We’re helping remote industry look forward to more power with fewer emissions, thanks to the sun.
In the north west of Australia mining activity is expanding very rapidly. Often it’s happening in remote areas – in towns like Nullagine, which is as far away from the nearest city as London is from Warsaw. Large mining operations need a lot of power, and since many are in places with no connection to the electricity grid they have traditionally relied on what power they can generate from diesel or gas.
While today’s power sources like diesel engines and simple gas turbines are cost effective, they are not environmentally sustainable. Transporting the fuel to remote areas not only increases the cost, but also increases the carbon footprint of the fuel.To help out, CSIRO and our partners are investigating ways to make this power generation more environmentally sustainable, and we’re using the region’s most abundant natural resource – sunlight.
In this project, CSIRO and our partner GE will be designing a new gas-powered remote power station, suited to north west Australian conditions, where the natural gas gets a renewable energy ‘boost’ before it goes to the turbine. This boost happens in a solar-driven chemical reaction that upgrades the natural gas into a product called syngas. This solar-enhanced syngas, which we call SolarGas™, contains 25% more energy than the original gas – all of which has come from the heat of the sun. We walked through the process (and showed you photos of our test facility with its field of focusing mirrors) in an earlier blog post SolarGas: what’s it all about?
The sun-enhanced gas now passes to the turbine as usual, where it creates electricity. The ‘waste’ heat from this process is then harnessed to power a second turbine – a steam turbine – which creates extra electricity.
This two-turbine daisy chain, known as a combined cycle power station, is already frequently used for electricity generation. Our design will add the solar stage in the most efficient way, and model the system to see how it performs and what it’ll cost. We expect that adding solar will reduce overall cost, as well as lowering emissions.
The project will be the first time that a combined cycle power station is integrated with the SolarGas™ process in a detailed model. We hope this project will provide a stepping stone to the construction of demonstration plants in the Australian Outback.
The project, worth $700,000, will utilise CSIRO expertise in solar thermal technology and solar syngas reactors in partnership with world leaders in power station technology, GE Australia and the GE Global Research Centre in the United States.
You can read an interview with the project leader, CSIRO’s Robbie McNaughton, in the January issue of the Pilbara Echo.
The ultimate result of this work will be the use of less fossil fuel, for more power, with reduced emissions. That’s good for industry, and good for the environment!
To celebrate our 100th blog post, we’ve put together (in no particular order) a list of 100 things you may not know about solar research at CSIRO. Today: more about our high-temperature solar thermal fields including why we’re putting helicopter parts on our solar tower, and the strange animals and messages that occasionally crop up in our heliostat fields.
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- We call our heliostat design the ‘Spider’ due to its eight radial struts holding the mirror at the correct curvature. The design provides strength, rigidity and accuracy of focus.
- The mirrors are glued to the heliostat frames with the same material used in the manufacture of buses and caravans.
- The bonding glue on the mirrors is strong enough to withstand winds of over 200 km/hr – much higher than even the most extreme once-per-hundred-year wind conditions for the site.
- When each new heliostat is made we measure the curvature of the mirror surface at over 500 separate points to an accuracy of 10 millionths of a metre. Only if it meets our standards for focusing accuracy do we then install it in the field.
- We have used a ‘hail gun’ to test heliostats against hailstone impact. They passed.
- Each heliostat and its components are held together with 55 bolts – for a total 24,805 bolts in Solar Field 2 alone.
- The footings for the heliostats on the edges of the field are bigger than those in the middle. This is because the outermost heliostats will be exposed to higher winds than the sheltered, innermost ones.
- Solar Field 2’s mirrors have been used to spell out things like our organisation’s name, the year, and the Earth Hour logo. Despite journalists’ suggestions, we have never used them to spell ‘Don’t forget the milk’.
- Also despite journalists’ suggestions, the solar fields cannot be used as a ‘death ray’. This is because the combined reflections from the heliostats can’t be focussed anywhere but the top of our tower. (Rest easy, suburb of Mayfield; you remain safe.)
- Companies and research institutions from other countries have travelled to Australia to conduct experiments using CSIRO’s solar fields.
- There are unofficial reports that one of our solar engineers has personally signed several singe marks he’s left on the tower during experiments. His identity shall be kept anonymous for his own protection.
- CSIRO used to be home to several sets of solar troughs, but these were removed in 2010 to make way for the much larger Solar Field 2.
- The main experiment on Solar Field 2 is our Solar Air Turbine project. This uses just air and sunshine to generate electricity.
- The turbine is a modified helicopter engine, and is expected to be installed in the next few months.
- When the Solar Field 2 air turbine is fully operational, it’ll deliver about 150 kW of electricity to our site during the sunny hours of the day. Anything we don’t use ourselves can be sold on to the grid.
- Planning is under way for a thermal storage system to be added to Solar Field 2, making it able to store thermal energy for use after sundown.
- The Solar Field 2 tower is capable of supporting 15 tonnes – just in case we want to install some hefty experimental gear up there.
- Our tower and heliostats were manufactured locally, by a company on the NSW Central Coast.
- A CSIRO report has estimated that the cost of electricity from solar thermal power stations could drop to 13.5 c/kWh by 2020, with prices as low as 10 c/kWh technically feasible.
- CSIRO’s high temp materials laboratory in Newcastle can test new molten salt mixtures at temperatures up to 1000°C. Molten salts are used for storing solar thermal energy and have enabled the Gemasolar plant in Spain to generate energy 24 hours a day.
- SolarGas, which we make in Solar Field 1, contains 20% solar energy.
- Before CSIRO built its solar towers, we used a dish to carry out high-temperature solar thermal experiments. The dish was located at CSIRO’s Lucas Heights site.
- Our current tower-based solar receivers are ‘cavity receivers’ – that is, the area that’s heated up is inside a cavity. This means they have less heat loss compared to ‘external receivers’ such as used by other types of solar tower.
- For most of our experiments, we have more power available from the heliostats than is required. An automatic control system chooses which heliostats to use on the target and puts the spare ones in ‘stand-by’ positions close to (but missing) the receiver, where they sometimes make visible halos in the air. Stand-by heliostats can be brought on-sun if light cloud or haze develops and we need to maintain power levels.
- It’s cool to stand in an operating solar field – literally. The heliostats reflect most of the heat that would otherwise reach the ground.
- There’s a thriving local ecosystem in and around our solar fields. Regular visitors include lots of birds – magpies, corellas, herons, hawks, swamp hens and more – as well as less-welcome visitors like hares (that chew exposed cables) and the occasional reptile.
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.
It’s been a busy month here at the Solar Energy Centre with a couple of new experiments being installed and operated.
One of the big additions we made to the tower was to add a new level: a mezzanine platform that was lifted up by crane. On it we’ve installed components for a new type of SolarGas reactor. This is one of our new projects that’s taking shape rapidly. Look for more information and updates over the coming months.
Photos: S Morgan and T Ritchie
The support the Australian Solar Institute (ASI) provides to solar research in Australia has meant it’s now possible for three new CSIRO solar research projects to go ahead. What are they, I hear you say? Glad you asked. In this three-part post I’ll share the project descriptions from the ASI website, followed by my own explaination.
Project 2: Solar hybrid fuels
ASI contribution: $1,585,853
Total project value: $3,917,350
Partners: Chevron, Orica, Colorado School of Mines, and a range of leading national and international researchers in the solar fuels area.
Summary: CSIRO will increase the efficiency of solar hybrid fossil fuels by developing and demonstrating new catalysts and membrane reactors to make the fuels at low temperatures compatible with conventional solar thermal storage. The product, known as syngas, will be suitable for electricity production in gas turbines and for making liquid transport fuels. The project also includes the assembly of a panel of national and international experts to formulate a Solar Fuels Roadmap for Australia.
Solar@CSIRO explains: I’ve written about SolarGas™ a few times before on the blog, so you know the basics: that we’re making it in Solar Field 1 by heating natural gas and steam to over 800°C using the power of the sun. At these temperatures the gas and steam react to form the product we call SolarGas, in a process that basically stores solar energy in a gas. Amongst the other uses of SolarGas, it’s possible to make diesel fuel from it – meaning one day your car could be running on fuel that got part of its energy (recently & renewably) from the sun.
One day your car could be running on fuel that got part of its energy (recently & renewably) from the sun.
Our SolarGas reactor can only function, obviously, during daytime. It’d be nice though to hook it up to a thermal storage system so that we could use stored solar heat to operate when there’s no sunshine. But the problem is that the current SolarGas process needs temperatures over 800°C, while commercial thermal storage fluids like molten nitrate salts start to break down once they are heated over 600°C.
One solution is to find thermal storage fluids that stay stable at higher temperatures. We and other organisations already have scientists working on that. But this project takes the alternative approach: finding ways to take the SolarGas process (and other similar solar-hybrid fossil fuel processes, e.g. using biomass, algae or brown coal instead of natural gas) and make them able to operate at lower temperatures. Hopefully, by working at the problem from both ends we’ll end up with a process and a storage fluid where the operating temperatures overlap.
It’d be nice to hook our SolarGas production process up to a thermal storage system so that we could use stored solar heat to operate 24 hours a day.
The issue is, though, that you can’t lower the temperature of SolarGas-like processes without the efficiency of the reaction also going down. That means although you might have 24 hour operation, you’d be getting a lot less bang for your buck (so to speak). But there’s a trick we have up our sleeve called a membrane reactor that might be the solution. It uses a thin metal membrane through which only hydrogen – which is part of the SolarGas product – can diffuse. If the hydrogen keeps getting removed through the membrane as soon as it’s produced in the reactor, more hydrogen keeps getting made to redress the balance, increasing the yield from the reaction again.
We’ll also need to make sure we have catalysts that can operate properly at these lower temperatures, and that’s another part of this project.
Ultimately it’ll lead to a plant being constructed to demonstrate this technology – possibly in Western Australia, where there is a heap of both solar energy and gas.
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The other main stream of this project addresses important practical questions like: what types of solar fuels will be most suited to Australia’s needs? What are the potential economic benefits? Which areas of research are most critical? What’s the best strategy for bringing the technology to commercialisation?
The project addresses important questions like: What types of solar fuels will be most suited to Australia’s needs? What are the potential economic benefits? Which areas of research are most critical?
To answer these, we’ll be bringing together solar fuels experts from all over the world. This group – made up of industry members and research leaders – will be working with CSIRO and other stakeholders to create a ‘roadmap’ for solar fuels in Australia. The end product will be a public report that outlines all the major opportunities and barriers facing the commercialisation of solar fuels, and the environmental, social and economic outcomes of different commercialisation pathways.
In summary: it’s not only important to know how to do something – both in the sense of making a process work and making a project happen – but it’s also a good idea to know why you’re doing it – what the benefits are, both to the hip pocket and the environment. In this project we’re going to try and get answers from all angles on solar fuel technologies.
It has been a good week for CSIRO’s SolarGas™ reactor. The reactor – which was recently down in our workshop here at CSIRO Newcastle – was reintroduced to concentrated sunlight in Solar Field 1 on Thursday morning, and it’s been passing its start-up tests with flying colours. When I was down in the field this morning it was being held steady at just under 600°C while engineers continue the process of recommissioning it to its usual operating conditions of 800°C and above.
The reactor is now operating with several improvements including a new and better temperature monitoring system.
Don’t know what SolarGas is? Read this previous blog post for a description of how it works and why it’s useful.
ECOS magazine has just published an article describing how the energy research we’re doing today could soon become part of your everyday life. In addition to talking about our solar work, it mentions our other fields of endeavour – such as the clothing we’re developing that could one day use the movement of your body to charge your phone, or the UltraBattery that could power your car and act as an extra back-up supply for your house. Read the article here.