Using renewable energy is an
option for a variety of reasons. Practicality
and cost to be connected to the electrical grid is the
primary reason. The second is for people who like the idea
of being independent and not relying on the grid for
electricity and for environmentally
Using alternative energy can
be expensive. It is often economic to install an off-grid
system for people living a distance from the grid. However
when the grid is available, going off-grid is probably not
economic at this stage.
The intention of this page is
to broaden your knowledge of what is involved, approximate
costs and existing technologies currently in use.
Solar PV panels are by far the most
common generation source. Solar panels are easily installed, last a very long
time (upwards of 20 years), very low maintenance and can be
installed anywhere with a decent northerly view (Southern
hemisphere) or southerly view (northern hemisphere)
including urban areas.
However they do not produce a
high output for the area and cost involved. They are only
useful when the sun is out (cloudy conditions produce very
If available this option is
ideal. With a reliable water source and good head then a
house can easily be powered by hydro. However few locations
are suited to using hydro which limits its use.
Most locations have wind at some stage. However
access to a turbulent free air flow is important. Turbines
are suited to hills and areas away from buildings and trees.
Generally wind turbines are not installed in urban areas due
to noise and visual pollution. Turbines have to be able to
withstand storms. Additionally wind is not always reliable
(less than the sun) so large battery storage or the grid is
required. Wind speed and power output is related cubically.
So low winds produce very little output compared to wind
speed slightly higher. So what you find is huge amounts of
power available in storms and little in daily breezes.
The following information
gives a rough cost to install a system to an existing
some countries the power companies will buy the
electricity, otherwise the generated electricity
supplements your power requirements.
Generally a solar hot water system will be installed as
heating water absorbs most of a household energy bill.
Electricity is not generally used as a primary source to
heat water due to its very high energy requirement.
However often excess power (when batteries are full) is
diverted to a heating element to heat water.
find the approximate income you will generate, go on
to your national weather service website and find the annual
sunshine hours at your location. Multiply this number of hours by the
generating capacity in kilowatts (1000W = 1kW). Then
divide this by the daily electricity rate in $/kWhrs.
this basic calculator to calculate the very rough cost of
installation and pay back of a solar system
pay off time is normally about 20 years which is 5%
annual return on investment - comparable with a decent
interest rate at the bank.
hot water heating is a viable option for sunny areas.
Installation will be between $5-8,000 and will pay off
faster than solar electricity installations.
batteries must store electricity from the windy and
sunny days for use during the dullest and calmest period
you would expect in a year. The less reliable the
generating source, the larger the storage capacity
required. Large battery storage is key to a reliable
system. A back-up generator will often be installed when
power is low or when demand is higher than the system
can handle for instance when using large power tools.
The DC power from the battery bank is turned into 240VAC
to use with conventional appliances using an inverter.
Heating is generally not generated by electricity but
wood or fuel is combusted. This space heats, cooks food
and heats the water using a wetback and/or califont.
cycle batteries are able to be discharged further and
more frequently than car batteries. They are very
expensive and make up a bulk of cost. Additionally they
require replacing every 6-10yrs.
your site is suited to wind then this is generally
cheaper per unit of generated electricity but this is
often used in conjunction with solar. With a very
reliable water supply then hydro can be used by itself.
energy conscious family living off grid would use 3-7
kwhrs/day. The bulk of use will be lighting and
appliance use, since all heating will be from combusted
fuel or solar water heating. When considering cost, it
must be considered that reliance on fuels will increase.