Molecular chemistry: A new way to store solar energy

Researchers are developing an innovative method for storing solar energy using photochromic molecules, offering promising prospects for the energy sector.

Share:

Researchers are developing an innovative method for storing solar energy using photochromic molecules, offering promising prospects for the energy sector.
The conversion of the sun’s rays into energy has been mastered thanks to photovoltaic panels.
However, efficiently storing this energy for later use remains a major challenge.
Scientists are now exploring the use of photochromic molecules to meet this challenge.

The principle of photochromic molecules

Photochromic molecules change structure under the effect of light, a property that has long been exploited in various fields.
By exposing them to ultraviolet light, these molecules can store energy by altering their chemical configuration.
This stored energy is then released in the form of heat on demand, providing a means of controlled storage. Teams from CNRS and École normale supérieure (ENS) Paris-Saclay are working on this system, known by the acronym MOST (Molecular Solar Thermal).
They are using molecules from the diarylethene family, capable of undergoing multiple charge/discharge cycles without noticeable degradation.

Potential applications in the energy sector

This technology could revolutionize thermal storage in buildings.
A fluid containing these molecules would circulate over roofs, charging up with solar energy during the day.
At night, it would release the accumulated heat for heating, offering an alternative to current battery-based storage systems.
The researchers were able to precisely quantify the energy storage and release mechanism, a significant advance for system optimization.
This deeper understanding opens the way to industrial applications and improved energy efficiency.

Challenges and prospects for the industry

The development of new methods for storing solar energy is crucial for the energy sector, in search of efficient and sustainable solutions.
The chemical approach offers advantages in terms of cost and flexibility, using abundant and recyclable organic materials.
Challenges remain, including improving the long-term stability of the molecules and increasing their storage capacity.
Interdisciplinary collaborations are underway to overcome these obstacles and accelerate the industrial implementation of this technology.
Advances in the field of photochromic molecules are opening up new prospects for energy storage.
By combining scientific innovation and practical applications, this approach could transform current energy management methods in the sector.

The global photovoltaic films market is expected to see significant growth, reaching $41.59bn by 2034 due to the development of new solar technologies and the increasing demand for encapsulation suited to these innovations, a recent study indicates.
Italian group Plenitude has begun building Entrenúcleos, a 200 MW photovoltaic plant near Seville, set to deliver more than 435 GWh a year from 2026 while trialling locally produced green steel.
The state-controlled refiner has launched a 7.5-megawatt photovoltaic unit off Qingdao, the country’s first commercial installation designed for fully saline waters, intended to supply its future renewable hydrogen production.
The Emirati company Global South Utilities plans to install up to 250 MW of solar capacity in Madagascar, a project aimed at strengthening the national electricity network heavily reliant on fossil fuels and frequently facing energy deficits.
Emerging economies from the BRICS group now account for more than half of global solar electricity production in 2024, driven mainly by China, India, and Brazil, according to a new report by the organisation Ember.
Star Trade, a subsidiary of HD Renewable Energy, has signed a power purchase agreement with Lightsource bp to manage electricity distribution from a 115 MWp solar project located in Chiayi, strengthening their presence in the Taiwanese market.
TotalEnergies will develop a 1.8 MW photovoltaic installation for Daehwa Pharmaceutical, covering approximately 20% of the annual energy requirements of the production site located in Hoengseong-gun, South Korea, under a 20-year agreement.
Quinbrook Infrastructure Partners announces full operational launch of Cleve Hill Solar Park, now becoming the largest active photovoltaic power plant in the United Kingdom with a total installed capacity reaching 373 MW.
European photovoltaic module manufacturer BISOL is integrating G12R solar cells into its product range, replacing the former M10 cells, to improve product performance and technological competitiveness starting from the second quarter of 2025.
Adani Green Energy Limited becomes the first Indian company to achieve 15,539.9 MW of operational renewable capacity, cementing its position among the global top 10 independent green power producers.
Italian group Pronur establishes itself in Saudi Arabia with support from AstroLabs, aiming to provide advanced technologies in the renewable energy sector and develop new industrial partnerships.
Ascent Solar Technologies, Inc. announces the launch of a $2mn public offering to finance working capital, product development and general expenses.
Ardian Clean Energy Evergreen Fund takes control of 117 photovoltaic plants totalling 116 MW in Italy, further consolidating its presence in the country’s renewable energy sector.
Zelestra has secured $282mn financing from Natixis CIB, BNP Paribas and BCI for its Aurora project, combining a 220 MWdc solar plant and 1 GWh storage capacity in the Tarapacá region, Chile.
Egypt has been building an industrial photovoltaic solar complex in Ain Sokhna since June 19, aiming to stimulate strategic local production with a total investment of $200 million funded by the Chinese group Sunrev.
Générale du Solaire has inaugurated in Leutenheim, Bas-Rhin, a floating photovoltaic plant of approximately 20 MWc installed on a former gravel pit, marking the region's first large-scale project supported by successful local participatory funding.
Plenitude and Modine have signed an agreement to build a photovoltaic plant with an installed capacity of 1.585 MWp in Pocenia, designed to power thermal and refrigeration equipment at Modine’s Italian industrial site, without initial investment.
Namibia begins construction of its largest solar plant, Sores|Gaib, aiming to reduce dependence on energy imports by leveraging its solar potential, considered among the highest globally according to the World Bank.
Bangladesh’s interim government has ordered mandatory deployment of solar systems on public building rooftops to reduce reliance on costly fossil fuel imports amid a fragile economic backdrop.
The Energy Progress Report 2025 shows an improvement in global electricity access to 92%, but highlights that 666 million people remain without electricity, particularly due to insufficient international funding for rural areas.