Reducing emissions in landfills is difficult – here’s how not to do it

The government says it wants to reduce GHG emissions, but when you try with landfill, it hits you over the head with a fine. Does this do your head in? Wait, it gets better.

Now, this story is complicated!

And it’s mad, but sadly real!

And it contains loads of acronyms. Sorry about that, but please bear with me.

You have probably heard about the Kyoto Protocol and the Paris Agreement.

The Kyoto Protocol committed developed countries that signed the Protocol to reduce greenhouse gas (GHG) emissions in accordance with agreed targets.

The Paris Agreement is a non-binding agreement to limit increases in global temperature.

Both documents require Australia to report its GHG emissions. For this purpose, Australia has its own legislation called the National Greenhouse and Energy Reporting Scheme (NGERS).

How do you measure GHG emissions? Good question. There is the IPCC (the Intergovernmental Panel on Climate Change), a group of scientists who develop methods to do this for the various industries that emit GHG.

For most GHG emitters, measurement is pretty straightforward (just kidding).

Take internal combustion engines used in cars, buses and trucks. You have a clearly defined input (a standardised fuel) and a measurable output from the exhaust pipe. Or take coal fired power stations. Same thing; although coal has a great variety, the emissions come out of a stack where they can be (pretty) reliably measured.

So far, so good.

Measuring GHG emissions from landfills and agriculture is a very different story.

Imagine a large landfill, several hectares of land, some areas filled and covered, some areas half-filled and half-covered (sorry, guys, for using plain English), and some areas have open waste being compacted. It’s raining. You have no idea what’s in the waste coming in, hour by hour, day by day – sometimes it’s wet, sometimes dry, sometimes cold, sometimes hot. Why do I mention this? These factors impact the so-called decay factor, which is how quickly carbon (in waste) decays and forms GHG.

Anyway, the Australian government, in its wisdom, decided landfills have to be reported under NGERS, but agriculture does not. Agriculture? Too difficult. Landfills? It’s difficult, but the IPCC has given us a method.

You can look it up: Chapter 5 of the IPCC’s Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories.

Australia has chosen the first order decay (FOD) model, which has a number of variables. Check out the table below, which shows the uncertainty factors of those variables. By the way, SWDS means solid waste disposal sites = landfills.

As you can see, I highlighted the biggest range; the uncertainties vary between -50 per cent and +300 per cent for some of those variables.

And they accumulate, meaning each variable has its own uncertainty factor, and they add up.

Those are big numbers, meaning there are very big uncertainties in estimating the GHG emissions from the first order decay model.

When you take all the above uncertainty factors and the variability of the climate into account, you know that the model will not give you a realistic number in terms of actual emissions generated. It will give you a number, that’s all. It’s a bit like the lottery. The IPCC knows this, but they don’t really care. Why? Because they are more interested in consistency of reporting than accurate numbers. Remember, this is an international reporting tool with many uncertainties. What we report as GHG emissions for landfills isn’t real. But if we keep reporting using the same method year in and year out, we get a trend and see what’s happening regarding GHG emissions at a national and international level. That’s all.

I know what you are thinking right now. When is this guy coming to the point? I told you, bear with me, it’s complicated.

We are knowingly under-reporting GHG emissions.

This is where you say: “What? How?”

Okay, the IPCC assumes that methane has a CO2 equivalent  (CO2-e) factor of 28, meaning methane is 28 times as bad a GHG as CO2 is. As we report all GHGs in CO2-e form, we need to have a conversion factor for each of the different GHGs. The conversion factor for methane is 28. The IPCC uses a so-called Life Cycle Analysis or LCA. LCA is a tool (another method) that evaluates and quantifies the environmental impacts of a number of variables and their total impacts over a period of 100 years.

Basically, it’s about consistency in the method. The issue is that methane doesn’t last 100 years. It stays in the atmosphere for about 20 years, some say less (NASA says 7 to 12 years). The real CO2-e factor of methane is around 84 times CO2 for 20 years or more than 100 times for 12 years. Yes, you read that correctly; we are underestimating (and underreporting) the GHG impact of methane from landfill gas by a factor of at least 3 (84/28= 3). Have you ever heard climate scientists telling us that climate change is happening faster than estimated? Hmhm? I know what you are thinking…

Does that make any sense to you? No? Me neither. However, if you think of NGERS as a reporting tool, consistency is more important than accuracy so that numbers from all sorts of activities from all countries can be compared worldwide. Landfill gas is not that important in the overall scheme of things.

But, yes, if you think that’s slightly mad, you are not wrong. Unfortunately, it gets worse.

Emissions are measured: GHG generated minus GHG captured (and oxidised, but let’s keep it simple). Landfills capture the gas they generate and either flares it or burn it in a reciprocating engine, generating heat and electricity – like a truck engine, just bigger. How much they capture is called “capture efficiency” (CE). The CE is calculated by dividing the GHG captured (or GHGcap) by the (assumed) GHG generated (GHGgen). In a formula, it would look like CE = GHGcap/GHGgen.

We can measure what gets captured as it goes through accurate flow meters. We cannot measure how much GHG is generated. Remember, we don’t know what’s in the waste. Remember also that we are knowingly underreporting, and the NGERS method has many variables with loads of uncertainties (above table).

NGERS stipulates that the CE cannot be more than 75 per cent (or 95 per cent if you are using a bespoke method, which no one is using). If you capture more (than 75 per cent), then the Government, in its wisdom, assumes the landfill generated more than was assumed (duh, we knew that already) and makes you pay for the assumed over-generation. Hello?

This is where you say: “Are they mad?” Answer: Yep!

Why?

The Government says it wants to reduce GHG emissions, but when you do, it hits you with a fine. Does this do your head in? Wait, it gets better.

On 3 May this year, the Government released a paper, “Reform Options for ACCU ( = Carbon Credits) Landfill Gas Methods”, plus a “Supporting technical report”.

Quote from the Technical report:

“Because of the uncertainty associated with the model (meaning NGERS – author note), the CE of many projects (landfills) supplied by project proponents are above 100 per cent, even reaching values of 400 per cent or more. That means the project is capturing more gas than is predicted to be produced by the methane generation model. These landfills do not have CEs exceeding 100 per cent, but rather the model has underestimated how much gas has been produced by the landfill.”

That describes accurately what I said above. In lay terms, the Government knows that its NGERS model is underestimating GHG emissions, yet it insists on using an inaccurate tool to create caps (either 75 per cent or 95 per cent) of what one can capture and punishes you if you capture more.

I know it’s complicated, so let’s recap!

The Government turned a reporting tool with known uncertainties into a regulatory tool.

Terrible mistake!

If you run a landfill and capture GHG emissions, the Government tells you to use a reporting tool that comes up with gobbledygook (the technical term for something unintelligible) to measure your capture efficiency: CE = GHGcap/GHGgen. A real number divided by an estimated number that can be out by a few hundred per cent equals gobbledygook.

You are asked to reduce your GHG emissions, but you have zero control over what you receive and what the weather will be like. And when you capture more than gobbledygook, you are being punished.

Insane?

Yep!

Having heard all this, you ask: “So, what’s going to happen?” Let me tell you. The big landfills, which are outperforming in GHG capture and take most of our waste, will simply turn off their capture mechanism and let the methane go….so their capture efficiency goes down. Cheap. Easy. And wrong.

But at least they won’t get penalised by the Government.

As I said, it’s completely insane.

Thanks, Mr Bowen!

If you’d like to do something useful, simply remove that silly cap for landfills and incentivise them to capture as much GHG as possible.

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