UK rotating stabilizers to use 100% renewables to help grid security: Statkraft

London — Statkraft expects to use 100% renewable energy to power its new rotating stabilizers in the UK, the Norwegian company told S&P Global Platts late July 6.

The two synchronous machines, to be manufactured and installed by GE Power Conversion at Statkraft's site in Keith, Moray, northeast Scotland are to provide stability services to the transmission network under contracts awarded by National Grid Electricity System Operator earlier this year.

The rotating stabilizers are powered by energy drawn from the grid. This energy flows through the grid connection which also delivers the stability services to the grid, Statkraft said.

"The contract for that import power is not yet signed but we expect it to be a 100% renewable energy supply contract. More importantly, without the project, National Grid ESO would need to turn off renewables and turn up fossil fuel generation," it said.

In broad terms, importing 1 MW of energy to power the project would enable an extra 100 MW of renewable generation to run and save 100 MW of fossil fuel generation and CO2, it said.

Statkraft has been awarded four stability contracts (two at Keith and two at Lister Drive, Liverpool) by National Grid ESO.

The stabilizers are to provide stability services, such as inertia, short circuit level and frequency.

This has traditionally been provided by using the kinetic energy in the spinning parts of large thermal generators when they were providing electricity to the grid.

The rise of non-synchronous generators such as solar, wind and interconnectors, and the closure of coal-fired power stations, means these services can no longer be taken for granted as a by-product of thermal generation, and are being procured separately by the system operator.

The agreement between Statkraft and GE comes at a critical time for the UK power network as it battles to integrate the growth in renewable power.

Julian Leslie, Head of Networks at National Grid ESO said the use of rotating stabilizers for grid services was "the first of its kind anywhere in the world and is a huge step forward in our ambition to be able to operate the GB electricity system carbon free by 2025."

"Our contracts for stability services with providers such as Statkraft are cheaper and greener, reducing emissions and saving money for electricity consumers," Leslie said.

In January National Grid ESO agreed five innovative grid stability contracts worth GBP328 million ($410 million) over a six-year period.

Contracts with Drax, Rassau Grid Services (Welsh Power), Statkraft, Triton (Deeside Power) and Uniper will see the parties either build or modify assets to provide stability services.

The assets were not directly identified, but include Drax's Cruachan pumped storage plant in Scotland, Uniper connection points at Killingholme and Grain (both gas plants), Triton's connection point at Connah's Quay (another gas plant) plus two connection points for Statkraft.

"In total, the contracts are procuring 12.5 GVA seconds of inertia, the equivalent of the inertia provided by approximately five coal-fired power stations," National Grid said.

This would save consumers up to GBP128 million over the six-year period while reducing carbon emissions associated with the services, it said.