Solar power comparison
is the solar comparison spread sheet that was presented at the November
2009 NERG Meeting - it is an Excel file. The following should
Please note - The
figures in the spread sheet and the results obtained are a rough guide
only - calculating the amount of solar energy fed into the grid each
day compared with how much is used is almost impossible. On
hot days you may run your cooling system and this could have a huge
effect. We recently had new insulation placed in the roof and
this has made a enormous difference to the cooling of the
house. Before we would be turning on the cooling around
midday now it is often 3 to 4 PM before it is needed.
Click here for the solar
comparison spread sheet
rates shown from the various power companies were correct at the
time, they can be changed in the yellow fields beside each
company name - the feed-in tariff is entered as a negative number.
that to obtain the feed-in tariff you need a new meter that registers
peak and off-peak usage and that your energy company will charge you
more for everything under this (Service charge goes up as do usage
feed-in tariff is a "nett" tariff meaning that any power that you use
during the day will be provided by the solar system and the
meter will only register the amount of energy actually fed into the
need to make some assumptions and guesstimates to suit your situation
these are made in the brown boxes at the top of the spread sheet are
- The average
amount of solar power generated per day - note this is an
average so must allow for yearly and weather variations
average amount of solar power that the home will use during a day
- this is a complete guesstimate.
average amount of power consumed by the home - both peak and off-peak(11:00
PM till 7:00 AM)
you want to compare the cost of power with the new meter and no solar
just enter 0 in the solar generated and the solar used cells.
estimate of the payback period has been included - need to enter the
price you pay for the system in the appropriate cell.
At current prices and with the "best" power company payback
for Greg's system is about 10 years.