Marcus Osei didn’t plan to end up in ESG compliance. He studied economics in Accra, did a master’s in environmental law in Frankfurt, and spent his early career doing environmental permitting work for an infrastructure consultancy. When Vortex Energy — a mid-sized renewable energy developer with projects across Germany and Poland — asked him to build their ESG compliance function, he wasn’t entirely sure what that meant yet. Two years in, he has a clearer view than most. We spoke to him over video call from his office in Berlin.
Q: ESG is a term that gets used to mean almost anything. When you say ESG compliance, what are you actually talking about?
A: That’s exactly the right place to start, because the confusion about what ESG means is itself one of the core problems in this space. When I talk about ESG compliance at Vortex, I mean three distinct things that often get blurred together. First, there’s regulatory compliance — meeting the mandatory obligations that come from things like the EU Taxonomy Regulation, the Corporate Sustainability Reporting Directive, and the supply chain due diligence laws. That’s genuine compliance work: there are rules, there are deadlines, there are penalties for non-compliance. Second, there’s voluntary framework alignment — things like reporting against GRI standards or TCFD recommendations, where we’ve made commitments to stakeholders about what we’ll disclose. Third, there’s what I’d call ESG risk management — identifying environmental, social, and governance risks that could affect the business, regardless of whether there’s a specific regulation attached to them. All three matter, but they require different approaches and different conversations with the business. The mistake a lot of companies make is treating all of ESG as either pure voluntary disclosure or pure box-ticking, when the reality is more layered than that.
Q: You joined Vortex specifically to build this function. What did that actually involve in the first few months?
A: Mostly listening and documenting, which felt frustratingly slow at the time but turned out to be essential. Before you can design any controls or reporting processes, you need to understand what the company actually does — where its environmental footprint sits, what its supply chains look like, what social commitments it has already made, sometimes without fully understanding the compliance implications. In the energy sector, the complexity is real. Vortex develops and operates wind and solar projects, which means you have land use agreements with farmers, construction contractors with their own supply chains, grid connection agreements with transmission operators, and community benefit obligations written into planning consents. Mapping all of that took about three months. The other thing I had to establish early was credibility with the data owners. A lot of ESG data — energy consumption figures, waste volumes, workforce statistics — sits in operational systems that are managed by people who have never thought about external reporting. Building relationships with those people, helping them understand why the data matters and what quality standards we need, is slow work, but it’s the only way to build a reporting process that actually holds up.
Q: The EU Taxonomy Regulation is now central to how investors assess whether energy assets are genuinely sustainable. How has it changed your work?
A: It’s made the work much more rigorous and, honestly, much more interesting. Before the Taxonomy, ESG reporting was largely self-referential — you could decide what to measure, design metrics that reflected well on you, and publish a sustainability report that told the story you wanted to tell. The Taxonomy changes that by setting out specific technical screening criteria that determine whether an economic activity can be classified as environmentally sustainable. For a wind energy developer, that sounds like it should be straightforward — renewable energy is green, right? But the Taxonomy also requires you to demonstrate that you’re not causing significant harm to the other five environmental objectives, and that you’re meeting minimum social safeguards. The Do No Significant Harm assessments are genuinely demanding. We had one project where the biodiversity impact assessment flagged potential effects on a protected bat species, and working through whether the mitigation measures we’d put in place were sufficient under the Taxonomy criteria required engagement between our environmental consultants, our legal team, and the relevant German state authority. It’s not a paperwork exercise — it requires substantive analysis and documented decision-making.
“The biggest misconception about ESG compliance is that it’s soft. People hear ‘sustainability’ and they think it’s about writing nice things in an annual report. But when you’re doing a Taxonomy alignment assessment, you’re working with technical screening thresholds, life-cycle analysis data, and biodiversity impact metrics. The technical rigour required is comparable to financial reporting — in some ways it’s harder, because the methodologies are still evolving and there’s much less established practice to lean on.”
Q: Greenwashing risk is something a lot of compliance functions are trying to get their arms around. How do you handle it internally?
A: This is where ESG compliance gets uncomfortable, because greenwashing risk isn’t only an external communication problem — it starts inside the organisation, with the claims that get made in board presentations, investor updates, and product marketing before they ever reach a public disclosure. My approach is to position the compliance function as a pre-publication review step for any sustainability-related claim that goes externally, whether that’s a press release about a new project, a slide in an investor deck, or copy on the website. That’s created some friction with the marketing and IR teams, who don’t always love having a compliance sign-off on their language. But we’ve had a few near-misses — claims about carbon neutrality that were based on carbon offset purchases rather than actual emissions reductions, which would have been both misleading and potentially caught by the EU Green Claims Directive once it comes into full force. Catching those internally is much better than finding out about them after a journalist or an NGO has published a critical analysis. The other thing I try to do is make sure our public commitments are grounded in what we’ve actually verified we can deliver, not in what sounds aspirational. Ambition is good; commitments you can’t substantiate are a liability.
Q: For someone earlier in their career who wants to move into ESG compliance, what does that path look like?
A: The good news is that ESG compliance is still young enough that there isn’t one canonical path — which means people coming from very different backgrounds can find a way in. I’ve met strong ESG compliance professionals who came from environmental law, from financial audit, from supply chain management, from corporate governance. What matters more than a specific prior role is a combination of technical curiosity and the ability to translate between disciplines. You need to be comfortable reading regulatory text and understanding what it requires. You also need to be comfortable talking to engineers, procurement teams, and CFOs in their own terms. That bridging role is the core of what ESG compliance actually involves. What I’d suggest practically: get familiar with the EU Taxonomy Regulation and the CSRD — read the actual texts, not just summaries. Understand the GRI standards, not because you’ll necessarily report against all of them, but because they’ll give you a vocabulary for thinking about ESG topics systematically. And try to get exposure to sustainability data — volunteer to work on your current organisation’s sustainability reporting, or get involved in supply chain due diligence work. The people who are going to do this well in five years are the ones who are building that substantive knowledge now, before the regulatory requirements are fully bedded in and everyone is scrambling to catch up.