Solar Thermal and Vanadium Flow Storage is Scaling Up

Abengoa is a world leader in solar thermal technology and is making the largest hybrid solar plant incorporating vanadium redox flow storage. They have already developed, designed, built and/or operated solar thermal plants in four continents, with a total capacity of 1.9 GW, representing approximately 30% of capacity worldwide. They are is currently participating in 52% of solar thermal capacity under construction.

They are deploying a 3.5 MW solar micro-grid linked to a 1 MW/4 MWh vanadium redox flow storage unit at Vametco Alloys mine in South Africa.

Vanadium Flow Batteries

Vanadium is an element that can commonly exist in four different oxidation states. Vanadium ions in the flow battery can change from V2+ to V5+.

Vanadium flow batteries (VFB) have two tanks of electrolytes dissolved in water and separated by a proton exchange membrane. Both electrolytes are based on vanadium. VFB can be charged and discharged tens of thousands of times over decades. The VFB charge levels do not degrade. Every 10-20 years, the membrane that the ionic species crosses over will need to be replaced. A lithium-ion battery would have to replace the entire battery after it has degraded over time.

Li-ion batteries have higher energy density. Costs are similar between lithium-ion and VFB for fixed storage. VFB has no risk of fires.

Abengoa is a World Leader With Solar Thermal

Abengoa develops the two most widely used commercial solar thermal technologies:

Towers produce electricity from concentrating solar energy and a field of heliostats. The receiver point is on the upper part of a tower. Abengoa has over 130 MW solar towers in operation and 110 MW under construction.

Parabolic trough captures solar energy through a parabolic trough collector that allows the heating of a heat transfer fluid for the use of the heat in a conventional thermal cycle. Abengoa has built more than 1,600 MW in operation and 650 MW under construction.

SOURCES – Abengoa
Written By Brian Wang,