Sea-water-powered heating system sets sustainable example in Marseille, France

The pilot eco-district of Îlot Allar, in Marseille, France, is testing an innovative thermal smart grid – powered by 75 % renewable energy – to deliver both heat and air-conditioning to buildings in the area. The secret of this innovative EU-funded smart grid? It captures energy from the sea surrounding the port of Marseille.

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The Massileo energy network connects a sea-water energy-recovery station in Marseille’s harbour to heat pumps that provide buildings with heat, cool air and hot water in the eco-district of Îlot Allar. © Îlot Allar Moderate-Temperature Water Network The Massileo energy network connects a sea-water energy-recovery station in Marseille’s harbour to heat pumps that provide buildings with heat, cool air and hot water in the eco-district of Îlot Allar. © Îlot Allar Moderate-Temperature Water Network

" Using sea water as an energy source helps us transition away from fossil fuels. In addition, the high efficiency of the buildings and the energy transfer between users further reduce the buildings’ energy consumption. "

Arnaud Westrich, Managing Director, Optimal Solutions

The eco-district of Îlot Allar houses buildings made from sustainable construction materials and an energy-efficient thermal grid, supported by digital outreach to help citizens become more efficient about their energy consumption. 

The smart grid generates energy using the ocean’s sea water. The energy network, called Massileo, is a temperate water loop connecting the sea-water energy-recovery station in Marseille’s harbour to heat pumps in the urban districts. From the pumps, the energy provides buildings with heat, cool air and hot water. 

The project also turns individual buildings into energy producers. For example, the heat generated by a pump to cool an office is recovered and used to heat hot water in another building, so no energy is wasted. 

The heat pumps are designed to automatically adjust to work only at the required rate, thereby ensuring energy-efficiency savings in the eco-district. According to the project team, this has led to a reduction of 80 % CO2 emissions compared to a conventional fossil-fuel-based heating and cooling system in the same area. 

The system allows for heating household hot water in the summer and cooling computer labs in the winter to save more energy. Overall, the thermal grid currently supplies the 2.7-hectare district, which includes 58 000 m2 of offices, shops and a hotel. 

About 75 % of the grid’s energy supply for the delivery of heat, air-conditioning and warm water to the buildings comes from renewables – seawater heat recovery and heat exchange between the buildings. 

With a heat/cold production capacity of 21 MW, the smart grid has the potential to supply energy to 500 000 m2 of buildings – and reduce emissions even further.

Setting the example

The Îlot Allar eco-district was conceived as an example of sustainable living and buildings on the Mediterranean. Allar’s buildings were specifically designed with the thermal grid energy system in mind.  

Plans for expansion of the pilot eco-area are already in the pipeline with the powerful smart thermal energy grid preparing to heat almost 10 times the number of buildings it currently serves. 

This is testament to the sophistication of the thermal conversion system behind the smart grid. Although its operating costs are similar to those of a conventional heating or cooling system, the installation and upkeep costs are substantially larger. It is these costs in particular that were covered by EU funds.

Total investment and EU funding 

Total investment (national public, EU and private) for the project “Îlot Allar Moderate-Temperature Water Network” is EUR 9 660 950 with the EU’s European Regional Development Fund contributing EUR 941 938 through the “Provence Alpes Côte d'Azur” Operational Programme for the 2014-2020 programming period.

Draft date

31/08/2017