Orkney has plans for ground source heat pumps at four new public buildings, thought to be the largest geothermal project of its kind in Scotland. Renewable energy systems such as these can help island communities to reduce their dependence on fuel imports and reduce carbon emissions. And, looking at Eigg, in the Inner Hebrides, they do more than that. They can also affirm a sense of identity and can inspire other communities to take the initiative.
Eigg gives prominent mention of its sustainability ambitions on its official website. And little wonder. It’s a great example of what can be achieved when a community has the will to get something done. The islanders hope that others will make the same sort of commitment. This site invites other islands across the world to share their green experiences.
For years, people on Eigg were dependent on their own individual generators for electricity. This really meant a dependence on fuel imports, which is particularly tough for a small island. Logistics mean that small islands simply can’t take advantage of economies of scale through high-volume imports of diesel. Shocks on the oil and gas markets are worrying for most of us. To an island off the national grid, it must have put a strain on budgets and peace of mind. And individual generators do little to reduce emissions.
Enter some clear-sighted, motivated individuals with a plan. In February 2008, Eigg Electrical switched on the island’s first twenty-four hour power.
They have three hydroelectric generators: one of them supplies 100kW, the other two supply 5/6kW each. Four small wind-turbines give a combined 24kW. Photovoltaic panels give 30kW. That’s a total generating capacity of 164kW.
The largest single source of power is the 100kW hydroelectric generator. But since there are spells when the island’s streams run more slowly, particularly in summer, the plans made sure that the burden was spread across complementary sources. The wind turbines are usefully operative most months of the year. Solar power works well in summer months, and summer days are wonderfully long in Scotland.
The operation of the system is rather brilliant. To ensure an even distribution of supply, accounting for different times of year and different times of day, there is an arrangement of batteries. They connect to the system through three inverters, which convert battery power to mains ac power. This, in turn, connects to the island’s grid through a transformer. The system allows a two-way flow. When more power is produced than is needed, the batteries are recharged. When there isn’t enough power being produced by water, wind or sun, the batteries feed in to the grid. And if the batteries fall below a certain level of remaining power, two diesel generators switch on automatically to make sure that no one goes short. (For those of you who love technical detail, there’s a lot of interesting stuff in this Eigg blog.)
Sometimes the renewables generate more power than is needed by the island’s households and businesses. When that happens, the excess is used to heat community buildings. Nothing goes to waste.
There are 11km of cable, but they are underground. The sites of the turbines were chosen with care so that the views were left as unspoiled as possible.
This overview of the technology is only part of the story. The scheme wouldn’t work without the consent of the inhabitants, and without their full, enthusiastic participation. Each house is restricted to 5kW, which is enough for a few domestic appliances. With the use of meters, households learned how to spread their consumption across the day. When the proposals were put to islanders, the vote was unanimously in favour. They could see the bigger picture, the common good.
Are there lessons here for the rest of the UK? We, too, are all so alarmingly dependent on others for our energy supply. Investment in renewables, learning how to use them, consideration of local conditions, cooperation with our neighbours, taking a realistic view of a situation, wasting nothing – that’s how to tackle our energy needs.
We are – all of us – islanders.