The Scottish Government held a public consultation on its Heat in Buildings Bill, requesting responses for it to consider before the deadline in March 2024.

As a result, we gave our response that focused on the importance of bioenergy in Scotland's net zero energy mix. The consultation asked “Do you agree that the use of bioenergy should continue to be permitted in certain circumstances?” and in our view, it is critical that it does. The following is our response submitted to the Government, in which we evidence why bioenergy is so important to Scotland.

Current Wood Energy Usage

The most recently published figures available identify 8,362 biomass installations across Scotland [1]. Maps provided within the report identify the location of these installations, with the highest density found in rural areas. These installations range in size from a few kW heating domestic properties through to multi – MW steam boilers providing low carbon hot water and steam to some of Scotland’s key industries.

These installation used a total of 1.4 million oven dried tonnes of wood fuel in 2021, which is approximately 20% of the total output from Scotland’s Forests [2]. This is approximately equivalent to 3,730 GWh of useful heat, meaning 70% of Scotland’s current renewable heat generated comes from biomass installations.
To send a signal to markets that biomass will be removed from the supply chain, would not only be detrimental to meeting Scotland’s current renewable energy targets, but would also create a significant gap in the economy and reduce new tree planting as there would be less financial incentive to plant.

Each MWh of delivered heat is supported by a robust supply chain, with people employed in procurement of the materials, processing, transport, service and maintenance and more. To rule out biomass as an option for future heat generation would mean the loss of these skills and jobs from the Scottish Economy. This would inevitably be detrimental, as a significant proportion of the roles are found in rural areas of Scotland, adding critical value to local economies. These areas are already under pressure to retain their workforce due to higher costs of living, lack of access to alternative work and dwindling populations. Promoting biomass as a sustainable energy that is suitable for rural applications will reverse this trend and lead to a strengthening of the rural economy.

Previously, the argument in support of biomass systems was of the economic benefit to Scotland that they brought before the argument of carbon was identified. A report commissioned by The Fraser of Allender Institute identified the value of woodfuel specifically to the Scottish economy and job creation, that every new job created by an increase in demand for wood fuel will create an additional 2.79 jobs in other Scottish industries. Every one new job in wood fuel will therefore support a total of 3.79 jobs in Scotland [3].

Forecasted Energy Available from Residues

While some apprehension is given to the potential for forestry to be felled specifically for energy generation, we at Reheat are against this method of woodfuel production. We believe in a sustainable approach to forest management where thinning, residues and forest byproducts that cannot be used for construction or other long-term products should be used for energy production in line with the EU’s RED III directive [4]. Scottish forestry datasets provide an insight into the felling predictions for years up to 2046 [5]. Using peer reviewed published literature, we can estimate the potential residues available from forecasted commercial felling, and therefore estimate the potential energy available from this resource, avoiding high quality virgin timber being used for energy [6].

Using Forbes’ 2014 figure of 34m3 of timber available per hectare of planting, 92.6 tonnes of residues could be available per hectare. This equates to 2.73 tonnes of residues (or brash as it is colloquially known) per m3 of timber. This means in the period of 2022 – 2046 there would be a total amount of between 50 – 146 million tonnes of brash available for energy conversion, depending on recovery rates. The lower estimate is if recovery rates were 34% of the total, or what is defined as the maximum required to be retained within UK Forestry Standards [7]. The upper estimate is if 100% of residues were collected. From these millions of tonnes of material available, using a calorific value of 20 MJ/kg, there could be between 11,502 – 33,831 GWh of energy available annually. With domestic heat demand of approximately 35,500 GWh per year in Scotland, and non-domestic approximately 10,268 GWh residues could play an important role in providing a significant proportion of this energy [8].

The market for forestry residues that the biomass heat sector has created in Scotland has also gone a long way to underpinning the health of the wider forest economy, which has seen record investment in sawmilling and other processing activities in recent years. With a GVA of ~£1bn and ~25,000 employees, many of which are in rural areas, the forestry and timber processing sector is an important part of the Scottish economy. Further growth in the biomass heat market would help to underpin this sector and create the economic climate for further growth, while the stagnation or reduction of the biomass heat market would undermine the case for expansion of both forestry processing and for forest and woodland area.

Higher production volumes, supply chain efficiencies and lower prices would also mean that in the longer-term, residues could be even more competitive with fossil fuels, potentially without carbon taxation or subsidies being applied.

Heat Pumps – Not Appropriate for Every Scenario

We believe that there is a misplaced focus on low temperature heat pumps as a solution for decarbonising the heating in single domestic properties, which is a peculiar quirk of Climate Change Committee advice and UK policy which appears to have been adopted by the Scottish Government without necessarily considering the wider issues and implications.

For example, low temperature heat pumps require changes to building heating systems, often necessitating the replacement of radiators, etc., which is not always possible or economic. Much of Scotland’s existing housing stock, particularly traditional buildings, may not be appropriate for heat pumps or connection to low temperature heat networks, and there should be alternative supported options available - one fifth of Scotland’s housing stock was built before 1919, and much of that which was built prior to modern building standards being introduced in the 1990’s is also very hard to heat cost effectively.

The argument for heat pumps as a low/no regret option as capital and ongoing cost is known and presented as a positive in the consultation, however this is true of other well-established technologies such as biomass, and ongoing fuel costs can also be calculated from readily available market data.

Bioenergy, particularly solid biomass, is also well suited to heat networks, and biomass dominates in countries where heat networks provide large proportions of the countries’ overall heating, particularly in Scandinavian countries and in central Europe. Overall, biomass contributed 20.6% of the energy sources in heating and cooling in the EU27 in 2022. This equates to 83.2% of total renewable heating and cooling in the EU27 in 2022 [10].

All Energy Strategies Should Align – Biomass Strategy

As recently as August 2023, the UK Government published their long-awaited Biomass Strategy [11]. In this document the UK government sets out their view to 2050 on how biomass resources will be utilised. Presenting various scenarios on how they anticipate sustainable biomass will be utilised in the short (2020’s), medium (to 2035) and long term (to 2050). In each scenario, it is envisaged that biomass will be utilised for power, heat and transport to assist with reaching the UK’s net zero target. Whether this is alongside carbon capture and storage (CCS) technology or not is a separate question, but without a doubt bioenergy will be part of the energy mix.

Scotland’s Draft Energy Strategy and Just Transition Plan published January in 2023 set out the aim of using bioenergy to support Scotland’s journey towards net zero [12]. The Energy Strategy states on page 74 bioenergy should be used where it can best support Scotland’s journey towards net zero, which is to decarbonise rural and remote locations heating requirements. To effectively then ban the use of these resources to assist with decarbonisation is directly contrary to this stated aim.

Further afield, banning bioenergy technologies would put Scotland out of step with the latest policy position of the EU. The Net Zero Industry Act is a recently established framework used to strengthen Europe’s manufacturing ecosystem. Biomass technologies are considered as primarily used for the production of net zero energy. In the United States, 13% of all primary energy consumed is renewably sourced, and biomass provides approximately 2% of all energy consumed [13].

Biogenic Carbon vs Fossil Carbon

The consultation makes reference to how Scottish Government policy is aiming to eliminate the use of carbon-based fuels for heating our homes and buildings. This is equating the emissions from fossil fuels to biogenic carbon, which is an ill-informed approach to carbon emissions [15].

The burning of fossil fuels releases carbon into the atmosphere that has been locked up underground for millions of years. Burning biomass emits carbon that is part of the biogenic carbon cycle. This biogenic carbon was absorbed from the atmosphere as the plant grew, and therefore the net carbon in the atmosphere remains the same. Burning fossil fuel increases the total carbon in the atmosphere [16]. They are not the same and grouping bioenergy into the same category as fossil fuels such as gas, oil and LPG as “Polluting Heating” is we believe, an incredibly ill-informed approach to energy systems and their carbon balances.

Per kWh of energy, the kilograms of carbon dioxide equivalent produced from fossil and biomass sources are contrasting. Coal, kerosene and LPG produce 0.37, 0.26 and 0.23 kg CO2e per kWh respectively [17]. Electricity and natural gas are slightly less at 0.20 and 0.18 kg CO2e per kWh respectively. Biomass in the forms of wood chip, logs and pellets produce between 16 times and 34 times less carbon, which again is biogenic and not fossil based, at 0.01 kg CO2e per kWh. This figure (0.01074 kg CO2e) is comparative to the emissions anticipated from the electricity grid in 2045, which at that point is projected to be decarbonised at 0.00788 kg CO2e per kWh.

Air Quality

Poorly installed firewood and peat burning stoves alongside open fire, can lead to negative impacts on local air quality. These negative impacts can be in the forms of NOx and particulates, and are more likely to be related to poor quality fuel than equipment, although smaller domestic appliances with poorly designed flues can contribute. New installations carried out by accredited installers, should not contribute substantially to negative air quality [18]. This is due to new combustions systems sold being designed in accordance with EU Eco-design rules, which minimize emissions [19]. By promoting the use of accredited installers fitting appropriate equipment, there should be minimal impacts on local air quality. A larger problem which does require a solution is the selling and use of inappropriate feedstocks for combustion, such as wet wood (>20% moisture content). Stricter regulations about what fuel is permitted to be burnt, and enforcement through local agencies should be adhered to. There is a significant market for home heating fuel from sources such as locally felled trees and arboriculture, which is an important revenue stream for many small businesses, but it should not be to the detriment of local air quality.

Economics

There is significant value to be gained from using biomass for heating. This is a value that may otherwise be lost if the material wasn’t harvested or collected for energy application. The value is completely dependent on the fuel type, quality and quantity. For wood chip of 30% moisture content, a value of between £115 - £150 per tonne can be realised by a supplier [20]. Using an average cost of £132.50 per tonne and a value of 3.5 MWh/tonne of wood, this equates to approximately £37.90 per MWh of heat delivered, or 4 pence per kWh. For comparison, oil is currently 5.6p/kWh, gas is 10p/kWh and electricity is 30 p/kWh [21]. Not only does biomass stack up as a cost-effective energy source, it keeps that economy local, adding the value to rural farms and suppliers instead of sending it out of the country to refineries and multinational corporations [22]. If between the years 2022 – 2046 the forecasted residues available were harvested for energy and between 276,063 – 811,949 GWh’s were generated, this value associated with this at today’s price per kWh could be between £11 - £32 billion.

References

[1] Energy Saving Trust, “Wood Fuel Demand and Usage in Scotland,” 2023.
[2] Forest Research, “Forestry Facts & Figures 2023,” 2023.
[3] The Fraser of Allander Institute, “A Report to Scottish Enterprise Forest Industries Cluster from the Fraser of Allander Institute,” University of Strathclyde, Glasgow, 2006.
[4] European Union, “DIRECTIVE (EU) 2018/2001 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 11 December 2018 on the promotion of the use of energy from renewable sources (recast),” Official Journal of the European Union, p. 328/82, 2018.
[5] Forest Research, “25-year forecast of softwood timber availability,” 2022.
[6] D. E. M. F. B. W. R. O. E.G.A. Forbes, “Brash bale production on a clear-felled farm forest and comminution of bales to a biomass energy fuel,” Biomass and Bionergy, pp. 124 - 132, 2014.
[7] B. H. V. S. E. C. G. B. K. A. d. V. H. K. H. R. Titus, “Sustainable forest biomass: a review of current residue harvesting guidelines,” Energy, Sustainability and Society, pp. 1 - 32, 2021.
[8] M. G. &. C. M. R. E. &. E. Michael Kelly, “Expanding Scottish energy data - heat,” Climateexchange, 2022.
[9] Bioenergy Europe, “Report Bioheat,” Bioenergy Europe, 2023.
[10] Department for Energy Security & Net Zero, “Biomass Strategy,” 2023.
[11] Scottish Government, “Draft Energy Strategy and Just Transition Plan delivering a fair and secure zero carbon energy system for Scotland,” 2023.
[12] U.S. Energy Information Administration, “U.S. energy facts explained,” 28 February 2023. [Online]. Available: https://www.eia.gov/energyexplained/us-energy-facts/.
[13] Supergen Bioenergy Hub, “Supergen Bioenergy Hub Input to the Environmental Audit Committee Inquiry on Sustainable Timber and Deforestation,” Supergen, 2023.
[14] IEA Bioenergy, “Fossil vs biogenic CO2 emissions,” 24 January 2024. [Online]. Available: https://www.ieabioenergy.com/iea-publications/faq/woodybiomass/biogenic-co2/.
[15] UK Government, “Greenhouse gas reporting: conversion factors 2023,” 25 January 2024. [Online]. Available: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2023.
[16] HETAS, “HETAS Registered Installers,” 24 January 2024. [Online]. Available: https://www.hetas.co.uk/consumer/services/installers/.
[17] EU, Ecodesign and Energy Labelling, 2024.
[18] Usewoodfuel Scotland, “Cost of Wood Fuel,” 24 January 2024. [Online]. Available: https://usewoodfuel.co.uk/guidance-for-biomass-users/planning-a-biomass-installation/fuel-selection/cost-of-wood-fuel/.
[19] Boiler Juice, “Average Home Heating Oil Prices for Scotland,” 24 January 2024. [Online]. Available: https://www.boilerjuice.com/heating-oil-prices-scotland/.
[20] K. Hutchinson, “The impact of the woodfuel sector on the rural economy: A scoping study,” Rural Policy Centre, 2013.
[21] Fraser of Allander, “A Guide to Scottish GDP,” 28 02 2024. [Online]. Available: https://fraserofallander.org/scottish-gdp-guide/#:~:text=By%20far%20the%20largest%20is,%2C%20and%20fishing%20(1%25)..
[22] World Bioenergy Association, “Global Bioenergy Statistics 2022,” 2022.

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