Traditionally power plants were built close to cities and other areas of significant consumption. While renewable such as wind and solar offer the promise of clean, sustainable energy, these facilities are located much further away from the people and businesses they serve so the need to store and transmit energy is crucial to fulfilling the promise of green, smart energy.
Jenny Hogan, director of policy at Scottish Renewables, observes, “Much of Scotland’s tremendous green energy resource lies away from our largest towns and cities, and transferring the vast amounts of power produced by hydropower stations and wind turbines to where it is needed calls for a step-change in the way we work with energy. If we are to maximize the benefits of moving towards decentralized local renewables generation, and away from more traditional sources of power, we must change the way in which we transmit and distribute that power across the network.”
Scotland’s islands are a mecca for wind, wave and tidal projects and Hogan reports that Orkney already generates more renewable electricity than it can use.
But she also notes, “Like most of the Scottish islands [Orkney] remains locked in, unable to reach the rest of the UK network at all for lack of a fit-for-purpose interconnector cable.
These challenges, though, are not insurmountable. And in finding solutions we can also find new opportunities.”
The UK’s first smart grid was established in Orkney in 2009. The upgraded energy infrastructure has enabled increased deployment of renewable power generation at a fraction of the cost of transmission hardware upgrades.
Hohgan explains, “At times of peak demand—when kettles are switched on during the break in Coronation Street, for example—every joule of energy produced by Orkney’s renewable energy fleet could potentially be used. A short while later, when TVs are turned off, that demand falls, but power is still being produced. This situation, exacerbated by pinch points in the transmission network, means generators must shut down to prevent damage to the grid.
SSE Power Distribution worked with the University of Strathclyde to develop what is called the active network management approach, where generators control their output, in real time, to match available network capacity.
According to Hogan, “The active network management system allows power flows at several points on the network to be monitored, and power flows from multiple new renewable generators to be controlled without being closed off. The connection of this level of renewable generation on Orkney by conventional network upgrading and reinforcement would have cost around £30 million, and would have meant a long wait and substantial environmental impact. In contrast, the total cost of developing and delivering the Orkney Smart Grid has been around £500,000.”
A similar approach is being implemented on Shetland and is expected to bring benefits to more than 700 homes.
Hogan adds: “Controlling how energy is generated and how it is used is a relatively simple process, but it is only by tying those two activities together that we can start to reap the broader benefits of our investment in renewable energy.”