Instead of pv on your 80 yard bank you could grow your own solar array from willow. With a three year coppice rotation you could provide your home with a sustainable and carbon neutral supply of useful energy to heat your house.
I don't have an 80 yard bank - but there is an area that willow could be relevant.
There are many types of willow available - assuming I want to run a log burner, rather than make cricket bats...

 - which is the type that has the growth factor for a 3 year rotation ?

Is there a good website reference?