Sustainability of biomass

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Within the right boundary conditions, biomass can play an important role in the energy transition

The public debate on the use of biomass for energy applications is heated, especially with regard to the use of woody biomass.

Whether the use of biomass for energy applications in a sustainable way can contribute to the energy transition has been the subject of intense debate for some time now. Arguments against the use of biomass mainly focus on one application of biomass, namely the co-firing of wood in coal-fired power stations and its use in central biomass boilers that can, for example, be used for district heating. The arguments say that valuable nature is being lost, that there is competition with agriculture, that wood burning is being used as an excuse to keep coal-fired power stations open, that the polluting emissions of nitrogen oxide and particulate matter are too high and that on balance CO2 is released by burning biomass.

Arguments for the use of biomass are that biofuels can significantly reduce net CO2 emissions along the entire chain, that under the right conditions it can be used without negative side-effects on nature and the food supply, and that it will be difficult to achieve a sustainable energy supply without biomass, with or without negative emissions. According to three of the four illustrative IPCC scenarios (‘pathways’), net negative greenhouse gas emissions will be necessary to keep the temperature rise below 1.5°C on the long-term (Special Report: Global warming of 1,5°C, figure SPM.3B). Also the IPCC’s Fifth Assessment Report, which describes what is needed to keep the temperature rise below 2 degrees, mentions that scenarios usually show a temporary excess of CO2 emissions (Summary for policy makers). For later compensation of these emissions, reforestation, land use change and the capture and storage of CO2 released during biomass combustion (BECCS) are the most important options.

To be able to make a judgement on this, it is good to look in more detail at the various types of biomass that are used and the sustainability requirements that are imposed on them.

Some applications of biomass are widely acknowledged.

The recent report on the availability and applications of sustainable biomass from the PBL provides important information for the debate. This report takes stock of and assesses the various arguments. The report discusses not only the use of different types of biomass for energy applications, but also its use as a raw material. The report points out the different perspectives from which the participants in the debate look at the use of biomass, and shows which applications do have agreement. The climate targets are not up for discussion, just as land use change that releases CO2 on balance must be minimised. The importance of preserving nature and biodiversity is widely acknowledged. Wood may continue to be harvested for certain purposes. These include the use of wood for paper and cardboard, as building material and raw material for the chemical industry, and for energy applications for which there are no good sustainability alternatives (aviation, maritime shipping, industry). Energy applications are ranked at the bottom of the list of preferred applications. There appear to be fewer objections to the use of residual flows for energy applications. The greatest confidence is placed in the sustainability of biomass from the Netherlands and subsequently from the EU.

In addition to wood, many other types of biomass are used as an energy source.

There is a wide range of different types of biomass used for energy; it is not just wood as the debate seems to suggest. Wood often involves residual flows from production forests, the main products of which are beams and planks and raw material for the paper industry. Production forests are not nature but forestry, which is actually a form of agriculture. Nature is only degraded if the area of forest is expanded at the expense of nature. Other woody biomass comes from the pruning and thinning of wood from parks and nature reserves in the country. Also vegetable and animal residual flows from the food industry, the biogenic part of household waste, animal manure and sewage sludge are sources of biomass. The types of biomass are not fixed: in the future, seaweed from the North Sea could make a substantial contribution.

The relative shares in the end use of energy for various applications in the Netherlands are shown in the graphs below. The total share of biomass in final energy use in the Netherlands in 2019 was 5.1% (source: CBS). The total contribution of all forms of renewable energy in 2019, including i.e. wind and solar, was 8.7% of the final energy consumption. Biofuels were thus responsible for more than half of the renewable energy in the Netherlands. In the future, the ratio of renewable energy of biomass to wind and solar energy is expected to shift due to the rapid growth of wind and solar energy. The table shows that imports of wood pellets fell to zero in 2015 and started again in 2018. In recent years, the use of biomass in coal-fired power stations has declined because the MEP subsidy expired and co-firing was not subsidised in the SDE, the subsequent subsidy scheme. From 2016, however, there was a new subsidy in the SDE+ up to a maximum of 25 PJ of energy produced, which has also been used. For this reason, an increase in the use of biomass in coal-fired power stations is expected in the coming years. The subsidy for the co-firing of wood pellets in coal-fired power stations will stop in 2025, which means that the use is expected to decrease again thereafter. In 2030 it will stop altogether because the generation of electricity from coal will then have to stop, and the last coal-fired power stations are expected to close. The Climate and Energy Outlook (KEV) shows an increasing trend in the use of biomass in boilers by companies.

Figure 1. The shares of the different types of renewable energy in the gross final energy consumption in The Netherlands (Source: Climate and Energy Outlook 2019)

 

Figure 2. The shares of the different types of bio energy in the gross final energy consumption in The Netherlands (Source: Climate and Energy Outlook 2019)

 

Table 1. Balance sheet solid biomass for energy, 2013-2018 (source: CBS)

Biomass can be considered climate-neutral if consumption and regrowth are in balance.

Most people agree on the undesirability of using some types of biomass for energy applications. Cutting down forests to make way for palm oil production for liquid biofuel, soya for cattle feed or sugar cane for fuel bioethanol is very damaging to biodiversity, as are the greenhouse gas emissions resulting directly from deforestation. The climate neutrality of other crops is less straightforward. Although more CO2 is released when biomass is burned compared to burning coal for the same amount of heat (source: emission factors RVO), CO2 is captured during the growth of biomass, which means that there is a relatively short carbon cycle. It is possible to keep the specified amount of carbon constant over the year by balancing the felling and re-growth in a forestry area. If natural forest is felled to make way for production forest, net CO2 is often released, because a production forest usually captures less CO2 per hectare compared to natural forest.

There are strict requirements for biomass that is used as energy.

An important part of the discussion is about the desirability of the import of wood pellets. If more and more countries start importing wood pellets, a shortage may arise, which could lead to an expansion of production forests at the expense of nature areas. Due to its small size, high population density and relatively energy-intensive industry, the Netherlands has limited opportunities to generate sufficient renewable energy, but it does have high energy consumption. Not many countries need as much import as the Netherlands, however, as can be seen from the table, a limited proportion of the total biomass used in the Netherlands consists of imported wood, which means that the availability and total demand for exported biomass by the Netherlands is not that big. Furthermore, in consultation with the environmental movement, the Netherlands has set strict requirements for subsidies for the use of biomass for co-firing [REF: RVO].  European requirements for biomass are set by the EU in the Renewable Energy Directive II (REF: REDII).

Advantages of biomass use are opportunities for application in controllable renewable energy, for negative emissions and in building the biobased economy.

A frequently mentioned disadvantage of wind and solar energy is that they are not always available to the same extent. This does not apply to the two other forms of renewable energy with great potential in the Netherlands: geothermal energy and biomass. Biomass can be used for CO2-free adjustable electrical and thermal power. Another interesting aspect of using biomass is that the CO2 released during combustion can be captured and stored. This counts as negative CO2 emissions (which is true when as much is re-grown as is combusted). Establishing a market for sustainable biomass for energy also helps to create a circular economy based on biological materials that can contribute to the sustainability of the petrochemical industry. This application is widely supported according to the PBL report. The challenge is to combine the advantages of using biomass with the preservation of valuable nature and sufficient agricultural land. Taking into account the aforementioned preconditions, this should be possible for a limited quantity of biomass, including woody biomass.

Increased criticism from the House of Representatives in the Netherlands has led to the intention to draw up a phase-out strategy for energy applications of woody biomass that will not jeopardise the energy transition.

In response to increased criticism, the House of Representatives adopted a motion to discontinue the use of woody biomass for energy applications. In response, the Minister of Economic Affairs has drawn up a parliamentary letter. This states, among other things, that there will be no new subsidy for the production of electricity from solid woody biomass, that stricter emission requirements will apply to smaller boilers, and that there will be a phase-out strategy for the generation of heat from solid woody biomass. In addition, care will be taken to ensure that the transition to a sustainable energy supply is not jeopardised. Energy companies with plans to build biomass power stations and boilers have reacted negatively to the changed position of the House of Representatives and warn that this will lead to the postponement or cancellation of the constructions, which will make it more difficult to achieve the climate targets. For example, Vattenfall has postponed its decision to build the biomass power plant in Diemen.

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