Report on EUBC&E Side Event – Can bioenergy pay back carbon debt in time?
The SUPERGEN Bioenergy hub successfully hosted a parallel event attended by scientists, decision makers and stakeholders at the 22nd European Biomass Conference and Exhibition in Hamburg on Tuesday 24th of June. Click here for further details and a brief report.
The event started with an introductory presentation from SUPERGEN bioenergy hub director Patricia Thornley, before expert presentations from Uwe Fritsche (IINAS, Germany), Alessandro Agostini (European Commission, Netherlands), Gerfried Jungmeier (Joanneum Research, Austria) and Carlo Hamelinck (Ecofys).
There was a consensus that bioenergy is “carbon neutral” in the long term, but there were issues with some forest bioenergy systems in the short to medium term. The “cumulative emissions” framing of climate change was used to argue that every unit of greenhouse gas (GHG) released had to be accommodated in an increasingly tight GHG budget and so with bioenergy it was important to be confident that releases of (even biogenic) carbon did not excessively deplete the remaining emission space.
While the long term emission balance was the most relevant parameter for the global carbon budget determining global mean temperature rise, other impacts of GHG releases (including on biodiversity and ocean acidification) were strong drivers for a medium term (5-20 years) reduction that necessitated taking account of these dynamics. A table was presented from a joint IEA bioenergy task meeting that identified the bioenergy systems and time frames where there was most potential for GHG emission to exceed anticipated levels.
The GHG balance was noted to be particularly sensitive to the carbon intensity of the substituted fossil fuel, forest growth rate, biomass conversion efficiency and residue decay rate.
However, there were strong arguments that there was a need to look beyond bioenergy in appropriate policy responses. Producers do not necessarily know in advance how their feedstock will be used and forestry is an industry with multiple products, so a more holistic approach to forest management is necessary and a consequential rather than an attributional approach to LCA was more appropriate for assessing the long term impact of bioenergy policy. This would need to take into account other issues, such as: competition for land between food, energy and other purposes; competition with other renewables and the impacts of intensified management.
Work was presented which had considered the impact of forest management (increased thinning and decreased rotation length) in Austria on a combined set of energy and product services (including wood for paper production and furniture). This showed some increases in greenhouse gas emissions per unit of land when wood was partitioned for fuelwood from the forest system compared to a “business as usual” scenario. However, it was important to take into account the forest type and it was noted that existing IPCC guidelines already address changes in forest C storage pools and land use, although this was not “labelled” as bioenergy. It was recommended that a systematic approach to the forest system that simultaneously considered energy and wood products was the most appropriate methodological approach.
The strategic role of bioenergy for global future energy provision was emphasized in the face of diminishing (and increasingly expensive) fossil fuel reserves and the high level of global land availability was contrasted with the very small proportion used for bioenergy at present. It was pointed out that the indirect and marginal impacts of bioenergy systems were frequently considered in calculations, but rarely in the fossil equivalent comparison. Indirect land use change (ILUC) related to biofuels was discussed and it was argued that, even when this was taken into account, there was still scope for substantial greenhouse gas savings with biofuel pathways, but that these might not be sufficient to meet future EU thresholds and so would not be incentivised in future. It was also argued that ILUC was a “one-off” debt that was repaid during future production, whereas fossil fuels can never repay their carbon debt. In that sense it was argued that ILUC was a carbon “investment” worth making, particularly if safeguards to promote biofuels with low indirect impacts were in place.
There followed a lively panel discussion that covered the importance of integrating food and fuel applications in overall land use systems, the relevant life cycle comparators and the importance of looking at the whole forest system. Copies of presentations on request from Dr Laura O’ Keefe (laura.o’keefe@manchester.ac.uk).
