According to Vis et al. (2010), several are the international conventions and agreements at international level that have been adopted in the field of biomass. These international instruments are the following:
• Convention on Biodiversity (CBD);
• United Nations Convention to Combat Desertification (UNCCD);
• United Nations Framework Convention on Climate Change (UNFCCC);
• Conventions of the International Labor Organization (ILO).
The signing parties—among them the EU member states—have put in place legislation for implementing these conventions.
In addition to these international documents, sustainability criteria have been integrated in European and national legislations that are either directly linked to bioenergy production or in sectors indirectly influencing biomass production. In this context, an important regulation on a European level is the EU Directive on the promotion of the use of energy from renewable sources (2009/28/EC 2009), which has been adopted in April 2009. Besides setting national targets for the share of renewable sources in the energy and transport sectors, it currently is the only legally binding legislation that defines sustainability criteria for biomass that is used for bioenergy purposes, more exactly for the use of biofuels and bioliquids.
The criteria set up in Article 17 are to be applied to imported biomass as well as to biomass produced within the EU. The most important criteria are as follows:
• A total of 35 % minimum greenhouse gas (GHG) emission savings (50 % from 2017 and 60 % from 2018);
• No biomass production on primary/undisturbed forests and wooded land, nor on highly biodiverse natural grassland;
• Restricted biomass production on protection areas (legally protected areas on a national level, further areas designated for the protection of rare, threatened, or endangered ecosystems, or species on an international level) as well as on highly biodiverse non-natural grassland; production of raw material is allowed as long as it does not interfere with protection purposes and if it is necessary for preserving the grassland status;
• Restricted biomass production on land with high-carbon stocks (forests, wetlands, and peat lands);
• The cultivation in the EU has to comply with the minimum requirements for good agricultural and environmental conditions (as referred to in the Council Regulation (EC 73/2009 2009) on common rules for direct support schemes for farmers under the common agricultural policy).
The cultivation of protected areas, forests, and non-natural grasslands is allowed under certain restrictions: The production of raw materials should not interfere with nature protection purposes, forest use is allowed as long as the forest is not converted into arable land, and grassland may be used, if the biomass use is necessary to preserve its grassland status. Biofuels and bioliquids produced from waste and residues (other than agricultural, aquaculture, fisheries, and forestry residues) only need to fulfill the sustainability criteria regarding the 35 % minimum GHG savings.
Furthermore, the EC shall report to the European parliament and the council on the following issues:
• The impact on social sustainability in the EU and in third countries of increased demand for biofuel;
• The impact of EU biofuel policy on the availability of foodstuffs at affordable
prices, in particular for people living in developing countries;
• The respect of land-use rights;
• Whether the country has ratified and implemented different conventions of the International Labor Organization;
• Whether the country has ratified the Cartagena Protocol on Biosafety and the Convention on International Trade in Endangered Species of Wild Fauna and Flora.
All the latter criteria are not binding since they only need to be reported to the EC. However, they give a hint on which aspects are regarded as important by EU member states in the field of bioenergy production.
The sustainability criteria defined in the EU renewable energy directive are only applied to biofuels and bioliquids and not for solid and gaseous biomass sources. To fill this gap, the EC has compiled a report on sustainability require- ments for the use of solid and gaseous biomass sources in electricity, heating, and cooling. It defines most relevant sustainability issues for this type of biomass, but refrains from proposing any binding criteria at EU level due to considerable differences in feedstock and since no sustainability risks are expected for domestic biomass production from wastes and residues. However, it recommends following the sustainability schemes laid down in the EC renewable energy directive if single member states want to introduce national sustainability schemes for solid and gaseous biomass used in electricity, heating, and cooling.
Whereas the EU Directive on the promotion of the use of energy from renew- able sources (2009/28/EC 2009) directly focuses on biofuel and bioliquid production, the inclusion of sustainability criteria in European environmental, waste, and water policies indirectly influences the production of biomass for bioenergy purposes. Examples are the establishment of an ecological network of special areas for conservation (the so-called Natura 2000 Network) or the prioritization of waste avoidance and recycling in waste policies. These directives and policies have to be implemented at national level leading to own national goals regarding the share of renewable energy and the decrease of GHG emissions. Furthermore, national regulations exist for the establishment of protected areas, management practices in agriculture (e.g., the share of grassland that can be converted), and regarding other sustainability aspects.
Besides binding legislation, certification systems have been established that shall ensure a sustainable production of agricultural and forestry biomass in general, but also biomass specifically produced bioenergy purposes. The entry is voluntary; however, once being a member, the rules have to be followed. Examples of certification systems are the following:
• Roundtable on Sustainable Biofuel (RSB);
• Forest Stewardship Council (FSC) for Forestry;
• Roundtable on Sustainable Palm Oil (RSPO);
• Roundtable in Responsible Soy (RTRS);
• Better Sugarcane Initiative (BSI);
• International Federation of Organic Agriculture Movements (IFOAM).
Various sets of sustainability indicators and criteria have been developed either specifically for bioenergy production systems or in sectors that are related to bio- mass production. They for instance serve the purpose to measure the impact of bioenergy production on environment, economy, and/or society.
At European level, several indicator sets have been developed for measuring the progress toward certain goals related to biodiversity or nature protection. Being a signer of the Convention on Biological Diversity (CBD), the EU sets itself the tar- get to halt the loss of biodiversity and restore habitats and natural systems by 2010 in its 2001 Strategy for Sustainable Development (CEC 2001). In this context, the SEBI project (Streamlining European 2010 Biodiversity Indicators) developed a set of 26 indicators that shall help monitor the progress toward the 2010 target (EEA 2007). In 2004, a core set of indicators has been developed, comprising agriculture, biodiversity, climate change, and water (EEA 2005).
In view of recent developments addressing sustainability of biomass production, the emerging focus on the role of forests and sustainable forest management related to climate change and energy, and the implementation of the European renewable energy directive, a working group has been established on sustainability criteria for forest biomass production, including bioenergy. Based on a gap analysis of the existing Ministerial Conference on the Protection of the Forests in Europe (MCPFE) tools, recommendations have been developed on minimum requirements for sustainable forest management, with special focus on bioenergy and climate mitigation (MCPFE 2010).
Last but not least, guidelines and handbooks have been published on how to establish bioenergy systems in a sustainable way. Examples are the framework for decision makers on sustainable bioenergy and the sustainability standards for bio- energy published by WWF (Fritsche et al. 2006).
Worldwide, many approaches and activities are underway that address sustain- ability within agriculture and in bioenergy production, especially the development of sustainability criteria, which showed strong progress in recent years. However, up to now, there is no set of internationally accepted criteria and derived indica- tors. The criteria defined within the European Directive (2009/28/EC 2009) are
currently the only legally binding criteria and only cover part of the bioenergy (liquid biofuels). These are to be seen as a minimum approach that does not cover sustainability with all its relevant aspects.
It is important to highlight the following regarding the use of biomass for the generation of electricity. Electricity generation from biomass is characterized by the following:
• Non-volatility of the power output: Biomass represents—similar to fossil fuels—a fuel source for thermal power plant. Thereby, the “stop” or “start” power production only depends on the operation strategy or plant type (peak- load plant versus base-load plant);
• High variable costs: As a hindrance compared to other renewable energy sources for the generation of electricity for almost all kinds of biomass fuel costs appear to very variable;
• Various energy conversion concepts: Today, apart from simple combustion, various technological concepts exist for power production from biomass. In general, a distinction between biomass-fired CHP plant, biomass-fired power plant, and cofiring in the conventional thermal plant has to be made;
• Biomass represents a competitive resource: In general, the energy use of bio-mass is in competition to the material used. Furthermore, competition occurs within the energetic fraction: Biomass represents a traditional resource for heating, especially in rural areas;
• Various fuel fractions occur: The generic term is used to describe a broad set of different fuels; definitions in literature are often not-harmonized between the various countries, creating in some cases confusion in the use of this term;
• Long distance transportation: Long distance transportation of biomass
resources should be avoided, since besides ecological concerns the economics are very sensitive to such costs (Resch et al. 2006).