Electricity generation in Australia is the biggest single source of CO2 producing about 195 million tonnes of annually which is equivalent to 35% of our total CO2 emissions or to personalise this, the average household consumes 8000 kw of electricity per year which the generation of produces 8 tonnes of CO2. In addition, transmission and distribution losses occurring when power is transported over long distances can exceed 16%. Putting together you own power system can help you reduce your reliance on coal fired electricity generation and reducing your reliance on the system, it can also be fun!
One of the things that strikes me every time I start to do stuff for myself, whether it is raising my own seedlings, making a worm farm or baking my own bread, is that to do things for yourself you have to know “stuff”. All sorts of “stuff” and putting together an alternative energy system is no different. To plug an appliance into a wall socket and turn it on doesn’t require much thought or understanding – you just do it. To do things for yourself you have to understand some theory about the thing you are going to do. So before jumping right in I’d like to cover off a bit of theory about electricity. If you know this stuff already, just bleep it out and move on!
Electricity comes in two flavours –
Alternating Current (AC) which is the type of current that is supplied to your house power and lighting sockets and that powers your lights and appliances. Due to its particular characteristics it cannot be stored in batteries.
Direct Current (DC) is used in your car to run it’s electrical system and can be stored in batteries. This is an important distinction because if you are developing your home power system and thinking that you can use solar panels (which produce DC) to run your AC appliances directly you are bound to be disappointed.
There are a few other terms that need to be introduced – volts, amperes (or amps), watts and ohms.
Volts are a measure of potential difference, but can be thought of in terms of electrical pressure, like water pressure in a pipe, the greater the pressure, the more it will flow along the pipe.
Amps are a measure of current or the amount of electricity flowing along a wire and is like the amount of water flowing along a hose over a given time.
Watts are a measure of power used by a light, appliance whatever and can be calculated by multiplying the voltage required by the appliance by the number of amps it consumes. This is important when working out what size inverter that you need (if you are going to use one, that is!), and
Ohms, which are a measure of electrical resistance, in other words when electricity flows down a wire, there is a certain resistance to that flow in much the same way as water drags on the inside of the pipe down which it is flowing, which reduces the flow at the other end. Resistance is usually reduced by providing thicker wiring or configuring the system so that you use shorter runs of wire.
Before we leave the theory stuff there will be two electronic “black boxes” (a black box is where you pump stuff in one side and it comes out the other side changed somehow but you have no idea how the black box does it!) that we need to mention –
A rectifier which converts AC to DC and an inverter which changes DC to AC and in the context that I will be using it, changes 12 volts DC to 240 volts AC or in other words, what your alternative power system produces into what your house appliances and lights use.
I know that was painful but it is important to understand some basic electrical concepts because it will make designing and building your own system, or operating a system someone has built for you, much easier.
