There is definitely an ROI, especially with recent prices (current tariffs are around 33p kWh) Then there's the likes of Ripple Energy's solar park co-op offer

There is definitely an ROI, especially with recent prices (current tariffs are around 33p kWh) Then there's the likes of Ripple Energy's solar park co-op offering. The levelised cost of buying in is around 2.5p kWh, with another 2p kWh going on maintenance. The return on the 1st (and active) co-op agreement there via a wind farm is 28p kWh, no reason why the solar park would give different returns than the wind one. Here in the UK grid pricing is more or less the same nationally. Unfortunately there's much less of a return in Winter months due to higher latitudes, though in Summertime the days are longer than in many other countries.