What size system will I need to run my home?
That entirely depends on your energy usage
and your geographical location. A 1 kW system will cover
between 16 and 25% of the energy consumption of a medium
household. A 4 kW system will cover aprox 100% of the energy
consumption of a medium energy use household.
Does roof orientation really matter?
Most certainly. For example, a system with
solar panels facing in a westerly direction will generate
far less than one with a northerly aspect.
How does a Grid Connect Solar system generate
When sunlight shines onto your Solar modules,
our advanced photovoltaic (PV) technology converts the light
into direct current (DC) electricity. Your system’s
inverter then converts the DC electricity into 240V alternating
current (AC) electricity for normal use in your home.
How is the solar electricity metered?
In Australia there are two different ways
of metering the electricity your Solar system produces.
One method used is called ‘net metering’. Electricity
utilities allow the excess electricity generated (generation
exceeding consumption) by your solar system to be sent to
the grid at the retail rate for that given time period by
allowing the utility meter to effectively spin backwards.
This arrangement allows all electricity produced by your
system to be used to offset the remaining portion of your
utility bill. In other words, the utility buys back the
excess electricity your Solar system exports to the grid
at the same retail price you pay for that electricity. However,
for most large homes or homes with high electricity demand,
a solar electricity system will cover only a portion of
the total demand, thereby simply reducing the amount you
take from the grid.
The second method used is ‘export metering’
or ‘gross metering’. This is where utilities
allow all the electricity generated by your solar system
to be sent to the grid at the retail rate for that given
time period. This is done via a dedicated utility meter
which is separate from your utility consumption meter. This
arrangement allows all electricity produced by your solar
system to be offset against your entire utility bill. In
other words, the utility buys back all the electricity your
Solar system produces, at the same retail price you pay
for that electricity.
What will happen in utility electrical blackouts?
By law, any grid-connected solar electricity
system must shut down until utility power returns in order
to assure a safe working environment for utility line workers.
The system will automatically come back online when the
blackout is over.
With grid connect systems, what can I do to keep
power during a blackout?
You will need battery back-up.
How much of a reduction in carbon dioxide emissions
will I achieve?
Using a comparison to a car, the average
vehicle in Australia travels 20 000 km per annum, which
is equivalent to 3.3 tons of carbon dioxide discharge annually.
A 2kw grid connected system will prevent 3.3 tons of carbon
dioxide being generated through coal fired power generation
- so it's the equivalent of taking a car off the road each
How safe is a Grid Connect Solar system?
Solar electricity systems are very safe.
They have no moving parts and require very little maintenance.
Solar components carry all appropriate/recommended electrical
certifications. As with any electrical appliance, you should
always use proper care when handling solar system components.
iSustain Australia highly recommends that installation and
maintenance of solar systems be handled by BCSE-accredited
solar installers and that licensed electricians be used
for grid-connected systems.
Remote Area Power Systems FAQ
How much does a RAPS cost?
A RAPS system to provide all of the power
requirements for an energy-efficient house with a typical
range of appliances can cost between $15,000 and $50,000.
The size of the system needed will depend on the number
of people in the home, what appliances are in use, and how
often they are used. Rebates are available to pay for up
to half of the system costs.
Connecting to a grid may cost $10,000 per kilometre of power
lines, making the option of a RAPS system a viable alternative.
The cost of a small renewable energy system to run a farm
shed light using one panel and a small battery can be as
low as $200.
How does a remote power system work?
The DC electricity produced by the wind
turbine or solar panel array is routed through wiring to
a solar regulator or charge controller, which regulates
the charging of the deep cycle battery bank. DC appliances
can then be run off the battery or via a power inverter
to supply standard household appliances with 240 volt electricity.
How many solar panels will I need?
This will vary greatly, but as a very general
guide, 75 to 120 watts of solar panels are required for
every 200 AH of batteries.
How many batteries do I need?
Depends greatly on your energy requirements.
For example, if you just wish to run a notebook all day,
LED lighting and a few small appliances intermittently,
a 100 AH battery may suffice, assuming you have the correct
sized solar panel to charge it. To run a household will
require far more battery storage.
Solar Panels FAQ
What is a solar panel?
A solar panel converts light energy into
electricity without causing pollution. Solar panels are
also referred to as a photovoltaic or PV modules (photo
= light, voltaic = electricity).
How does electricity get stored
for use after sun goes down?
With Remote Access Power Systems (not on
mains power) the energy is stored in deep cycle batteries
for use as required.
Grid connect systems direct excess electricity produced
during the day back into the local electricity grid. This
turns your electricity meter backwards in the process. You
then receive credit for any power that you put back into
the grid. At night time, you automatically use electricity
straight from the grid.
Can solar panels work in the shade?
The output of any panel will be reduced
or cut off if shaded. However, some solar panels do work
better than others in the shade. If a single cell is heavily
shaded, that cell is cut off.
Deep Cycle Battery FAQ
What is a deep cycle battery?
Deep cycle batteries used in solar power
systems are batteries designed to be discharged over a long
period of time (e.g. 100 hours) and recharged hundreds or
thousands of times, unlike conventional car batteries which
are designed to provide a large amount of current for a
short amount of time.
Power Inverters FAQ
What is an inverter?
Most household appliances use alternating
current (AC) electricity, which is what comes out of the
power point of a mains-grid connected house. However, the
batteries used in RAPS supply (DC) electricity. To make
conventional appliances run in a RAPS house, this DC electricity
must be converted to AC.
This conversion is done by a device called an inverter.
The inverter is connected to the battery bank, and provides
mains-type AC electricity to the house. The inverter needs
to be sized to suit the house's electrical requirements,
a common size being around 2000 watts, or 2 kilowatts.
Do power inverters store power?
Power Inverters cannot store power, they
just act as a 'converter' to change the power from a 12VDC
power source to 240V AC. This enables you to use normal
household appliances and tools from your vehicle.
What are the different types of inverters?
There are two different types of power
inverters: modified sine wave and true sine wave inverters.
Modified sine wave inverters
The difference between the two types is how close the output
power replicates standard AC mains power.
The difference in output between mains power, modified sine
wave and true sine wave inverters is shown below:
A modified sine wave inverter can adequately power
some household appliances and power tools. It is cheaper,
but may present certain compromises with some loads such as
computers, microwave ovens, laser printers, clocks and cordless
tool chargers. Virtually all low cost inverters are "modified
sine wave". A modified sine wave is easier and cheaper
to produce than a sine wave inverter. True sine wave
A true sine wave inverter is designed to replicate
and even improve the quality of electricity supplied by utility
companies. To operate higher-end electronic equipment, a sine
wave inverter is recommended. Efficiency has reached up to
about 98% and the electricity from these devices is of a higher
quality than grid power almost anywhere in the world.
To operate an inverter and supply power to
an appliance, a suitable 12V DC power supply is required.
This can be a vehicle, boat or caravan battery, portable power
pack or an independent 12V lead acid battery. For most applications,
a deep cycle battery is recommended for best performance.
For 24V power inverters a 24V DC power source is required
and are designed for those that use a 24 Volt System or battery.
A regulator is an electronic device which
controls the voltage of the charging source. Regulators are
used to stop the batteries from being overcharged. When the
batteries are fully charged, the regulator halts the flow
of power from the solar panels to the batteries. Additionally,
a regulator stops any power flow from the batteries at night.
The controller is also used so that the batteries get charged
at the correct voltage. In order to calculate the Amp rating
of a controller you must follow this simple equation:
Amps x Volts = Watts.
So, if you have a 175W panel at 24 volts the following calculation
should be made Amps x 175 = 24, then the regulator should
be at 175/ 24= 7.3 Amps.
The solar regulator's measured amp rating
should slightly exceed the total amp rating of the solar panels.
You should buy a charger which is 1/10 of
the battery size. ie. If you have a 100amp deep cycle battery,
buy an automatic 10amp battery charger.
Different types of batteries require different charging regimes.
SLA (sealed lead acid), AGM (absorbent glass matt) and gel
batteries are traditionally charged at a lower voltage than
flooded lead acid batteries. This varies depending on the
manufacturer and you should always check what charging voltage
is required before you buy deep cycle batteries and a battery
The terms "wind energy" or "wind
power" describe the process by which the wind is used
to generate mechanical power or electricity. Wind turbines
convert the kinetic energy in the wind into mechanical power.
This mechanical power can be used for specific tasks (such
as grinding grain or pumping water) or a generator can convert
this mechanical power into electricity to power homes, businesses,
schools, and the like.
Wind turbines, like aircraft propeller blades, turn in the
moving air and power an electric generator that supplies an
electric current. Simply stated, a wind turbine is the opposite
of a fan. Instead of using electricity to make wind, like
a fan, wind turbines use wind to make electricity. The wind
turns the blades, which spin a shaft, which connects to a
generator and makes electricity.
The vagaries of the wind in different areas,
differing loads, land mass heights and potential structures
that will cause wind turbulence are major considerations.
The closer you are to the sea the greater likelihood of stronger
winds. This has its own challenges with wind strengths that
can destroy the generator. Turbulence must be considered.
One of the best non technical methods is
with a kite. You have streamers tied to the kite string and
by taking careful note of how the streamers react you can
easily judge how far you need to have the generator placed
from the cause of the turbulence.
No easy answer. In some cases it is the tower with guy wires
not able to support the structure adequately. In turbulent
areas bearings. Most modern wind generators do not have brushes,
replacement of leading edge protective tape in sandy areas