Key issues in estimating energy and greenhouse gas savings of biofuels: challenges and perspectives

Abstract

HIGHLIGHTSLand-use and land-use changes may overestimate the biofuel sustainability.Environmental and social acceptability is essential in making biofuel-support policies. Keywords:Energy balance Greenhouse gas (GHG) balance Biofuels Sustainability Life cycle assessment (LCA)The increasing demand for biofuels has encouraged the researchers and policy makers worldwide to find sustainable biofuel production systems in accordance with the regional conditions and needs. The sustainability of a biofuel production system includes energy and greenhouse gas (GHG) saving along with environmental and social acceptability. Life cycle assessment (LCA) is an internationally recognized tool for determining the sustainability of biofuels. LCA includes goal and scope, life cycle inventory, life cycle impact assessment, and interpretation as major steps. LCA results vary significantly, if there are any variations in performing these steps. For instance, biofuel producing feedstocks have different environmental values that lead to different GHG emission savings and energy balances. Similarly, land-use and land-use changes may overestimate biofuel sustainability. This study aims to examine various biofuel production systems for their GHG savings and energy balances, relative to conventional fossil fuels with an ambition to address the challenges and to offer future directions for LCA based biofuel studies. Environmental and social acceptability of biofuel production is the key factor in developing biofuel support policies. Higher GHG emission saving and energy balance of biofuel can be achieved, if biomass yield is high, and ecologically sustainable biomass or non-food biomass is converted into biofuel and used efficiently.

Waste to biodiesel: A preliminary assessment for Saudi Arabia

“…In this regards, the life cycle assessment (LCA), cradle to grave approach, is a valuable tool to understand the environmental and economic benefits of the process and its products (Nizami et al, 2017). LCA mainly consist of steps such as functional unit, scope, system boundary, reference system, data source and allocation (Rathore et al, 2016). The proposed waste to biodiesel technologies would be multi-dimensional, since various waste feedstocks for biodiesel production as well as other value-added products involved.…”

“…Biodiesel from non-food sources such as sewage sludge, waste cooking oil (WCO), microalgae and animal fat wastes along with non-edible oil seeds such as Jatropha, Pongamia, Neem, Camelina, and Soapberries has gained significant attention due to positive energy balance and economic and environmental values as compared to both petrodiesel and conventional feedstock based biodiesel (Rathore et al, 2016). Moreover, a lot of non-food sources, as mentioned above are classified as wastes and would provide enormous economic and environmental benefits if used for biodiesel production.…”

Investigation of yields and qualities of pyrolysis products obtained from oil palm biomass using an agitated bed pyrolysis reactor

“…Reliance on fossil fuels also creates negative environmental impacts, which contribute to global warming and climate change. The global consumption of fossil fuels not only impacts the environment but also poses a risk to energy systems in terms of both energy security and energy sustainability, particularly in the countries that need to import fossil fuels (Rathore et al, 2016). In light of these concerns, many countries, both developed and developing, are looking to overcome these issues by searching and innovating renewable energy resources.…”

Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides

“…These new methods for reducing biodiesel production costs offer improved production technologies for better yield, reduced capital costs, and reduced raw material costs, of which feedstock cost is the most dominant [125]. Therefore, many studies of various non-food feedstocks including waste cooking oil (WCO), microalgae, and non-edible seed oils such as Jatropha, Pongamia, neem, Camelina, soapberries, and animal fats, along with low-cost technologies, were performed in attempts to reduce the cost of biodiesel and to commercialize its products in both developing and developed countries [126,127].…”