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!
The Helix is a science magazine produced by CSIRO’s Double Helix Science Club, and it’s hugely popular with primary and high school students. And why wouldn’t it be, when it’s filled with stories like those from the latest issue:
- The species of shrimp that’s strong enough to punch through aquarium glass
- How scientists can tell how old a person is from their smell
- The exploration of Antarctica, what causes the Aurora Australis, which dinosaurs used to roam the southern continent, and whether you can surf the net in Antarctica
… and, this month, a short piece about our SolarGas research here at Newcastle. There’s also a solar hexaflexagon on the back cover that’s ready to be cut out and assembled and flexed and flexed and flexed (and flexed – it’s addictive).
You can track down a copy of The Helix in newsagents or by joining the Double Helix Science Club.
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.
In yesterday’s post you saw how we make SolarGas™. Here, I’ll take you through some of the ways it can be used. As you can see in the diagram below, it’s a versatile product.
I’ll explain a few of these uses point-by-point. The numbers refer to the diagram.
1. SolarGas can be burned to get heat or electricity
SolarGas is a combustible fuel, just like the original natural gas – but here’s the important thing: if you burn it, you get around 25% more energy than there was in the original natural gas. This extra energy is the ‘solar upgrade’.
For example, if you were to use SolarGas in your gas stove to boil five eggs for breakfast, it’d be as if you were cooking one of those eggs with pure solar power. (The energy for the other four would have come from what was already present in the original natural gas). You can also think about it like this: you’ve boiled five eggs, but you’ve only generated the greenhouse gas emissions associated with boiling four. Or, to put it yet another way, five eggs have been boiled, but we only had to take enough natural gas out of the ground to cook four.
Likewise, if we’re talking about burning the gas in a 5 megawatt turbine to make electricity, it’s like we’re getting five megawatts for the environmental ‘price’ of four. Given that natural gas use is projected to remain a significant source of energy in Australia in the coming decades, wouldn’t it be great if we could in effect get a bonus amount of energy from the resources we have, by adding solar power?
2. SolarGas can be used to build transport fuels
The SolarGas molecules are extremely nifty and useful little chemical building blocks. They are ideal for connecting together in a process called Fischer-Tropsch to make fuels like methanol or diesel.
These building blocks are so useful, in fact, that there already exists a significant industry that makes them using more traditional methods. In the traditional process the extra energy in the product gas, which is called Synthesis Gas or syngas for short, comes not from the sun, but by burning part of the natural gas.
By using the SolarGas process instead of the traditional syngas process, we end up with the same product but with less consumption of fossil fuels, and less production of greenhouse gases. And again, if you used the product fuel to run a car, that car would be partly powered by sunshine.
3. SolarGas can be used to make hydrogen
SolarGas is already 3/4 hydrogen gas by volume, but we can increase the amount of hydrogen by putting it through what’s called a Shift Reactor. Ever see all those episodes of Top Gear where they speculate on a future where our cars run off hydrogen fuel? Hydrogen is only truly environmentally friendly if it’s made using renewables – and this process goes a long way towards satisfying this requirement.
For example, most of the hydrogen produced in the world today is made by the traditional syngas process described above – which burns natural gas to get the energy required. Globally, this process is used to produce about 80 million tonnes of hydrogen every year (and growing!), which creates about 1.5 billion tonnes of carbon dioxide… which is about three times Australia’s annual emissions. What a difference we could make if SolarGas becomes the process of future industry.
4. The stored solar energy can be recovered in the form of heat.
If we wanted, we could extract the solar energy from the SolarGas by reversing the original reaction. This recreates the original natural gas – which can be re-used – and releases the solar energy in the form of heat at about 300°C. In essence, then, the natural gas is in a ‘closed-loop’ system – it goes round and round, picking up solar energy, storing it until it’s needed, releasing it, and then starting the cycle again.
5. Waste heat from making SolarGas can be put to other uses
No matter what is done with the SolarGas, in the process of making it there’ll be some ‘waste’ heat. As with the last scenario, this heat will be at temperatures lower than the original 800°C (otherwise we’d use it to produce more SolarGas). Even so, it’s a whole lot of energy that we can use to provide further efficiency by combining it with other processes. In the future, this ‘waste’ heat – the stuff that disappears up the chimney in conventional processes – will be used to provide further benefits like industrial process heat, air-conditioning and refrigeration and water desalination.
So that’s my go at explaining why we at CSIRO think SolarGas is a great project to be developing. Of course, there’s always more to read on the CSIRO website as well. Any further questions? Leave a comment!
It’s a clear spring day in this photo of Solar Field 1 at our Newcastle site. There’s obviously plenty of sunshine to power solar panels or solar turbines. But in this case there’s more going on than meets the eye. Even after the sun has set we’ll still have a supply of solar energy, thanks to what’s in the small shed circled below.
In the shed is a group of gas cylinders. They’re holding the product of a process that CSIRO has developed to near commercial demonstration that captures and stores solar energy for later use. Because the added solar energy is stored in the chemical bonds of a gas, we call the product SolarGas™.
SolarGas isn’t just a way of storing solar energy. It’s also a way to add solar energy to fuels like natural gas, and it can even be used in production of many liquid fuels and fine chemicals which currently rely on finite fossil fuel feedstocks. It’s been one of the main areas of research and development for our solar thermal team over the last decade, and that’s because we think it’s a really versatile product that’s well suited for Australian resources and needs.
I get asked questions about SolarGas all the time from people ranging from school students to scientists. For people who don’t work in process industries (that’s most of you, I’m guessing) I’ve realised that to really get across why SolarGas has so much potential, it’s necessary to take a bit of time to start at the beginning and explain the concepts involved. Unlike a system that produces electricity – which we can all relate to, because we use it to power our kitchen blenders and so on – SolarGas applications are more varied and perhaps might seem a bit further from home (related more closely to, say, the industrial manufacture of hydrogen rather than lighting our houses at night). Nonetheless, it has the potential to have huge benefits that are worth understanding. That’s why I’ve chosen to spread this article over two sections, and why I’m going to write it for the sort of reader who prefers to call a fire ‘hot’ rather than ‘exothermic’. No apologies.
How it’s made
To make SolarGas, we use mirrors to focus solar energy onto a series of metal pipes, which creates temperatures of around 800°C inside them. Through these pipes we flow a stream of natural gas mixed with something else. This ‘something else’ can be steam or carbon dioxide – both pretty common ingredients, suited to different situations.
These metal pipes form our SolarGas Reactor, and they have been carefully designed so that inside them the conditions are right for a chemical reaction to occur. This reaction converts the natural gas and steam (or carbon dioxide) to a new mix of gases, and in the process ‘sucks up’ a whole lot of solar energy into the new gas molecules in what is called an endothermic reaction. If you could touch the pipes where the reaction is going on (and we wouldn’t recommend it) you’d feel that they’re actually cooled as energy transfers from solar heat to chemical bonds – thus changing it into a form that, unlike the energy in sunlight, can be stored in bottles or pumped from place to place.
It’s interesting to note that steam and carbon dioxide are the products of normal combustion. So here, where we’re using them as the reactants, we’re in essence turning the usual reaction around using energy from the sun. That’s neat.
So, the result is that we’ve produced a new gas that has more energy than the gas we started with – and this extra energy came from the sun. The video below gives an overview of the process. In this example, the more common steam version of the reaction is shown.
You might have noticed that the video shows what SolarGas is. It’s made up of hydrogen and carbon monoxide – specifically, three units of hydrogen gas for every molecule of carbon monoxide gas. This mixture makes the gas very useful in a number of ways.
But that’s a topic that deserves a post of its own. Next: Part II – how it can be used.