Hitachi Energy’s roadmap for eliminating SF6

Above: EconiQ™ live tank breaker (LTA), 145 kV (Photo Credit: Hitachi Energy)

Recent months have seen Hitachi Energy (formerly Hitachi ABB Power Grids) announce several new projects involving its EconiQ™ portfolio of SF6-free high voltage equipment. 

Notably, the company has signed what it calls a “frame agreement” with Norway’s major distribution grid company, BKK Nett, to install EconiQ™ 145 kV live tank breakers (LTA) in more than ten substations in western Norway. For Hitachi Energy, “this is the very first frame agreement globally for its EconiQ™ eco-efficient breaker technology.”

Norway plans to cut at least 50% of its greenhouse gases by 2030 with the target of achieving carbon-neutrality by 2050.

The first project in the Hitachi Energy frame agreement is the Askøy substation, located on an island west of the city of Bergen. BKK Nett is rebuilding the substation to meet growing electricity demand from businesses and households.

“This frame agreement with BKK Nett marks an important milestone as the very first for the new EconiQ™ breaker technology”, said Markus Heimbach, managing director of the high voltage products business at Hitachi Energy. 

“With such an eco-efficient technology, we are able to build future-proof substations with lower environmental impact”, said Atle Isaksen, head of grid development at BKK Nett.

The new EconiQ™ LTA 145 kV breaker uses a mixture of carbon dioxide and oxygen as the insulation gas instead of sulphur hexafluoride, a greenhouse gas that has been the norm for decades due to its superior insulation and switching properties. The EconiQ™ high voltage portfolio essentially eliminates the CO2-equivalent emissions associated with the insulation gas and has been proven to significantly reduce the carbon footprint throughout the total lifecycle, says Hitachi Energy.

Meanwhile, in Scotland, Hitachi Energy is supplying SP Energy Networks with EconiQ™ gas-insulated lines (GIL).

Like Norway, Scotland has ambitious goals to decarbonise its energy system, and aims to reduce greenhouse gas emissions to net zero by 2045. On its path to carbon-neutrality, SP Energy Networks is upgrading an aging energy infrastructure and introducing advanced technologies to better manage power flows in the grid.

One such project is the Windyhill 275 kV substation located northwest of Glasgow. Built in the 1960s, the air-insulated substation plays a significant role in the SP Energy Networks transmission network – and is indeed part of the critical infrastructure node for emergency network recovery.

It is now being modernised as part of the SP Energy Networks “RIIO-T2” business plan (RIIO-T2 being the network price control scheme established by the UK regulator setting out what the UK gas and electricity transmission network companies are expected to deliver for energy consumers over the period 2021-2026).

Hitachi Energy will deliver 1500 meters of EconiQ™ GIL, which contains no sulphur hexafluoride, instead making use of an alternative insulation gas mixture.

The Windyhill substation refurbishment is expected to be completed in 2025.

In addition to the EconiQ™ GIL, Hitachi Energy will also deliver 15 bays of its 300 kV gas-insulated switchgear (GIS), a technology “pioneered by Hitachi Energy which can be installed in confined spaces and can operate in extreme environmental conditions.”

In a further development of the EconiQ™ offering Hitachi Energy has announced the introduction of EconiQ™ transformers. 

These are said to “have co-creation at their heart.” The transformers “will be tailored based on specific customer sustainability requirements and using proven scientific methodologies, such as environmental life cycle analysis.”

For example, a 115/21 kV, 40 MVA EconiQ™ transformer is estimated to reduce carbon dioxide emissions by about 23% over its life-cycle, while reducing eutrophication and water toxicity impacts by about 15%. It would also eliminate the related environmental impacts in the rare event of mineral oil leakages. The EconiQ™ transformer life cycle analysis assumes the electricity mix of the European Union and is based on a 35 year operational life and 75%  transformer loading. 

The EconiQ™ transformers have been developed using eco-design principles in order to maximise sustainability over the life-cycle. Within the designs, key aspects are further optimised such as enhanced energy efficiency and the responsible use of materials through processes such as recycling and waste disposal. The use of biodegradable insulation fluids with higher flash and fire points helps to safeguard surrounding ecosystems from the risk of pollution and increase safety. In the first phase, EconiQ™ transformers will be available for liquid-filled applications.

The transformers are manufactured using fossil-free electricity in Hitachi Energy’s factories. The business has set targets in its Sustainability 2030 plan to become carbon-neutral in its own operations and it expects to hit the first-step target, achieving 100% fossil-free electricity in its own operations, by 2022.

EconiQ™ roadmap

As part of the Cigre 2021 virtual conference in August, and four months on from the launch of Econiq™, Hitachi Energy announced the “acceleration of its development of eco-efficient solutions”, launching what it called its EconiQ™ roadmap, with the aim of enabling “the industry as a whole to reduce carbon footprint and rapidly transition to eco-efficient solutions.”

The EconiQ™ roadmap outlines the Hitachi Energy portfolio of switchgear and breakers for various voltage levels in the R&D pipeline. This includes live tank breakers, dead tank breakers, hybrid switchgear and gas-insulated switchgear.

A key milestone to look out for will be EconiQ™ gas-insulated switchgear at 420 kV, expected for release at the end of 2022, “demonstrating the scalability and robustness” of Hitachi Energy’s technology, the company says. “It will be the world’s first commercial alternative to SF6 for gas-insulated switchgear that includes a circuit-breaker for power transmission networks”, thereby significantly lowering the environmental impact.

“The EconiQ™ high-voltage roadmap is one key pillar of our Sustainability 2030 strategic plan”, said Markus Heimbach. “The upcoming launch of the EconiQ™ 420 kV GIS will be the breakthrough in the industry for SF6-free solutions for higher voltage levels.”

For all its metal enclosed switchgear (GIS, dead tank circuit breaker (DTB) and hybrid switchgear), Hitachi Energy is employing a mixture of synthetic fluoronitrile gas (C4-FN, a fluoronitrile with four carbon atoms (C3F7CN) developed by 3M under the commercial name Novec™ 4710) with carbon dioxide and oxygen as the eco-efficient gas that will replace SF6 for insulation and switching.

In a recent white paper issued by Hitachi Energy, it is concluded that metal enclosed switchgear based on this C4-FN/CO2/O2 gas mixture delivers the best life cycle assessment results, while achieving the reliability and compactness of SF6 based switchgear. 

In April 2021, Hitachi Energy (then called Hitachi ABB Power Grids) and GE announced a “landmark” cross-licensing agreement relating to the use of fluoronitrile based gas mixtures as an alternative to SF6 in high voltage equipment. 

Up to then Hitachi ABB Power Grids had favoured gas mixtures employing fluoroketones (typically in combination with O2 and CO2) as an alternative to SF6 (see Eliminating SF6: an agreement between rivals).