So first off my opinion
Biogas sounds slightly disgusting.
Which, to be fair, is because some of the things we make it from are slightly disgusting.
Food waste.
Sewage.
Animal manure.
Agricultural waste.
Stick the right organic material into the right environment and microorganisms start breaking it down.
One of the gases produced is methane.
Methane burns.
Now we’ve got fuel.
There is something wonderfully circular about turning stuff we’d rather get rid of into useful energy.
So how do we make it?
The process is called anaerobic digestion.
The important word there is anaerobic.
Without oxygen.
Organic material is placed into a sealed digester where microorganisms break it down.
The resulting biogas normally contains a mixture of gases, particularly methane and carbon dioxide.
The methane is the useful bit from an energy point of view.
It can be burned to produce heat.
It can fuel a generator to produce electricity.
Or the gas can be cleaned up further to produce biomethane.
That can potentially be used much more like conventional natural gas.
Hang on, methane is a greenhouse gas
Yep.
And quite a potent one.
That initially made me wonder how burning biogas could possibly be considered useful environmentally.
But the carbon argument is different from digging fossil carbon out of the ground.
The carbon in biogas came relatively recently from the biological carbon cycle.
Plants absorbed CO2 while growing.
Animals ate plants.
Waste was produced.
The material decomposes.
We’re cycling carbon that was already moving through the current environment rather than releasing carbon that had been locked underground for millions of years.
That’s the basic argument anyway.
But there is a pretty important catch.
You really don’t want the methane escaping.
Methane leakage matters
This is where the engineering starts becoming much more important.
If the whole point is capturing methane and using it productively, leaking that methane into the atmosphere isn’t particularly helpful.
So plant integrity matters.
Pipework matters.
Valves matter.
Storage matters.
Monitoring matters.
Suddenly a technology that sounds almost agricultural starts looking like another serious industrial process.
Which of course it is.
And we haven’t just made gas
After anaerobic digestion you’re also left with digestate.
That material can potentially be used as fertiliser.
So the process isn’t simply:
Waste → Gas
It’s more like:
Organic material → Biogas + Digestate
Now we’re potentially recovering both energy and nutrients.
That’s the part I find particularly appealing.
We’re taking a waste stream and trying to extract additional value from it.
But where did the feedstock come from?
This seems like an important question.
If we’re taking genuine waste that already exists and turning it into useful energy, that seems fairly easy to understand.
If we’re deliberately growing crops primarily to feed an anaerobic digester, things become more complicated.
Now we’re using land.
We’re using fertiliser.
We’re using machinery.
We’re potentially competing with food production or other uses for that land.
So once again, saying something is “renewable” doesn’t automatically tell us whether it’s sensible.
We need to understand the whole system.
And that’s where the data gets interesting
Imagine operating a biogas plant.
I’d want to know:
What material went into the digester?
How much?
What’s its composition?
What’s the temperature?
What’s the pH?
How much gas are we producing?
What’s the methane concentration?
How much gas is being used?
How much is being flared?
Are we seeing unexpected losses?
What’s happening to the digestate?
Suddenly we’ve got biological processes, industrial equipment and energy production all represented in the data.
That’s a pretty interesting combination.
Biological systems must make forecasting interesting
A gas turbine is complicated.
But it’s still a machine.
Anaerobic digestion adds biology into the process.
Microorganisms don’t particularly care about your monthly KPI.
Change the feedstock and gas production can change.
Change the temperature and things can change.
Upset the biological process and I imagine recovering it isn’t necessarily instantaneous.
That makes me think historical operational data could be incredibly useful.
Not just:
How much gas did we produce yesterday?
But:
What combination of feedstock and operating conditions produced the best result?
Now we’re getting into optimisation.
Possibly even machine learning.
And suddenly yesterday’s cow muck has become a data science problem.
I didn’t expect to write that sentence.
So where is my head at?
I like the idea of biogas most when it’s genuinely turning unavoidable waste into something useful.
Food waste exists.
Sewage exists.
Animal waste exists.
If we can capture energy from those materials while also managing the waste, that feels sensible.
I’m less immediately convinced when we’re deliberately producing large amounts of material purely to feed the process.
As usual, the interesting bit is in the detail.
Where did the feedstock come from?
How efficiently was it converted?
How much methane escaped?
What happened to the digestate?
The label biogas doesn’t answer those questions.
The data might.
And that’s where my head is at the moment.
Gareth Winterman