What are the benefits of renewable energy systems for my home?
Renewable energy systems make use of solar powered resources, wind turbines that generate electricity, biomass crops and heat pumps that concentrate heat absorbed by the air, ground or water to heat buildings in winter and cool them in summer. With various technologies available to install in your home which systems will provide the most benefits.
Which renewable energy systems are best for your home?
Your choice of renewable energy resources will depend on the prevailing climatic conditions, the characteristics of your home, and the relative advantages and disadvantages of each renewable energy source. If you are planning to construct a passive house, or to retrofit an existing building, it is worth getting professional advice.
The following table summarises the relative advantages and disadvantages of renewable technologies.
|Solar water heating||Can be applied just about anywhere (depending on the amount of sunlight). Requires very little maintenance. Size can easily be adjusted according to needs and available resources.||The building roof may not be correctly orientated (i.e. may not face south). The system must be complemented by other water heating technology when there is insufficient sunshine.|
|Heat pumps||Can be used for heating, cooling and producing hot water. Electricity and lowgrade heat are available from a variety of sources. The electricity needed to operate the heat pump can come from renewable sources. Natural refrigerants are now being used that have zero or very low environmental impact.||Investment costs are relatively high. Sufficient space is needed if a ground source collector is used. The refrigerant needs to be recovered at the end of the system’s life. The electricity used by the heat pump may still come from a power station using fossil fuel.|
|Biomass for heating||Can include wood waste (woodchips, pellets). Is a “carbon neutral” resource: burning it emits exactly the same amount of CO2 as was absorbed by the living tree. Local sources can be used, reducing the need for transportation.||Requires an appropriate chimney, which can increase investment costs. Flue gases may include toxic substances and particulates. Adequate storage space is needed for the fuel.|
|Photovoltaic cells||No significant maintenance needed over a lifetime of 20 to 30 years. More efficient and cheaper products are appearing on the market. Electricity is produced locally, eliminating distribution losses. Size can easily be adjusted according to needs and available resources.||Relatively expensive technology, although the payback period is already down to around 15 years. The building roof may not be correctly orientated (i.e. may not face south). System should be connected to the grid to cover periods when there is insufficient sunshine.|