Climate effects from biomass and other energy sources Recommendations

Transcription

1 Climate effects from biomass and other energy sources Recommendations 1 July 2013 MEMO Biomass is a valuable source of energy and is expected to contribute a significant part of the energy system in Denmark in the coming years. But the question of the actual climate impact of the energy produced with biomass is increasingly debated in scientific and climate political circles. Therefore, CON- CITO has had calculations made of the climate impact from a variety of different energy sources, including biomass sources. These are published and analyzed in the main report showing that virtually no sources of energy are completely CO2-neutral and that several types of biomass emits levels of greenhouse gas emissions that are at par with or greater than emissions from the fossil fuels they replace. In this light, CONCITO in this memo presents nine specific recommendations to promote the sustainable use of biomass in a Danish context. Authors: Thomas Færgeman Torben Chrintz The memo is funded by: Fiolstræde 17B DK-1171 København K Tel: info@concito.dk

2 1. Background Biomass is a valuable source of energy, partly because it can be stored. In addition, it is an energy source that in Denmark can be produced both in agriculture and forestry, making it interesting from a business policy perspective. Biomass is especially attractive as an energy source as it has so far been considered to be CO2-neutral in national and international climate policy, so that the use of biomass instead of fossil fuels could be expected to contribute to a reduction in anthropogenic CO2 emissions. However, the question of the actual climate impact of biomass is increasingly debated in scientific and climate political circles. Therefore, CONCITO has had calculations made of the climate impacts from a range of different energy sources, including biomass sources, which are publicized and analyzed in the report "Climate impacts of biomass and other energy sources". The calculations are based on consistent and transparent LCA methods building on given and well-defined assumptions in relation to the production of one kwh and one MJ of energy respectively, and show that virtually no energy sources are CO2-neutral. The results are not solely linked to Denmark. In Denmark, biomass is expected to constitute a significant part of the energy system going forward. In part because of the Danish Energy Agreement of March 2012, the use of biomass for energy and transport purposes in Denmark is expected to increase from approximately 134 PJ to approximately 170 PJ in The increase is expected to come from an increased use of biogas, bio fuels, as well as conversions to biomass in the central combined heat and power plants. 1 As a climate think tank, we believe it is important to have the best possible basis for choosing the energy sources with the lowest climate impact. CONCITO therefore presents a number of recommendations for the use of biomass in a Danish context. 2. Recommendations The Energy Agreement includes provisions for the preparation of an analysis of the use of bioenergy in Denmark: "The analysis should focus on whether the right conditions for an efficient and environmentally sustainable use of biomass resources in the Danish energy supply are in place. The analysis must also assess CO2 displacement". It is also apparent from the agreement that the analysis should be presented by the end of CONCITO s recommendations take a point of departure in the fact that the aforementioned analysis is currently well underway, and our recommendations are therefore closely linked to the analytical work carried out by the Danish Energy Agency. 1 Mandate for analysis of bioenergy set out in the Energy Agreement of 22 March

3 CONCITO notes - in line with a number of other sources (including reports by the EU's Joint Research Centre, the European Environment Agency Scientific Committee and the British Government) - that environmentally sustainable biomass is a limited resource, although there continues to be scientific disagreement as to how much is available for human use. Therefore, a pragmatic approach in relation to sustainability is to say that it is "surplus" biomass, which may be used. CONCITO also notes that there may be options to increase production of sustainable biomass in Denmark in future. Based on these findings and a general precautionary principle, the specific recommendations are as follows: 1. As environmentally sustainable biomass is a very limited resource, biomass must be used with great consideration It must be acknowledged that biomass is not by definition CO2-neutral. 3. Guidelines for the calculation of the climate impacts of biomass should be adopted. These guidelines should include all sources of greenhouse gas emissions. This task should ideally be undertaken in cooperation with the other EU countries, inspired by the calculation methods expected to be applied in the UK Tax exemptions of biomass and subsidies for biomass should consequently be re-evaluated and differentiated based on the actual CO2 emissions of biomass. 5. The possibilities of increasing production of environmentally sustainable biomass in Danish agriculture and forestry should be promoted as much as possible, for example by: the establishment of nurse trees in forestry in the establishment of new cultures, through selective plant breeding in agriculture and 2 In the UK, the Committee on Climate Change recommends that the share of biomass in the energy system should not surpass 10 % of total energy consumption. See In the total Danish energy system this would correspond to approximately PJ towards Here it is recommended to operate with more than one time horizon when analyzing the impact of biofuels on greenhouse gas emissions. Accordingly, the effect of different instruments on greenhouse gases should be considered over several time horizons, for example 10, 20, 50 and 100 years, so that the actual emissions in a given year can be calculated. 3

4 using energy crops when converting agricultural land to other uses, for example in order to protect the aquatic environment, provided that this does not conflict with other climate and environmental considerations. 6. The available quantities of environmentally sustainable biomass should be used where it provides the greatest value to society. This may also be in other sectors than the energy sector. 7. Renewable energy sources with very low CO2 emissions such as wind and solar power should be given even higher priority in energy policy. 8. In the case that the use of wood pellets in central power stations is politically maintained, this should be a temporary measure, in the sense that once the existing installations are worn out, they should not be re-placed by new wood pellet-based installations. 9. Regarding biogas, a comprehensive strategy should be drawn up that does not rely on corn as a supplement in production, but utilizes other alternatives with a smaller climate impact. This strategy should also address the challenges of methane emissions from biogas plants. 3. Main results from CONCITO s report CONCITO s report estimates the climate impacts of a range of different sources of energy at an overall level with particular focus on energy from biomass. The results show that virtually none of the energy sources are CO2-neutral with the chosen set of assumptions and calculation methods, and that several of them - depending on the choice of time horizon - can emit levels of greenhouse gasses that are on par with or greater than the fossil energy sources they replace. CONCITO s calculations are so-called consequential LCA calculations. This means that we try to calculate the greenhouse gas emission from demanding an additional unit of energy, in addition to the amount already consumed. This approach entails, among other things, that if the amount of sustainable biomass is limited and already has been exhausted, then an additional demand will have a different climate impact per unit of energy than when using the limited available amount of sustainable biomass. 4

5 Emissions of greenhouse gases from the various types of biomass come from three different sources: process energy (e.g. drying and transportation of wood pellets), indirect Land Use Change - iluc (i.e. the displacement of use of land), and delayed/accelerated CO2 emissions (e.g. that branches on the forest floor, which would otherwise rot in the course of 20 years, are collected and made into pellets or wood chips, which are then burned now). In the case of agricultural biomass sources, such as biogas, it is particularly the iluc effect from feeding e.g. corn into a biogas plant, which produces a relatively high discharge of greenhouse gases. In the case of biomass types from forestry, such as pellets, it is especially an accelerated CO2 emission that causes increased emissions. There are other ways to determine the impact of biomass than with a consequential LCA. Some would argue that for example through certification schemes sustainable wood pellets can be separated from the unsustainable. The point here is that the available amount of sustainable wood pellets is limited, and that focus, therefore, must be on how an increased demand can be met. It is this focus CONCITO has had in the present study. This way of thinking conversely implies that for example forestry can be intensified, so that in addition to planting small beech trees on a cleared forest area larch trees that can be harvested after 20 years can also be planted. In this logic, however, the additional biomass will only be available after 20 years. Similarly, it is probably possible to increase straw production through the selection of other cereals without affecting food production. In this case, the additional biomass could be harvested and used from year to year. Finally, new biomass could be produced on soils that are currently not cultivated. It is emphasized that the calculated results are based on a number of methodological choices and data inputs containing substantial uncertainties. However, comparing the results to other similar studies shows that the results are largely coinciding: Biomass produced on residues and straw have lower emission values than biomass produced on the whole trees and sales crops. Energy from wood from climate zones with short rotation times is in terms of climate effect better than energy made from wood from climate zones with long rotation times. Biogas based wholly or partly on corn will increase the climate impact compared to biogas based solely on manure. 5

6 The climate impact from biogas is sensitive to the volume of methane leakage from biogas facilities, which should therefore be given considerable attention. Liquid biofuels based on waste products (manure/straw) result in lower greenhouse gas emission levels than biofuels from cultivated crops or forestry products. Wind, and to some extent solar power, generally entail a significantly smaller impact on the climate than electricity from most types of biomass. The uncertainties in the data in CONCITO s report are significant. Going forward, it is recommended that these uncertainties are reduced. This is particularly true regarding the modelling of iluc, the assessment of potentials for the use of residual products, and the identification of marginally affected suppliers of raw materials for bio fuels, i.e. where are crops cultivated, and in which regions is forestry affected. Further, there is a considerable need to clarify the potential for increasing biomass production on marginal land or by increasing productivity in existing systems so that these iluc effects can be minimized. 4. Perspectives in the recommendations In the target of the Government Platform to reduce CO2e emissions in 2020 by 40 % compared to 1990, the use of biomass takes up much space as an instrument. In total, biomass accounts for approximately two-thirds of the total amount of renewable energy, with increasing importance of imported wood pellets to replace coal in the power generation sector. On the basis of CONCITO s own calculations, and similar calculations from i.e. The Department of Energy & Climate Changes (DECC) in the UK, CO2 emissions from the Danish use of biomass in 2020 is estimated at 4.5 to 7 million tonnes CO2e - a discharge that is not accounted for in the official compilation of Denmark's greenhouse gas emissions. The use of biomass in the base year 1990 was very low. Assuming a Danish emission level of 69.3 million tonnes of CO2e in the base year 1990, a 40% reduction in 2020 correspond to a reduction of approximately 27.7 million tonnes of CO2. When including in this number, the emissions from the use of biomass as calculated in the CONCITO report, the emission reduction will be 20.7 to 23.2 million tonnes CO2e, equivalent to % reduction, not 40 %. Applying a worst case scenario for the wood pellets the real reduction fall to 23 %. 6

7 These discretionary calculations call for extreme caution when uncritically using biomass as a tool to fulfil the reduction targets as biomass can have a high emission level in production and combustion, which is not included. The types of biomass that have a benefit compared to fossil fuels are actual residues such as waste and to a limited extent residual products from forestry and agriculture, provided that the use for energy purposes does not displace other application, and that natural decomposition would otherwise be very fast. Other usage may be such as feed or material consumption. The volume of biomass that is available here and now for the energy sector is, from this point of view, limited, and biomass should therefore not constitute one of the quantitatively most influential instruments in Danish climate action. Conversely, the available biomass should be used with the maximum possible CO2 benefit, and this can entail a much more advanced application than simply incineration, for example the use of straw in a more high-tech context or as a supplement in biogas installations, if this results in the greatest overall energy efficiency. Similarly, it is necessary to maintain an open mind as to whether the use of the available biomass has the largest CO2 benefit when used in the energy sector, or if usage for feed and material purposes is preferable from a climate and sustainability point of view. The calculations in CONCITO s report clearly show that wind and in part also solar energy cause the most genuine reduction in CO2 emissions, and that funds should therefore be channelled towards these instruments at the expense of biomass. Biomass can provide great benefits by balancing the energy system, just as better transmission lines and cooperation with the rest of Europe can. In any case, there should be a documentation requirement for the use of biomass in the energy system in order to demonstrate the resulting emission of greenhouse gases on an objective foundation. Here the approach used in CON- CITO s report provides an example to build on. Alternatively, the British model can be applied. It establishes the maximum permissible emissions from production of electricity using biomass to 285 g CO2e/kWh. This limit is tightened progressively, and is expected soon to be reduced to 200 g CO2e/Kwh. In addition, the British calculations are extended with some of the elements that are also included in CONCITO s calculations, including iluc and accelerated/delayed absorption of CO2. The present recommendations are the expression of the professional judgment of the CONCITO secretariat based on dialogue with CONCITO s members. As the members of such a broad organization as CONCITO will not always be 7

8 able to academically or politically agree, CONCITO s members can in no way be held accountable for the final recommendations. British principles for the use of biomass In 2012, the British government adopted The UK Bioenergy Strategy. The strategy indicates the adoption of four overall principles for the use of biomass: There are [ ] risks and uncertainties associated with bioenergy: whether it genuinely contributes to carbon reductions; the availability and price of sufficient sustainably-sourced biomass; the relationship between bioenergy and other uses of land, such as food production, and other uses of biomass, such as for construction materials; the environmental impacts on air quality, biodiversity and water resources. [ ] The UK Government has a responsibility to ensure that its policies only support bioenergy use in the right circumstances. This strategy is based on a statement of four principles which will act as a framework for future government policy on bioenergy. In summary the four principles state that: 1. Policies that support bioenergy should deliver genuine carbon reductions that help meet UK carbon emissions objectives to 2050 and beyond. 2. Support for bioenergy should make a cost effective contribution to UK carbon emission objectives in the context of overall energy goals. 3. Support for bioenergy should aim to maximise the overall benefits and minimise costs (quantifiable and non-quantifiable) across the economy. 4. At regular time intervals and when policies promote significant additional demand for bioenergy in the UK, beyond that envisaged by current use, policy makers should assess and respond to the impacts of this increased deployment on other areas, such as food security and biodiversity. Source: bioenergy-strategy-.pdf 8