Solar-integrating micro-grid with flow batteries inaugurated by Virginia utility Dominion

The flow battery is inaugurated at the project's launch ceremony. Image: Ranpdolph-Macon College Flickr page.
US utility Dominion Resources is to install zinc iron redox flow batteries made by Vizn Energy onto a micro-grid to test their suitability for integrating solar onto a local circuit.

Dominion Resources, which supplies electricity and natural gas to customers in the eastern US states of Virginia and North Carolina, has built what is claimed to be a “fully integrated solar and battery storage site”. The project, at local educational facility Randolph-Macon College, will pair a 50kW PV installation consisting of 256 solar panels with two “unique battery technologies”.

One of these battery types is Vizn Energy’s zinc-iron flow battery, which has now already been installed. The other battery type was not revealed by the college or utility. The main purpose of the project and batteries will be to smooth the variable output from the solar array to maximise the usable amount of solar electricity. 

Simply put, flow batteries use liquid electrolyte to store energy and provide scope for scaling up of battery size. They are often used in larger scale energy storage applications than are lithium-ion or lead acid batteries. Vizn’s Z20 redox flow battery is claimed to be made with non-toxic materials and with abundantly available zinc and iron. It uses water-based electrolytes with a two phase flow system. Vizn claims it can withstand high numbers of daily discharge cycles while dealing with temperature variation.

The college inaugurated the micro-grid with a ceremony held yesterday, which coincided with Earth Day. The project is being built as part of Dominion’s wider Solar Partnership Program, which the utility says will study the impact and benefits of community solar projects to help Dominion gain better understanding of the technology. The program also commits the utility to promoting the growth of solar in the region.

The project is one of a growing number of such test or pilot projects in the US. In February, PV Tech Storage reported that a college in California will be supplied with energy management system software by Geli and vanadium flow batteries made by Imergy.

Vizn recently made operational expansions, opening new executive headquarters in Texas. The company said it could provide 1MWh of batteries in the first half of this year. In the large-scale sector, Vizn also received attention when its batteries were assessed by one analysis firm’s whitepaper as being an economically “viable alternative” to gas turbine peaker plants in the US. 

The micro-grid's solar array. Image: Randolph-Macon College Flickr page.