Mikael Ehrs, lecturer at Novia University of Applied Sciences, encourages owners of biowaste streams to consider alternatives to biogas production. If the bio-waste generated in connection with your own production, or more specifically the side streams, is processed into transport fuel, for example, you will get a better price than if you just produce biogas and use it for heating. Ehrs also admits that producing biogas for combustion requires the least effort.
‘The easiest way is to produce heat with biogas, no purification is needed. Transport fuels have an even better price, but they are the most complex,’ explains Ehrs.
Novia has recently conducted a study on the profitability of producing fuel from potato production by-products in South Ostrobothnia. This type of potato material is obtained from farms, packaging plants and potato peelings. From a technical point of view, the potato side streams from these locations are ideal for fuel production, but on the other hand, potato peelings and side streams from potato factories can also be used for other purposes – they can be used as animal feed or even as food for humans when processed into potato flakes.
Ehrs says that there are many other side streams that are suitable for use as raw material for biofuel in Ostrobothnia. For example, waste sludge and leaves and stems left over from greenhouses could be utilised better than they are today. There are enormous amounts of different types of bio-side streams in the southern parts of Ostrobothnia, ten times more than is needed as raw material for the biogas plant currently in operation in Jeppo, for example.
Costs can be reduced
The problem with biofuel production has been the cost, but Ehrs sees opportunities to reduce costs. He cites a recent study by Vamk University of Applied Sciences as an example.
‘Steel tanks and pipes are usually the most expensive part of a biofuel plant. According to Vamk’s research, equipment that purifies biogas for transport fuel can often be manufactured more cheaply by using mostly plastic parts and 3D-printed plastic nozzles.’
Based on Novia’s own research, Ehrs points out that utilising waste heat can improve the return on biofuel production. Up to a third of biogas production is used to keep the bioreactor sufficiently warm. If this heat can be taken from waste heat from processes adjacent to the bioreactor (ethanol distillation, e-fuel reactor, data centre), fuel production becomes more profitable. Greenhouses can also utilise excess carbon dioxide to make plants grow faster – up to half of natural biogas can consist of carbon dioxide.
Location can save money
Ehrs praises the Rannikon Biokaasu project. Its upcoming biogas plant in Härkmeri, Kristinestad, will process agricultural waste from the surrounding area, side streams from the region’s commercial horticultural centres, and commercial and industrial bio-waste. The plant can also produce gas from marine biomass, such as fish from managed fishing waters and seaweed.
‘They have planned the plant next to large side stream sources, so transport distances are very short. They also have an idea to later sell their gas production through another company, Gas1,’ explains Ehrs.
Mikael Ehrs, lecturer at Novia University of Applied Sciences, has investigated the possibilities of producing fuel from potato cultivation by-products as part of the Power of Potatoes project.