Utility Week

10 | 31ST AUGUST - 6TH SEPTEMBER 2018 | UTILITY WEEK Interview from burning biomass may eventually be reabsorbed, this can take decades or even centuries. Cutting down trees to burn in power plants, it said, not only releases the carbon stored in the trees themselves, but also stops them from continuing to grow and absorb more, as well as freeing carbon trapped in the soil. The report warned it can be 10 to 20 years before a forest returns to being a carbon sink following replanting. It said even burning waste materials from the wood industry – although much better – can increase the amount of carbon dioxide in the atmosphere, if they would have otherwise been used to produce products. Gardiner takes a very different view. He insists bio- mass, "if done in the right way", can contribute to the growth of healthy forests: "I'm very comfortable that what we're doing is the right thing. It's actually contrib- uting to capturing more carbon in the forests, not less." Drax's website claims the company only sources feed- stock from carefully managed working forests, while ensuring that carbon stocks are not diminished by their demand, as required by the government's criteria for sus- tainable biomass. Gardiner says the company also makes use of residual materials and thinnings, which previously would have been used to produce pulp and paper. With those mar- kets in decline, "pellets have effectively slotted in there as very good alternative". He also stresses the need for some form of thermal generation to fill the gaps le by renewables. Surely, he argues, biomass is better than gas and coal, both of which "emit carbon that been locked up for millions of years." And, says Gardiner, combining biomass with carbon capture and storage (CCS) to generate negative emis- sions – which he describes as "green CO2" – would give it an unparalleled position: "You're actually contribut- ing more to the reduction of CO2 in the atmosphere than solar or wind could do." Drax is planning to do exactly that by testing CCS on one of its four biomass units. It's not the first time the company has had a crack at CCS. Drax was a key partner in the White Rose project – a scheme to build a coal-fired plant with CCS next to its existing power station. It pulled out of the project in Sep- tember 2015, just a few months before the government cancelled the £1 billion commercialisation competition in which it was taking part. However, biomass with CCS presents a much more exciting prospect for environmentalists than supposedly clean coal. Drax has an ally in the Committee on Climate Change, which in its 2018 progress report again highlighted the potential for bioenergy with CCS. It also drove home the importance of CCS more generally to the cost-effective decarbonisation of the economy. The message appears to have been taken onboard by the government. Earlier this year it launched a new task- force to push forward the development of CCS. Gardiner is encouraged by its creation. "We've been working closely with that taskforce so we understand where it's going and we can contribute ideas," he says. Drax is still undertaking a feasibility study before deciding whether or not to press ahead with its CCS pilot. "If it does work economically, and we have reasonably high hopes that it will, then it fundamentally changes what we're doing here," says Gardiner. At the same time, the government is obviously reluctant to let Drax take up any more of what's le of the dwindling budget for low-carbon subsidies. Gardiner recognises this and says the company is working tirelessly to trim costs so it can carry on burning biomass once its existing subsidies eventually run out. It currently costs it around £75/MWh to generate power from biomass. "We think if we can get it down to £50/MWh then we can continue to run with- out subsidy," he adds. To reach this goal, it is targeting both "smaller, incre- mental efficiency improvements all through the chain" and bigger savings from cheaper feedstock. Gardiner cites a recently announced deal that will see a new sawmill set up next to one of Drax's existing pel- let plants in the US: "What we've agreed is a long-term contract to buy their residuals – the sawdust, the bark, the dry shavings… It's much cheaper because there's no transport costs. It's cheaper because it's residuals – for them a by-product. And that significantly brings down the cost of our pellets. There's a lot of work going on to do similar things like that." The company is also looking at how new technologies might help: "For example, could we extract sugars from the wood and then sell that as a by-product before you make the pellets?" As for the two remaining coal units, Drax has given up on trying to convert them to biomass and has instead opted to replace them with combined-cycle gas turbines. To do this, it will install four new 600MW gas tur- bines and repurpose the two existing steam turbines to each generate up to 600MW more using waste heat from the exhausts. The total capacity of the power station will rise to almost 6.2GW – making it one of the largest in the world. The company also wants to build two 100MW bat- tery storage systems. Drax acquired four open-cycle gas turbines projects in 2016, and these, along with the re-powering project, are all part of its plan to find a new role supporting the power grid as more and more renewables come online. "We're doing black start, we're doing reactive power, we're doing inertia, we're doing all sorts of services," explains Gardiner. He says one of the main challenges it faces is the failure of the energy market to properly reward thermal generation for the value it provides. There is not enough transparency over the procurement of balancing and ancillary services, he complains: "It's difficult to know what exactly the grid wants. There's lot of different deals that different people get." National Grid has been working to rationalise, stand- ardise and simplify these services, but Gardiner believes this is all happening "a bit slowly". More importantly, he says, the capacity market has led a race to the bottom on price. "The capacity that we want to build will provide not just megawatts but system support. It doesn't get valued in any way differently from demand-side response or from an interconnector that can't provide those services," he says. When asked whether this issue should be addressed through changes to the capacity market itself or to afore- mentioned balancing and ancillary services, Gardiner is ambivalent. Ultimately, he says, there is definite need for new gas capacity and so one way or another it will even- tually get built. The question, as far as he is concerned, is not if but when. "[With CCS] you're actually contributing more to the reduction of CO2 in the atmosphere than solar or wind could do."

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