It’s one of the biggest international events of the year for solar thermal experts and for the first time it was held in Australia!
The SolarPACES (Solar Power and Chemical Energy Systems) executive committee meeting and conference enticed experts from countries including USA, Spain, Germany, France and China. During the event they discussed important solar thermal issues and all the latest developments in the technology, markets and the future of the technology.
CSIRO’s Wes Stein told us, ‘We’re hearing from the experts about their experiences in their different countries, not only around research and technology programs, but also around the measures that have made advancements possible in their country.’
This is important stuff for the future of solar thermal research and technology – to help get this technology operating efficiently and make it more affordable.
CSIRO’s two solar towers were operating for the visitors during the event as working examples of the technology.
To celebrate our 100th blog post (did you see our custom solar cell?), we’ve put together (in no particular order) a list of 100 things you may not know about solar research at CSIRO. Today: our high-temperature solar fields, the connection they have with solar companies that were operating before Europeans settled Australia, some stories about stuff we’ve melted, and how a vacation student’s work is embodied in over 600 heliostats.
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- CSIRO’s two high-temperature solar tower facilities go by the practical and descriptive names of CSIRO Solar Field 1 and CSIRO Solar Field 2. Despite what you might think, they’re not necessarily the most unimaginative titles in solar research tower history.
- Solar Field 1 was opened in 2005 and is primarily used for SolarGas research, and Solar Field 2, which will make electricity using an air turbine cycle, was opened in 2011.
- We also had several rows of solar parabolic concentrators or ‘solar troughs’. Four of these units were originally developed by ANU. Two additional units were later installed for testing on behalf of a client.
- The Energy Centre at Newcastle only opened in 2003, but concentrating solar thermal research at CSIRO goes back to the 1980s using small dish and trough units. Concentrating solar power itself goes back much further – the first commercial trough system was in Egypt in 1913, and operating systems were being exhibited as far back as the 18th and 19th centuries.
- CSIRO Solar Field 2 is bigger than Field 1, and collects about two and a half times as much energy.
- Solar Field 2 has been designed to be ‘peaky’ – that is, the layout of the heliostats maximises the peak field output at the expense of the overall annual energy capture. This is to extend the field’s research capabilities.
- Our solar fields can have several different experiments mounted on the towers at any given time. Currently Solar Field 2 hosts an air turbine receiver, a SolarGas experiment, and a high-temperature testing rig.
- The two solar fields are most commonly used to run processes at temperatures from 800 to 1000°C.
- The highest temperature we’re aware of having generated was around 1700°C with Solar Field 1, when we melted a piece of ceramic. We don’t actually know what the maximum temperature we’d be able to reach is, as it would depend on the receiver material and conditions.
- There are 621 heliostats installed in total at the Newcastle site. Laid side by side, the mirrors would make a reflecting surface large enough to cover four tennis courts.
- Due to their excellent focusing, even a single CSIRO heliostat can generate temperatures high enough to melt aluminium – which has a melting point of 660°C.
- The reflectivity of our mirrors is about 92%. For comparison, the mirrors you have in your bathroom are likely to be about 84% reflective.
- Our mirrors use low-iron glass, which transmits more infra-red energy than normal glass. This makes the glass more see-through at wavelengths we can’t see – but which our solar receiver can use.
- Dust and dirt on the mirrors can reduce their reflectivity by a few percent. For our purposes we only need to clean them occasionally, usually just before experiments requiring ultra-high temperatures. That’s when lucky Brendo gets handed the mop and squeegee.
- When our solar fields are operating, the mirrors look like they’re standing still – but each heliostat is actually changing its orientation by a tiny amount several times a minute to keep up with the sun as it moves across the sky.
- The mirrors in our heliostats also look like they’re flat, but in reality each one is very slightly (and precisely) curved in a dish-like shape so as to focus the reflected light.
- Because the different mirrors in our solar fields have different distances from the receiver, they need to be built with different focal lengths. We have four different focal lengths for Solar Field 2 and five for Field 1.
- The company that supplies our mirrors has been making components for concentrating solar thermal systems for over 240 years – dating back to before Europeans first settled in Australia.
- A vacation student made integral contributions to the design and engineering of CSIRO’s heliostats. The results of his work are now present in over 600 heliostats. Vacation studentships are periodically advertised on CSIRO’s website here.
- Our heliostat frames are ‘steel origami’: the mirror support struts are made by folding laser-cut sheets of stainless steel. This simplifies assembly, keeps the structure strong and lightweight, and helps keep material and fabrication costs down.
Now that we’ve had a few days to catch our breath after the official opening of Solar Field 2 on Saturday, I thought I’d take the chance to say a bit more about the event. For most of us the day started with an early morning glance out the window and a sigh of relief at the perfectly clear sky. As it turned out, we couldn’t have asked for a better day to demonstrate the solar field.
Despite the sunshine it was as cold a day as you’d expect this close to the winter solstice. Nonetheless, the Prime Minister and other special guests braved the elements (and the heights) to visit the top of the solar tower. As the PM commented afterwards, the view from the top is an interesting one for people in the energy industry. You can see a dramatic spectrum of technologies, from the coal loaders of Newcastle Harbour, to the Kooragang Island wind turbine and, of course, CSIRO’s own wind and solar facilities.
Once the tour had finished we started up the field and demonstrated it in action. Everything went like clockwork, and we were able to show how even on a midwinter’s day the solar receiver can be run at its design operating temperature. The conditions were so good for solar power that even after the VIPs departed, some of the engineers kept the field running to carry out more experiments. Why waste good weather?
You can read the Prime Minister’s press release about the event here.
After more images and videos? Click here for CSIRO multimedia relating to the tower and launch.
Ever wondered what it looks like when we ‘turn on’ Solar Field 2 in the morning? Then have a look at the video below, which shows the process of bringing all the mirrors on-sun. We demonstrated this to our VIP guests during the official opening of the field on Saturday. After some nice shots of the field you’ll see the receiver opening, the mirrors moving, and several hundred focused beams of sunlight being directed into an aperture just a metre wide.
Below are two stills from the video. The first one shows spots of focused light that are moving across the tower on their way toward the solar receiver.
This next image shows one heliostat focusing its light onto the target plate for calibration. Most of the others are already pointing into the receiver aperture where they are starting to heat air to around 900°C.
I think it looks pretty cool. We’re excited to have been able to show it off to our guests on the weekend.
Our new solar field was officially opened this morning by Prime Minister Julia Gillard. Also in attendance were Minister for Resources and Energy Martin Ferguson, Member for Newcastle Sharon Grierson, and Member for Shortland Jill Hall.
Our visitors braved the crisp winter air to climb the tower and enjoy the view, and after they’d returned our engineers started up the field to give them an on-sun demonstration.
I’ll be posting photos and a full report on Monday – stay tuned.
Newcastle’s two solar ‘power towers’ have been featured in Climate Spectator. In the same week as CSIRO’s Solar Cooling project was featured (see blog post), an article has been published in which Robbie McNaughton, the engineering manager here at the National Solar Energy Centre, answers questions about our high-temperature solar thermal facilities. He explains the basics of our SolarGas research (running in Solar Field 1) and our Brayton Cycle project (in Solar Field 2) and discusses how the technologies will be used.
From the article:
A new solar array at the CSIRO’s energy research centre in Newcastle is the world’s largest demonstration of a new technology that uses concentrated solar energy to heat air rather than liquids. In many ways it works the same as a gas turbine: compressed air is heated, and then the air expands through a turbine to create power. “We’ve just eliminated the combustor,” said Robbie McNaughton, the engineering manager at the National Solar Energy Center, during a visit to the centre last week.
The technology is known as a solar air turbine, but its official name is a Solar Brayton Cycle. And because it needs no water, it is uniquely suited to Australian conditions, where the best solar radiation often coincides with the least amount of available water. And because it lacks the complexity of rival technologies, and can operate as a modular, stand-alone system, it is also suitable for remote locations such as mine sites.
We’ve had a very busy few weeks since I last updated the blog. Solar Field 2 has been running very well and has now notched up around 70 hours of on-sun receiver tests. It won’t be long before we can reveal the details of exactly how successful our experiments have been – watch this space!
On Saturday it was sunny, and some of the solar team were here at work running more tests with Solar Field 2. They shone about 600 kW of thermal energy into the receiver, which is approaching the maximum power this receiver is designed to handle. The system was run just long enough for everyone to confirm that everything’s functioning well. More tests will be carried out tomorrow and Wednesday, weather permitting.
The image above is from the software we use to operate Solar Field 2. It shows a scenario like the tests done on Saturday, where about half of the mirrors are shining light into the receiver aperture. I’ve added an annotation showing where you can see their reflected yellow rays focusing to a point.
The other half of the mirrors—the ones that aren’t in use—are in their ‘standby’ positions. Another annotation shows how they’re pointing to different spots on a semicircle of sky around the receiver. These are specially selected safe positions that mean the mirrors are close to the target in case they’re needed quickly, but don’t pose a hazard to anything in the meantime.
Jin-Soo Kim, the CSIRO research scientist who is heading up the receiver development programme, took this photo from the base of the tower while all the heliostats were in their standby positions on Saturday. At the focal distance of the mirrors, where the light is most intense, you can see it reflecting off the vapour and dust in the sky.
Last week we did the first tests with sunlight focused on Solar Field 2 receiver. With the engineers who developed the receiver monitoring the temperature and performance of the receiver tubes, we shone light from 20 of the 451 heliostats onto the target.
The field performed perfectly. Although the test was done late in the day – around 5 pm when the sun was low in the sky – the focusing was excellent with very little light spilling onto the edges of the aperture.
The thermal power in the receiver reached about 30 kW, which is a nice easy first test. When we’re sure things are working as planned we will gradually ramp things up. Ultimately, when the system is running under full power at noon on a summer’s day, it will be able to collect over 1 MW of solar thermal energy.
Today the news of Solar Field 2 becoming operational has been picked up by a whopping 152 different Australian media outlets.
Here is an extract from the Sydney Morning Herald article:
Hold a magnifying glass over a leaf and the sun’s rays will concentrate on a small spot. Wait a few minutes and the heat will become so intense, the leaf will catch fire.
CSIRO scientists and engineers are using this principle, well known to young children, to run a solar-energy power station in the Newcastle suburb of Mayfield West.
The magnifying glass has been replaced by large concave mirrors that concentrate the sun’s energy 1000 times its normal intensity onto a receiver, where it can heat air in a turbine engine to create electricity.
Some of the 451 mirrors, called heliostats, started bouncing the sun’s rays onto the receiver for the first time this week, making the plant the largest of its kind in the world.
The CSIRO’s Energy System Manager, James McGregor, says the beauty of this type of solar thermal technology, called a solar air turbine, is that it can create electricity from the limitless resources of air and the sun – crucially, it requires no water. In full production, the demonstration plant’s Brayton Cycle system will be able to produce 0.2 megawatts of electricity, enough to power about 100 to 200 houses.
It’s exciting for us to see the level of interest in this project and we hope it’s sustained as we keep making progress.