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Denmark could make 100% green transition of the gas grid by 2035

Since 2014, when upgraded biogas – biomethane or green gas was first injected into the Danish gas grid, it has reduced Denmark’s fossil carbon dioxide (CO2) emissions by 675 000 tonnes cumulatively. For 2018 alone biomethane is estimated to reduce the country’s CO2 emissions by 800 000 tonnes. Furthermore, an assessment by Grøn Gas Danmark suggests that Denmark has the potential to make a 100 percent green transition of the gas grid by 2035.

Aarhus University’s biogas research plant in Foulum. Built by Xergi in 2007, the Foulum plant is one of the world’s largest of its kind and the University has its own livestock and crop research and production in the surroundings. Research at the full-scale biogas plant is focused on advanced technologies for improving the biogas production including optimisation of the biogas potential and improvement of methods such as pre-treatment, high technology separation of nutrients, thermal conversion of the residual fibres after digestion, high solid digester technology and upgrading of biogas to biomethane.

According to Grøn Gas Danmark (Green Gas Denmark), an advocacy network comprising of stakeholders within the biogas-to-grid value chain, the calculations show that, with the right framework conditions, there is potential for biomethane (green gas) to cover Denmark’s expected gas consumption of 72 PJ in 2035. The calculations are based on assessments of the potential that were produced by Aarhus University and compared to projections for gas consumption in Denmark.

Green gas potentials (PJ/year) in Denmark with (from the bottom) existing feedstocks without straw and methanisation, efficiency improvement, straw and finally methanisation ( graph courtesy Grøn Gas Danmark).

The potential of 72 PJ is based on a continued increase in the use of manure and waste, an efficiency improvement of biogas production and a 50 percent utilisation of straw resources. Aarhus University points out that a utilisation of the gas grid’s potential for electricity storage through methanisation could boost the potential to 100 PJ.

Green gas is the gas of the future. Our calculations show that it is possible for Denmark to become the first country in Europe to become independent of fossil gas. A complete green transition of the gas grid is a real possibility. In other words, the around DKK 55 billion (≈ EUR 7.4 billion) invested by Danish society in the gas grid could have an important role in the green energy system of the future, said Carsten Jensen, Managing Director of Danish Gas Distribution.

Technology will drive efficiency improvement 

A decentralised production of biomethane is currently being established across the country; during the period 2014 to 2017, twenty-one biogas upgrading plants were connected to the gas grid.

We have produced more green gas over the last 3 years than in the previous 30 years combined. That means that the share of green gas in the gas grid is rising, and next year we expect that 11 percent of the gas will be green. As such, we are already the country in Europe with the highest share of green gas in our gas grid, said Jensen.

The development of green gas for the gas grid began with the energy agreement from 2012 that was supported by a large political majority. The government has also an ambition to increase the anaerobic digestion (AD) of animal manure to 50 percent of the annual manure production by 2020.

Since then, we have witnessed an industrialisation of the sector. Many of the facilities that are built today are 25-50 times bigger than the biogas facilities that we have traditionally had in Denmark, and the new facilities are able to transform more biomass to gas. All the facilities together contribute to the impressive growth in the production of green gas, said Ole Hvelplund, Managing Director of Nature Energy, Denmark’s largest biogas producer.

The Foulum facility includes a complete 1.5 tonne per hour cereal straw briquetting line from C. F. Nielsen / Kinetic Biofuel. Research has shown that adding a small percentage pre-treated straw in the form of briquettes can significantly increase the yield of manure-based biogas plants.

The green transition of the gas grid follows the same recipe as the green transition of the electricity grid, and with only five years under its belt, the transition is still in its infancy. However, biomethane producers are expecting the costs of production to fall in the future:

There has never been spent as much resources on developing the production of green gas as there is today. We are witnessing a growing professionalisation among producers and an increasing production among both large and small facilities. New organic by-products are being used in large-scale productions, and the producers anticipate advances in technology over the coming years. However, it is still too early to say how much we will be able to reduce costs by, remarked Hvelplund.

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