On 07/20/2011 04:03 PM, Falcon wrote:
On Wed, 20 Jul 2011 12:40:21 +0200, Tom P wrote ...
On 07/20/2011 11:50 AM, Falcon wrote: [..][..]
In the UK the difference between the price paid to someone like you
with PV panels and the average household tariff is, therefore, around
28p/kWh (31- 32 Euro-cents/kWh).
That is a spectacular difference. Here the tariff has gone down from 33c
to 28c since 1st Jan. Household rates for power are around 22-24 cents
depending on the contract. There are also cheaper deals for flat rates
and upfront contracts.
Tom, could you clarify the figures you quoted earlier, please? I think I've
misunderstood something along the line.
I thought you said that 2,000 kWh had been delivered by your panels in the
first six months of operation (which is pretty good) and that your
supplier, RWE, had just transferred 526¤ to your bank account, I assume as
a result of sales of surplus energy to the grid.
At an average feed-in price of 30 cents per kWh that suggests you sold ~
1,750 kWh of the 2,000 kWh generated to the grid, leaving just 250 kWh
consumed by yourself. Only 41 kWh of your PV-supplied power per month is
used to power your home? That can't be right, surely? I thought only your
surplus energy should be sold to the grid? I get through an average of 40-
50 kWh per WEEK and my consumption is well below the UK national average.
Is your personal electricity consumption figure really that low? or have I
done the sums wrong?
And I'm really not sure how a difference of ~5 cents between the price you
get and the price you pay for grid-supplies can result in a good return on
an 11,000¤ investment.
Have I misunderstood something?
In a word - yes. Everything.
[..]
Picture:
House wiring --<--<--Meter 1 -<--x--connection point--<--- grid
PV installation -->--Meter 2-->-/
There are two completely separate meters, one for domestic consumption,
one for the grid feed-in.
The grid feed-in feeds 100% of the power generated into the grid via its
own meter. The 2,000 kwh is what the PV installation has fed into the
grid as measured by the meter. This has absolutely nothing to do with
the domestic consumption. None of the power generated by the PV
installation is used privately.
In fact, our domestic power supplier is not even the same company as the
grid utility. We have a contract for power with a local city. The city
has a contract with the grid utility that lets them provide me with
power. Quite likely the grid utility has a contract to sell power from
my PV installation somewhere else.
As far as the payments are concerned, the agreement is that the grid
utility company pays a monthly installment calculated on the basis of
the projected power generation. At the end of the year the meter is read
and the balance settled. The actual yearly figure will then be used as a
basis for the monthly installment for the following year. This is
exactly the same as the procedure used for monthly installment payments
for power consumption, just the other way round.
That means that the 526¤ payment is less than the power is worth that
has actually gone into the grid. The balance will be settled at the end
of the year.
I hope that this clarifies things.