Drax Group began its clean energy journey at its North Yorkshire power plant – the UK’s biggest – a few years ago when it became one of the largest decarbonisation projects in Europe by upgrading two thirds of its generating units to use biomass instead of coal.
Continuing its clean-energy ambitions, this February they announced that carbon dioxide had been captured for the first time ever at the plant using innovative new bioenergy carbon capture and storage technology (BECCS).
The achievement is part of a new, world first BECCS pilot project at the station and is hoped to be a key step in the company’s ambition to eventually transform the plant to be completely carbon-negative.
“The IPCC and the Committee on Climate Change are both very clear that BECCS is a key technology in the fight against climate change,” says Carl Clayton, a research and innovation Engineer at Drax.
“Being carbon negative means the power we produce would help to reduce the amount of carbon dioxide accumulating in the atmosphere – negative emissions are vital if we are to meet our climate targets.”
Today, around 70% of the electricity produced at Drax’s North Yorkshire power station is classed as renewable energy because it comes from sustainable wood pellets. This makes the plant the UK’s largest renewable energy source.
However, while electricity is technically created from a renewable source, it still omits CO₂ into the environment, unlike wind or solar power, making it less environmentally friendly.
To tackle this issue, the government’s Clean Growth Strategy has identified BECCS as one of several greenhouse gas removal technologies that could remove emissions from the atmosphere and help achieve long term decarbonisation.
Keen to explore the potential of this emerging technology, Drax invested £400,000 into the new pilot project, which is using BECCS technology developed by Leeds-based C-Capture to capture one tonne of CO₂ a day.
The technology, originally developed at the School of Chemistry at Leeds University, uses an organic solvent to capture carbon from the plant’s flue gases.
Drax started working with researchers at C-Capture in 2017 and announced the pilot in May 2018, this year of collaboration previously allowed it to ensure the solvent developed was compatible with the biomass flue gas at the station. Together the company and researchers completed a lab-scale study into the feasibility of re-utilising the flue gas desulphurisation (FGD) absorbers at the power station.
“FGD equipment is vital for reducing sulphur emissions from coal, but it is no longer required to control sulphur on four of the generating units at Drax that have been upgraded to use biomass, because the wood pellets used produce minimal levels of sulphur,” explains Clayton.
Continuing to the next phase of the project, in late 2018, the teams installed a demonstration unit at the plant to isolate the CO₂ produced by the biomass combustion.
“For the project, we’re using a completely new solvent that isn’t an industry standard product and, as ever, when doing something as innovative as this, there are always challenges,” says Clayton.
“Because there isn’t a blueprint for us to follow we’re using the expertise we have here at Drax power station, and by working closely with the team from C-Capture, have proven that the technology works,” says Clayton.
When coupled with carbon capture storage (CCS), the overall process will remove more CO₂ from the atmosphere than it releases, according to the company.
Researchers are now analysing data being recorded from the CO₂ capture process throughout the pilot to understand the potential it has and how it could be scaled-up in the future.
Eventually, Drax wants to capture 10,000 tonnes of CO₂ a day from each of the plant’s four biomass units – amounting to 40,000 tonnes of captured CO₂.
“The C-Capture pilot project is about proving the technology and process and exploring options for scale up – either via a bespoke plant or by repurposing existing assets at Drax, which could be more cost effective and quicker to develop than previous CCS projects we’ve been involved in,” explains Clayton.
However, as part of the BECCS pilot, other options for a similar re-purposing of existing infrastructure to deliver more carbon savings are also being examined.
For example, Drax is also working with the Humber Local Enterprise Partnership, CATCH and others to explore the role carbon capture, usage and storage (CCUS) can play in turning the Humber Estuary into the world’s first ‘net-zero – carbon cluster by 2040’.
According to Clayton, the Humber is strategically important as it is the most carbon intensive industrial cluster in the UK.
“The deployment of a new technology like CCUS could be most transformational there – reducing carbon emissions, extending the life of carbon intensive businesses, protecting jobs and creating growth,” says Clayton.
The firm also has plans to repower its two remaining coal generating units to use high efficiency, flexible gas. By reusing some of its existing infrastructure, including the grid connection and cooling towers, the development will be cost effective and very competitive, says Clayton.
It could also enable Drax to stop using coal as soon as 2023, ahead of the government’s 2025 deadline, reducing its emissions whilst playing a vital role in supporting the system as more renewables come online, adds Clayton.
Using the CO₂
Part of the research being carried out during the BECC pilot project includes identifying and developing ways to store and use the CO₂ being captured.
Asked what business model the company is considering in regards to justifying the investment for a full-scale BECC-enabled plant, Clayton says that while the company has so far invested its own money into the project, it is in talks with a range of other commercial entities about what markets could be available for its stored carbon to generate another revenue stream.
The firm, he says, is in discussions with the British Beer and Pub Association about the possibility of its members using the captured CO₂ for the drinks industry. It is also exploring how it could be used in the creation of synthetic fuels.
“For now, however, the carbon captured is being placed back into the power station’s flue gas and is then being re-released into the atmosphere,” he says.
“This is temporary until the process is tuned and stable and the CO₂ purity is verified and optimised; we are working with several partners to develop on-site storage to enable downstream usage.”
Clean energy growth
BECCS has huge potential for the UK according to The Royal Academy and Royal Society of Engineers, which has estimated that the technology could enable the UK to capture 50 million tonnes of CO₂ per year by 2050 – approximately half the nation’s emissions target.
Therefore, Clayton says the company would like to see a framework from policymakers to help it progress faster with the technology, “especially as the government published its pathways document last year with a commitment to progressing this work in 2019,” he adds. The government has already invested £2.2 million in support to C-Capture to develop the carbon capture technology.
In the meantime, it’s likely the data and research from Drax’s ongoing trial of the C-Capture technology will provide the basis of how – and if – it can be scaled up in the future.
“As the largest user of sustainable bioenergy in the world, Drax Power Station is a great location to trial this technology,” says Clayton.
“We hope that in undertaking this work, we will further our knowledge of the engineering involved and produce findings that could be applied to CCUS projects more broadly, both in the UK and abroad.”