The newly completed 19.9MW Gemasolar concentrated solar thermal (CSP) plant has become the first to provide 24hrs of uninterrupted electricity into the grid. Utilising the "power tower" design where a field of mirrors focuses the sun onto a central tower, Torreso's plant also contains tanks of molten salt which can be heated to ~500 dC and then used to produce electricity once the sun goes down.
The power tower with molten salt storage CSP is designed to provide power during the day while also storing excess energy as super hot molten salt to provide up to 15 hours of extra electricity. Torreso's Gemasolar plant, which only started operating at full capacity in late June is the first CSP power tower plant to incorporate salt storage, an addition that greatly increases its capacity factor (the percentage of time the plant is producing electricity).
Torresol believes that over time its new plant will produce electricity for the grid on average 20 hours a day, with 24hr production possible during the summer when sunlight is at a maximum.
This milestone is important as it expands the ability of renewable electricity technologies to provide baseload or near baseload electricity either separately or in conjunction. CSP with molten salt storage was also a key component of the Beyond Zero Emissions 100% renewable energy plan for Australia. Seeing the technology demonstrated successfully will help the case for building similar plants here in Australia.
Given Gemasolar is a first of a kind, the cost of building it was obviously more than for established renewable technologies such as wind. But you need the deployment of technologies to bring down costs through building up knowledge about how to construct, run and improve plants and to generate demand which fosters further innovations and generates economies of scale. Let's hope Gemasolar is the first of many.