Biogas usage options
Biogas is a renewable fuel that can be used in a number of ways. Biogas can be used in boilers to provide heat only, in combined heat and power plants (CHP) to generate both electricity and heat, or upgraded to biomethane and then injected into the gas network or used as a vehicle fuel.
Ramboll has extensive experience in advising clients on all these methods. We also advise on the development of gas networks for biomethane, in settings where no suitable infrastructure exists already.
Biogas is made up of methane, carbon dioxide, hydrogen sulphide, water vapour and other minor constituents and particulates. The methane, and therefore the energy, content of the biogas can increase by removing the other constituents - the methane content can be increased to 98% or more. In this form, biomethane is suitable for injection into the gas network or used as a vehicle fuel.
Ramboll has advised a number of clients on biogas upgrades, which creates high grade renewable fuel and removes those constituents that have the potential to corrode or cause mechanical wear to a facility.
There are a number of technologies available for the removal of CO2, which are continually being improved and developed upon. It is important to choose the most appropriate technology for the task, based on plant-specific parameters.
Biogas as a vehicle fuel
Biomethane can be compressed or liquefied into Compressed BioGas (CBG) or Liquefied BioGas (LBG), which can then be used as a vehicle fuel. Natural gas used as a vehicle fuel can lead to a 20-30% saving on carbon emissions. The process of capturing biomethane can lead to a 100% reduction in greenhouse gas emission compared to other energy sources.
Vehicles running on biomethane have lower emissions of particulates, NOx and SOx and are known to be quieter running than engines running on petrol or diesel.
Ramboll has been involved in pre-construction planning, design and inspection of a significant number of vehicle fuelling stations.
Anaerobic digestion of sewage sludge and organic waste
A city with a population of one million has the potential to generate 17,300,000 Nm3/year of raw biogas from sewage sludge. This is equivalent to 110 GWh; enough energy to provide heat and electricity to 4,400 households.
Alternatively, 280,000 homes can be supplied with heat and electricity from biogas generated from 8 million tonnes of organic waste.
Ramboll has considerable experience in the preparation of anaerobic digestion (AD) plant business models.
The underlying analyses investigate appropriate composition and volumes, consider the security of feedstock, evaluate the potential energy production levels and digestate output, and identify and evaluate end markets. Once a conclusion on the feasibility and scale of a plant has been reached, Ramboll can select, design and procure the correct reception facilities and waste handling equipment as well as the AD plant itself.
Our services after the pre-study stage cover the entire project cycle from preliminary design, permit applications and EIAs to final design, tendering, supervision, commissioning and performance tests. We also perform periodical inspections and analysis of risks and operational safety.