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There are many reasons to visit Iceland. This former Viking stronghold is now the most peaceful country and home to the happiest and most literate people in the world — one in 10 Icelanders on average reportedly has published a book. A nation of glaciers, volcanoes and waterfalls, Iceland is also, at least metaphorically, one of the greenest places, generating all of its electricity from renewable sources such as hydropower and geothermal energy.
But there are challenges. Landsnet, the island’s transmission system operator, must maintain an electrical grid that can balance and move large amounts of power between the capital Reykjavik, where 90 percent of the country’s 330,000 citizens live, and a large and power-hungry manufacturing sector dominated by the aluminum industry. It’s not an easy task, and Landsnet is now pioneering advanced software, controls and an analytics system to make sure changes in power supply and demand won’t cause a problem the Icelanders’ Viking ancestors have never been known for: low inertia.
First, some background: Inertia is the basic physics concept that anything that moves will keep moving at the same speed unless some force causes it to change. A system with low inertia is like a merry-go-round with just a couple of kids riding it. One of them scrapes his shoe along the ground and quickly slows it down. But if 20 kids are spinning — a high-inertia situation — the kid scraping his shoe will hardly change the rotating frequency.
The grid receives electricity from generators that move at a constant frequency, just like the merry-go-round. When a power-hungry load suddenly disconnects from a high-inertia grid with lots of generators, the grid frequency will barely change. But when a generator or load goes offline in a low-inertia grid like the one in Iceland, Landsnet has to act quickly to return the frequency to its normal level.
This can be a real headache. If the frequency drops or climbs too quickly, it can knock down parts of the grid and cause power failures. It can even cause a geothermal power station to automatically disconnect from the grid to protect the equipment from large stresses. Dramatic changes in frequency can also create “electrical islands” as different areas on the grid react to the changes. This can lead to blackouts.
A power outage is always bad news for customers like Iceland’s aluminum smelters, which need an uninterrupted flow of huge amounts of electricity to smelt the metal. A loss of power can stop the process, and if not restored within 4 hours, the metal can solidify in the smelting pots and ruin the production line.
In the past, operators would deal with the problem by keeping reserve generation running and relying on a strong transmission network. But with the advent of fast communications and control, companies like Landsnet can now use new measurements and analytics to make the grid smarter and even allow it to heal itself.
Landsnet already deployed on its lines and other assets a piece of GE software called a Wide Area Monitoring System. It can collect, analyze and visualize real-time information from the grid. Next, the GE supplied the grid operator with control systems that use this information to maximize the grid capacity. Together, these systems minimize the effects of the disruption so the grid can get back on track faster. “The Icelandic grid is particularly interesting for me because of the dynamics and stability issues,” says Douglas Wilson, chief scientist for such systems at GE Energy Connections, who moved his family from Edinburgh to Iceland for the first six months of 2017.
Wilson is now designing and installing controls in multiple locations on the Landsnet grid that will allow energy producers and customers to respond and contribute to grid stability. The data will allow the system to spot disturbances and give the smelters, factories and generators control signals within half a second to rebalance and restore the system.
Grid stability is a concern throughout Europe, and it’s the focus of MIGRATE, the international project that’s investigating requirements for Europe’s future electricity grid. As one of project’s participants, Landsnet is contributing what it is learning from dealing with its own low-inertia grid. “I would expect similar issues as in Iceland to appear in countries towards the edges of Europe, such as Denmark, Spain, Portugal and the Balkans, where there are areas with low inertia,” Wilson says. “We will be applying the learnings we get here as we look to the future of the European grid.”