A tale of two islands – what to do with too much energy?

Remote and rugged, a refuge from modern life – the cultural myths surrounding islands and their inhabitants have a fierce hold over our imaginations. Reality is often more prosaic, but could we learn how communities on islands – awash with wind, sunshine, wave and tidal energy – are pioneering use of natural resources? As the global energy supply tightens and the world grows ever hotter, the need to muster clean energy becomes acute. 

We look at creative approaches of two award-winning islands: Ærø in Denmark, and Orkney, off the north coast of Scotland.

You can literally feel the energy in the Orkney Islands – apart from the few days a year the wind doesn’t blow. From his home desk on a blustery Orkney Mainland (the principal island in the archipelago), Neil Kermode, managing director of the European Marine Energy Centre (EMEC) can see his garden wind turbine spinning vigorously. With average winter winds of 36km/h, the device produces 16,000 kilowatt-hours of electricity each year – more than enough to power his own home and electric car. The rest, he sells back to the UK grid – underwater cables connect Orkney to the Scottish mainland. Regulation (by SSEN) currently prevents him installing a domestic battery for storage.

The Orkney Islands have become the poster child of progress in clean energy and work similarly to Kermode’s house but on a larger scale, selling excess back to the grid. Some 80 per cent of the islands’ total energy use is fossil-fuelled; the remaining 20 per cent is from electricity, “and we have largely succeeded in decarbonising that”, says Kermode.

Ratios of electric car charging points per head are among the highest in the UK. Since 2013, the islands have generated more than 100 per cent of their electricity needs from renewable power. They are at the vanguard of green hydrogen technology, and their geography makes them an ideal place to learn how to harness the fierce tides and waves that lash the shores. Last year, plans were unveiled to transform an oil terminal into a world-first large green hydrogen plant – using wind to produce hydrogen at industrial levels.

“Orkney is saturated with renewables,” says Kermode. “We are showing the art of the possible – and also the inapplicability of some of the regulations that are holding us back.”

Islanders can measure how much electricity is produced and how much they buy back. There’s too much natural energy here to make use of. On windy days, community turbines are disconnected to avoid overloading the energy grid – and that’s a waste, say islanders, who pay 2p more per kilowatt-hour of electricity than the rest of the UK, due to historic charging regimes.

All islands embracing clean energy face the same problem when the wind doesn’t blow, and the sun doesn’t shine. “The biggest challenge is energy storage,” says Halfdan Abrahamsen, project manager at Ærø Energy Lab on the island in southern Denmark, now famous for its world-leading electric ferry. “Batteries are expensive, and there are emissions linked to their production.” More dependable tidal energy is still on the cusp of exploitation.

Both Orkney, in the wild waters where the North Sea and Atlantic meet, and Ærø, in the Baltic Sea, have a long history of harnessing the wind before global warming made this a necessity.

Back in 1951 on Orkney’s bleak and blustery Costa Head, where winds blow above 125mph (200km/h), engineers built a tall tower topped with blades of spruce and plywood to create one of the UK’s first wind turbines. Now the islands host some 730 domestic and 12 larger turbines.

In Denmark, it was in the 1980s that engineers on Ærø built some experimental turbines, inspired by the prospect of ‘free’ energy after the oil crisis. When the price of oil subsided, the economics no longer made sense. But now the island boasts six 2MW turbines. which produce more than enough for the 6,000 residents – up to 140 per cent of their electricity needs. By 2030, the island aims to be self-sufficient for renewables, which is “certainly a challenge”, says Abrahamsen. Domestic and large-scale solar panels contribute to the mix in sunnier months, but wind is the dominant source.

While the ice winters that used to lock Ærø off from the mainland now may be a thing of the past – the last was in 1995 – islanders welcome the sense of independence that comes with an element of self-​sufficiency. Onshore wind turbines here are owned by the community – cooperatives have long been a feature of Danish life. “All over the world, people say ‘not in my own back yard’,” says Abrahamsen. “But as an islander said, a wind turbine is ugly, but it looks a lot better if you know it’s making you money.”Both islands have picked up an EU prize recognising them as among the most sustainable in Europe. The RESponsible Island Prize, funded by the research and innovation programme Horizon 2020, was won by Ærø in 2020, while Orkney came third the previous year. Judges were impressed by the innovation and community involvement.

Despite the awards, neither island has a perfect carbon footprint; Orkney ferries run on diesel and regulations have so far hamstrung attempts to experiment with hydrogen instead, some remote homes still burn oil, and planes fly in. Ærø offsets emissions from any imported electricity in the quiet times and buys woodchip from Poland to boost electricity for its domestic heating system – the EU ranks biomass as carbon-neutral. Electric cars are fewer on Ærø than the mainland, but more charging points are coming. “I’m sure we’ll see growth in the coming years,” says Abrahamsen.

While the idea of island life among Ærø’s cobbled streets, fairytale houses and beach huts might seem appealing and quaint to outsiders, being able to nip across to the mainland easily is crucial, says Abrahamsen. And the island boasts a world first – Ellen, the world’s largest fully electric ferry. Laden with 55 tonnes of batteries, the ferry can travel a round trip of 22 nautical miles (40km) without diesel back-up on board – seven times further than other electric ferries. This matters – maritime fuel is among of the most polluting.

“We’ve pushed the envelope,” says Abrahamsen. “When we launched, we wanted to show that this was possible on large regional passenger ferries.” By 2035, if not earlier, the island aims to electrify the three remaining diesel ferries, but to do this, the island must generate more power – Ellen requires 10 per cent of the island’s electricity supply. Plans are afoot to build a shore-based battery to charge ferries between trips. Down the line, Orkney may decide to electrify ferries, says Kermode, and there are plans to experiment with a hydrogen cell on board.

Ærø is a place where ideas can fly, says Abrahamsen. It was a teacher at the island’s school of navigation who teamed up with an engineering colleague to propose an emissions-free ferry; as a result, islanders went on to secure EU funding to develop the technology. “It’s a small community with a lot of specialised knowledge. If citizens have a good idea, our office can help.”

In another quirk, a small 16th-century manor house in the north of the island is now warmed by a heat pump that harnesses the temperature differential between water in its refilled moat and the air. “That warms the manor all winter… this illustrates the creativity involved in Ærø’s transition,” says Abrahamsen.

Both islands face the same problem as communities the world over: how to store energy to ride through the lulls. In 2015, the first hydrogen projects began on Orkney, with an initiative to use renewables to electrolyse hydrogen. A new electrolyser is in the pipeline, says Kermode, but capacity will remain at 1MW. Experiments have shown it’s more economical to use hydrogen for fuel rather than a storage medium to potentially discharge back into the grid. Experiments are under way to create emission-free aviation fuel, and even use hydrogen to distil whisky.

In the future, tidal may provide energy security. Tides around the islands can reach 12 knots and waves can be steep; innovative turbines have been trialled. “The sovereignty of our waters means we don’t have to rely upon imported fuels with the associated efforts to protect those supply lines,” says Kermode.

Even car and house batteries could eventually play their part in storing excess energy, he says. Charged in times of abundance, they could be leveraged for power in the lulls and the dark. A four-year project – ReFLEX Orkney – is pioneering a digital connected system that aims to link and manage energy use and storage, in part by encouraging electric cars – an extra 140 are now on the island as a result, with more expected.

Energy storage on Ærø takes place in a 75- million-litre warm water storage tank built a decade ago, big enough to give three months’ worth of heat for some 1,600 households.

In 2008, the tiny Scottish island of Eigg made news by becoming all but self-sufficient in renewable energy, with its own micro-grid installed for the 60-strong population (now 110). Neither Ærø nor Orkney aim to be cut off from mainland supply, which Eigg lacks, but they want to cut costs and generate as much energy as they can.

Both locations are often described as living laboratories. “The advantage of an island,” says Kermode, “is you can try stuff out and understand the impact of it. Imagine trying to electrify the whole of the cars in Manchester or London. The scale of investment required here for big experimental changes is comparatively small.”

Academics often visit Ærø because the geographical limits offer better data. “It has clear boundaries, it’s disconnected from the chaos of the mainland,” says Abrahamsen. “We are pioneers in renewable energy. We have an open-door policy – if citizens have a good idea they can present, and we supply the project management and help with the funding. It’s not an island thing, it’s a community thing.”