Hydrogen makes it possible to transport and store energy, which today is considered to be the main axis for the development of our future energy mix. In the island region, local production from renewable resources finds all its meaning. Beyond the controlled axis of power generation from hydrogen that can be stored for long periods of time, we are currently developing a system that allows the production of colds at the same time.

It is therefore a matter of developing an autonomous system that will enable the provision of electricity and air conditioning to the home or service area located on the island. The sun is the primary source of energy: the electricity produced by photovoltaic panels is stored either directly in the form of hydrogen or in batteries for short-term or long-term use.

When we need electricity, we use a hydrogen fuel cell: hydrogen reacts in a controlled manner with the oxygen in the air. So this reaction allows electricity to be generated, but also water and heat, because it is “exothermic”.

This allows it to be used later to convert this heat (as well as those generated during the electrolysis of water during the storage phase) into cooling without the external input of energy. The “thermochemical reactor” itself is integrated into a conventional heat pump, and the assembly is designed to allow operational optimization in all operating conditions in the presence and absence of solar energy.

Energy challenge in isolated areas

In most areas, energy networks are interconnected to improve their stability. On a European scale, for example, it makes it possible to balance an area with a surplus of power generation (e.g. a lot of wind) with areas with temporary production shortages.

Isolated areas, especially islands, are a special case because they are isolated from intercontinental networks. So these areas have management Energy management systems Is very specific, especially can be controlled with “isolated micro networks”. This isolation of power grids significantly limits the infiltration rate of intermittent energies such as solar and wind energy.

The idea of ​​generating renewable energy from time to time using a hydrogen vector on these micro grids is not new. The original is a combination of the three vectors of electricity, heat, and hydrogen: power generation, heat generation, and / or cooling production. This approach makes it possible to increase the energy output of fuel cells and water electrolyzers in particular, and in general, by modifying the heat generated by electrochemical reactions.

Our system was the first Designed and built, Optimized and tested in Belfort. It was later containerized and the boat was taken to Tahiti. Arriving in early 2021, it was installed on the site of the University of French Polynesia GEPASUD LABORATORY For system testing and performance evaluation steps under actual use conditions. In fact, Tahiti is an island and tropical region with plenty of solar resources throughout the year, but high intervals and air conditioning represent an important part of total power consumption.

Diverse storage technologies are the key to a resilient system

To compensate for intermittent gies energy fluctuations, storage components are essential. Storage techniques Is very different And Are characteristic features Based on their nature (electrical, chemical, mechanical, thermal), efficiency, storage capacity, charge / discharge time, response time, autonomy, and return on investment. The difference in features is that there is no such thing as a “compatible” storage system.

Facing the limitations of existing thermal and electrical storage systems, a New scientific approach This RECIF project explores here the definition and optimization of a complex system that combines several components with different and complementary features. In this context, thermochemical storage processes, fuel cells, and electrolyzers and hydrogen storage are innovative and promising solutions.

Thermochemical processes Especially relevant Their operational flexibility for cold storage / production and their high effective energy density Storage. Such processes are based on reversible solid / gas chemistry, i.e. they can be carried out in one direction or another depending on the operating conditions. Ultimately the delayed energy of the water, thermal or mechanical, allows it to be stored in the form of a chemical potential to allow for a direct delay of the cold.

Therefore, the thermal energy emitted by the existing electrochemical reactions in fuel cells and electrolyzers can be utilized, significantly increasing their ultimate goal. “Efficiency” (“Energy efficiency” is broader because it includes recycling and life cycle analysis).

An artificial intelligence system controls the flow of electricity within the entire system, combining solar resource forecasting and power demand and cooling at different times. Management The goal of this management tool in development is to maximize the features of each subsystem, with the goal of maximizing energy, financial efficiency and sustainability.

This article is co-authored with Sebastian Fivere, Engineer and CEO at Belfort’s H2SYS.