Upgrading the insulation values in your house is often the first place to start rather than installing expensive micro-generation systems. The existing UK housing stock is thought to be amongst the leakiest in Europe and has a reputation for poor workmanship regarding insulation standards and air tightness.
Insulation is relatively easy to install and would also be a fraction of the cost compared to renewable energy systems.
Micro-generation systems are not a viable solution to reducing carbon emissions unless the existing housing stock is properly insulated first. Energy-efficient measures need to be taken before renewable energy is introduced, otherwise it will undermine the purpose.