Orkney's strong winds and powerful tides have attracted renewable energy pioneers for decades. For much of the year the islands produce more energy than they can use. Turbines are shut down and green energy goes to waste. The UK government has spotted an opportunity, funding the REFLEX project which aims to use that excess energy to develop new ways to power a community. Tom Heap visits Orkney to see how hydrogen storage, huge batteries and electric ferries and cars can be lashed together with clever software to remove fossil fuels from an entire energy system. Producer: Alasdair Cross