US could have built with the $ and manpower being spent on
Iraq?  Any mathematicians able to tell us how much a rebate $100B would
provide?   Assume there are about 110 million "households" in the country
and maybe half of them would be suitable for solar.

> If I use power at the existing levels, and
> if PG&E increases rates consistent with the past 22 years, payback is in
> 11 years. But, with some conservation, and if PG&E really jacks up
> prices, as they are expected to do, then payback could be in as few as 8
> years.

The equation could tip the other way, though.  That's part of the risk
equation that my wife fears.  What if they tax solar arrays by the square
foot?  You can't exactly hide them.  There are powerful economic interests
aligned against solar and they give steamer trunks full of money to
lawmakers everywhere, every year to make sure the balance stays tipped in
their favor.  I wish people would make solar a campaign issue instead of the
ones that the press loves so much, like gay marriage.  )-:

> My goal is not to be self sufficient, nor to get my bill to 0. That
> would be stupid. The real goal is cut off the top two or three tiers
> where electricity is as high as $.31 / Kwh.

You're casting an important vote with the only voting mechanism that seems
to work anymore - the dollar!

> This is why I am running around with a spreadsheet and two Watt's Up
> power meters measuring everything. This linear supply is hard-wired, so
> I could only put an amp-clamp on it. I will try to put a cheater cord on
> it for a while and re-measure the actual wattage soon.

I did that with Kill-o-watt when the power prices here just about double.
There are so many little devices in a house that draw a few watts here and
there that it adds up.  I've designed a summer/winter configuration where I
switch to CFL's and low-draw power supplies in the summer where there's a
double whammy for electrical use:  the rates double again and the spill heat
is a liability now, where it's really an asset in the winter.

> Thanks everyone for the interesting discussion.

Thanks for your report.  Discussions like this cause a lot of percolation in
people's minds, especially when they're writing that check to the power
company.

As for predictions, I seem to recall in the Popular Science mags of the '50s
that we would be now living in an age of nearly cost-free nuclear power.
Har-har!

--
Bobby G.