SolarGas Part 2: Why it’s so usefulPosted: Friday, 30th September, 2011
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!