How
To Choose a Grid-Connect PV System
This
information is intended to help you to gain an understanding of
how much power you are currently using; how much power you will
obtain from different grid-connect systems, and how much of a percentage
of your needs they will supply.
Step
1: The best starting point is to work out how much electricity
you are already using. Go back and dig out your electricity bills
for the last year. We want the full 12 month period so we can get
a true daily average. Total up the number of kilowatt-hours you
have used over the course of the year, and divide that number by
365. Now you've got your average usage in kilowatt-hours per day.
Step
2: The next step is to start looking at the grid-connect
systems that are available, your location, and calculate how much
electricity they can produce.
To
do this we'll use an excellent calculator provided by the Australian
National University (see image at left).
Click
here to open the photovoltaic power simulator at the ANU.
Step
1. Let's simplify things by retaining the 1 Kw (1000 W) system setting.
Step
2. Select your location by clicking on the 'Location' button
Step
3. Set the pitch of your roof by cliccking on the 'Photovoltaic
Array Design' button; entering the pitch angle, and hitting the
'Done' button.
Step
4. Click on the 'Simulation Type and Date, select Year, and hit
the 'Done' button.
Step
5. Near the bottom of the calculator you should see the calculated
annual power output, for a 1 Kw system. If you plan a 2Kw system,
then double this figure. If a 3 Kw system, treble it, etc.
Step
6. Divide the annual figure by 365, and you have the average daily
power your system will produce.
In
Canberra, for example, 1Kw PV system will produce about 4.8 Kw/hours
per day
Perhaps
your household is using an average of 20 kilowatt/hours per day,
calculated from you electricity bills. That means that a 2Kw system
producing an average of just under 10 kilowatt/hours per day would
provide almost half your electricity needs.
Now
you should be able to relate the different systems to the amount
of power they will give you; and the percentage of your power that
they can contribute. Please remember two important things...
- the
figures above presume an optimum installation. Variations from true
north and from the optimum tilt angle will reduce the power output,
as will shading, and
- buying
a grid-connect pV system only makes economic sense if you have already
taken steps to save power in your home!
Now
you should be ready to return to the main grid-connect page to check
out just how little a PV system will cost! Just hit your Back button,
or click
here to return to the Solar Power main page.
Call
Enviro-Friendly today on (02) 6282 6266, and find out how a PV system
can help you
"Save energy, save money, and save
the environment."
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