Renewable energy is not synonymous with sustainability. The term renewable refers largely to the naturally regenerative nature of the energy source, whereas sustainability has a broader scope, including economic, social and environmental considerations. Although renewable energy technologies are generally perceived as being more sustainable compared to nonrenewable sources, due to smaller environmental impacts, there is still a need to develop agreed standards to reduce and manage these impacts. The environmental and social impacts of large hydropower reservoirs are one prominent example, including their potential to release carbon dioxide and methane from decaying biomass in tropical locations. Concern about minimizing impacts has led to the development of policy principles and guidelines under the coordination of the World Commission on Dams. Biofuels are another example, as their production in some circumstances has been associated with unsustainable land use and land-use change, with potential consequences for GHG balances, biodiversity and food security; at the same time, there is also a risk of excessive water use and contamination (UNEP 2009).44
Different renewable technologies may, therefore, rank differently according to
44. Impacts on GHG balances vary depending on feedstock, location, input and production methods, previous land use, conversion technology, all throughout the life-cycle (UNEP 2009).
varying sustainability criteria. Methodologies to quantify effects and trade-offs are still under development.45
For biofuels, the sustainability challenge is slowly being addressed on the project and policy level. National biofuels policy, regulatory frameworks, international standards, and environmental
impact
assessment
methodologies increasingly incorporate sustainability criteria and standards. criteria
For example, sustainability for biofuels and bio-liquids were developed
and adopted in the EU Renewable Energy Sources Directive (EU Directive 2009/28/EC), to be implemented by member states. Certification schemes can be used for validating the fulfillment of sustainability criteria. However, many countries lack the institutional capacity to effectively implement and enforce certification schemes, inhibiting the development and adoption of sustainability standards for biofuels.
Another challenge is balancing stringency and flexibility, as manifested in the introduction of sustainability standards for biofuels in the EU, which has led to trade disputes within the WTO. Overly rigid standards would be a disincentive for producers to enter the market and may limit investment, particularly in developing countries (Devereaux and Lee 2009). Policy makers, therefore, need to balance long-term sustainability concerns with shorter-term interests when promoting renewable energy.