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The Euroméditerranée (Euromed) Ecocity has harnessed the energy of the sea to provide heating and cooling solutions for businesses and residents

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The challenge: harnessing the thermal energy of the sea

Marseille's new Euromed 2 Ecocity sets far-reaching goals with its energy-efficient architecture and focus on renewables. Dalkia subsidiary Optimal Solutions has created a "Massileo" marine energy network to supply heating and cooling solutions in the area.


The solution: seawater heat pumps

Already implemented in Monaco, Sète and Biarritz, and in Scandinavian countries such as Norway, marine energy solutions harness the heat found in seawater through centralised or decentralised heat pumps that turn an endless supply of energy into heating or cooling services according to seasonal needs. Although the technology requires careful implementation, it is extremely efficient, producing 4 kWh of renewable thermal energy for every 1 kWh of electricity used.

How does it work ?

Seawater temperatures can range from 12°C to 24°C depending on the season. The water is sourced near the shore at a depth of four metres. It is piped to a heat exchanger made of corrosion-resistant titanium that is connected to a moderate-temperature freshwater loop. The energy-depleted water is then emptied back into the sea. The freshwater loop supplies heat pumps used to provide hot water and heating (or cooling in summer).

4 kWh

of energy for every 1 kWh of electricity used

80 %

reduction in CO2 compared with fossil-fuel solutions

75 %

renewable and recovered energy sources


flue gas emissions


Dalkia will use its smart water system to successfully reduce energy consumption for users and provide them with a clean, sustainable energy source. www.massileo.frEconomic benefits : 4 kWh of energy for every 1 kWh of electricity used, reduced VAT of 5.5%. Environmental benefits : 80% reduction in CO2 compared with fossil-fuel solutions, 75% renewable and recovered energy sources, no flue gas emissions. 



The EDF Group marine geothermal project is a cornerstone of the Euromed Ecocity, which will soon connect nearly 500,000 square metres of housing, offices and businesses. This exemplary solution allows us to meet the challenges of the energy transition while at the same time keeping costs down. The test initiative could eventually be replicated in other coastal cities in the Provence-Alpes-Côte d'Azur (PACA) region and all the along the northern Mediterranean coast.




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