New geothermal heating plant started operations in Paris, France

Date: 6 April 2017

A new geothermal district heating plant has started operation in the Clichy-Batignolles municipality of the greater Paris region in France.

Late last month, the Paris City Hall launched a new geothermal heating plant in the municipality of Clichy Batignolles in the greater Paris area. With this new heat plant, homes of a new eco-district will be supplied with heating and sanitary water. Apart from providing environmental benefits, the geothermal plant is also planned to pave the way for a new type of localized power generation network. For the companies in charge of the project, it is also an opportunity to demonstrate that geothermal energy has strong role to play in the energy mix in the Île-de-France region (the area around Paris).

The region around Paris region is a particularly favourable territory for the development of geothermal energy because of the composition of its subsoil. Ile-de-France has significant resources because its soil has many aquifers (layers of underground rock that allow water to circulate). At present, the region alone accounts for two-thirds of the national production of geothermal energy (for heating), thus covering the needs of more than 200,000 households. And this number could increase even if the city of Paris decides to develop other intramural geothermal station projects.

The ZAC Clichy-Batignolles project, located in the 18th arrondissement of Paris, is a project that saw its start in 2012. To develop this eco-district, the Paris City Hall immediately wanted to set up a local energy supply and respect ‘environment. The goal is to provide energy at a lower cost to residents by using available resources and reducing the supply chain.

In the case of the eco-district, the resource was all found: the groundwater of the Albien extends 650 meters below ground, covers an area of 80,000 square kilometers and its water reserve is estimated to about 700 billion cubic meters of water. With so much hot water available, choosing a geothermal station was thus quickly established. The city of Paris commissioned the companies Eau de Paris and Compagnie Parisienne de Chauffage Urbain (CPCU) to carry out the project. In 2014, drilling began for the installation of the geothermal doublet. The production well was inaugurated in July 2016 and the re-injection well in December of the same year. Once the two wells were put into operation, the geothermal station was quickly operational.

In the long term, the City of Paris and the companies in charge of the project estimate that the geothermal station of Clichy-Batignolles will cover the heating and sanitary water needs for 83% of the 7,500 inhabitants of the eco-district. This is a dream-like performance demonstrating that local energy production has a bright future ahead. With only 50 square meters of installations, it will be possible to heat 54 hectares of housing. The viability of the project could accelerate the development of other geothermal stations in the Paris region to develop a new type of energy network, based not on very large production units but on smaller and more numerous structures capable of drawing the best Local resources available.

To realize this innovative project, Eau de Paris and the CPCU worked hand in hand to combine their respective technologies and to maximize the efficiency of the geothermal system. The aim was to develop an installation capable of heating but also to ensure the production of running water. All this while respecting the constraints of space since the space allocated to the installations should not exceed 50 square meters on the surface. The station operates on the model of a geothermal doublet, with two wells in the system: a first well used for production and a second well used for the re-injection of l ‘water. The aim of this system is to minimize heat loss in the production line.

Concretely, the geothermal station is composed of three successive rooms. The first two production pieces are managed by Eau de Paris and allow water to be extracted from the soil at 30 degrees Celsius. The water is then re-injected at the end of the thermal circuit at a temperature of 10 degrees Celsius. This circuit is 650 meters long, which prevents the water from being too cold at the end of the circuit and does not cool the water table. In addition to these two facilities, the third room is managed by the CPCU. This is where the heat exchangers that operate the thermal differential are installed. These exchangers make it possible to recover energy resulting from the thermal difference that exists between the water that enters and the water that leaves the circuit. A second operating system makes it possible to heat the water according to the network in which it will be sent. The water for the heating network is heated to a temperature of 45 degrees Celsius; The water to the running water network is heated to 63 degrees Celsius.

Thanks to the performance of this installation, the Clichy-Batignolles geothermal station should not only be particularly efficient, but it should also make it possible to limit the emission of greenhouse gases. Indeed, in addition to its energy performance, a geothermal station also has the advantage of being more environmentally friendly than a condensing gas boiler: it emits an average of five times less CO 2 in the air. A further argument in favor of a mode of energy production which has a clear future ahead.

Article published in ThinkGeoenergy