MaRINE RENEWaBLE ENERGY  Last year the Offshore Valuation Group, a collection of academics, industry and Government experts, concluded that marine renewable energy from the North Sea would be worth at least as much as oil has been, and could power the whole of the UK by 2050. The Scottish Government estimates that by 2020 the industry could be employing 40,000 people and bringing in ?30 billion  of investment.  Wind pOWER  Scotland s onshore wind capacity is now greater than both our nuclear stations put together and plenty more is possible while still protecting our most important landscapes. Scotland s peak electricity demand is 5GW and onshore wind can now provide up to 2.7GW, with another 10GW in the pipeline. Offshore wind is going to be even bigger but is just  beginning to take off, with Donald Trump s favourite scheme off aberdeen part of the 10GW already planned.  Wave and tidal  Scotland really is leading the world on wave and tidal power development,  with major companies coming here  from abroad and several Scottish companies with successful medium-scale machines already in the water.  Up to 1.6GW is expected to be running by 2020 but the long-term potential is more like 20GW.  Hydro  Large-scale hydro was the major renewable energy success of the 1940s, 50s and 60s, bringing electricity and jobs to the glens of Scotland. There are still some big schemes that could be developed but much of the focus is on schemes at the estate, farm or community scale.  Solar  Solar photovoltaic panels make electricity, solar thermal