Taarnby: city of smart solutions

Ramboll has collaborated with Taarnby Forsyning (TF), a municipal utility company, to establish a new district cooling system based on smart sector integration with the existing district heating network in the new mixed-use urban and business area near the Copenhagen airport.

Ramboll played an important role in preparing a feasibility study for the project and a business plan, highlighting:

• the profitability of establishing a district cooling system based on a large-scale heat pump installation and a cold-water storage tank
• the benefits of using the same heat pump installation in combination with ground source cooling and wastewater

This approach reflects a cost-effective synergy between district heating and district cooling through the co-production of heating and cooling. The energy plant is located at Taarnby Forsyning’s existing wastewater treatment plant where the price of land was cheaper, saving 25% of the investment costs needed to build the new facilities.

Ramboll designed all the installations, networks, and connections, and assisted with tender documents and supervision of the construction work.

The project helped the local community in Taarnby save 80 million DKK compared to alternative solutions.

The mechanism of a smart energy system

A smart energy system is a system in which renewable energy production, distribution, and consumption are linked together intelligently in an integrated and flexible way. Taarnby is a world-class example of smart sector integration, also known as sector coupling, between the heating, cooling, electricity, and water sectors.

Raymond Skaarup, general manager at Taarnby Forsyning explains:

“Many energy centres combine heating and cooling, but only to a certain extent. In our case, we benefit from economy of scale through an unprecedented setup where nothing is wasted: when we produce cooling, heat is generated and sold in the district heating system. In addition, the heat from the wastewater and the ground source cooling gives us two important energy sources: hot water for district heating during winter and cold water for district cooling during summer. I call this sector coupling at its best,”.

The new heat pump installation comes to complement the existing district heating system, which produces cost-effective energy based on cogeneration of heat and power, residential waste, and natural gas, covering around 60% of the total heat demand for large buildings in the Taarnby municipality, including Copenhagen Airport.

Effectively, the project adds:

• district cooling, wastewater, and ground water as components of the existing integrated energy system in Copenhagen
• a heat pump installation, which is simultaneously connected to a 2,000 m3 cold-water tank and the district heating system, allowing for optimised energy production considering electricity prices as well as the alternative heat production costs of all plants producing heat for the Greater Copenhagen district heating system
• lower impact on the environment through reduction of noise, vibration and use of space for individual cooling equipment

With the demand for cooling on the rise, Taarnby Forsyning plans to add ground source cooling to the system in the second stage of the project’s development from 2020-2030.