10 Uses of Biogas

Here is our list of 8 biogas uses in points. While reading this, bear in mind that biogas is most often made from organic waste materials which would otherwise have no use. The waste digester feedstocks can usually be obtained at a low cost or for free. Above all, it is a sustainable fuel which can be made for as long as mankind grows crops and eats food.

Our List of 8 Ways that Biogas is Used

1. Electricity Generation as a Biogas Use

Before 2017 biogas was consumed for electricity generation at its point of manufacture both in Food Waste Biogas plants and in commercial agricultural Anaerobic Digestion Plants. This is the first of our biogas uses, electricity generation is done with only minor cleaning of the raw biogas.

Biogas from landfills is usually also used for this purpose and combusted in large reciprocating engines. Some water scrubbing may be used before landfill biogas is used in this way.

Prior to the use of landfill gas collected and combusted in engines to generate electricity, a chemical called siloxane, which forms hard deposits inside the engine, may have to be removed.

Biogas is easily combusted in large rugged gas engines of the type which in the less rugged form are powered by diesel fuel. The resultant energy within the biogas can be used directly for cooking, by burning it in the presence of oxygen.

Denmark's government, now followed by a number of others, has decided to enter strategic partnerships to develop biogas uses. In particular, it is used for vehicles to run on electricity, as well as natural gas and hydrogen.

Watch our video about the “8 biogas uses” below, and return afterwards for more details in the full article by scrolling down below:

2. Compression of Biogas to Fill Gas Cylinders

Next in our list of biogas uses is the compression of biogas to fill gas cylinders. Biogas can be compressed, in the same way as natural gas is compressed to CNG, and used to power motor vehicles. Biogas is cleaned and upgraded to natural gas standards when it becomes bio-methane and is then suitable for compression (to make it into a liquid).

In Scandinavia, many users of the CNG fuel have vehicles from tractors, to cars, to buses all designed, or retro-fitted for natural gas use.

Some European sites even have RNG from a local biogas plant system, piped directly to a nearby fueling station without using the natural gas pipeline.

3. Upgrading Biogas to Biomethane (RNG) for Use as a Natural Gas Replacement

The second of our biogas uses is upgrading biogas to biomethane (also known as Renewable Natural Gas (RNG). During upgrading (purification) the carbon dioxide and water are removed. At the same time, small amounts of hydrogen sulphide and other traces of impurity are removed.

In other words, what people call “renewable natural gas” (RNG) is biomethane that has been cleaned to meet natural gas pipeline quality standards.

Biomethane is practically identical to natural gas. Conventional natural gas is almost entirely just methane. All the biomethane needs in order to be used to replace natural gas in the gas grid is:

• the addition of a small amount of another high calorific gas to raise its calorific value to that of non-renewable natural gas
• pressurization to the .grid pipeline pressure.

Since 2017 when the cost of biomethane was reduced by new technology used in its production the majority of new biogas plants have been designed to be used to produce biomethane.

4. Biogas Use in the Transport Sector to Power Vehicles

Just like natural gas, biogas can be compressed and used to power motor vehicles of all types.

The decoupling of production and utilization by transport in gas cylinders also makes it possible to use biogas as fuel for a rising number of natural-gas-powered vehicles.

Biogas processed into biomethane and used as fuel can make an important contribution to climate protection, enhance supply security and reduce noise emissions.

Biogas, when purified, is essentially just a form of natural gas with the big advantage that it is renewable, and therefore need never run out.

The proliferation of natural gas use as a transportation fuel is tied to government incentives and the density of infrastructure. As fuel economy and greenhouse gas emissions standards become increasingly stringent in world markets (particularly for medium and heavy-duty vehicles).

The use of natural gas is also an effective way to reduce carbon emissions, but even more effective in reducing GHG carbon emissions is the use of biogas (biomethane).

It is convenient to modify vehicles to use methane as fuel in such a way that they can continue to use conventional fuel when outside the range of a gas refuelling station. Equipment designed for the conversion of petrol engines to use natural gas or petrol is readily available from a number of manufacturers in Italy and the U.S.A.

Natural gas contains some higher alkanes (ethane, propane, butane, etc.) besides methane. These give it a higher calorific (heating) value than pure methane (biomethane).

Delhi, the Indian capital has the distinction of having the country's first public transport fleet that runs on two types of clean fuel:

• biogas (RNG), and
• compressed natural gas (CNG).

This includes some 16,000 buses-in Delhi run on CNG, according to Indraprastha Gas Ltd, a Delhi government undertaking, which is the sole supplier of CNG in the capital. This was set up to share expertise and experiences to support sustainable energy systems in India, with a special focus on biogas. Sweden is moving ahead as a pioneer in biogas technology, using it for heating, power generation and fueling vehicles.

5. Biogas Used for Cooking in Domestic Gas Stoves

Biogas can be used in similar ways as natural gas in gas stoves, lamps or as fuel for engines. Compare this with natural gas, which contains 80 to 90% methane.

The use of biogas as a fuel for gas stoves reduces pressure on wood fuel supplies and displaces the consumption of petroleum products. The benefit of this biogas use is that it can reduce the ever-increasing demand for household wood fuels. This demand is leading to vast deforestation. Such deforestation will be reduced once the widespread adoption of biogas production takes place.

In addition to bio-digestion, there are also some innovative biogas companies that produce liquid natural gas made from bio materials by processes which don't require anaerobic digestion. These may also be used in domestic cooking stoves.

Village women, and the whole community, gain from the use of biogas instead of wood fuel. Instead of spending many hours each day walking to the forest and collecting wood fuel, they can use their time in taking care of their children.

Natural burning is preferred because it is free (if you do the work to run the biogas plant every day), while the biogas fuel commercially available is often too costly.

6. Biogas Use as Fuel for Portable Electricity Gen-sets

5th of our biogas uses is as a fuel to power portable electricity generating sets. Most off-grid homes use portable gen-sets, which are Internal Combustion (IC) engines combined with an alternator or dynamo. The gen-sets used for running on biogas are the same ones as those used for running on propane gas or natural gas. They find out the daily power consumption and use that as a guide to their gen-set requirements.

The generation of electricity is the single largest use of fuel in the world. About 41% of that energy came from coal, another 21% came from natural gas, and the rest was covered by hydro, nuclear, and oil at 16%, 13%, and 5% respectively.

7. Using Biogas to Sell Offset Carbon Credits as a Means to Obtain an Income from CDM Payments in Qualifying Countries

Sixth on our list of biogas uses is its use as a means to obtain an Income from CDM Payments in Qualifying Countries under the Kyoto Agreement of the 1990s.

Green gas or biogas offers several sustainable development benefits since it is a greenhouse-gas-neutral and clean source of energy.

Most biogas has a methane component of 50 to 60%, a CO₂ component of 35 to 50%, and a relatively small amount of hydrogen sulfide (H₂S) and ammonia. In comparison, the methane component of natural gas amounts to over 80%.

8. Direct Conversion of Biogas to Electricity in a Fuel Cell

As our final example of biogas uses we list the direct conversion of biogas to electricity in a fuel cell. In fuel cells, the gas is burnt to heat a special electrical cell.

This electrical cell when heated creates an electrical current/ electricity.

This process requires very clean gas and expensive fuel cells, but there is a lot of potential in this technology for the future.

Domestic central heating boilers are already available which in addition to providing the hot water to heat a home, include a fuel cell which produces electricity as well.

Biogas Uses – Conclusion

We hope you have been enjoying reading about the eight biogas uses we have identified and listed above.

The potential uses for biogas are many and varied. Most importantly it can be used to generate electricity, as a transport fuel, or as renewable natural gas.

It can also be used in a number of industrial processes.

The use of biogas is growing rapidly around the world. In many countries, it is already being used on a large scale to generate electricity and/or to power vehicles.

It has the potential to replace a significant amount of fossil fuel use and to make a major contribution to reducing greenhouse gas emissions. There are many challenges to the widespread use of biogas, but it has great potential as a renewable energy source.

Have you ever thought of getting involved by producing biogas, or promoting the idea of large-scale commercial biogas production in your area.

[Article first published on 15 December 2018.]