100% renewable district heating

Project brief

Starting point

In 1994 the Danish town of Marstal developed a project to install solar collectors on a swimming pool. The success of this 8,000 m2 installation formed the basis for a plan to install a large-scale solar heating plant connected to the district heating plant.

As part of the EU’s Lisbon Strategy to become the “most dynamic and competitive knowledge-based economy in the world” the Seventh Framework Programme (FP7) for Research and technological development provides funding for research-related activities and supports knowledge development and sharing projects that have a “European added value”. This is the case of the SUNSTORE4 project.

An EU flag project

Marstal Fjernvarme (Marstal District Heating) has, through the EU’s FP7, received pledges of support for the SUNSTORE4 project. The project is, along with 10 other European projects selected to be a part of the so-called “EU flag projects”.

The aim of the project is to demonstrate a large scale innovative, cost-effective and technically 100 % sustainable renewable energy system. Marstal Fjernvarme’s nearly 1,500 consumers will now receive 55% of their thermal energy from the solar production and 45% of their thermal energy from locally produced biomass (energy willow). The project also includes a heat pump which is “moving” energy to the energy storage and a turbine, a so called ORC (Organic Rankine Cycle) which is an electricity-producing device that can use the energy from the flue gas produced in the biomass boiler.

A European perspective of the system concept and thereby of the demonstration project is that it is potentially applicable and adaptable to different regions of Europe with different types of conditions. The total budget for the project is EUR 15.1 million. From the EU, the project has achieved EUR 6.1 million in grants. The participating partners contribute to the project with EUR 0.4 million.

Expected results

  • An innovative integrated 100% renewable energy system focusing on energy and cost efficiency with a high replication potential in a European context;
  • An estimated heat cost price in Northern Europe of 50-55 EUR/MWh excl. salaries for the staff;
  • A technical reliable energy system based on proved individual technologies, where innovation is related to integration of these individual technologies;
  • An innovative flexible energy system, which can deal with the challenges related to summer overheating, including ORC and a compressor heat pump using CO2 as refrigerant;
  • A long term full scale pit heat storage including a heat pump to cool the storage and thus reduce heat losses;
  • Innovative solar system focusing on increasing system efficiency and lower production cost;
  • Innovative biomass CHP system.

Target groups

SUNSTORE4 has three main target groups:

  • renewable energy players,
  • district heating utilities and
  • manufacturers.

In addition, SUNSTORE4 also interacts with two secondary target groups:

  • municipalities and urban planners
  • and large heating consumers.