Over the last decade, road construction companies have developed innovative solutions that integrate new functions into roads, such as the ability to generate renewable energy. One such technology involves harvesting solar thermal energy through a heat exchanger made up of pipe registers integrated into the pavement. The energy is mainly harvested during the summer, taking advantage of the large black surfaces that roads offer. However, heating needs are significantly higher in winter than in summer, making seasonal storage a critical aspect of this technology. Recent developments have focused on understanding and optimizing the storage of solar heat using shallow geothermal technologies. This paper examines the capability of thermoactive pavement to harvest solar energy and recharge a geothermal probe field. The authors present observations from two operational facilities in France, which provide renewable heat to a customer office at a toll station near to Paris and to social housing in Normandy. Two main parameters were studied: the annual energy balance between the pavement and the probe fields and the evolution of the temperature annually and over several years. Based on these two experiences, the ability of thermoactive pavement to recharge a geothermal probe field has been positively assessed. Like solar thermal energy, this system contributes to the regeneration of the soil. This ensures the long-term dimensioning of geothermal production and allows for optimization of the geothermal field's size. The road infrastructure, on the other hand, does not require additional space, as it is already an integral part of our urban landscapes.

The Greater Paris Region has become the largest geothermal basin in the EU, with 2 TWh of annually delivered heat. Today, geothermal energy is considered as a solution to reduce carbon emissions and stabilise energy costs. Around Paris, this energy source could double in the mid term and various French cities have launched new projects. While some of the district heating systems were initially conceived with geothermal energy, many others were using gas or coal as their principal source of energy. Switching to geothermal resources may require extensive adaptations, particularly with reservoirs between 60-80°C. With 40 years of experience, MANERGY gained a solid knowledge in optimising temperature regimes for publicly and privately operated district heating. The presentation will focus on:

· The development of deep geothermal energy in the Greater Paris Region and projects in France

· Lessons learnt in switching to geothermal resources from a technical perspective

· How technical considerations could have a decisive impact on the financial balance of district heating systems

Operating deep or high-temperature geothermal wells involves several well integrity challenges due to the extreme conditions encountered downhole. With a particular emphasis on the energy sector, Vallourec has been delivering premium tubular solutions for decades, designed to withstand even the most severe conditions, including corrosive environments, high pressure, and high temperatures. Drawing on its extensive expertise in the oil and gas sector, Vallourec has expanded its portfolio to address the unique challenges of geothermal applications including the specialized demands of deep geothermal projects. This presentation will explore how Vallourec's experience in the oil and gas market can be leveraged in the geothermal environment through the use of premium connections, high-collapse pipes, well design optimization, and material selection to enhance well life without compromising profitability.

The combined production of heat/electricity and lithium from hot and deep geothermal waters could be a local and sustainable solution for reducing our carbon footprint to produce energy and critical raw materials. The geothermal lithium concept is based on the combined use of heat from hot, deep water and the extraction of lithium naturally present in the brine.

Lithium is an alkaline metal with interesting electrochemical properties that make it an essential mineral resource in the battery industry. On Earth, lithium is concentrated in the Earth's crust in solid form (rocks and minerals) or liquid form (salt lakes and geothermal waters).

The supply risks are particularly important for lithium and concern both economic and geopolitical criticality and also societal, ethical and climatic impacts. In such a context, the development of a local industrial sector for lithium production from geothermal resources can have a strong impact on our territories. Coupling heat production and lithium extraction from geothermal water should allow the Upper Rhine graben area in Germany and France not only to develop a competitive industrial sector but also to contribute to the reduction of environmental impacts by producing at a local scale a renewable energy and lithium with a low carbon footprint.

AQUAPROX's main R&D laboratory in Le Mée Sur-Seine (France) :

- The R&D Team,

- the R&D Equipment

- the current projects.

The general working method of the R&D Team, with 30 years of experience in geothermal activities, explained using the example of the new antiscale additive GeoDisperse 210 for Deep Geothermal Systems (“High Enthalpy”):

1.) Detailed analysis of the problem

a) Chemical composition of the water,

b) Chemical composition of the scale deposits,

c) Molecular/crystallographic structure of the scale deposits

2.) Selection of suitable active ingredient molecules, taking into account biodegradability and safety for the technicians,

3.) Water chemical simulation of on-site conditions

4.) Formulation of synergistic combinations of active ingredients to design high-performance target products

5.) Performance testing of these target products

6.) Selection of the "Most Performant", stability tests of the latter

7.) Conclusions, preparation for industrialization