I see a lot of neat things here. I am a great fan of solar PV, and I have been
successful in using it. Wind is good if location is appropriate. Small hydro
can be good for some, and I would like to live where it was.
What is common to everyone, 'efficiency'!
By now we have all started using CFL (compact fluorescent lamps, you know those
twisty things) lights. They use much less power (Watts) for the amount of light
they produce, but even so they are very inefficient and waste 25-50% of the
power they do use if they are measured for their powerfactor losses.
Powerfactor losses account for 15% of all the energy paid for by the nations
utilities customers on the average nationally. This can be proved by these
utilities actually planning their capacity requirements on this figure. In fact
if you are a major industrial or commercial user the utilities will charge you
extra if you don't correct your own powerfactor. As far as the small consumer
is concerned, the utilities have historically wanted you to buy more power, so
they didn't tell you about these losses you do have to pay for.
When I built my solar PV system, I went all through my home looking for things
to do to reduce my needs and make the very expensive initial cost of the PV
system as small as possible. This took about 1 year to complete and the I sized
and designed my solar system. After I bought the hardware for the system, I was
reading the inverter manuals.. (Really I do read instruction manuals as strange
as that may be to some) .. and I tripped over the statement that the inverters
had a powerfactor of 1.0
I dug into my mental archives over powerfactor, since I knew I had NOT
considered powerfactor in my planning. It had been in 1962 when I had last
considered Powerfactor, but at that time I was designing power supplies for
NCR's mainframe computers. As I recalled we were able save a significant
savings in the AC power requirements for those mainframe computers by correcting
the powerfactor losses from the power supply transformers with 60 cycle tuned
I proceeded with my solar PV, figuring the losses in my home were not
significant, but I started looking for a powerfactor meter, and I eventually
bought one that had a wattmeter and would record its readings for input into my
computer. I didn't tell my wife how much, just that I was ($850.00).
It is a neat tool, and like most techie types would, I started measuring things.
The refrigerator, water heater, stove top, ovens, and finally the 240 input from
the meter to the house.
OUCH, the powerfactor was a miserable 0.81, with my PV solar turned off. It
should ideally be 1.0 and this meant that in the year before I put in the PV I
had wasted 4458 kWh of the 23,464 kWh I had paid $4,446.00 for in that prior
year. This meant I had lost at least $844.00 to the bad powerfactor.
The 4458 kWh used to offset the powerfactor loss would also work against
whatever power I generated myself as well as any power I was planning to draw
from the grid, so I decided to find some compensating capacitors to install to
correct the bad powerfactor. It was not easy but I did, it cost $350.00, but it
easily has paid for itself.
The only problem with fixing this powerfactor loss, I had sized my PV system so
that when my utility and I settle at the end of each year I had planed to pay
about $400.00 on my bill (annually) to keep from giving them any credit. Last
year that's about where we finished, but this year it looks like I'll have at
least a $300.00 credit on my account that they just get to keep. Oh well I
won't have to pay anything!
(see my 10kW grid tied solar system at "www.baber.org")
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