Marius Walters

Cleaner production of cleaner fuels: wind-to-wheel - environmental assessment of CO2-based oxymethylene ether as a drop-in fuel

The combustion of fossil fuels within the transportation sector is a key driver of global warming (GW) and leads to harmful emissions of nitrogen oxides (NOx) and particulates (soot). To reduce these negative impacts of the transportation sector, synthetic fuels are currently being developed, which are produced from renewable energy stored via catalytic conversion of hydrogen (H2) and carbon dioxide (CO2). A promising class of synthetic fuels are oxymethylene ethers (OMEs). This study conducts a prospective environmental assessment of an OME-based fuel using Life Cycle Assessment (LCA). We investigate an OME1-diesel-blend (OME1-blend), where OME1 replaces 24 mass% of diesel fuel. Such an OME1-blend could be a first step towards an OME transition. For the production of OME1 from CO2-based methanol, we consider both the established route via condensation with formaldehyde and a novel direct pathway based on catalytic combination with CO2 and hydrogen. To close the carbon loop, CO2 supply via biogas and direct air capture is considered. In a best-case scenario, hydrogen is produced by water electrolysis using electricity from wind power in the European Union as an input. The direct pathway reduces the required process steps from three to two and is shown to allow for an improved utilization of the energy provided by hydrogen: the exergy efficiency is increased from 74% to 86%. For combustion, we conducted experiments in a single cylinder engine to determine the full spectrum of engine-related emissions. The engine data provide the input for simulations of the cumulative raw emissions over the Worldwide Harmonized Light Vehicles Test Procedures (WLTP) cycle for a mid-size passenger vehicle. Our well-to-wheel LCA shows that OME1 has the potential to serve as an almost carbon-neutral blending component: replacing 24 mass% of diesel by OME1 could reduce the GW impact by 22% and the emissions of NOx and soot even by 43% and 75%, respectively. The key to achieving these benefits is the integration of renewable energy in hydrogen production. The cumulative energy demand (CED) over the life cycle is doubled compared to fossil diesel. With sufficient renewable electricity available, OME1-blends may serve as a promising first step towards a more sustainable transportation sector.

Fuel cell range extender for battery electric vehicles

The will to reduce carbon dioxide emissions, the desire for independence from fossil fuels and increasing renewable sources of electrical energy has driven the development of electrified propulsion systems for vehicles in recent years. Despite a significant increase in driving range with the introduction of lithium ion technology, the storage of electrical energy in the vehicle still is the biggest challenge. This paper provides an overview of state of the art battery and range extension technology. Furthermore, it shows the key issues in range extender development. Finally, a fuel cell range extender working with hydrogen is introduced which is under development in the public funded project “BREEZE!” with partners from industry and research institutions.

Range extender systems for electric drivetrains in medium duty distribution vehicles

The expected growth of trade is a major challenge with regard to environmental sustainability. Especially in urban zones more distribution traffic will further worsen the local pollutant situation. Electrically driven distribution vehicles as part of low-carbon city mobility concepts can be one answer to this challenge. Based on requirements and boundary conditions of a typical distribution vehicle, representative load profiles and the demands for the electrical system are defined, leading to a power requirement for the traction motor of 150 kW and battery capacity which shall support at least 100 km of electric range. To cover longer distances of up to 200 km per day, different range extender powertrain configurations with combustion engines and also a fuel cell system are discussed in a simulation study, while the pure electrical vehicle with 200 km range is investigated for comparison. This results in investigating overall seven different vehicle configurations, covering energy consumption as well as package and costs aspects. The investigation shows that a benefit in fuel consumption is possible with all the range extended vehicles compared to the conventional vehicle. A benefit in operation cost and therefore a return of invest is highly depending on the daily mileage and prices for energy.