What do the methods of producing biodiesel look like?

Biodiesel is increasingly viewed by some as an attractive alternative to conventional diesel fuel. Biodiesel produces less carbon dioxide per unit of energy compared to regular diesel, with emissions from soy-based biodiesel being 67% to 77% lower. This is measured in terms of carbon intensity, which calculates the greenhouse gases emitted per energy produced. Switching to biodiesel from traditional diesel significantly reduces the overall emissions of greenhouse gases.

However, the most readily available fuel, straight vegetable oils (SVOs), cannot be used in engines due to major maintenance problems. Over time, SVO’s high viscosity and boiling point lead to inefficient combustion and increased strain on the engine. This results in the buildup of carbon deposits, which can severely affect engine performance and reduce lifespan. Additionally, SVO is incompatible with modern emission control systems, potentially causing damage and costly maintenance and operational problems. For these reasons, SVO is not viable for long-term use in diesel engines.

These issues are remediated when SVO is turned into crude biodiesel. An essential step in this process is called transesterification. According to A.E. Atabani, A.S. Silitonga, et al., “The main problem [in transesterification] is the processes are relatively time consuming and needs separation of the vegetable oil/alcohol/catalyst/saponified impurities mixture from the biodiesel.” To improve the accessibility and availability of biodiesel, researchers should investigate solutions to address the time-consuming aspects of the transesterification process.

Another problem explored by the same researchers above is that the wastewater usually generated during this process can damage nearby ecosystems. Wastewater treatment usually costs around “0.5–2.0 kWh per cubic meter of treated water.” This can add up very quickly if SVO continues to be refined into biodiesel.

To make this entire process easier, practitioners may consider making SVO treatment plants fully self-sustained through onsite wind power, onsite solar, or onsite geothermal. Therefore, the energy expenditure generated during the SVO treatment process is not further contributing to CO2 emissions, grid strain, or other negative production externalities.

Biodiesel offers a promising, cleaner alternative to traditional diesel, though it faces challenges such as time-intensive production processes and environmental concerns from wastewater. Addressing these issues through efficient practices and renewable energy could enhance its viability and sustainability.

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Written by Mustafa Haque, Public Policy Intern

The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.