Can biogas be used in natural gas pipelines?

Biogas can be used in natural gas pipelines, but before this is possible the biogas needs to be upgraded to Renewable Natural Gas (RNG). So the gas transitions well in to distribution pipelines. In this article we will explain more about the upgrading of biogas and the advantages of using the biogas in natural pipelines.  

How are natural gas pipelines currently used?

In a report of the EIA (The U.S. Energy Information Administration), it is stated that the largest part of the natural gas pipelines – 36 percent – serve the generation of electrical power Industrial machinery uses 33% of the natural gas output; 16% goes toward the heating of homes and residential water supplies; 11% is used for heat/water in commercial buildings and the last four percent is used as fuel for cars, trucks, buses etcetera.

What is Renewable Natural Gas?

Biogas can be injected into natural gas pipelines, but there are specific requirements that the biogas needs to meet. Basically the biogas needs to be upgraded to Renewable Natural Gas (RNG). The main difference between raw biogas and RNG is the contents of Methane (CH4). Raw biogas contains about 60-65% CH4. Whereas RNG has a CH4 content of at least 90%.

To make Renewable Natural Gas from raw biogas, the following steps must be taken:

• Moisture has to be removed;
• Carbon dioxide (CO2) needs to be removed;
• Nitrogen (N2) contents needs to be reduced;
• Oxygen (O2) needs to be reduced;
• Trace-level contaminants needs to be removed. This includes Siloxanes, volatile organic compounds (VOCs) and Hydrogen sulfide (H2S).

What are the advantages of using RNG in natural gas pipelines?

There are three big advantages of using RNG in natural gas pipelines. Below these advantages are explained:

1. Fuel availability and Diversity

Renewable Natural Gas is made from biogas, which can be generated continuously from multiple sources (for example livestock or Municipal Solid Waste landfills). Which means RNG is highly available. This means it is also a great substitute for fossil gas!

2. The quality of local air

The combustion of RNG and fossil gas is similar, which means that pipeline operators make no distinctions between the two gasses. The difference is that fossil gas contains multiple non-methane hydrocarbons. For example propane, pentane, ethane and butane.

RNG does not contain these non-methane hydrocarbons. Which makes a big difference in the emissions of vehicles. Thus when we use RNG instead of fossil gas, the local air pollutant emissions are being reduced dramatically.

3. Greenhouse Gas (GHG) emission reductions

Besides the vehicle emissions, there is a additional benefit over fossil gas, because RNG has a lower total carbon footprint. This is because of the CH4 emissions that are reduced due to the emissions of organic waste used to produce the RNG. It is even possible for a RNG to have a negative carbon footprint!