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Power Grid

What A Gas! Utilities Look To Green Alternative To Global Warming’s Worst Culprit

Amy Kover
January 10, 2020

António Guterres did not mince words. “The point of no return is no longer over the horizon,” the United Nations secretary-general said in a speech last month as he kicked off COP25, the U.N.’s much-anticipated climate change conference in Madrid.

On that grim note, Guterres got to work, spending the first two weeks of December with leading policymakers, climate experts and scientists planning how the world can reduce greenhouse gases — the most notable offender being carbon dioxide — and become carbon-neutral by 2050.

Meanwhile, a few miles north in the offices of RED ELÉCTRICA DE ESPAÑA S.A., engineers are making strides of their own. The Spanish grid operator is working to reduce a lesser-known — but even more potent — greenhouse gas called sulfur hexafluoride, or SF6.

For the past four decades, utility companies have relied on SF6 to decrease the footprint of their substations; its insulating characteristics make it more attractive than other inflammable and larger solutions. Those substations receive energy from the grid and adjust voltage for power transmission and distribution to businesses and homes. The gas, held in pressurized chambers of high-voltage equipment surrounding the power equipment, is an amazing insulator and arc extinguisher.

Trouble starts when SF6 leaks: Its global warming potential is 23,500 times worse than CO2 when compared over a 100-year period, and the gas could linger in the atmosphere for more than 3,000 years, according to the Intergovernmental Panel on Climate Change. The power transmission industry accounts for over 80% of the world’s SF6 use and, as the appetite for energy grows, the gas’ concentration in the atmosphere has increased by 40% over the past 10 years.

However, utilities now have a better alternative: Green Gas for the Grid (g3, pronounced “gee cubed”). Developed by GE Renewable Energy’s Grid Solutions after over a decade of research, in collaboration with 3M, the new gas reduces global warming potential of the  SF6 gas by more than 99% while retaining the same insulating qualities. It also allows electrical substations to keep the same compact dimensions — an important quality in areas that need lots of energy but have little space to house grid equipment. “g3 offers power companies a way to reduce their physical and environmental footprint and expand the grid without using SF6, therefore decreasing their environmental impact,” explains Vera Silva, chief technology officer for GE Renewable Energy’s Grid Solutions.

That’s partly what convinced RED ELÉCTRICA DE ESPAÑA S.A. to become the first utility in Spain to incorporate g3 technology. The country will use the gas for its new transmission system on the Canary and Balearic islands, which need energy to support millions of tourists visiting pristine beaches and volcanic sites.

The Spanish power transmission company will join 17 utilities worldwide already using the technology, including Scotland’s SP Energy Networks and Scottish and Southern Electricity Networks, Switzerland’s Axpo and Engadiner Kraftwerke, France’s RTE, Germany’s TenneT and the Netherlands’ Stedin.

g3 has become an attractive solution for renewable energy projects as well. “If you are connecting an offshore farm which offers significant reduction to greenhouse gas emissions, you also need to consider how it will interconnect to the rest of the grid,” Silva says.

Beyond building cleaner transmission systems, utilities also need to figure out how to remove SF6 from their existing ones. “This is a critical link,” Silva explains. “On one hand, you want to reduce the impact of a new installation, and the second thing is to go after the existing footprint.”

GE Renewable Energy’s Grid Solutions has created a timeline — or road map — of g3 product introductions to help utilities adapt the new gas with minimal headaches. For instance, in 2017, the U.K.’s National Grid was the first company to install g3 equipment. Pioneering utilities like National Grid will have their pick of g3-friendly equipment by 2025, when most GE Renewable Energy high-voltage products will be SF6-free. And word of g3 is beginning to spread beyond Europe: South Korea and California have both expressed interest in using g3 to eliminate SF6.

What might really win this global warming battle is making SF6 as infamous as CO2.

“Right now [the impact of SF6] is very niche knowledge,” Silva says. “But when people begin to ask, ‘Where are the other greenhouse gas emissions coming from?,’ GE is ready with a solution.”