Biogas – renewable energy at its best

Anne Kujanpää


Anne Kujanpää
Project Manager, B.Sc. Automation technology

The popularity of biogas as a form of renewable energy has increased at a great pace in Finland during the last decade. Pioneering small-scale innova­tions have over time grown into industrial operations and the demand for biogas as a replace­ment for fossil fuels has created a good basis for the emergence of new biogas operators. In the last few years, the digestate produced by biogas plants has started to find its place as a recycled nutrient product that can be used as a replacement for industrially manufactured fertilizers.

Honestly “bio”

When biogas is mentioned, people almost always have a preconceived idea about it. If nothing else, the prefix ‘bio’ is in one way or another connect­ed to environmental friendliness and a subject that will in the future have a strong position when we move on to more sustainable energy solutions. Biogas might otherwise be a foreign concept to the uninitiated, but the things mentioned above are already a solid starting point, since biogas is truly environmentally friendly bioener­gy. In order to promote conservation of the environment and standardize environmental license policies within the EU, the planning of larger biogas plants must also take into account the BAT (Best Available Techniques) reference document defined for waste treatment. The best biogas plant pro­cesses, whether big or small, enable the production of environmentally friendly and sustainably produced local energy, as well as soil conditioner and recycled nutrients suitable for even the needs of organic production. When material that has gone through the digestion process is used as it is in fields or as processed into commercial fertilizer products, the product can safely be called ecological.

Raw materials appropriate for a biogas plant i.e. feed is created huge amounts in both nature and the soci­ety’s operations. Household bio-waste, sludge from sewage treatment plants, food industry by-products, agriculture manure and many other organic ma­terials can be used as feed. In addition to digestion plants, biogas can be collected from landfills where biogas is formed in the depths of old landfill banks. In Finland, landfills gases are largely utilized, but elsewhere in the world landfill banks still contain a lot of energy production potential.

Biogas’ role as a replacement for fossil fuels

At the moment, biogas is widely utilized in its gaseous form, either as crude gas with a methane content of about 60% or after being processed into biomethane with a methane content of about 98%. Lately, the liquifying of biogas has also gained a foothold in Finland, which is great. When we talk about just the traffic use of biogas, or more accurately biomethane, both gaseous and liquified forms have their users. In traffic, com­pressed biomethane (CBG) is mainly used by passenger cars and, for exam­ple, refuse trucks and buses. Liquified biomethane (LBG) on the other hand is better suited to powerful heavy vehicles and, on an even larger scale, marine traffic. When biomethane is liquified, larger amounts of it can be fit in a vehicle’s fuel tank, which enables longer drives between refueling. Heavy vehicles using liquified biomethane are already used to some degree in road transport and once the fueling network of liquified methane has been expanded, we can certainly expect traffic contractors to move on from using fossil fuels. There already is a reasonable amount of refueling stations for compressed biomethane in Finland, excluding the eastern­most and northernmost parts of the country. Since the biogas market is still evolving, it must be said that natural gas still has its own role in traffic use.

Biogas and biomethane developed from it have, as a form of renewable energy, been well-received by indus­try. Industry aims for carbon neutrality and biogas can support this goal very well. Many industrial operators have replaced fossil fuels with renewable energy, with one option being switch­ing to biogas. Having an industrial plant located within a reasonable distance from a biogas plant can at best create excellent solutions for the needs of both plants. The industrial plant can supply by-products to be used as raw material at the biogas plant and the biogas plant can supply gas or electricity and heat produced from gas for industrial needs. There­fore, an industrial plant does not need to be located close to a gas network in order to use biogas. There already are some off-grid biogas plants of indus­trial size that operate outside of gas distribution networks, and more are being planned. Cooperation between industry and biogas plants enables keeping the transport distances to areas outside the gas network reason­able. Additionally, utilization of biogas supports the implementation of sec­tor integration. When planning biogas plant investments, things such as end users of gas and their location and the availability of the plant’s raw materials required to produce some additional value for the operations of the farm. There are even household-specific biogas production devices in the world, but these devices are more likely to inspire a new hobby related to the production of renewable energy than actual financial benefits.

Even though the traffic use of biomethane will likely in the future be largely focused on heavy equipment, due to the high volume of fuel the equipment uses, passenger car traffic should not be forgotten. Unfortunate­ly, the decision-makers in Europe have sent slightly concerning signals to car manufacturers in relation to emission standards, and the passenger cars using biomethane as their fuel are not at the top of the manufacturers’ list of priorities. From the manufacturers’ viewpoint this is understandable, since the vehicles manufactured must meet are also considered carefully. Elomatic has been part of several biogas plant projects in tasks such as producing feasibility surveys and planning the plant process. Elomatic’s wide-ranging competence is visible in the charting of the optimal location for the plant project, estimating of investment costs and in the implementation stage of the project.

Finland has considerably more production potential of biogas than is currently being utilized. Realizing that potential has posed a challenge for biogas experts for a long time and a huge amount of work has been done for it. The fact is that the operations of a biogas plant are business opera­tions which are affected by political decisions and assistance forms and incentives that are build around the plant projects. Sure, on a smaller scale biogas can be produced for non-com­mercial use, for example, on a farm it can used to produce heat and/or electricity and to replace fossil fuels. But even in these cases the plant is strict emission standards. However, we still hope that the decision-makers will rule that when it comes to emissions, the emissions created throughout a vehicle’s entire lifecycle would be con­sidered, not just the emissions created during use. In this way, the gas-fueled passenger cars could be kept on the market to create low-emission traffic. Here it is good to specify that the term ‘gas-fueled vehicles’ refers to gas-fueled vehicles equipped with a combustion engine, not vehicles that use hydrogen as their energy source

Agriculture holds great potential for biogas production

On a European scale, Finland is still a small operator in the biogas indus­try, although there has been some growth. Growth potential can still be detected in the production of biogas, and the feed produced by agriculture in particular has a huge amount of potential. Animal manure and, for ex­ample, previous year’s fodder contain energy and utilizing it should still be enhanced. Digesting the side streams of agriculture creates locally produced, renewable energy at its best. At the same time, methane, which would be released into the air as greenhouse gas as a result of spreading manure on farms, can be now collected. Another current focus point for development efforts is the further processing of the digestate produced by biogas plants. Thanks to further processing solutions, biogas plant operations could be made more profitable and the ben­eficiaries would include the environ­ment and, of course, users of the final products. With processing, different nutrient products can be separated from the digestate and in this way, the nutrients can be focused on the areas where they are needed the most. In places where animal manure is creat­ed on a large scale, the soil’s nutrient level is usually such that nutrients can be transported to other areas that have less nutrients. Performing further processing at a plant can decrease the storage and transport amounts of final products, which will further improve operations’ profitability and the envi­ronmental load caused by transport. In the case of a biogas plant, the finan­cially most sensible options must be considered, and pondering this often produces new and more sustainable innovations.

Biogas has its place in the future

The operations of biogas plants of the future will likely be a little dif­ferent from those of today. At the moment, there are several projects ongoing around the topic of how the operations of biogas plants could be enhanced and what kinds of new components could be created around the operations. In addition to the fur­ther processing of the final products produced by biogas plants, the focus could also be directed at developing the collection of carbon dioxide and possibly producing hydrogen from biogas. Producing hydrogen from renewable raw materials is an inter­esting addition to energy production but here, too, new innovations are required in order to make the pro­duction as sensible as possible. Will larger-scale production be profitable with just crude gas or will it absolutely require processing biogas into biome­thane? That remains to be seen. There is so much research being done that this matter will advance at a great pace in the next few years and biogas plant operators will likely have a key position in the development.

This year, we can also expect a decision on making biogas part of the national distribution obligation, which is hoped to promote the use of biogas as transport fuel. In April 2021, the Finnish Government submitted a government bill concerning the promotion of the traffic use of biofuels to Parliament. The implementation of this bill is currently expected. This will also make biogas taxable, despite which the benefits are still estimated to be adequate enough to increase traffic demand for biogas. Sustaina­bly produced biogas is a very good part of energy production when the discussion is about decreasing carbon dioxide emissions in the near future. Biogas is an excellent form of energy for security of supply as well, be­cause it can be produced locally from renewable raw materials and, there­fore, it can be used to replace energy imported from abroad.

Finally, it is good to remember the little fact that the effort of us all is needed in the sorting of bio-waste in particular so that the organic waste of households is not incinerated with mixed waste. Organic waste has poor value when incinerated, but it is an excellent raw material for a biogas plant’s processes. In Finland, the sorting of bio-waste is largely in order, but as long as material suitable for di­gestion process still ends up in mixed waste, there is room for improvement. Biogas will have its own foothold in the future and Elomatic wants to participate in the building of a cleaner future and help its clients implement carbon-neutral energy solutions

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