CSIRO Goes Supercritical on Solar Thermal.

Whilst I might tend towards nuclear being the best option to satisfy our power needs (fission for now, fusion for the future) I see little reason for us to not pursue renewable technologies. Solar and wind have both proven to be great sources of energy that, even at the micro scale, have proven to be great sources of energy that have great returns on investment. Even the more exotic forms of renewable energy, like wave power and biomass, have proven that they’re more than just another green dream. However the renewable energy which I believe has the most potential is concentrated solar thermal which, if engineered right, can produce power consistently over long periods of time.

CSIRO Solar Thermal Heliostats

Solar thermal isn’t a recent technology with functioning plants operating in Spain since 2007. However compared to most other forms of power generation it’s still in its nascent stages with the numerous different approaches being trialled to figure out how to best set up and maintain a plant of this nature. This hasn’t stopped the plants from generating substantial amounts of power in the interim however with the largest capable of generating 392MW which might not sound like a lot when you compare it to some coal fueled giants but they do it without consuming any non-renewable fuel. What’s particularly exciting for me is that our own CSIRO is working on developing this technology and just passed a historic milestone.

The CSIRO maintains an Energy Center up in Newcastle where they develop both energy efficient building designs as well as renewable energy systems. Of the numerous systems they have there (including a traditional photovoltaic system, wind turbine and gas fired microturbine) are two concentrating solar thermal towers capable of generating 500KW and 1MW respectively. Their larger array recently generated supercritical steam at temperatures that could melt aluminium, an astonishing achievement. This means that their generating turbines can operate far more efficiently than traditional subcritical designs can, allowing them to generate more power. Whilst they admit they’re still a ways off a commercial level implementation the fact they were able to do it with a small array is newsworthy in itself as even the larger plants overseas haven’t achieved such a goal yet.

Looking at the designs they have on their website it seems their design is along the traditional lines of solar thermal, using the steam created to directly feed into the turbine to generate electricity. This, of course, suffers from the age old problem that you only generate power when the sun is shining, limiting its effectiveness to certain parts of the day. The current solution to this is to use a heat storage medium, molten salts being the currently preferred option, to capture heat for later use. Thankfully it seems the CSIRO is investigating different heat storage mediums, including molten salts, to augment their solar thermal plant with. I’m not sure if it would be directly compatible with their current set up (you usually heat the molten salts directly and then use them to generate steam down the line) but it’s good to see that they’re considering all aspects of solar thermal power generation.

Considering just how much of Australia is barren desert that’s bathed in the suns radiation solar thermal seems like the smart choice for generating large amounts of power without the carbon footprint that typically comes along with it. The research work that is being done at the CSIRO and abroad means that this technology is not just an environmentalist’s dream, it’s a tangible product that is already proving to have solid returns on investment. If all goes well we might be seeing our first solar thermal plant sooner than you’d think, something I think all of us can get excited about.

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