Sustainable lithium made in Europe

How geothermal energy contributes to clean mobility

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Vojens District Heating

One of the largest solar district heating systems in the world

The consumer-owned district heating company Vojens Fjernvarme is one of the largest solar heating in the world, with 70,000 m2 of collectors, with one of the largest underground thermal storage pit (200 000 m3). The water volume is separated from the district heating water by a heat exchanger and the surface of the water is covered by the liner and an insulated cover and draining system. This storage is operated as an inter-seasonal heat storage, which allows the solar plant to deliver more than half of the annual heat demand of the network. The rest of the heating demand is provided by 3 gas engines, a 10 MW electric boiler, an absorption heat pump, and gas boilers.


One of the biggest hermal pit storage, Vojens District Heating

Technical details:

  • Energy generation: 49 MW at peak effect
  • Energy sources: solar thermal collectors, gas engines, electric boiler, absorption heat pump,
    gas boilers
  • Storage capacity: 200 000 m3
  • Supplied temperature: maximum 95° C

Heat pump integration in a food commercial refrigeration system

Recovering heat from display cabinets for additional usage

On average, 50% of the energy in supermarkets is consumed by refrigeration systems to keep food safe, fresh and healthy. Saving energy is therefore a top priority for retailers as it represents a major cost factor. Demonstrating energy and emission savings also contributes to a positive image of the retailers, increasing attractivity for consumers. Finally, with the large number of retail and wholesale enterprises in Europe (around 5.4 million according to EuroCommerce’s Facts & figures, last visited on 11 December 2019) and the availability of dedicated technologies, this sector has a major role to play when it comes to achieving the European energy and climate goals.

Integrated system


  • Supermarket in Northern Germany (average outdoor temperature: 8.8 °C), built in 2016
  • CAREL Heos water loop system to cool 17 low-temperature cabinets and 23 medium temperature cabinets, all using HFC R-410A as a refrigerant. Charge sizes could be reduced significantly ranging from 1/5 to 1/3 compared to those of traditional systems
  • All cabinets equipped with CAREL electronic expansion valve (EEV) and brushless DC compressor (BLDC) with a cooling capacity of around 2 kW at 18 °C ambient temperature.
    Modulation of the CAREL EEV and BLDC compressor to avoid on/off operation, allowing for an increase of the evaporation temperature by approx. 6 K from -11.3 °C to -5.5 °C
  • Modulation of the EEV and BLDC compressor to avoid on/off operation, allowing for an increase of the evaporation temperature by approx. 6 K from -11.3 °C to -5.5 °C.
  • Water-Water heat pump using CO2 as a refrigerant with two goals:
  • To cool the water of the water loop system down to 16-18 °C
  • To recover, upgrade and transfer the heat from the water loop for heating purposes and sanitary hot water production


  • Energy savings: each cooling cabinet saves around 34% energy (compared to on/off cabinets) due to the increased evaporation temperature which effectively means that less compressor work is required to achieve the desired cooling effect.
  • Synergies: the CO2-based heat pump enhances the energy efficiency of the entire shop by recovering most of the heat rejected by the cooling cabinets to use it for space heating and sanitary hot water production.
  • Lifetime: compressor modulation allows to reduce frequent on/off operation with the benefit of reduced wearing and servicing, increasing the useful lifetime of the equipment.

The BLDC compressor (right) generates the same average cooling capacity as the on/off compressor (left: 56% of 2658 W  1500 W – 5,123 BTU/hr) consuming just 34% of the input energy [34%  1 – 314 Welectric BLDC / (0.56 * 851 Welectric on/off)]

Mäntsälä combined data and heat

Waste heat from a data centre is transformed by heat pumps to supply heat in the local district heating network

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Smart geothermal heat grid in Heerlen, The Netherlands

An example of Just Transition for coal mines with geothermal energy

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Stadtwerke Hassfurt goes for hydrogen cogeneration

A future-proof solution with virtually no emissions and easy to replicate. Made possible by cogeneration!

Stadtwerke Hassfurt, a German local utility, has realised a groundbreaking project for renewable regional energy supplies. It generates its own hydrogen from local renewable electricity and uses it in a cogeneration unit to supply regional customers with heat and electricity.

Stadtwerke Hassfurt partnered with 2G, a cogeneration manufacturer from Germany and a COGEN Europe Member, to install a cogeneration unit running on pure hydrogen. Stadtwerke Hassfurt produces its own hydrogen with an electrolyzer from electricity supplied by a local wind farm. The hydrogen is then stored in a storage facility. The 2G cogeneration unit closes the renewable circle. It transforms the hydrogen into heat and electricity which is supplied to its regional customers. Reaching efficiencies well over 80%, it is the most efficient and cost-effective way of using hydrogen. This fully decarbonised energy solution is ideally suited for local energy communities to provide their own heat and electricity.

  • Virtually no CO2 emissions
  • Most cost-effective way of using hydrogen

Join us at the EUSEW event ‘The Green Revolution Starts at Home’

On 20 June, the Decarb Heat initiative is co-organising with FEDARENE and the International Renewable Energy Agency (IRENA) a session in the framework of the EU Sustainable Week (EUSEW, Brussels on 17-21 June 2019).

About our session ‘The Green Revolution Starts at Home‘:

Europe consumes most of its energy as heating and cooling in households. With more than 80% of the heat delivered to buildings coming from obsolete, inefficient and polluting boilers, decarbonising this sector is crucial. A steep increase in the current 20% share of renewables in heating and cooling is required, together with improving the efficiencies of our heating and cooling systems, in order to achieve the Paris Agreement goals.

The solutions and technologies are already on the table such as heat pumps, district heating, cogeneration, biomass boilers and stoves, solar heat and geothermal energy. Moreover, various innovative tools and projects such as RELaTED, PLANHEAT and Hotmaps are being developed to assist cities and regions with the feasibility analysis, implementation phase and replication promotion of decarbonising heating and cooling.

There is the political momentum. With the Clean Energy Package being finalised and the Long-Term Decarbonisation Strategy under discussion, it’s the right time to start planning and implementing: what must Europe do to accelerate the uptake of all these solutions? From individuals and local authorities to European and international decisionmakers, the effort to unlock that full decarbonisation potential is collective – and a full decarbonisation possible well before 2050 if we act now.

This policy session will give a thorough overview of the heating and cooling sector in Europe with its opportunities, tools and technologies available for local, regional and national authorities. Join our session to find out more about this great decarbonisation potential!

For more information, detailed agenda and registration link, please visit the EUSEW website.

Reaction: More ambition needed to accelerate progress on energy efficiency and the deployment of renewables in heating: lessons learned from the 4th State of Energy Union report