Biochar is a possible way to reduce the carbon emissions that come from farming. It’s been in the news a little bit lately, and I think it’s got the potential to really help Australia reduce it’s eco-footprint, and hopefully will have other benefits for farmers too.
By RaeAllen at Flickr.com
Our agricultural sector is responsible for nearly 20% of our climate-change emissions, so a new technique for farmers would have a huge impact. Biochar doesn’t need any special advances in technology, so there are trials of it starting up already.
Basically, you start with biological materials, like crop waste, animal manure, forestry offcuts, etc. This waste is usually left to rot in the field, which returns it’s trapped CO2 to the atmosphere. But you can take that waste, and put it through a process called pyrolysis instead, which means burning it in the absence of oxygen. It’s a bit like bbq-ing a steak - the inside cooks by pyrolysis, since there’s no oxygen inside it, while the outside burns if you leave it too long because it’s exposed to air.
When you pyrolysise the crop waste, it turns into charcoal. Why is that such a good thing, you wonder? Because the carbon is locked inside it, instead of being able to get out into the atmosphere. So we’ve tucked away our carbon in a much safer format.
But wait, there’s more! The bonus is that this charcoal can then be dug back into the soil, where all the bacteria and soil fungi that you need for growing crops soon move into the carbon. It actually makes your soil healthier and more nutritious for the plants. It also holds more moisture, which is very useful in our dry country, and prevents the water run-off that carries fertilisers into our rivers and oceans.
The other benefit is that the machines that do the pyrolysis create a synthetic gas. This gas can then be used to run the machine, and the leftover gas can be used to generate lower-emission electricity than our coal-fired power stations do.
The main drawback is that pyrolysis machines are expensive. I assume the price will come down as they become more available, same as any other product, but in the meanwhile farmers might have to get together in large groups to buy them for shared use. If they’re paid a fee for reducing carbon in the atmosphere (perhaps as part of a proper ETS), then that could go a long way towards making it affordable for them.
It’s an exciting prospect for Australia, and I’d love to see more action on it. If you’re interested in finding out more, here’s a few links to get you started:
Thanks for that informative post Julie. I learnt about Biochar today on the Carbon Accounting course. It has the potential to be a huge carbon sink. Not only great for the impoverished soil around the country, but a possible great money maker as well.
Gav