Renewable Energy - The Technology

Renewable energy generally covers those forms of generating energy that does not result in the depletion of a resource that is not naturally renewed.

This invariably means the use of energy that has come from the sun, either directly or indirectly. An exception being tidal power which is a result of the orbit of the Moon round the Earth.

Common means of tapping renewable energy include:

Solar Thermal

The direct collection of the heat from the suns rays, transfer and concentration. This is usually seen in the form of solar heating panels (or tubes), passive solar heating in greenhouses, buildings and conservatories shoul dbe included. For large scale use, solar thermal is used to concentrate the suns energy to generate steam and power turbines.

Solar Photovoltaic (Solar PV)

The generation of electricity using the energy bound up in sunlight. Solar PV is often seen in the form of distinct solar panels mounted on roofs or independently. It is generally considered a high cost way of generating electricity but can be significantly cheaper than traditional means when starting from scratch and developing infrastructure. Solar PV is now being used as building cladding for commercial premises, often a cheaper option than other means of cladding.

Natural Light

We all use it but is seldom mentioned as a renewable energy source except where used for the ongoing generation of electricity. Natural daylight is often designed out of buildings being replaced by controllable 'un'natural lighting. Natural lighting is free and can often be directed to areas away from windows using light pipes.

Heat Pumps

Seen in many forms from air conditioning units and fridges, through to ground sourced heat pumps. Traditionally used to cool air, now increasingly used as a heating system effectively converting a unit of electricity in to 4 times the equivalent of usable heat. Challenge is effectively managing the 'cold' side of the system to avoid icing up and the short term cessation of the cycle.

Wind Turbines

The natural development of the windmill, taking energy out of the wind and transferring it into a usable form, invariably electricity. One of the most cost effective forms of renewable energy given a reliable source of wind. Lowering costs have seen the popularisation of small scale wind turbines. Care must always be taken to ensure they are sited with sufficient wind to justify their installation.

Biofuel

Traditionally used for heating, a load of logs in the country can cost from £45 and avoids the use of coal. The renewable aspect is the fact that the CO2 released is regained by newgrowth where grown sustainably. The risk is always that the soil is depleted as plants take up trace elements which are removed from the local environment when the trees are felled and removed.

Increasingly used in cleaner forms, pelletised or turned into bio-ethanol or plant oil for use as a petrol or diesel replacement respectively. There is increasing concern about the inappropriate growing of 'food for fuel'.

Hydro Power

As with windmills, a form of power that has been with us for many years. Not only are large scale dams able to generate beneficial amounts of electricity but so to can small scale hydropower stations. All that is required is access to a suitable head of water.

Wave Power

The great white hope? The problem with wave power is the wave's themselves in that the technology is understood and there are many ways of using wave power, but waves vary so much in power! Wave power systems by their very nature must be able to cope with the tempest and the flat calm! New designs are looking at totally underwater systems where the extremes of weather can be mitigated. ESRU Research

Human and Animal Power

Shanks pony (walking), cycling, horse back riding and wind up radios and lights.