The following is an article originally published by Carbon Herald on March 31, 2025.
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?
That’s correct. 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 around a quarter of all the Low Carbon Fuel Standard (LCFS) pathways in California. So we’ve got a lot of experience on the compliance side.
Recently, we’ve been exploring the new carbon removal space. We see that there are many brilliant people bringing great ideas to life. However, they lack experience in auditing.
An audit is a specific process for verifying claims, and we felt that we needed to provide guidance on how to approach it effectively. This is how you should go about it, and these are the common mistakes to avoid.
Do you mind walking us through the five requirements for high-quality CDR audits?
Firstly, many organizations’ project leaders will come to us and ask us to check their systems to ensure that what’s being done is correct, and at a very basic level, it isn’t.
A specific hierarchy is 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 standard. We have registries that have interpreted specific ISO standards to develop their own standards. These standards might include more or less sustainability requirements, but they’re typically based on ISO.
Next, you do is design a methodology. A methodology lays out what you should do in a project to generate carbon credits. If you tick all the boxes, you can get carbon credits.
Once a project aligns with the hierarchy, adheres to the methodology, and complies with the ISO standard, the next step is to have it verified. This process occurs before you generate any credits, ensuring that your project satisfies all the requirements of the methodology and that the methodology fulfills all the necessary standards.
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 say, for example, “We’ve generated 400,000 metric tons of credits over the last year, and we would like that to be audited.” So you invite an independent third party to come in and make sure that the claim is correct.
All categories of claims are made against a document that outlines the boxes you must tick to ensure you can make the claims. That’s your audit hierarchy. We do not 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 beneficial because it facilitates a high-quality audit by providing access to all the information. It also means that you’re presenting a wealth of interesting data regarding these novel processes. Furthermore, there is ample opportunity for analysis to enhance the methodology.
We can enhance our understanding of science by examining all the data available to everyone. Any scientist can come along and analyze the data, suggesting improvements for the scientific processes. The challenge arises when the project proponent, typically the individual undertaking this valuable work, depends on external sources for information.
One classic example in the fuel space is used cooking oil or UCO, which a fuel plant uses to make fuel. If the people supplying that used cooking oil are reluctant to share their information, we can’t pass an audit.
You need a trusted auditor who will be transparent with all the parties. Still, there are cases where you won’t have a lot of information, and often, it’s because a fuel producer will also be competing against a UCO collector and buying from them at the same time. The UCO collector doesn’t want to disclose all their used cooking oil sources to somebody who could just call the restaurants themselves.
When writing supply contracts, you should include language to ensure your auditor can review all your data to get reasonable or limited assurance that what you say you’re doing, you’re actually doing. Or you’ll apply a penalty if you do not allow the auditor to review that information. If not, you’ll fail your audit, or you will 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?
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 credit generation requirements.
The problem comes when the methodologies are new.
For example, the California Air Resources Board’s LCFS regulation could be considered analogous to a methodology. It has very detailed instructions and is backed up by a large staff that interprets those instructions for new projects.
So you bring a project to the California Air Resources Board, and they will go through it in detail to ensure it fits the regulation. When a project comes along that has a novel process, CARB builds specific operating conditions into the project so that it meets the regulation.
The methodology lacks information and, in some cases, expertise. California has a large staff of very experienced modelers who understand greenhouse gas emissions. Still, this expertise is sometimes not available, or the methodology writers fail to recognize that best management practices must be used, which are not reflected in the project. Consequently, skilled auditors must point out that this isn’t correctly written; this project must have the following operating conditions that have not been implemented. That’s where the project is at the validation stage. If you go through a process, can this meet the methodology? Yes.
It could be as simple as a transportation emissions model that is overlooked. There are numerous transportation emission models, but you might select one that isn’t pertinent to your project, or you might decide on a method that renders it unusable for your project. A classic example is if I’m managing a fleet of trucks, it’s very easy to calculate my emissions because I know how much fuel I’m purchasing. For all the fuel used in the fleet of trucks, I can account for the fuel that goes into the fleet.
I’m taking this into account, and these go from A to B, but that doesn’t capture all the fuel used in that transportation.
However, it is important to consider all surrounding factors, and it is advisable to use an average emissions model rather than a model solely based on direct fuel-related emissions. This reflects an understanding of the life cycle assessment (LCA) modeling. It’s very tricky and sticky. EcoEngineers has ten Ph.D.s on staff in LCA modeling who are excellent at pointing out mistakes like these. An experienced modelers is essential to building out an 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 particular process you go through with an audit. You take the document and do a risk analysis, which 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 it could easily go wrong, and it will have a huge impact. I want to ensure that all the data is right.
For instance, when there are a hundred farms supplying biomass to this project and I have bills of lading demonstrating their activities, they maintain a good documentation trail, providing me with reasonable assurance. I might choose to visit one farm out of the hundred, but I’m not going to visit all of them, so my sample size remains small. However, if I go to that farm and discover that what they claim to be doing is incorrect, then I would expand the sample size. Thus, we follow a very structured process, and ANAB comes in to verify each step we’ve taken. We conduct an internal review, and also occasionally, we’ll be audited to make sure that our audit process, our documentation, and what we’re recording about the audit are correctly laid out.
What specific services does EcoEngineers offer to suppliers?
We offer all services on the audit side. This includes California’s LCFS, Canada’s CFR, Oregon CFP, 45V, M-RETS, as well as custom audits, MRV protocol creation, agricultural emissions verifications, Isometric, Puro.earth, Green-e, and Scope 1, 2, & 3 emissions reporting verification. We do a lot of quality assurance protocol (QAP) audits, which is a program for the EPA. We offer a wide range of services, and we can offer validation services, which include 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 at the end on the audit side.
On the consulting side, we can write all those documents in preparation for the audit. We write methodologies for clients, and we write project plans for clients against methodologies. 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?
Some market trends are occurring right now. If you visit the EPA website for class VI wells, there are, I believe, 20 class VI wells that will become operational 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. In the next two years, two gigatons of carbon storage will come 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. They want the projects to go forward and profit because they’ve put a lot of capital into developing them. And so there will be many people trying to sell CO2 because the 45Q tax credit means it’s pretty lucrative to store CO2.
I suspect that storage will start, and the oversupply of storage will drive carbon capture, particularly in the southeast of the US, both in the CDR and in the avoidance markets.
Read more: DOE Considering Funding Cuts For The Two Largest DAC Projects In The US
There are also some in California. Elk Hills, California Resource Corporation, is going forward with its big capture project in Southern California. A lot of storage is coming online, and people will match it with capture.
This development of carbon capture at point sources is also going to help all the CDR companies that are looking for direct air capture (DAC), which removes CO₂ from the air and then stores or reuses it, and other technologies where they’re capturing CO2 and putting it underground.
They’ll find that storage is very cheap and easily available. The problem we have with, say, DAC is where to get the energy. These are highly energy-intensive programs, and they won’t work with grid emissions.
If you look at the carbon intensity of the grid emissions per kilowatt-hour, you won’t be able to make those projects carbon negative.
So, you have to find sources of renewable energy, such as solar and wind energy. But all those solar and wind power projects are going forward anyway.
Author: Lisa Hanke
