MAN ETES Heats Up Energy Sector Coupling

Connecting electricity, heating and cooling 

Ideally suited to energy sector coupling, the MAN ETES technology is a novel approach to bulk energy storage that links electricity, heating and cooling. The technology solves two fundamental challenges: On the one hand, it helps balance the grid by absorbing large amounts of surplus or off-peak electricity from renewables and feeding it back into the grid on demand. On the other hand, it integrates multiple sectors by generating, storing, and providing thermal energy for heating and cooling purposes.The heat (up to 150+°C) can be made available both in the form of district heating and for manifold industrial processes e.g. food and beverage. Typical applications for the cold include the cooling of data centers or air-condition of large facilities like airports, shopping malls and many other possible applications. 

Visualisation of the new ETES heat-pump, district-heating plant in Esbjerg, Denmark (picture © Arkitema) 

The basic principle of the patented trigeneration energy-management is the reversible conversion of electrical energy into thermal energy via storage in form of hot water and ice. The solution is based on heat pump and thermal engine technologies using CO2 cycles and the storage of pumped heat. The turbo machinery technology coming from mission-critical applications of the oil and gas business as well as the process design of the CO2 cycles are the key elements and reflect MAN Energy Solutions’ core competences. 

By enabling sector coupling at large scale, ETES technology has the potential to enable a significant increase in the worldwide renewable energy contribution to total energy consumption. According to the European Commission, for example, heating and cooling in buildings and industry accounts for half of the EU’s total energy consumption and more than 70% of industrial energy consumption. The bulk of this heating capacity is generated using fossil fuels. European demand for cooling is also growing from a fairly small share to become a noticeable proportion of total final energy use, the EC says. 

Increasing the renewable energy contribution to the heating, cooling and power sectors not only represents a significant European policy goal. By intimately coupling the three discrete energy forms, ETES technology offers commercial advantages such as economies of scale and reduced capital expenditure that are not available with other approaches to energy storage. More significantly, the technology means that heating, cooling and electricity requirements of large cities can be met using only variable output renewable energy. 

Sector coupling put into practice 

The Danish port city of Esbjerg will be the first to deploy the new ETES technology in order to decarbonise a major part of its heat supply. Local multi-utility company, DIN Forsyning, has commissioned MAN Energy Solutions to supply a turnkey technology solution for heat generation, featuring two ETES heatpump systems. These will be installed Visualisation of the new ETES heat-pump, district-heating plant in Esbjerg, Denmark (picture © Arkitema) in a new district heating plant based on the operating principle of a heat pump – but on a large, industrial scale. With an overall heating capacity of 50 MW, the plant will supply around 100,000 local inhabitants with approximately 235,000 MWh of heat annually. The location at the Port of Esbjerg will enable the use of renewable power from nearby wind farms and seawater as a heat source for the generation of heating energy. The new district-heating plant will thus guarantee an emission-free alternative to the city’s current, coal-fired power plant, which at present provides approximately half of Esbjerg’s district heating and is scheduled for closure by April 2023. The operational flexibility of the heat-pump solution will generate electrical balancing power in the short term, and therefore maintain balance on the grid. 

The scope of supply for the project in Esbjerg covers the entire heat-pump system, including the heat exchangers, the piping for the CO2 and seawater cycles, the water pumps as well as the electrical infrastructure provided by ABB Switzerland and ABB Denmark. The core element is represented by two oil-free hermetically-sealed HOFIM® motor-compressor units with integrated expander, which are developed, produced and tested by MAN Energy Solutions. The absence of the dry gas seal system and the complete oil system as well as the use of a high-speed motor and active magnetic bearings results in an emission-free compression system with a small footprint. The key, innovative feature of ETES technology is the use of toxicologically and environmentally safe CO2 (R744) as a refrigerant for the entire system cycle. The CO2 -based heat-pump plant in Esbjerg will be the largest of its kind ever used in the world