Drax eyes battery storage to accompany gas and biomass conversions

UK power station operator Drax plans to complement its ongoing biomass conversions with gas and battery storage options at two coal power units, although new research that wind and solar are a more cost-effective solution has reignited the debate over biomass use.

Drax gave notice on Wednesday (13 September) to the Planning Inspectorate of its intention to repower two of its coal units to gas, and use battery storage to provide flexible and responsive capacity.

Plans for the gas conversion were announced in June and could create up to 3.6GW of new gas generation. Drax has since added that 200MW of battery storage could be added to the sites, although this would need to be backed by a 15-year capacity market contract.

Drax Power’s chief executive Andy Koss said: “We are at the start of the planning process but if developed these options for gas and battery storage show how Drax could upgrade our existing infrastructure to provide capacity, stability and essential grid services, as we do with biomass. This would continue to keep costs low for consumers and help to deliver Government’s commitment to remove coal from the UK grid.”

If installed, the battery system in Yorkshire would complement Drax’s ongoing plans to convert a fourth unit to biomass. Three stations have been successfully upgraded and account for 70% of the electricity produced by Drax and 16% of the UK’s total renewable power.

Drax has previously suggested that the biomass conversion of three of its power plant units will cut 12mtCO2e per year from the power station’s operations. Drax believes that, with support from the Government, the company could upgrade the remainder of the power station to run solely on biomass and provide up to 8% of the UK’s total electricity with reduced emissions.

A ‘dying industry’

However, a new report by the Natural Resources Defence Council (NRDC) has claimed that wind and solar can supply the UK’s needs for new electricity capacity while coal is phased-out. In fact, the report claims that those two options are more cost-effective than biomass.

With coal set to be phased-out of the UK energy mix by 2025, the NRDC report claims that biomass plants, even if already installed, would cost more to operate than building new solar and wind capacity.

Specifically, the report claims that Government support for another Drax biomass conversion through a Contract for Difference (CfD) would cost more than £360m compared to supplying the same electricity through offshore wind, which recently gained a strike price of less than £60 per MWh.

The Money to Burn II report claims that biomass would likely by “uneconomic” and “completely obsolete” within a decade. The report again laments the biomass industry for failing to take into account the carbon emissions associated with burning biomass for electricity.

“The UK government pours billions in subsidies into the biomass industry under programmes intended to promote clean energy. Last year, Drax alone received £1.48m a day to convert its old coal plants to burn biomass,” NRDC’s energy and transportation programme advocate Sasha Stashwick said.

“The results of this week’s Contracts for Difference auction put into stark relief the economic and strategic advantage of offshore wind compared to biomass in the UK. This report shows that solar and wind can reliably supply the UK with the new electricity capacity it needs while saving hundreds of millions of pounds in taxpayer resources and help the country achieve its climate targets. The options are simple: solar and wind are clean, cheap, and reliable. Biomass is a dirty, expensive, and dying industry.”

Drax has since responded to the findings of the NRDC response, noting the need for a mix of energy technologies to “ensure security of supply”.

“In 2016 Drax’s biomass generating units produced 16% of the UK’s renewable power – enough for four million households – and received 10% of the support paid to renewable power generators,” Koss said. “Biomass is the only reliable, flexible renewable power available at scale. At Drax we’re looking at ways to reduce the costs of this technology. The falling costs of renewables is great news, but we need a mix of energy technologies to ensure security of supply.

“Biomass is the only renewable technology which can be flexed up and down to meet demand and provide the balancing services which National Grid expects to become increasingly important as more and more intermittent renewables come on line and demand for power increases.

“The biomass we use delivers carbon savings of 68% compared to gas. The wood used to make our compressed pellets comes from sustainably managed working forests, which are growing in size. Since the 1950s, forest stocks in the US South – from where Drax gets most of its wood – have increased by more than 100%. We don’t take any wood fibre from sites that are protected or officially identified as having high bio-diversity value.”

Matt Mace

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie