Leader in Solar Electricity Self-sufficiency in France

Reservoir Sun

7. Affordable and Clean Energy 9. Industry, Innovation and Infrastructure 11. Sustainable Cities and Communities 12. Responsible Consumption and Production 13. Climate Action


To resell the electricity produced by a solar power plant installed on the building directly to its owner at a lower price than its current supplier. In 2018 it was the first company dedicated to solar electricity self-sufficiency in France.


Thérénia LEFAIT

Thérénia LEFAIT

Paul Van Vlierberghe

Paul Van Vlierberghe


Toulouse Business School

Toulouse Business School





The historical model, called grid injection, involves renting the roof of a building to build a solar power plant. The solar energy produced on the site is then sold to EDF (French electric utility company): that was before!

In October 2018 Philippe Reynard proposed a new model, as he says the "Solar 2.0". Considering the sun as an inexhaustible energy bank for making green electricity. With solar self-consumption, they produce and consume on site. A new direct way to get energy that frees companies and local authorities from the grid and reinforces their independence. They become real actors of the energy transition without any investment. Indeed, Reservoir Sun takes care of everything for them, from the analysis of their needs to the financing and realization of their project.

The company, Reservoir Sun is innovative: reselling the electricity produced on the building directly to its owner at a lower price than its current supplier. The latter makes considerable savings on its electricity bill and uses renewable energy. If the surface area used is insufficient to meet the customer's needs, this sustainable solution can be added to a conventional grid supply system.

Leader in Solar Electricity Self-sufficiency in France

Inauguration of the company's establishment at Les Docks in Marseille.


Phillipe Reynard was working with Gaz de France, where he learnt the basis of energy. Then, when he entered in the Engie group, he discovered new perspectives. Engie is a French multinational electric utility company, operating in the fields of energy transition, electricity generation and distribution, natural gas, renewable energy.

Already personally concerned by the environmental issues, he learnt new skills and developed a taste for innovation in Engie. As the head of building-integrated solar power at Engie, he was able to analyse that some customers were now rejecting this historical model and were seeking to turn to self-consumption, perceived as the Holy Grail. With the desire to take the lead in a new market, matching with his personal conviction and ideas, he opted for this business that is 100% focused on solar self-consumption. Thanks to all the knowledges he earned in Engie and his previous experiences, in a year and a half, the company has built up a remarkable reputation by holding 60% of the market share in France.

Overall impact

This incredible innovation had a huge impact on the energy market in France. With its policy of taking care of all steps of the process to build solar power plants, Reservoir Sun met with great success.

To start with private companies. Reservoir Sun seduced firms, we didn't really think into a sustainable commitment, for example firms from the CAC 40 (French stock market). They have a large impact on big companies and small and medium size business (SMB) with their expertise and advices on solar self-sufficiency in different sectors.

It is also attractive for public compagnies. Indeed it supports them in their energy transition by developing local energy, which promote the economic and social development and reach the state and UN environmental objectives on renewable energies.

Business benefit

As an agile company in full expansion, there are 54 employees today, compared to 23 when it was created. Phillipe Reynard is determined to maintain Reservoir Sun's agility, still in "start-up mode". After the development of the commercial sector, Reservoir Sun is structuring itself to face the industrial challenge generated by the desire to establish its plants throughout France. With the ambition of maintaining its position as the undisputed leader in the country, the company has set itself the goal of producing 100 megawatts per year with its solar power plants. This represents an investment of 100 million euros, which, to give an order of magnitude, corresponds to approximately 1 million square meters of roof space.

Focused on the BtoB model, the conquest of BtoBtoC is planned within the framework of collective self-consumption (shared between several companies or by the inhabitants of a collective residence). Exporting its expertise abroad is also envisaged, and not necessarily to the sunniest countries, as one might think.

Solar exploitation is of course more economical there because there is an opportunity to produce more electricity by advancing the same costs to build the plants, but sunshine is not the only variable. Needs expressed by the customers and their electricity bills have to be taken into account. Thus, self-consumption makes solar energy accessible to everyone, whether in Marseille or Lille, because sunshine is no longer the only criterion of profitability. Self-consumption consists of a global energy approach to our customers. Several factors are considered: the customer's needs, energy saving actions, the consumption profile, the site, the greening of its supply, the security of supply, etc.

Social and environmental benefit

The motto of Reservoir Sun is clear: "Directing his company towards the sun to draw its own energy from an infinite reservoir".

Reservoir Sun provides an excellent opportunity for companies to utilize green energy. The customer has no expenses for the building of solar power plants and receives a rent from the space used by Reservoir Sun. It also saves the company money, as the solar power plants significantly reduce the companies' bills while contributing to a greener impact and image.

Furthermore, Reservoir Sun creates a national network for an "ambitious action". This allows them to develop themselves across the whole country and promote their green actions across society. Covering 60% of the solar electricity self-sufficiency market in France, they are developing their reputation and turning companies toward a green future.


Philippe Reynard, CEO

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Reservoir Sun

Reservoir Sun

Marseille, Provence-Alpes-Côte d'Azur, FR

Business Website: https://www.reservoirsun.com/

Year Founded: 2018

Number of Employees: 51 to 200

Reservoir Sun proposes to free up building space to transform it into a green, de-carbonated and local energy reservoir.
Pioneer of the solar electricity self-sufficiency in France, Reservoir Sun helps companies and local authorities to become actors of energy transition.