Frequently asked questions
What is biogas? Is it dangerous to handle? Some of your questions may be answered in this Q&A.
Question 1: What is ”biogas”?
Answer: Biogas is a renewable gas (methane) formed naturally when organic materials are decomposed. As examples, waste products from households, food manufacturing industries and sewage may be used for biogas production.
Biogas is the cleanest fuel available today. Correctly handled, emissions in principle consist only of carbon dioxide and water. As the carbon dioxide comes from biological materials it does not contribute to climate change.
Biogas is locally produced. SLs biogas comes from sewage plats in the Stockholm area. It is the Stockholmers themselves that that contribute to the creation of more eco-friendly public transport
Question 2: What is ”natural gas” and ”vehicle gas”?
Answer: “Natural gas” is methane derived from fossils, and not more natural than oil. When it is used as fuel the emissions add to the existing carbon dioxide in atmosphere.
“Vehicle gas” is sometimes used as a comprehensive term for natural gas and biogas. Considering the fact that the two gases have significantly different impact on climate change the term “vehicle gas” can be misleading.
Question 3: Does biogas really decrease pollution caused by traffic?
Answer: Yes it does.
A bus driven with biogas only will decrease emissions of fossil carbon dioxide with up to 90% compared with a diesel bus.
The EU directive on renewable energy claims that only bio fuels decreasing emissions of carbon dioxide with at least 35% should be regarded as bio fuels. Using biogas will reduce those emissions with 75-90% over the total lifecycle depending on with source the production is based on.
The combustion of biogas is clean and therefore the emissions of particles and nitrogen oxides are relative low compared to burning of diesel.
Question 4: Is it more dangerous to operate buses with biogas than with diesel?
Answer: No, it is not
Biogas is light and non-toxic and has a higher ignition temperature than diesel. The gas is kept in a closed system which means that leakage can be avoided when filling up the bus. The risk of fire or explosions is not higher than the situation is when diesel is used.
Question 5: Should we not use biogas for heating houses?
Answer: No The transport sector is extremely reliant on fossil fuels and it is important to reduce the dependency of that. Biogas is a fuel very well suited for use in vehicles. Besides there are several bio energy sources that can be used to heat houses and produce electricity, and the share of renewable fuel is already much higher in these sectors than in the transport sector.
Question 6: What does biogas cost?
Answer: The price depends on who sells the gas but generally the price is lower than for diesel.
One of the tasks for the BBB project is to contribute to make biogas competitive to traditional fuels for buses.
Question 7: Is it really possible to replace all diesel fuel with biogas?
Answer: No. There will always be several fuels available on the market. The positive environmental effects from biogas are a strong argument to increase its share, especially for city buses.
In order to decrease the emissions from the transport sector it is necessary to use a combination of three strategies:
- Curb the fast growing transport sector
- Choose energy efficient transport modes: public transport, walking, cycling
- Increase the use of renewable fuels
One important task for the BBB project is to estimate the potential of biogas supply in the Baltic Sea Region