How to make your own power

If you are interested in learning how to make your own power - called 'micro generation' - there are lots of ways you can do this. Deciding which one is the right one for you will depend on what you want to achieve, the characteristics of your location and the amount of money you want to spend.

Here is a brief overview of the different technologies available and the merits and disadvantages of each one.

How to make Solar Power

Directly or indirectly, all power on earth comes from the sun. The power of the sun is immense - every square metre of sunlight to fall on the earth provides the equivalent of 1kW of power.

This power can be harnessed in several ways, with varying amounts of efficiency. For micro generation, the most common ways to harness this power is through solar hot water heating, solar electricity generation and ground source heat.

In order to use solar power, you need a site with a lot of direct sunlight, a south facing location with little or no shade.

Solar Hot Water

Solar hot water is one of the most efficient ways of generating power, with modern solar hot water systems converting between 50-75% of the sun's power into heat. Solar panels heat up fluids which are then run through a heat transfer unit to heat up water for use in your home.

During the summer months, a solar hot water system can provide enough hot water to provide all the hot water a typical household will need. During the rest of the year, solar hot water supplements the existing hot water system.

Typically, a solar hot water system can save £50-80 a year on the cost of heating hot water for a typical family home.

Solar Electricity

Solar PV electricity panels have traditionally not been as popular as solar hot water systems. However, with the falling costs of photovoltaic panels and the rising costs of energy bills, these are becoming more popular.

Depending on the type of solar PV panel used, solar electricity can convert between 6% and 22% of the suns energy directly into sunlight.

Solar PV panels typically generate electricity at either 12 volt or 24 volt. The power is typically stored in a battery and then either used with low voltage appliances, or inverted to 240 volts using a power inverter. A solar panel controller is used to stop the batteries from being overcharged.

Thanks to their modular design and low voltage, Solar PV systems are easy to design and safe and simple to construct, which make them ideal for DIY projects.

Ground Source Heat

All houses require ventilation in order to remain fresh. Houses with too little ventilation feel stuffy, often have condensation problems and can be quite unhealthy environments. Unfortunately, ventilation means loosing heat as hot air is vented from the house. Ground source heat is a way of replacing stale air with fresh air that is pre-warmed in the winter and cooled in the summer, based on the constant temperature of the earth.

Two metres underground, the earth remains at more or less a constant temperature of around 11°c. With ground source heat, air is brought into the house through pipes that are buried underground. The length of pipe is typically several hundred metres long.

As air flows through the pipe and into the house, the temperature of the air adjusts to the temperature of the surrounding soil: in winter, the air warms up whilst in summer, the air is cooled.

The result is that air coming in from outside the house needs less heating in winter, whilst in summer on hot summer days the cooled air coming into the house cools the interior down - a form of natural air conditioning without the unnatural dryness you often get with an air conditioning unit.

Ground source heat is a very effective way of supplementing the heating in a home and can dramatically reduce heating bills. However, it is often impractical to install it in existing buildings, and only works if you have a large amount of land available to install the heat pipes into the ground.

Wind Power

Modern wind turbines are virtually silent and can be a useful way of generating electricity where the average wind speed is above 5 metres per second.

Household wind turbine kits are available for around £1,500 which can generate 1-2kW of electricity per hour. As the average house consumes around 0.8-1kW per hour on average, these turbines can dramatically reduce the dependence on the national grid for electricity and are the cheapest way to provide power to a remote building that has no connection to the national grid.

However, it isn't all good news. Wind turbines need to be built high up - preferably around 10 metres high - in a windy position and away from any obstacles such as trees and buildings. They also need to be built away from major roads as the turbulence from main roads can damage the turbines.

Small wind turbines can also be used to charge up batteries used on boats or caravans. These wind turbines produce tiny amounts of power - often no more than 50-60 watts per hour, but are ideal for charging up batteries that are only used occasionally or for low power applications.

How to make Hydro-electric power

There are two types of hydro-electric systems - those that work with a water wheel and those that work with turbines. In either case, you will need fast flowing water and a drop in order to power the turbine to create the electricity.

Biomass

The most common biomass system used in homes is the world-famous AGA. Used for cooking, hot water and heating, the latest generation of biomass systems are environmentally friendly and very effective.

Biomass systems are becoming more popular in small industrial applications where they are used for generating electricity and heating for factories and large warehouses. Many industrial units create a lot of waste such as pallets, cardboard, packaging and paper, meaning that biomass systems can be very cost effective.

For biomass to work well, you need a large amount of raw materials available. Sawdust is a often used as a fuel as it is an abundantly available waste material. For home use, it is unlikely that you will be able to be completely self sufficient in your biomass fuel use unless you have woodland to maintain.

In Conclusion

In general, generating heat is simpler and more cost effective than generating electricity and certainly for households, a heat system is often the most cost effective system to install first if you want to reduce your power bills and reduce your carbon footprint.

Do not discount electricity generation though - for the right projects, generating your own electricity has many significant benefits and can be extremely cost effective. Of those technologies, solar photovoltaic panels are usually the easiest and most reliable way of generating this electricity.

Michael Boxwell is a technical architect and designer. He is the author of a number of books including the Solar Electricity Handbook and The Electric Car Guide series of books.