Sustainable Energy Generation: Burning Trees

Wera Hobhouse Excerpts

Tuesday 6th December 2022 Westminster Hall

[Selaine Saxby (North Devon) (Con)]

I beg to move,

That this House has considered the sustainability of burning trees for energy generation.

It is a pleasure to serve under you in the Chair, Mr Gray. I thank the Backbench Business Committee for finding time for this important debate.

In my mind, today’s debate is about changing scientific understanding as we decarbonise our energy supply. The burning of wood as a renewable energy source has been adopted by the UK and the EU as a sustainable option to replace coal. In the UK, we subsidise the use of biomass to generate energy by £1 billion. However, in recent years, scientists and industry have raised serious concerns about the actual benefit of burning wood for energy. I secured this debate so that we can have a discussion about how taxpayers’ money is being spent and whether, at this time of global energy disruption, we are investing in the best forms of energy generation for our planet and for our energy security.

Biomass became prominent when coal-fired power stations were converted into biomass power stations. That was subsidised to aid the phase-out of coal and originated at a time when biomass was cheaper than renewables such as wind and solar and had perceived additional benefits, such as providing consistent, reliable power. Now, however, Drax is the UK’s biggest single-point source of carbon dioxide emissions. Because of the technology installed, the power station must run predominantly on wood pellets and has only limited capacity for non-woody biomass such as energy crops and organic waste.

The whole lifecycle emissions of CO₂ per kWh are 41 grams for solar, 11 to 12 grams for wind and 948 grams for coal. For forest biomass, they are 1,079 grams. That is far from the assumed carbon-neutral outcome. The UK produces roughly 12% of its energy from biomass and 3% from coal. The UK’s carbon emissions have not dropped at the same rate as our reduction of coal would indicate. The reality is that more carbon is being put into our atmosphere currently than when we were burning coal.

The difference between the idea that burning wood for energy is renewable and the reality comes from two misrepresentations. Both come about from the wrong approach to the accounting for the carbon output. The emissions from cutting down trees are attributed to the land-use sector rather than the energy-generation sector. As we import the majority of our wood pellets, we are exporting our carbon emissions. Although that may look good, it does not achieve anything, as we all share our atmosphere and the effects that carbon emissions cause.

The Intergovernmental Panel on Climate Change allows such zero-rating of emissions based on the idea that every tree will be replanted and its replacement will harness the same level of carbon as its predecessor; unfortunately, that has proven not to be the case. Many studies have shown that the carbon payback times for forest biomass are decades or centuries away, depending on the type of forest cut down to produce the wood pellets.

We are entering a crunch point in our work to limit the effects of climate change, with tipping points in the melting of sea and glacial ice, sea-level rises, ocean acidification, permafrost melt and the Amazon biome. We do not have the time to wait decades or centuries for the carbon to be reabsorbed and sequestered; nor does such an approach fit in with the goal of carbon neutrality by 2050.

Trees only grow in their carbon-storing potential as they age. There is a very minimal decline in their efficiency as they photosynthesise and store CO₂ from the atmosphere, but that decline is far outweighed by their sheer size and capacity. A study carried out by 38 researchers across 15 countries measured 400 species across six continents. It found that 97% of trees grew more quickly as they aged and absorbed more carbon year on year. If a tree’s diameter grows 10 times as large, it will undergo a hundredfold increase in leaf mass and an increase in leaf area of between fiftyfold and a hundredfold.

Our forests are still the largest remover of carbon, and one study found that, across forests of all ages and types around the world, half the carbon is stored in the largest 1% of trees when measured by diameter. As trees age, they also store more carbon in the soil, so we are looking at not just our canopy but the carbon stored in the earth itself, much as we need to consider our peatlands and the blue carbon stored in the seabed.

The other issue with the accounting of emissions from the burning of biomass for energy is the carbon associated with the supply chain for sourcing the wood pellets required. The industry sources wood pellets from North America, eastern Europe, the Baltics and, historically, Russia. Covid and the war in Ukraine have significantly disrupted supply chains and put more pressure on available forests. Drax sources most of its wood pellets from North America. A BBC “Panorama” documentary has cast doubt on the claim that it just uses waste wood and has suggested that primary forests are harvested and timber- quality wood burned as biomass.

The Dogwood Alliance in Mississippi has been tracking the logging of forests in the south-eastern United States and the conversion of whole trees into wood pellets. The south-east is one of the most biodiverse areas of the United States, and another downside to the burning of wood for energy is the fact that such older and more mature forests are home to a greater diversity of flora and fauna. The wood pellets are shipped to the United Kingdom on enormous vessels that are in transit for 21 days. Drax receives 17 wood pellet deliveries a day, and the plant operates 24 hours a day, six days a week. The energy required to transport the pellets adds to their lifecycle emissions and uses up the very fossil fuels the pellets are supposed to replace.

This is not an attempt to discredit one company; it is about us better understanding what is going on in the name of renewable fuels and asking that a more rigorous analysis of the carbon cost of this form of power production be fully conducted—at one level, it makes sense because trees grow back—before we assume that we really are moving to a lower-carbon-generating fuel supply and that any subsidy that supports that reflects the true carbon cost of what is supposed to be carbon neutral.

I want to raise concerns about the industry’s efforts to store more carbon in an attempt to deliver negative emissions and remove carbon from the atmosphere. Although that is a laudable goal, and the bioenergy with carbon capture and storage—BECCS—system is included in the United Kingdom’s net zero pathway, it is important to note that it is based on the flawed accounting that calls burning biomass carbon neutral. It involves a number of risks and barriers.

BECCS is the process of capturing and permanently storing underground the carbon emitted by biomass energy generation. The carbon capture rate is not 100%. Research from Chatham House indicates that it is about 76%, and energy needs to be expended to maximise capture. The options are to maximise power generation or to maximise carbon dioxide capture.

The process would also be incredibly expensive—power stations are seeking new subsidies to develop BECCS, and it is projected that it would require £31.7 billion over 25 years, which is equivalent to £500 per person in the United Kingdom—and incredibly land hungry. It would require an area roughly 1.5 times the size of Wales to grow enough bioenergy crops to meet BECCS demand. That is 17% of the United Kingdom’s arable land.

Recently, global events have shown how important a reliable food supply is, and the United Kingdom must not reduce its domestic production of quality produce. There is already the challenge of finding the right balance of land for farming, living, energy production and industry, so using such a large percentage of our land for a form of expensive and unsustainable energy generation would be the wrong approach.

The Climate Change Committee has called on the Government to support domestic biomass supply to meet expected carbon-removal requirements for the industry; however, is that the answer? The United Kingdom is about to face a severe shortage of wood and is one of the least densely forested countries in Europe, at only 13% of land area. The idea that rather than using that wood in industry we should burn it flies in the face of the basics of reducing emissions. At the heart of what we are aiming to do is reducing our use of virgin products, reusing where possible and recycling where not, and looking at using such products for energy generation only once they have become waste.

When we log forests for wood products, the carbon remains sequestered for however long those products last—possibly decades or longer. I declare an interest as chair of the all-party parliamentary group for the wood panel industry. The industry is a UK success story, with gross value added in excess of £850 million per annum and an ability to meet 65% of the UK demand for wood panel products. It supports approximately 7,500 jobs across the UK and has an average salary of £36,000, which is significantly above the UK average. The industry has made great strides in supporting our net zero by 2050 targets and has had some success with efficient and carbon-negative processes.

The wood panel manufacturing sector uses more than 25% of the 11 million tonnes of wood delivered from UK forestry every year. The rise of the wood fuel sector, which itself consumes about 25% of the UK annual wood basket because it is subsidised, has distorted the market and created shortages in domestic supply. Manufacturing operations rely on the sustainable supply of wood materials such as forest roundwood and thinnings, sawmill products, and recycled wood, supplies of which are increasingly restricted, given the fact that the UK will reach peak wood availability in the early 2030s, followed by a forecast sustained drop soon after. We need to plant more trees, especially if we carry on relying on biomass for our energy generation.

The closure of the renewable heat incentive scheme to new entrants in 2021 was a welcome decision. Now is the time to transition to future support schemes that most strategically target taxpayers’ money and ensure a level playing field for all wood users. Will the Minister ensure that when the biomass strategy is released it does not contain a new tariff-based incentivisation scheme similar to the renewable heat incentive? Will he also clarify whether biomass is supported by the contract for difference subsidies? In 2020, the Government announced that they would exclude coal-to-biomass conversion projects from future rounds, starting with allocation round 4.

[Wera Hobhouse (Bath) (LD)]

Does the hon. Lady agree that it is extraordinary that the biomass industry is asking for a combined CfD that would combine biomass production and carbon capture and storage?

[Selaine Saxby]

I agree that that is part of the confusion in the entire strategy; we need urgent clarification. In AR4, dedicated biomass with combined heat and power were eligible to compete, although no contracts were awarded. The announcement of AR5, which starts in March 2023, has not come with any clarity on whether biomass will be eligible for that round.

The Government have done great work as we transition to net zero by 2050, but further investment in biomass is clearly the wrong strategy. It not only continues to contribute carbon to our atmosphere when we can now invest in significantly cleaner energy, but takes away from flourishing British businesses and exports our problems overseas. When the biomass strategy is released, I hope that the mounting evidence will be considered and that we can continue to increase investment in more sustainable energy sources rather than pursuing this path.

--- Later in debate ---

[Wera Hobhouse (Bath) (LD)]

I congratulate the hon. Member for North Devon (Selaine Saxby) on the very good way in which she introduced the debate and on bringing the debate to the Chamber.

Tackling climate change is the most important issue of our time. The IPCC notes that approximately 3.3 billion to 3.6 billion people live in contexts that are vulnerable to climate change. Between 1970 and 2019 the global surface temperature increased at a higher rate than in any period over the past 2,000 years. Since 1950, the global number of floods has increased by a factor of 15 and wildfires have increased by a factor of seven. This year alone, we have seen floods in Pakistan, drought and famine across east Africa and a heatwave in the UK.

There is still time to reduce the worst effects of climate change. The World Bank suggests that up to 260 million people could be forced to move within their countries by 2050, but immediate action could reduce that number by 80%. That urgency is why I cannot support the use of bioenergy. Bioenergy is not a renewable energy source. The low density of wood means that, when burned, it emits more CO₂ per unit of electricity than coal. That CO₂ can be offset only when new trees regrow, leading a large carbon debt to accrue over decades.

These timescales are much too long to meet urgent carbon budgets. We do not have the time for these emissions to be paid back. Time is not on our side when it comes to the climate disaster. The idea that bioenergy production can offset emissions is based on pure hope. If greenhouse gas removal techniques are not able to balance global carbon budgets, we risk an extra 0.7° to 1.4° of warming above our 1.5° target. That is the issue. We should not take that risk with people’s lives and the health of our planet.

Like fracking, bioenergy production can also be harmful to local communities. The company that runs Drax power station recently paid up to $3.2 million to settle air pollution claims against the wood pellet factories in the US. Residents in Gloster have spoken of their health declining since Drax began operations in the town in 2014. The health issues include breathing difficulties, dizzy spells, rashes, nosebleeds, occasional burning sensations and irritated eyes when standing outdoors.

Converting land to grow crops for bioenergy puts a massive strain on nature, soil and water. Energy crops can displace food production to other locations, putting forests and other natural systems at risk in other parts of the world. Meanwhile, intensive monoculture bioenergy crops rely on fertiliser and pesticide inputs, which harm soil health and nature.

Despite the clear issues presented, the Government continue to massively subsidise industrial-scale bioenergy. Drax receives more than £2 million a day in biomass subsidy, in spite of there being no obvious long-term climate benefit. Let us imagine the difference we could make if the Government put that money into true renewable energy and net zero adaptation. There are 5 GW of onshore wind currently awaiting planning approval, which could be fast-tracked to lower energy bills this winter alone. The UK could develop up to 11.5 GW of tidal stream by 2050, supporting over 14,000 jobs. Weak grid capacity is now the biggest issue holding back renewable energy development, yet the Government continue to stall plans to improve the grid.

Prioritising true renewable projects over bioenergy solutions is a no-brainer, as is the Government starting to subsidise oil and gas production through their windfall tax. I hope they will start to think straight and not force the people they are meant to serve to pick up the dire consequences of their policies.

--- Later in debate ---

[Dr Whitehead]

Yes, indeed, we need to take careful account of the points my hon. Friend has made about wider biodiversity issues. However, we have sources of material—starting with the idea of managed forests, under certain circumstances, or energy crops, under other circumstances—that are much shorter in their use and carbon sequestration, such as miscanthus and short-rotation coppicing of willow. Those can be produced with a very short time of burning and resequestration. However, as my hon. Friend has said, there may be other environmental consequences attached to the practice.

[Wera Hobhouse]

Is it not the outcome of today’s debate that burning wood or biomass is neither low in carbon nor a renewable source of energy—so why are we still subsiding the industry?

[Dr Whitehead]

That was the case I was trying to pick apart. Is it right that we should ever burn anything for power? If we burn some things for power, what are the circumstances under which we burn them and what are the constraints we have to put on their burning? One of the issues is just how much we pay for that burning. If there are better uses for the subsidies we might put towards that burning, then we should undertake those instead. We need to be very mean in terms of the resource we put into subsidies so that we get the best outcome for those subsidies.

We cannot draw an overall conclusion today about the wide issue of what is waste, whether it is appropriate to burn it under any circumstances and how we manage that waste stream. Clearly, with whole forests—even if they are managed—the production of timber that goes into houses and buildings is a much better way of sequestering carbon from that timber than burning it. Waste material, on the other hand, does not have the same uses, although the hon. Member for North Devon mentioned the wood panelling industry, where there are certain uses for roundwood and other timber that can sequester carbon in a better way than burning it. However, we still have the issue of whether there is a role at all for biomass burning and waste burning in future.

We have also had a discussion about CCS, on the back of burning wood, residual material and waste. That applies to energy from waste just as it does to biomass use. Of course, the Climate Change Committee is quite keen on BECCS. The idea is that the whole process can become net negative as far as contributions to net zero are concerned, and we are producing a net negative contribution to the overall carbon balance, providing that CCS works well and sequesters as much carbon as it is supposed to.