This interview has been edited for brevity and clarity.
Carbon dioxide removal (CDR) is one of the climate action pillars capable of delivering meaningful results towards global net-zero goals. Paired with CO2 emissions reductions, CDR is a tool that’s increasingly sought after by companies, organizations, and governments as a vital part of sustainability plans.
Last year, the CDR market experienced an increase in both purchases and deliveries, and the trend of growing carbon removal investments seems to follow into 2025, with relevant industry experts projecting further growth in the future.
While the interest for CDR is on the rise, experts warn that the current carbon removal levels are still falling behind the benchmarks needed to reach climate targets on time and the CDR sector is in need of rapid scaling to tackle the ongoing environmental crisis.
As the focus of CDR buyers switches from investing in the most affordable projects towards backing high-quality, durable solutions, carbon removal integrity and effectiveness emerge among the top priorities driving carbon removal purchases.
To ease suppliers with the task of verifying their activity against high-quality standards and generating trustworthy CO2 removal credits, clean energy consulting, auditing, and advisory firm EcoEngineers has put together a paper offering guidance on the auditing process.
Recently acquired by leading assessment and certification specialist LRQA and accredited by the American National Standards Institute (ANSI) National Accreditation Board (ANAB), EcoEngineers is a US-based company that also boasts established capabilities in the EU market, where it partners with auditing teams following regional rules and regulations.
Authored by Roxby Hartley, PhD, climate risk director at EcoEngineers, the paper titled “Five Requirements for High-Quality CDR Audit” outlines the main areas of focus for performing credible CDR verifications.
The five building blocks of the suggested framework include understanding the audit hierarchy, aligning assurance levels with claims, embracing the dynamic nature of audits, choosing competent auditors, and promoting transparency.
This practical approach stems from years of robust experience in guiding CDR projects to meet the highest standards of integrity and transparency. Following these steps with optimal accuracy enables carbon removal suppliers to confidently audit and verify projects in accordance with rigorous market standards.
In a recent interview with Carbon Herald, Dr. Roxby Hartley shared more about the paper and the intricacies of auditing CDR projects. You will find our conversation below.
Can you tell us more about the paper? It stems from EcoEngineers’ vast experience with its client base, right?
Right. EcoEngineers started as an audit company, and we have been auditors for the U.S. Environmental Protection Agency (EPA) for over 15 years. We audited like a quarter of all the Low Carbon Fuel Standard (LCFS) pathways into California. So we’ve got an awful lot of experience on the compliance side, auditing.
More recently, we’ve been moving out into the new carbon removal space. And we see that there are kind of a lot of inexperienced, brilliant people making great ideas come to life. But they don’t have the experience on the audit side.
An audit is a very specific process by which you have to verify claims, and we felt that we needed to put something out there to say, hey, you know, this is how you should be going about it, and these are the simple mistakes to avoid.
Do you mind walking us through the five requirements for high-quality CDR audits?
The first thing is that a lot of projects come to us and ask us to check their system to make sure that what’s being done is correct, and at a very basic level, it isn’t.
There’s a specific hierarchy that’s being developed about how you should document what you’re doing.
At the highest level of the hierarchy, we have the ISO standard, the international standards.
We have registries that have interpreted their own ISO standard to develop their goals. And they might include more or less sustainability requirements in them, but typically they’re based on ISO. So that’s the thing. The registry has a standard.
Then the next thing you do is you design a methodology. A methodology lays out what you should do in a project in order to generate carbon credits. If you tick all the boxes, you can get carbon credits.
So you have a project that fits the hierarchy, fits the methodology, and fits the ISO standard. The next thing is to have that checked. That’s called validation. This process happens before you’ve generated any credits, making sure that your project meets all the requirements of the methodology and the methodology meets all the requirements of the standard.
Relevant: LRQA Acquires EcoEngineers, Expanding Low-Carbon Expertise
And then right at the very end of this, you have the verification of credits where you go out and say, for example, we’ve generated 400,000 metric tons of credits over the last year, and we would like that to be audited. An independent third party comes in and makes sure that claim is correct.
All levels of claims are made against a document that says these are the boxes you have to tick to make sure you can make the claims.
So that’s your audit hierarchy. We do audit in a vacuum. We always audit against something that tells us whether they’re doing something correctly.
The paper also points out the importance of transparency. What steps should CDR suppliers take to ensure everything’s transparent?
That’s actually quite a sticky problem in many situations.
The registries often have very high transparency requirements, which is a good thing because that allows not only a high-quality audit because we can see all the information, but it also means you’re showing all this really interesting data for these novel processes. Then there’s a lot of analysis that can be done to improve the methodology.
We can improve our understanding of the science by looking at all this data that is available to everybody. Any scientist can come along and go through the data, suggesting improvements for the scientific processes. The sticky point comes when the project proponent, who is usually the person who’s doing all this great work, is relying on other outside sources for information.
One classic example in the fuel space is used cooking oil, where a fuel plant will use used cooking oil to make a fuel. The people supplying that used cooking oil are very, very conservative about sharing information, and we can’t pass an audit unless we can get that information.
What you have to have is a trusted auditor that all the parties will be transparent with. And still there are cases where you can’t have a lot of information, and often it’s because a fuel producer will also be competing against a UK collector and also buying from them, and the UK collector doesn’t want to disclose all their used cooking oil sources to somebody who could go and just call the restaurants themselves.
So the transparency is you have to have a trusted auditor. This means that when writing supply contracts, you should make sure to include, “If you don’t allow our auditor to review your data to get reasonable or limited assurance that what you’re saying you’re doing, you’re actually doing, then we can’t use you.” Or “If you don’t allow the auditor to review that information, a penalty will be applied because you will fail your audit.” Or you might not fail it, but you’ll probably have a finding against you that you can’t mitigate.
Are there roadblocks that suppliers should be prepared for when trying to go through the auditing framework?
I would say there might be gaps. This is why we talk about auditor competence. Auditors usually rely on a clear list of instructions with boxes that need to be ticked off, making sure everything meets the methodology requirements or the requirements of the credit generation.
The problem comes when the methodologies are new.
They haven’t been around one time. For example, the car bill, the CFS regulation, which is essentially a methodology. It’s got very detailed instructions and is backed up by a big staff who, in a way, interpret those instructions for new projects.
So you bring a project to the California Resources Board, and they will go through it in detail to make sure it fits the boxes very nicely. But there’s this area that’s not very clearly defined. And we’re going to go through this process to clearly define it in your project to give specific operating conditions for your project alone.
The methodology doesn’t have that information, and in some cases, you don’t have the expertise. I mean, California’s got this huge staff of very experienced modelers and an understanding of greenhouse gas emissions, but sometimes that is just absent, or the methodology writers don’t understand that you have to use these best management practices, and that doesn’t get reflected in the project. So you have to have very skilled auditors go, “Hey, this isn’t correctly written; this project has to have these following operating conditions that have not been implemented yet.”
So that’s at the validation stage for a project. If you go through a process, can this meet the methodology? Yes.
It could be as simple as a transportation emissions model, where they use one that misses. There are many transportation emission models, but you might choose one that isn’t relevant for your project, or you might decide to do it a certain way that it can’t be used for your project. The classic example is if I’m in a fleet of trucks, it’s very easy to count my emissions because I know how much fuel I’m buying, and for all the fuel that goes into the fleet of trucks, I can use the fuel that goes into the fleet.
So I’m taking this into account, and these go from A to B, but that doesn’t capture all the fuel that’s being used in that transportation.
If I’m in the fleet, I know how much fuel I’m using. If I’m purchasing transportation from an individual supplier, then I have to understand all the black holes. I have to understand all the transportation, all the other emissions that go into making that truck go from A to B. And we see a lot of people going, oh, we’re just going to use a few that we’ve done from that, and that’s it.
But you can’t, because I have to count everything else that surrounds it, and you should be using an average emissions model rather than a direct fuel-related emissions model. And that’s just an experience of life cycle assessment (LCA) modelling.
We’ve seen that quite a lot in the new projects, where they can’t just do this. That is why you need some experienced people to spot those mistakes. They need to be wary.
It’s very tricky and sticky. We have like five PhDs on stuff in LCA modelling that are excellent at pointing out mistakes like these. So you need good, experienced modelers to help you build out your LCA model.
EcoEngineers is one of the accredited Validation and Verification Bodies by the American National Standards Institute (ANSI) National Accreditation Board (ANAB). Can you tell us more about the significance of this accreditation?
ANAB is an auditor of auditors. It requires us to have very high documentation standards internally and training of all our auditors. We are audited on our audit process by them.
There’s a very specific process you go through with an audit. You take the document, you do a risk analysis, and this is verification. You say, “Of all the things I’m going to be looking at in your project, which are the ones that can go wrong and which ones will have the most impact?” And if I could easily go wrong, and it’s going to have a huge impact, I want to see all the data was right.
For example, when there are a hundred farms supplying biomass to this project and I’ve got bills of lading showing what they’re doing, they’ve got a good documentation trail, and I’ve got really good assurance. I might decide to visit one farm out of the hundred, I’m not going to visit a hundred farms, and my sample size is small. But if I go to that farm and find out what they’re saying they’re doing is wrong, then you expand the sample size. So we go through this very structured process, and ADAB comes along and checks each step that we’ve done.
We have an internal review, and also occasionally we’ll be audited to make sure that our audit process, our documentation, what we’re recording, everything about the audit is correctly laid out so we can come and certify something at the end.
What specific services does EcoEngineers offer to suppliers?
We offer all services on the audit side. We have ICC auditing capabilities, MMR auditing, capital auditing, and LCFS. We do an awful lot of quality assurance protocol (QAP), a program for the EPA. So we offer a wide range of services, and then we can offer validation services, which is checking over projects before they generate credits or checking over methodologies before they’re accepted to a registry.
And then we can do the verification audit for carbon credits as well at the end. So that’s on the audit side.
On the consulting side, we can write all those documents in preparation for audit. So we write methodologies for clients, and we write project plans for clients against methodologies as well. We feel like we do a really good job at helping people come to market with their carbon credits.
Besides improved auditing, what else needs to happen to catalyze the development of the CDR sector?
There are some market trends going on right now. If you just go to the EPA website for class VI wells, there are, I think, 20 class VI wells that are going to come online over the next two years.
This is in the US, and that doesn’t include North Dakota, Louisiana, or Wyoming. Those wells can store 100 million metric tons of carbon each. So in the next two years, there are two gigatons of carbon storage coming online in the US.
If you look at the amount of storage coming online, all those storage companies are going to be competing for carbon dioxide. Because they’ve put a lot of capital into developing these projects, they want the projects to go forward and profit. And so there are going to be a lot of people trying to sell CO2 because the 45Q tax credit means it’s pretty lucrative to store CO2.
So I suspect that storage will start and the oversupply of storage will drive carbon capture, particularly in the southeast of the US.
There’s also some in California. Elk Hills, California Resource Corporation, is going forward with their big capture project in Southern California. There’s a lot of storage coming online, and people are going to be matching it with capture.
This development of carbon capture at point sources is also going to help all the CDR companies that are looking for DAC and other technologies where they’re capturing CO2 and putting it underground.
They’re going to find that the storage is very cheap and very easily available. The problem we have with, say, DAC is the question of where do you get the energy? These are highly energy-intensive programs, and they won’t work with grid emissions.
If you look at what the carbon intensity of the grid emissions is per kilowatt-hour, you won’t be able to make those projects carbon negative.
So you have to find sources of renewable energy like solar and wind. But all those solar and wind power projects are going forward anyway.
