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Alternative fuels

Introduction

LPG, LNG, CNG – acronyms like these are set to shape the future of mobility. Find out about the world of new and sustainable fuel options!

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Alternative Fuels

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In an effort to make vehicles more efficient and the air cleaner, petrol and diesel are increasingly being replaced by alternative fuels. These include natural gas, hydrogen and synthetic methane and biomethane.

Natural gas vehicles produce up to 90 percent less nitrogen oxide emissions than diesel cars and significantly less CO2 emissions, as well as making much less noise. In addition, biomethane can be blended into the natural gas to reduce CO2 emissions even further.

Natural gas is particularly suitable for use in road freight transport – either in liquefied form (LNG – Liquefied Natural Gas) or compressed as a gas (CNG – Compressed Natural Gas). In addition to natural gas, biogas produced from fermentation can also be used in the area of mobility.

Power-to-gas technology makes it possible to produce hydrogen or synthetic methane using renewable electricity. Both hydrogen and synthetic methane can be used as alternative fuels to make transport sustainable.

Germany, as the world’s leading car exporter, exerts a significant influence on the global market. German manufacturers are actively involved in developing alternative fuels and the corresponding vehicles. In 2015, 56,000 vehicles powered by alternative fuels were registered in Germany (see German Energy Agency, in German). German companies are also heavily involved in developing power-to-gas technology.

In addition to conventional fuels and electricity, alternative fuels exist with underdeveloped potential due to their limited distribution.

Natural gas and liquefied petroleum gas (LPG)

Gaseous fuels are compressed for use in order to raise their energy density, which is essential for the transport sector, to an economic level. As a drivetrain technology, gas engines are basically similar to conventional petrol engines. Following the principle of the gasoline-powered engine, the fuelair mixture is added to the cylinder and ignited. Savings of 15 percent on CO2 emissions are possible with LPG and natural gas (CNG/LNG), compared to using a petrol engine.

Due to the high degree of technical complexity, natural gas refuelling can only be carried out at specially equipped refuelling facilities.

Biofuels

First-generation biofuels, such as vegetable oils, are relatively inefficient in terms of using raw materials. Nowadays second- generation biofuels such as biogas, biomass-to-liquid (BtL) and lignocellulosic bioethanol are used. These have a more positive energy balance and climate footprint compared to first-generation biofuels.

Biogas upgraded to biomethane can be used in natural gas vehicles and access the existing infrastructure. BtL and bioethanol are liquid fuels and can be used instead of gasoline or diesel.

For more information on biofuels see bioenergy.

Hydrogen

When used in a fuel cell, hydrogen can be a low-carbon alternative fuel for the transport sector. The hydrogen in this case is obtained from electrolysis. A problem here is that hydrogen cannot be integrated into the existing charging infrastructure.

Synthetic fuels

Other synthetic fuels can be obtained in subsequent steps after an electrolysis process. These are similar in their application to the known liquid and gaseous fuels.

For more information on synthetic fuels, see sector coupling technologies.

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