Two MAN ETES heat pump units will decarbonize Esbjerg's heat supply © MAN Energy Solutions
The heat pump solution Electro-Thermal Energy Storage (ETES) is a unique bulk en- ergy management technology developed by MAN Energy Solutions. Centered on a large-scale heat pump plus storage concept, it links electricity, heating, and cooling in a highly efficient reversible process. The core technology is the multi- stage hermetically-sealed HOFIM® turbo-compressor that, in this application, operates as a heat pump. An ETES system progressively compresses and expands non-toxic and natu- ral CO2 to store or release energy from insulated water tanks. The simplicity of the energy storage is coupled with an incred- ibly robust and reliable industrial compressor that is already well-proven in the most extreme subsea oil and gas applica- tions. The current round-trip efficiency of ETES is of the order of 45%, with continued development expected to push that up to around 60% over time. However, unlike chemical batteries, the system efficiency and capacity remain constant throughout its 35+ years design life. In converting electricity into thermal energy and vice versa, the hot side may include up to four storage tanks for efficien- cy reasons, each at a different temperature, that can supply district or process heat, for example. Simultaneously, the cold side can supply rapidly growing markets such as data centers with significant cooling demand or district cooling networks. The ability of ETES to efficiently exchange energy forms also makes it ideally suited for sector coupling in which commer- cial, industrial, and residential energy needs have meshed. For instance, so-called waste heat from industry could be used to inject energy into the storage system for use as electricity by other consumers. The heat pump process can, of course, also be easily powered by renewable resources, When power demand is high, the sys- tem draws thermal energy from storage and converts it into electricity. The system's speed and flexibility mean it is ideal- ly suited to serve both the short-term electricity spot markets
as well as long duration energy storage (LDES). Thus, the ETES system can deliver ancillary services for the grid and capitalize on favorable conditions when they arise, offering significant ar- bitrage opportunities. A real-time reality As fantastic as this technological breakthrough sounds, its most straightforward configuration is already a reality. The Dan- ish port city of Esbjerg is close to completing a 50+ MWthermal heat-pump system that will play a significant role in making the entire city carbon-free by 2030. Danish multi-utility com- pany DIN Forsyning operates the city's district heating network. It will use two large-scale CO2 Heat Pump Units that will supply around 235,000 MWh of heat annually to 25,000 households. The heat pump solution will replace a coal-fired CHP and save up to 100,000 tons in CO2 emissions annually – the equivalent of the annual CO2 emissions of around 55,000 cars. The devel- opment marks a real advance in city-scale energy manage- ment. Coupling the heat pump system with a district heating net- work also gives another level of flexibility as the heating system itself retains thermal inertia. Esbjerg also has an existing 25'000 m3 hot water tank able to provide additional flexibility. Hence, the network can fully meet customer demands with zero in- puts for up to 10 hours. With the full-scale deployment of MAN's solution now under- way, heat pumps are proving that they can balance the diverse energy needs of a large modern city and succeed in a host of other applications besides. Meeting our needs for both energy security and net zero requires a radical rethink of our energy system, but we don't necessarily have to reinvent the wheel. Low-cost, easily scalable energy storage, and reliable, proven heat pumps are not a science fiction solution but a viable an- swer that can be deployed today.
For further information please contact: Raymond C. Decorvet, raymond.decorvet@man-es.com
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