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GeoWatt researches fourth-generation thermal grids for balancing the local demand of groups of users for heat or cold with the available supply.


Closed project



Use of fossil energy can be drastically reduced by maximum integration of renewable energy sources (geothermal, solar thermal, etc.), maximum reuse of energy (utilisation of residual heat and cold), and deployment of suitable buffer mechanisms in the network. At GeoWatt, we develop innovative concepts and tools to enhance the efficiency of thermal grids while minimising risks, capital expenditures and operating costs and maintaining or improving consumer convenience and comfort. GeoWatt will develop proof of concept solutions for innovative technological concepts intended to act as catalysts for interaction with local industry and to attract international industrial partners.

Fourth-generation thermal grids have major potential to increase energy efficiency and the share of renewable energy in building heating and cooling. Instead of individual buildings or techniques, GeoWatt focuses on the optimisation of entire thermal systems in which the supply for heat and cold is matched to the corresponding demand of user groups. One of the questions it addresses is whether building fourth-generation thermal grids is economically advantageous compared to investment in energy neutral (or nearly energy neutral) new buildings and comprehensive energy renovation in historic centres. Accurate simulation tools are required for proper estimation and comparison of the yields, capital expenditures and operating costs of fourth-generation thermal grids. The performance and cost of the required ‘building blocks’ of a thermal network impact the overall cost as well as the potential yield.

Within GeoWatt, we implement innovative concepts and demonstrators for smart substations, thermal storage and thermal grids with low return temperature. We also develop tool kits for designing fourth-generation thermal grids and geothermal plants. All technological developments are tested against a prototype fourth-generation thermal grid in the Genk region.

Our research concentrates on:

  • optimisation of energy demand and temperature regimes in buildings
  • development of an active substation as an interface between the grid and users
  • innovative solutions for heat generation and storage
  • smart charge level monitoring for thermal storage
  • control of thermal grids with the aim of creating flexibility
  • economic feasibility of fourth-generation thermal grids

For the optimisation of overall energy supply in cities, the thermal and electrical grids should not be regarded as entirely separate. These different grids are already being joined by a number of components that can generate both heat and electricity, such as heat pumps and geothermal stations.

Researching the seamless integration of electrical and thermal systems and optimal management in a multi-energy market environment is also the singular purpose of EFRO project 936.

GeoWatt is the second work package in the project 'Towards a Sustainable EnergySupply in Cities' and is a part of the Strategic Action Programme Limburg (SALK). It enables EnergyVille to create an even better integrated first-rate research centre by 2018, with a 1,400 m² laboratory facility, top-notch equipment, expert teams and fourteen pioneering demonstrators, in partnership with local industry. This research centre will be a focal point for international industrial partners.

More specifically, three innovative research tracks were developed:

  • SolSThore - highly integrated PV systems in buildings, connected with smart grids and combined with battery storage
  • GeoWatt - thermal networks of the 4th generation that bring local demand and heat and cold demand of large groups of users in balance
  • SmarThor - the techno-economic framework necessary to form CO2 neutral smart energy clusters integrating thermal and electrical energy alike.

This project is a cooperation by the University of Leuven, VITO, imec and the University of Hasselt. It receives the support of the European Union, the European Regional Development Fund ERDFFlanders Innovation & Entrepreneurship  and the Province of Limburg.

Want to know more about the project? Download the booklet with an overview of all technologies and conclusions here  or go to the news item of the closing event where you can find the posters (used for the poster sessions, all presentations and scientific publications (developed during the project).

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Carlo Mol


Carlo Mol

Programme Manager Energy Technology at EnergyVille/VITO