New solar hybrid combines energy storage with record system efficiency
- A team of researchers from the University of Wisconsin-Madison and the King Abdullah University of Science and Technology in Saudi Arabia say they are developing a highly-efficient solar system which integrates photovoltaics, storage and energy delivery.
- The research collaboration published findings last week in the journal Chem, sketching out the general design principles of a "solar flow battery" with a record 14.1% solar-to-output electricity efficiency.
- While the solar flow battery system is not an economic solution just yet, the scientists say with cost reductions and further efficiency improvements the idea could help to electrify remote areas not connected to a distribution grid.
The research collaboration asserts in an announcement that its most recent model can store and deliver electricity "more efficiently than any other integrated device currently in existence."
The current 14.1% efficiency rate is eight times better than earlier models of the group's solar flow battery, but researchers still see room for improvement
"We believe we could eventually get to 25% efficiency using emerging solar materials and new electrochemistry," Song Jin, a professor of chemistry at the University of Wisconsin-Madison and one of the project's developers, said in a statement. "At this efficiency range, without using the expensive solar cells, it should be quite competitive with other renewable energy technologies. Then I think commercialization could be possible."
The solar flow battery has several capabilities: it can immediately generate electricity from sunlight, store the energy electrochemically, discharge energy from the battery and even charge the battery with a grid connection. The integrated nature of the system has inherent advantages as well. Typically solar energy is turned into electricity and then stored, but the solar flow battery will store the energy before turning it into electricity, helping reduce losses and inefficiencies.
The research says integrated solar flow batteries will be "especially suitable as distributed and stand-alone solar energy conversion and storage systems in remote locations and will enable practical off-grid electrification."
Other research efforts are working to integrate solar and storage. Earlier this year the U.S. Department of Energy awarded the University of Texas at Austin $3 million to support the development of a utility-scale silicon carbide solar inverter. Aiming to address the impacts of solar's intermittence, the new M4 Inverter converts the direct current output of solar panels to medium-voltage alternating current, "eliminating the bulky and costly low-frequency transformer," according to a description of the project.
Similarly, in Germany scientists at the Friedrich-Alexander-Universität are looking at molecules for solar energy storage that could allow for controlled electro-chemical release and effectively integrate storage into the solar panel.
Follow Robert Walton on Twitter