District heat biomass

Zero carbon heat – lessons from Denmark

Progress on decarbonising heat has been slow but technology, policy and finance options are available to accelerate developments.
Published: Thu 14 Mar 2019

The decarbonisation of heating especially in northern hemisphere countries is key for meeting emissions targets of the Paris Agreement but overall progress has been limited. What is the problem and what can be done about it, given that technologies are available, although some such as heat pumps and hydrogen need further development, and district heating networks are in place in several countries?

Consider the scale of it. According to the IEA, globally heating and cooling account for almost half of the total energy consumption, split equally between heat for use in buildings and heat for industrial processes, and over a quarter of the CO2 emissions. Likewise in Europe, where household heating and hot water reach almost 80% of final energy use, but the majority of the heating and cooling is generated from fossil fuels and only about one-sixth is from renewable energies.

“Cooling and especially heating is a problem facing governments all around the world and falls far behind the electricity sector in moving to renewable generation,” Energy in Buildings Policy Advisor Ian Manders explains in an Engerati webinar now available on demand.

“There is a lot more we can do to make progress on reaching zero carbon heating and I believe it to be primarily policy rather than an engineering issue,” continues Manders, a former deputy director of the UK district heating and CHP association who has worked with governments to introduce legislation and policy on building energy use.

The heat problem

Manders states that from his observations and those of others, a major issue is that political barriers have slowed the uptake of renewable heat and the growth of heat networks. For example, in the UK, gas is effectively subsidised with a 5% VAT rate and no carbon tax, while another issue is that the gas distribution systems are generally well built out and their costs written down.

“As a result, gas is relatively cheap and serves to discourage a shift to disruptive technologies which have to pay for their infrastructure or may have higher operating costs,” he says. He adds that policy makers are now in a conundrum and see heat as “difficult”, facing issues such as the organisaitonal changes required at the individual building level, funding these high cost changes, addressing fuel poverty and the absence of a heat market.

“All of these issues ultimately cause problems for politicians.”

Lessons from Denmark

As an example of a country that has largely decarbonised its heat, particularly in the cities, Manders turns to Denmark, where he has served as an advisor to the government.

“Denmark has done some remarkable things and now has a system that is flexible enough to decarbonise buildings that are connected to the district heating network,” he says, explaining that the country’s efforts can be traced to the 1970s.

At that time, with its reliance on increasingly expensive oil, particularly for space heating, a concerted effort was started to reduce fuel usage and switch to alternative fuels. This resulted in a drive away from oil boilers primarily to district heating but also gas. As a result, almost two-thirds of buildings are connected to district heating, primarily in the cities – in Copenhagen it is 98% – but also in smaller towns and villages.

For comparison, about 11% of the world’s space and water heating needs are supplied by district heating. In the UK, where the focus was on gas due to its North Sea availability, just 2% of buildings are connected to these networks.

Coupled to the drive to district heating was a similar drive towards co-generation, utilising the heat from power generation but also developing small plants to run on local fuels or waste. As an example, the Assens Fjernvarme Amba biomass plant in western central Denmark, which is run as a cooperative, delivers among the cheapest heat prices in the country.

“This small scheme shows how heat delivery is a fundamental part of the community in a way it isn’t in other countries,” Manders comments.

Heating solutions

So what are options for countries to decarbonise heating with the high costs involved, for example for Denmark to reach the remainder of its population not served by district heating and for other countries such as the UK, where the cost has been estimated as much as £4,000 per capita?

“We are talking about big bills which will involve a substantial switch of resources and that is going to need a national decision, as there was in Denmark,” Manders says.

He remarks that governments need to “bite the bullet” and move away from any support for fossil fuels and support renewable energies and the networks needed for it to become price competitive.

“Another important issue we are not seeing is that governments need to start preparing the public and convincing them of the value of green energy. It’s not just about climate change but about other issues such as air pollution, and as we have seen in Denmark the prices of wind have dropped significantly,” he adds.

“Ultimately there is no silver bullet and we need the different technologies that are available and different solutions. As heat can’t be piped around the country it is a local matter and needs to be planned and developed at a local level. And we need to start now with the technologies that are available.”