Barriers in the Biofuel-Producing Chain and Revision of Environmental Impacts

Abstract

The production of various types of biofuel greatly depends on the choice of feedstock and the implementation of technological options. Analysis of the biomass supply chain for a biofuel allows evaluation of the cumulative environmental impacts that result, such as the impacts of feedstock production (land use changes, manufacturing fertilizers) and fuel (production, distribution, storage), as well as the accessibility of resources to be used. The main problems in sustainability of first-generation (1G) biofuels are their impact on the food supply, competition for land and water, physical availability, and access and trade of biomass associated with increased food and feed prices (the debate of food versus fuel). The UK Royal Academy of Engineering and 178 Netherlands scientists declared that some biofuels, such as diesel produced from food crops, have caused more emissions than those produced by fossil fuels. Our investigation shows that fertilizer production creates greenhouse gas (GHG) emissions of 0.9–1.2 kg CO₂e/l biodiesel. The use of fertilizers causes additional emissions that exceed the emission from their production by 2- to 5.5 fold. Thus, the production and use of fertilizers for cultivation of biodiesel feedstocks generate much greater GHG emissions compared with the rate of mitigation based on the use of biodiesel. To address these challenges, biofuel producers must shift to the use of feedstock originating from an organic agriculture approach and to the use of microalgae.

Advanced biofuels (second-generation, 2G) produced from nonfood crops, woody or grassy materials, straw, animal fat, forest residues, sawmill by-products, waste cooking oil, etc., and from algae (third-generation, 3G) are considered suitable replacements for 1G biofuels, because their feedstocks can be grown on marginal lands that are usually not suitable for crop cultivation and thus do not directly compete with food production or land use. The advantages of algae as feedstock include efficient conversion of solar energy, absorption of CO₂ and pollutants, use and reuse of wastewater, and less consumption of freshwater. However, our analysis shows that photoautotrophic growth of microalgae has no potential for the mitigation of GHG emissions and can be applied only for a separate purpose. Further, cultivation of microalgae in photo-bioreactors can have only limited application as these rectors require a high energy input.

High capital investment, operation costs, the overall cost of biomass production (fertilizers, energy, freshwater), and other technological challenges must be addressed. The benefits of algal biofuels include the possibility of reaching a high flow of investments without subsidies, if business models and environment-driven approaches can be achieved through payments for mitigation of waste and air pollution, combined with creating a transformative model in which all elements generate direct economic, societal, and environmental benefits for the well-being of both people and nature. The main barrier to algal biofuel production potential is ineffective international and governmental policies, which create difficulties in coupling the goals of economic development and environmental requirements.

Activities that directly or indirectly reduce pollution should receive payment for their Life Conserve product. Therefore, the world must create new legislation, regulations, and guidance to address and promote the activity of corporations and other companies for mitigation of environmental challenges through new economic models and instruments. Only the development of the Global Life Conserve Industry can help solve problems related to sustainable development.

Macroalgal biomass can be used to produce several types of biofuels, but significant technological barriers are associated with energetic balance and cost-competitiveness.