If you generate renewable electricity in your home or business, you can feed back into the grid any electricity that you don’t use. Under the Smart Export Guarantee ( SEG ) you will be paid for every unit of electricity that you feed back. You won’t be paid for any that you use yourself.. The Feed In Tariff (FIT) WAS a government incentive that paid households and businesses to generate their own energy from ‘renewable’ sources. 
PV (Photovoltaic), extract from SEG: Guidance for Generators
1.12. For PV, wind and micro-CHP installations up to 50kW, applicants will be asked to demonstrate that their installation and installer are suitably certified. You may have an installation certificate to demonstrate this. This may be a Microgeneration Certification Scheme (MCS) certificate, but the SEG also recognises that other schemes may be equivalent to MCS.
1.13. If you do not have an MCS certificate, your installation and installer should be accredited in accordance with EN 45011 or EN ISO/IEC 17065:2012. You should speak to your chosen SEG licensee to understand exactly what information they need from you.
Any tariffs offered to installations with a TIC greater than 5MW are offered under commercial contracts and not under the SEG legislation.
1.14. If you are unable to demonstrate that your installation is suitably certified, a SEG licensee is not obliged to offer payments under the SEG, but they can make payments if they wish.
file:///C:/Users/C/Downloads/seg_generator_guidance_-_final_for_publication.pdf
Feed in Tariff (FIT) (pence per kWh) SCHEME CLOSED TO NEW APPLICANTS MARCH 2019
This information is issued errors & omissions excepted.