Taking a punt with solar thermal

In February 2014, the largest solar thermal power station in the world came on line, the Ivanpah Solar Power Facility. Erected in the Mojave desert just 64kms from Las Vegas, I’m guessing that few of the visitors to the Mecca of gambling realise their slot machines are partially powered by the sun.

At 392MW it’s capable of generating enough power for roughly 140,000 homes and is an awesome demonstration of the latest solar thermal technology which uss mirrors to super-heat a fluid, creating steam and running a steam turbine.

The great promise of solar thermal energy (compared to photovoltaics) is that by generating heat, the energy can be stored in (for example) molten salts and then released after sundown or at times of peak demand. Although some other plants are doing exactly this (Gemasolar in Spain for example), Ivanpah has gone down another route, instead having an integrated gas turbine which can be fired up when needed.

The cost and complexity of storage is still relatively high, hence the reason Ivanpah chose a different solution–although putting storage in at a later date is an option, according to the developer. The good news is that Gemasolar has been running for almost 3 years and has proven storage can work at just under 20MW, so with technological development the potential for this latest generator is enormous.

Interestingly, using the sun to generate large scale solar thermal energy is not new. One of the oldest large plants in the world recently celebrated its 30th birthday and is still in operation today. SEGS 1 & 2 (at 14MW and 30MW respectively) are also located in the Mojave desert and although showing signs of age are living proof that this technology is real and has a respectable life span. The industry has, as you can imagine, come a long way since they were built in 1985.

Solar thermal, like all technologies, has strengths and weaknesses and building facilities that need 4000 acres of land has challenges. One of the great leaps forward at Ivanpah is that they reduced the amount of water typically needed for cooling by 95%; this entire facility needs only as much water as two holes at the local golf course.

Although Australia is blessed with some of the best solar radiation in the world so far we only have one major solar thermal plant; the 2MW Liddell Solar Boost project which uses the same principle to provide thermal boosting to a coal fired power plant.

Solar thermal shows great promise for large scale generation and perhaps most importantly, solar energy storage. It will be great to watch as more plants come online and this technology delivers even more clean energy.

Top image by Craig Dietrich via Wikipedia

 © 2014 Solar Choice Pty Ltd

Nigel Morris