From Neutral to Negative

Drax’s plan to demonstrate a new carbon capture and storage technology at its power station in the United Kingdom has global implications.
By Patrick C. Miller | June 27, 2018

Carbon dioxide capture and storage technologies are an intriguing concept, offering the potential to transform carbon-neutral biomass power plants into carbon-negative facilities. In the past, these technologies have been considered too costly and uneconomical to deploy, but this could soon change with the forward-thinking Drax Group forging ahead.

In May, Drax announced plans to build a first-of-its-kind bioenergy carbon capture storage (BECCS) project in Europe, which, in the long-term, could result in the generation of carbon-negative electricity at Drax’s biomass-fired power station in North Yorkshire, U.K.

The North Yorkshire plant—the largest power station in the country—is owned and operated by Drax Power Ltd. It supplies 7 percent of the country’s electricity needs and is the single largest user of sustainable biomass for power in the world. Of the electricity it produced in 2017, 65 percent was renewable—enough to power 4 million homes. 

Unlike the previous carbon capture and storage projects in which Drax has been involved, this one is an early pilot for a new technology that will examine the potential of a different form of post-combustion capture on biomass fuel, rather than coal. “This pilot is the U.K.’s first step, but it won’t be the only one at Drax,” says Will Gardiner, Drax Group CEO. “We will soon have four operational biomass units, which provide us with a great opportunity to test different technologies that could allow Drax, the country and the world to deliver negative emissions and start to reduce the amount of carbon dioxide in the atmosphere.”

A Decarbonization Strategy
The U.K. government’s Clean Growth Strategy identified sustainable biomass power stations used in tandem with carbon capture utilization and storage (CCUS) technology as a potential route to achieving decarbonization between now and 2050. BECCS is considered one of several greenhouse gas removal technologies that could help achieve long-term decarbonization. A report by the Energy Technology Institute in 2016 suggests, by the 2050s, BECCS could deliver roughly 55 million tons of net negative emissions annually in the U.K.—about half the nation’s emissions target.

“The biomass we use is considered to be carbon neutral because it is sourced from sustainable, working forests which are growing and absorbing carbon,” says Andy Koss, Drax Power CEO. “The majority of the biomass that we use comes from the U.S. South, where sustainable forest management means that trees are growing faster than they are being harvested, resulting in a net decrease of carbon in the atmosphere. The carbon captured will be stored on site at Drax in compressed form, with a view to working with a partner organization able to use the carbon to create further value in its own processes.”

For the demonstration project, Drax will partner C-Capture Ltd., a spinoff company from the University of Leeds. C-Capture develops proprietary solvent systems to remove CO2  from the gas streams of large-scale point sources, capturing it in a form suitable for storage. Drax will invest £400,000 ($537,000) in what could be the first of several pilot projects undertaken at the company’s power station to demonstrate BECCS technology.

“At Drax, we work with a number of universities in our efforts to understand and capitalize on emerging technologies and support STEM (science, technology, engineering and math) learning,” Koss explains. “Our R&I (research and innovation) team first met with C-Capture during a meeting at Leeds University aimed at exploring areas of mutual interest. Due to the nature of C-Capture’s proprietary solvent, the decision was made for them to be our preferred initial partner to trial their technology with our biomass flue gases. C-Capture’s role is an important one in the project, as their solvent is organic, low-cost and has low toxicity.”

Finding the CO2 Holy Grail
Chris Rayner, founder of C-Capture and professor of organic chemistry at the University of Leeds, says the company has developed fundamentally new chemistry to capture CO2 , and tests have shown that it should be suitable for capturing the carbon produced from bioenergy processes. “The key part is now to move it from our own facilities and into the real world at Drax,” he adds. “Through the pilot scheme, we aim to demonstrate that the technology we’ve developed is a cost-effective way to achieve one of the holy grails of CO2 emissions strategies—negative emissions in power production, which is where we believe the potential CO2  emissions reductions are likely to be the greatest.” 

In 2012, Drax began converting from coal to become a predominantly biomass-fueled electricity generator. “Our biomass generating units deliver carbon savings of 80 percent compared to when they used coal,” Koss says. “This takes account of the whole supply chain and is independently audited.”
Drax is the biggest single-site renewable generator in the U.K., and operates the largest decarbonization project in Europe. Drax Biomass is based in the U.S., and manufactures compressed wood pellets at two facilities in Louisiana and one in Mississippi, produced from sustainably managed working forests, supplying fuel used by Drax Power Station in North Yorkshire.

Moving Away From Coal
“We have invested heavily in converting the business to use biomass instead of coal,” Koss notes. “The transformation cost us around £700m (nearly $937 million), of which around half was the cost of converting the three generating units at the power station to biomass with the balance being investment in the U.S. supply chain, U.K. rail infrastructure and compliance with future emissions requirements.”

The first phase of the BECCS project began in May to determine if the solvent C-Capture developed is compatible with the biomass flue gas from the Drax Power Station. A lab-scale study into the feasibility of reusing the flue gas desulphurization (FGD) absorbers at the power station will also be carried out to assess potential capture rates. “Part of the C-Capture project is about repurposing existing assets at Drax, which should be more cost-effective, and quicker to develop,” Koss says. “FGD equipment is vital for reducing sulphur emissions from coal, but has become redundant on three of the generating units at Drax that have been upgraded to use biomass. The wood pellets used produce minimal levels of sulphur.”

Depending on the outcome of a feasibility study, the C-Capture team will proceed to the second phase of the pilot in the fall, when a demonstration unit will be installed to isolate CO2 produced by biomass combustion. “As the largest user of sustainable bioenergy in the world, Drax Power Station is as good a location as anywhere to trial this technology,” Koss stresses. “We hope that in undertaking this feasibility 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 U.K. and abroad.”

At Drax, the BECSS technology demonstration project represents another key step on the road toward using more environmentally responsible fuel to generate electricity. “For our people to get behind the project, they had to understand that for coal, the writing was on the wall,” Koss notes. “Once they understood that, we could develop a shared purpose and enthusiasm for finding the solutions required to achieve this major feat of engineering and extend the life of the plant.

“We needed to develop an entirely new supply chain, and convince suppliers and partners across the railways and ports that we were serious about biomass, so they would work with us,” he adds. “It was also vital that in developing our own wood pellet plants in the U.S., and in working with others who supply us with biomass, that we were able to ensure they adhered to stringent sustainability requirements.”

Koss says it’s too early to discuss exporting BECCS technology, but when asked how a successful demonstration would change Drax’s role in the area of long-term decarbonization, he replies, “If the world is to achieve the targets agreed in Paris and pursue a cleaner future, negative emissions are a must—and BECCS is a leading technology to help achieve it.”

In addition to environmental benefits, Koss explains that Drax has other reasons to develop and demonstrate BECCS technology. “We could be delivering reliable and flexible renewable power, which is carbon negative, helping the millions of households and businesses which rely on it to decarbonize, too,” he says. “If successful, the technology could help to extend the life of the power station, protect jobs both at Drax and in our supply chain, whilst tackling climate change and keeping the lights on.”

Author: Patrick Miller
Staff Writer, Biomass Magazine