Use of biomass for energy generation - Recommendations to policy makers

Summary of the expertise of the Scientific Advisory Board on Agricultural Policy, November 2007

In this expertise the Advisory Board analyses the current situation and future prospects of bioenergy. The Board assesses developments with regard to the political objectives of climate protection, energy supply and employment. Based on this, it derives recommendations for the further development of German bioenergy policy.

The Advisory Board supports German policy makers in their efforts to internationally lead the way in respect of GHG emission mitigation. In its assessment of bioenergy policy, the Board considers the GHG emission mitigation to be the main priority. But if Germany wants to achieve particularly ambitious objectives in GHG emission mitigation and to set a good example, the Advisory Board considers it particularly important to concentrate the scarce resources on the most efficient strategies. German bioenergy policy so far does not seem to be too successful in that regard. It uses high subsidy equivalents to promote selected bioenergy routes which are relatively expensive and in many cases inefficient in terms of GHG emission mitigation.

The bioenergy routes which policy has focused on so far (biofuels, maize based biogas) have relatively high CO2eq mitigation costs amounting from 150 to well over 300 €/t CO2eq. If German policy makers are using bioenergy in order to mitigate GHG emissions, they should concentrate on energy routes which enable climate protection to be achieved at CO2 mitigation costs of below 50 €/t CO2eq. This would comprise biogas generation based on manure, if possible with cogeneration of heat and power (CHP), CHP based on wood chips from short rotation plantations and the cocombustion of wood chips and (to a certain extent) straw in existing large scale power stations. Production of biodiesel and bioethanol in Germany achieves only a very low CO2eq mitigation level of less than 3 t CO2eq per hectare, while more than 12 t CO2eq/ha can be achieved with other bioenergy routes (e.g. wood chip CHP based on short rotation plantations).

Criticism of high subsidies of current bioenergy routes which are inefficient in terms of GHG emission mitigation and energy supply does not equate to a rejection of renewable energies in general. On the contrary: greater orientation towards efficiency in the bioenergy sector would correspond to greater climate protection at the same cost. A corresponding correction of the German policy could increase CO2eq mitigation achieved via bioenergy to many times of its current level with the same budget, and without more agricultural land occupied.

Renewable energies do, however, comprise more than just bioenergy. There is strong evidence that solar and wind energy will play a major role in the long term. The potential energy supply from sun and wind greatly exceeds energy demand, the challenge is to obtain continuous access to these sources. The Advisory Board recommends that German policy on energy and climate protection should attach much greater priority to tapping these sources and should focus more on importing these energies.

Compared with solar energy, the potential of bioenergy is relatively limited in the long run. There are three main reasons for this:

  • Solar energy can make use of land which is not in competition with the generation of biomass for the food sector, and far greater energy yields per unit of area can be obtained on this land than is possible with bioenergy.
  • The global scarcity of arable land means that prices for bioenergy rise if mineral oil prices rise, which in turn leads to an overall increase in agricultural prices. This also means that costs of raw materials for the bioenergy plants rises, while higher energy prices results in greater profit for solar energy.
  • With globally limited arable land available, a large scale expansion of bioenergy would necessarily lead to the cultivation of previously uncultivated areas (ploughing up of grassland, forest clearing). This would increase CO2 and N2O emissions, meaning that the expansion of bioenergy production on arable land might even be counterproductive for climate protection. It is not possible to control these risks with the certification systems planned by policy makers.

With respect to climate protection German policy makers should not further increase the support of bioenergy production on arable land. Step-by-step, they should direct support towards bioenergy routes which (a) do not compete with food production, (b) contribute towards avoiding methane emissions from manure, or (c) show particularly low CO2eq mitigation costs or a very high CO2eq mitigation potential.

The assessment of bioenergy policy based on the criteria of "security of energy supply" and "employment" leads to a similar vote:

  • Security of energy supply: If the current bioenergy mix were to be expanded to 30 % of Germany’s agricultural land, the energy generated would only cover 2.3 % of Germany's energy consumption. If the bioenergy strategy were concentrated on wood chips cogeneration plants, which produce very high net energy yields per hectare, this figure would increase to almost 9 %. This would then, however, leave no space any more for biofuels. If, on the other hand, policy makers would like to increase self sufficiency in fuels they would have to gear the support to biogas fuel (with direct feed-in of methane into the natural gas grid). If, in contrast, they were to favour the fuel related aim of "only" becoming as independent from mineral oil and natural gas imports as possible, it would appear advisable to make the import of biofuels the main pillar of the biofuel strategy from the beginning. The negative side effects of these options - competition with the cultivation of raw products for food, impact on GHG emissions (see above) - would have to be taken into account anyhow.
  • Employment: If bioenergy generation were expanded in arable regions, it would on balance be expected to have a slight positive effect on employment, but not in all cases. If, in contrast, the support of bioenergy implies animal production to be outcompeted, the employment effects for rural areas concerned would be clearly negative. Positive employment effects are to be found above all in technology development and in the export of plants and equipment. Policy makers should therefore concentrate mainly on the support of Research and Developement activities and export activities. They should not make German agriculture dependent on policy again, by providing high levels of support for inefficient bioenergy routes, or gear agriculture towards one sector (energy) in which the German agricultural is in fact hardly competitive and which is characterised by tough international price competition and low potential for added value products.

Overall, the Advisory Board therefore concludes that German bioenergy policy should be fundamentally revised. It recommends concentrating German bioenergy policy on bioenergy generation (a) in cogeneration plants or wood chip heating systems, and (b) on the basis of biogas from manure and residual material. The mandatory blending target for biofuels should be abolished and the Renewable Raw Materials Bonus for biogas should be used for other purposes. This fundamental restructuring of bioenergy policy should be carried out in phases. This would provide companies concerned with a protection of their legitimate expectations and sufficient time to adapt to new framework conditions.

Abbildung 1: CO2äq-Vermeidungskosten und Vermeidungsleistung.

The national bioenergy policy should clearly be focused on the increase in efficiency in order to reduce national CO2eq emissions per capita. However, this only contributes very modest to the necessary global reduction of GHG emissions. The Advisory Council therefore strongly urges the Federal Government to invest significantly greater resources into developing a global climate protection strategy.

A task force should be set up for this purpose, which should network internationally and develop effective strategies and action plans. The task force ought to have a long term mandate and be granted generous resources. The primary aim should be to cooperate internationally in the development and implementation of promising GHG emission mitigation strategies. This includes the need to expand the Kyoto process to more countries and economic sectors, but also the global adjustment of taxation of fossil energy sources, and efficient, internationally orientated support of the development of renewable energies.


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