Liquid storage of solar energy – more effective than ever before

20.03.2017
The molecular solar thermal system developed in Sweden (graphic: Chalmers University of Technology, Sweden)
The molecular solar thermal system developed in Sweden (graphic: Chalmers University of Technology, Sweden)

Researchers in Sweden have demonstrated efficient solar energy storage in a chemical liquid. The stored energy can be transported and then released as heat whenever needed while the storage medium is fully recovered – a so-called molecular solar thermal system.

Many consider the sun the energy source of the future. But one challenge is that it is difficult to store solar energy and deliver the energy ‘on demand’. A research team from Chalmers University of Technology in Gothenburg, Sweden, has shown that it is possible to convert the solar energy directly into energy stored in the bonds of a chemical fluid. The chemical process involved is based on the organic compound norbornadiene that upon exposure to light converts into quadricyclane.

“The technique means that that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it,” says Professor Kasper Moth-Poulsen, who is leading the research team. “Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80 percent of the incoming sunlight.”

The research project was initiated at Chalmers more than six years ago and the research team contributed in 2013 to a first conceptual demonstration. At the time, the solar energy conversion efficiency was 0.01 % and the expensive element ruthenium played a major role in the compound. Now, four years later, the system stores 1.1 % of the incoming sunlight as latent chemical energy – an improvement of a factor of 100. Also, ruthenium has been replaced by much cheaper carbon-based elements.

“We saw an opportunity to develop molecules that make the process much more efficient,” says Moth-Poulsen. “At the same time, we are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation.2

The research has made it to the cover of the scientific journal Energy & Environmental Science.

Volker Buddensiek

Similar Entries

Powin Energy, a manufacturer and developer of scalable energy storage systems for commercial and utility customers, announced today that its 2 MW/8 MWh Millikan Ave. Battery Energy Storage System in Irvine, California, is officially online. The BESS provides emission-free and highly reliable critical peaking capacity and grid support services to Southern California Edison. Powin Energy developed the project and manufactured, installed, and commissioned the system in less than six months from the date the project was awarded, an industry first for an energy storage asset of this size on a distribution system.

TrinaBESS announced today that the company will introduce its large-scale Energy Storage Solution ‘TrinaMega’ for German Market at Energy Storage Europe 2017, held in Dusseldorf on March 14th - 16th. The event, which has always been influential to German large-scale Energy Storage market, affords TrinaBESS a great opportunity to introduce its new Energy Storage Solution. TrinaMega is a modular design of thousands of lithium-ion battery cells, integrated and controlled by advanced software giving a future-proof alternative to traditional methods by assisting transmission, generation and distribution networks.

The U.S. residential solar energy storage market is experiencing unparalleled growth due to the increase in solar installations and the end of net-metering across numerous states. In order to meet the rapidly growing demand for storing solar energy, sonnen announces the launch of the sonnenBatterie eco compact. The streamlined eco compact is designed to increase grid-tied solar consumption and is available at up to 40 percent the cost of sonnen’s other products.

Younicos has signed an agreement with Kodiak Electric Association (KEA) in Alaska to design, install and commission an upgraded 3 MW battery-based energy storage system on Kodiak Island that will replace a system that was installed by the company in 2012. The project is expected to be complete by mid-August 2017, in time to support increased seasonal levels of wind power on the island.