Posted in | Biofuels

Food Industry Waste Can be Profitable for Biogas Production

The waste produced by the food industry can provide significant benefits, especially in the production of biogas, regardless of whether the biogas is utilized in vehicles or used for generating heat and electricity.

Emma Lindkvist, PhD student at Linkoping University (Image credit: Magnus Johansson)

This was the conclusion drawn by scientists from the Biogas Research Center in a newly published article.

The food sector—when measured in net sales—is the second largest industry in Sweden and also the fourth largest employer. The production in this sector is known to be highly efficient, with regards to the use of the main raw materials as well as energy consumption. However, to date, studies have not explored the feasibility of using waste in the form of organic by-products in the most efficient manner.

Much of the waste is used as animal fodder, and some goes to compost or combustion.

Emma Lindkvist, Doctoral Student, Division of Energy Systems, Linköping University.

Lindkvist also works at the Swedish Biogas Research Center, BRC, at Linköping University (LiU).

Along with other scientists at BRC, Magnus Karlsson from LiU and Jenny Ivner from Region Östergötland, Lindkvist has studied the food sector in a detailed perspective to explore how the organic by-products can help in creating the greatest advantage for the environment, for the economy, and for energy conservation. The research article has been reported in the scientific journal Energies.

Five regions selected

Five regions were selected by Emma Lindkvist and her co-authors to explore the Swedish food sector. The team contacted all leading food manufacturers in these areas, each of which had a certain character. For instance, one area was close to a major city, one was home to a huge fishing industry, etc., thus making sure that they had the broadest overview as possible.

We then analysed three scenarios: to continue as before, to produce biogas upgraded to vehicle fuel, and to produce biogas for electricity and heat production. And we looked at economic, environmental and energy profitability.

Emma Lindkvist, Doctoral Student, Division of Energy Systems, Linköping University.

In addition, the researchers studied a situation, in which considerable amounts of wind power were present in the system, and another in which the heat and electricity generated from biogas substitutes that generated from coal.

In all three perspectives, biogas is the better alternative. In four of the five cases, biogas that has been upgraded to vehicle fuel gives the highest economic gains. In the fifth case, biogas was profitable, but continuing to use the previous system was significantly more profitable. This is because the biogas potential in the waste is lower here than in the other cases,” stated Emma Lindkvist.

Biogas a better alternative

From energy-efficiency and environmental standpoints, continuing without change was often the poorest alternative. Some exceptions were a few cases, in which other energy was obtained from wind power.

When a coal-condensing power plant is utilized in the system, the biogas generated for heat and electricity production offers a benefit over the vehicle fuel derived from biogas, because it is assumed that the electricity generated from coal-fired power stations is used to upgrade the biogas. Conversely, when the upgrade is performed using electricity from wind power, the biogas used as a vehicle fuel is considered to be the most beneficial.

I was surprised to see that the different systems differed, and we plan to construct a model in the next step that will enable us to optimise the systems. We want to be able to follow individual streams of material. It’s possible that high-value waste should continue to be used as animal fodder: remember that animals need to get food from somewhere.

Emma Lindkvist, Doctoral Student, Division of Energy Systems, Linköping University.

However, the conclusion reached by the researchers is that with regards to energy conservation and care for the environment, the food sector should not be the sole stakeholder when it comes to making decisions about how organic by-products should be addressed; this strategy would be advantageous in the long run. Moreover, there should be a collaboration between the energy sector, the industries, and the public sector, as there is a large and lucrative potential for the use of biogas, lucrative not just for the energy sector and for the environment as a whole, but also  for the economy, which is equally important.

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