Alternative fuels for Tallinn Bus Company buses: Feasibility and environmental impact of diesel, bioethanol, hybrid and biodiesel alternatives

Title in Estonian: Tallinna Autobussikoondise linnaliinibusside alternatiivkütuste kasutuselevõtu asjaolude selgitamine: Uuringu lõpparuanne

Limiting greenhouse gas emissions, reducing air pollution and dependence on oil, as well as promoting local renewable energy production are some of the main reasons that many cities and transport companies have taken an interest in biofuels and alternative technologies over the last 20 years. This study, commissioned by the Tallinn Bus Company, evaluates the fuel consumption and environmental impacts of diesel, ethanol, biodiesel and hybrid buses and gauges the potential costs and benefits of adopting biofuels for Tallinn buses.

As a part of the assessment, four scenarios are analyzed in terms of the reduction of environmental impacts resulting from the choices to be made by the Tallinn Bus Company. Also analyzed are the costs of the alternatives up until the year 2020, taking into account the current conditions.

Tallinn’s public transport buses make up to 4% of the total Tallinn transport CO₂e emissions. If current trends continue, the amount of emissions from the buses will not increase, but emissions from car use will grow by 3-4% per year, as they have over the last 10 years.

A comparison of alternative technologies implemented to reduce the greenhouse gases of the Tallinn Bus Company by 2020 shows that the largest reduction would come from biodiesel buses (-83%), followed by bioethanol buses (-76%) and hybrid buses (-21%). According to the Estonian National Renewable Energy Action Plan, the share of renewables should account for 10% of the energy used in the transport sector by 2020. The action plan presumes that by the year 2020, 50% of public transport would be fuelled by 100% renewable energy. The scenarios of both biodiesel and ethanol buses would comply with the measure. In the case that all of the new buses purchased between 2011 and 2020 run on sustainable biofuels, 80% of the Tallinn Bus Company buses’ energy demand would be covered by biofuels.

However, the study finds, reducing the CO₂e emissions with a transition to biofuels is a rather costly and inefficient measure. A reduction of 1 ton CO₂e with the alternatives analyzed in the study would, at current prices, cost 206 €/ ton CO₂ reduced for hybrid fuel, 311 €/ ton for biodiesel fuel and 450 €/ ton for bio-ethanol fuel. Compared to the measures implemented in the energy and heating sector, the biofuel alternatives are 10 to 20 times more expensive. Furthermore, there are several measures in the transport sector, where the CO₂ cost-efficiency is ca. 15–70 €/ton.

Download the report (external link to SEI Estonia website)