Methane (CH4) is the primary component of both natural and renewable gas. As such, it is important to understand what it is and how it affects the environment or our climate.
Very often we hear reactions like:
”Yes, nice… but methane is a powerful GHG! (Greenhouse gas)”.
This is true when we compare it with CO2 methane has about 25 times stronger effect. In the scientific world, when we compare with other technologies, we multiply each gram of methane by this number in order to get it to a ‘CO2-equivalent’ version. From here, you can compare two fuels or two technologies on equal terms.
Because of the GHG impact of methane, we have to use it as efficiently as possible, and when we can, to capture it from the atmosphere and use it as fuel – this is what renewable methane is! In other words, when we capture it from the atmosphere rather than take it from the ground, we enter a closed-loop whereby methane emissions that would have been “naturally” released are avoided.
How to understand this?
As mentioned, the characterisation of natural gas performance in terms of WTT and TTW emissions must be (and it is) done as “CO2 equivalent”.
This means that we consider not only the CO2 generated but also CH4 (methane) and N20 (nitrous oxide), multiplied by their equivalence factors. These factors are generally considered equal to 25 and 298 respectively over a 100-year global warming potential for greenhouse gases reported by the United Nations Framework Convention on Climate Change (UNFCCC).
Aren’t there unused emitted methane emissions from transport?
⦁ On the TTW basis (remember this are the emissions from the vehicle), methane emissions emitted at the exhaust of the vehicle are around 0,1%. What does that mean? It means that 1 g of methane is emitted into the atmosphere for each 1000g of methane burnt (ref. to Thinkstep Study).
⦁ On a WTT basis (remember this are the emissions from the fuel or energy carrier), methane emissions from CNG operations are at 0,65% and at 1,07% for LNG ones.
Here’s what is really interesting when we add it all up
The current natural gas consumption in the EU from the road transport sector is approximately 2 bcm (billion cubic meters). Methane emissions from incomplete combustion in vehicles are approximately 1,5 Mt/year. Considering the fleet of vehicles (around 1.3M units) this means 1,14 kg CH4/year per car. Is that a lot?
Let’s compare the yearly CH4 emissions from a cow. We discover that a single cow emits approximately 100 kg CH4/year (Report from FAO: LIVESTOCK’S LONG SHADOW, environmental issues and options).
In other words, this is the amount equivalent to 80 cars from just a single cow!
In terms of statistics:
- Our EU NGVs fleet is around 1,3 Million units
- Our EU cows: 24 Million cows,
Therefore, our European cows emit as much as 1,920 Million NGVs.
Can’t we use the cows’ methane and apply it to transport?
The answer is “Yes”!
In fact, in our previous articles from these series, we’ve talked about renewable methane. We also covered its potential for the life-cycle of a vehicle, where we compare renewable methane with other fuels and electricity.
See more about life-cycle emission in this article:https://gmobility.eu/life-cycle-emissions/
The process is more simple than it sounds and there are many European companies that already work with farmers to collect cows’ manure. Instead of letting those emissions go into the atmosphere, they capture them by collecting the manure.
Why collect the manure of the cows? Because this is where the bacterias converting organic materials from the cows’ diet into methane live. Simply collecting these and putting them all together, allows us to capture them and later use them in transport.
So, what’s next?
Well, having understood this information, now you know how to compare the emissions of different vehicles correctly. You know that methane emissions are important and that by producing biomethane, we utilise them in transport, rather than letting them go into the atmosphere.
Now you understand why we need to think more broadly about which vehicles are deemed clean and not neglect the source of energy.
We need to ask for more renewable fuel like biomethane to be used so to have a significant impact already in lowering greenhouse emissions.