District energy can accelerate the transition to a low carbon society

This piece is co-authored by Jens-Peter Saul Group CEO, Ramboll,and Jens Ole Hansen, Global Market Director, Ramboll Energy. The article has also been published on Jens-Peter Saul's blog onHuffington Post.

How can you accelerate implementation of the Paris Climate Accord? That is the common theme of the side events at Cop22 Climate Conference in Morocco right now.

One relatively simple – and cost-effective - answer is to make the world’s energy systems more flexible, reliable and efficient with district energy. Because district energy is an approach that can be employed all over the world – with a global technology customised to local conditions, including coordination and co-creation with all relevant private and public stakeholders.

Let me explain: In cities, people have the same energy needs at the same time, so it makes sense to look at energy supply on a much larger scale: The density of a city enables thermal energy to be produced and stored centrally and then distributed throughout the city via city energy grids.

In Copenhagen, where Ramboll’s head office is located, almost 98% of the heat comes from the district heating grid, where Combined Heat and Power plants use the surplus heat from electricity production as heating for homes and offices – instead of just letting it out in the sea as is the case in many other countries.

The system’s main advantage is higher energy efficiency, but added values include cheaper and more reliable energy for the citizens – and a higher probability of meeting climate goals for the decision makers. This is mainly because of the system’s high energy source flexibility: The Avedøre Plant just outside Copenhagen is being converted from coal to biomass, and a growing percentage of the city’s waste is being used for energy production in the district heating system.

Other clients are discovering the advantages. In London, Ramboll is partner in a pioneering project that will use the waste heat from the London Underground to produce district heating. A report commissioned by the Greater London Authorities has found that enough heat is wasted in London to meet 70% of the city’s heating needs.

Capturing this heat and delivering it to the heat network would dramatically improve fuel bills, fuel poverty, fuel security and carbon emissions.

In North America, more and more colleges and cities are looking to convert their old steam water systems, which can be costly to operate and maintain, as well as being a potential safety hazard. The Nordic hot water district energy system is more flexible, has a reduced risk of leakages, a higher degree of efficiency, and better possibilities of integrating renewable energy.

Ramboll is now helping a handful of clients in US and Canada, introducing hot water district energy and we will in a few months open a new office in New England, dedicated to energy services.

Among the new clients are MIT (Massachusetts Institute of Technology) and the city of Cambridge, where the task is to conduct a Low Carbon Energy Supply Study for the whole city.

Ramboll is already conducting a renewable energy study for the Ivy League University Dartmouth to help the old New Hampshire institution reach its sustainability goals: The University uses oil today, but after the district energy conversion it will be also be able to use solar, biomass and other renewables, and this part of the green transition means CO2 reductions of up to 80%. By using seasonal thermal storages Dartmouth will utilize the excess energy from the cooling production during summer to displace fossil energy during winter.

So, if it is customised to local conditions, the district energy approach can be employed in most countries. As the United Nations Environment Programme puts it, it is a tried-and-tested answer to modern urban energy issues - and thus it can accelerate implementation of the Paris Accord and the low carbon society.