Reducing our dependence on oil would help our environmental goals, and also reduce the need to have too much to do with volatile parts of the world, with obvious savings in the armies etc.. Our gas supplies are running out, and local generation would be better than being an importer of fuels.
With the electric car revolution on the horizon locally generating more green electricity would seem to be the future as demands are going to go up. The public dislike talk of new fossil fuel based power stations or nuclear generation. If this task were to be carried out by the general populous in a safe, legislated way, over thousands of private properties and small businesses the result could be the emergence of new hardware manufacturing lines for the technical industry; It could mean currently unemployed people with expertise in engineering/builders or simply people with land could enter self employment in running small businesses in a whole new home based industry, reducing people on jobseekers allowance.
The creation of modern water mills etc. could help the currently stalled building industry.
The more popular small scale generation becomes, the more mass produced the equipment would be, making it cheaper to buy and more approachable for individuals to buy into, even if it is just to earn discounts off of their bills; increasing the percentage of green energy generated in the UK, whilst not having to entertain costly discussions and campaigns against large scale development regarding other environmental concerns like habitats and views etc.
It would bring the UK closer to its carbon targets that currently may not be met, and possibly make the UK lead the way in 21st century crowd-generation of power.