Solar heating is becoming an increasingly popular option for domestic water heating, basically using the heat of the sun to warm the water. It's economical and green, reducing both your fuel bills and carbon dioxide emissions. Obviously once you've paid for the installation of your system, sunlight is free! You can apply for help with installation costs from the government's Renewable Heat Incentive, and may even be able to receive payment for the heat you generate. Solar heating can be used all year round, although a conventional boiler or immersion heater may be needed to make the water hotter when there isn't enough sunshine.
Micro-CHP (micro-combined heat and power) is a new way to generate both heat and electricity simultaneously from a single source. The main emphasis is on heat, and in a domestic setting the ratio of heat to electricity produced will typically be around 6:1, generating around 1kW of electric power. Any electricity produced but not used can be sold to the National Grid.
Micro-CHP systems run off mains gas or LPG at the moment, although will probably be powered by oils or bio-liquids in the future. Of course gas and LPG are fossil fuels, but because a micro-CHP system uses these in a much more efficient way than traditional means of energy production it is still considered to be low carbon technology, as less carbon emissions are produced. They are very similar in size to an ordinary domestic boiler, but have the additional benefit of being able to generate electricity for the home at the same time as heating water.
The costs of installation, servicing and maintaining a micro-CHP system are comparable with a standard domestic boiler, but your engineer must be approved by the Microgeneration Certification Scheme. Another bonus of this system is that you can earn 10.5p for each kWh of energy you generate and 3.1p for each kWh you export to the grid.
Biomass systems are basically wood-fuelled heating systems that burn pellets, chips or logs. A wood burner can heat a single room, whereas a wood boiler can be used to power a central heating or hot water boiler. Burners can also have back boilers attached to them. Biomass systems can also benefit from the government's Renewable Heat Incentive in the same way as solar heating systems.
Biomass is a very low carbon option. Ideally wood should be sourced locally and plants replaced to create sustainability. Some carbon dioxide is emitted when wood is burned, but it is much less than with fossil fuels - around 7.5 tonnes a year less than coal or electricity. Financial savings depend on the system being replaced, but wood is often cheaper than other fuels. A wood-fuelled boiler can typically save around £600 a year compared to electric heating systems and cost about £100 a year less than gas.