Challenge
A growing reporting scope, a small team, and “death by spreadsheet”
By 2024, Wellington Airport had reached Airport Carbon Accreditation Level 4+ Transition, the second-highest tier in the only institutionally-endorsed carbon management certification programme for airports. Getting there had required years of expanding the GHG inventory, collating evidence, and going through the full ACA application and verification process largely on spreadsheets and email.
The cost was felt across the calendar year:
- Tenant data was collected via quarterly emails, follow-ups, and reminders, a manual process that consumed significant time
- Invoices, evidence and source data lived in folder structures that were workable but required a lot of hands-on maintenance
- The annual reporting load consumed a significant share of the sustainability team’s available capacity
“If I was being melodramatic, I’d say it was death by spreadsheet. Doing a greenhouse gas inventory for an organisation like ours, with the number of stakeholders and tenants we have to gather data from, is a mountain of work. Lots of invoices, lots of self-organising, and lots of email follow ups.”
Josh McIvor, Sustainability Manager, Wellington Airport
The pressure wasn’t going away. Wellington Airport’s sustainability data was tied to multiple high-stakes commitments at once: ACA Level 4+ renewal every three years with annual interim reporting, sustainability-linked loan targets requiring independent assurance, GRESB benchmarking driven by parent company Infratil, and (at the time) mandatory Climate-Related Disclosures under the External Reporting Board regime.
The team needed a data foundation that could carry all of it without growing the team to match.
Action
A complete carbon inventory, automated tenant data, and an auditor-friendly system of record
Wellington Airport implemented BraveGen’s Carbon Accounting product as the single source of truth for emissions data across the precinct.
The deployment did three things in parallel:
Expanded the inventory to 100% of organisational boundary
BraveGen made it much easier to expand tenant data to cover 100% of tenants in what would have otherwise been a very cumbersome and time-consuming process.
Automated tenant data capture via smart forms
The majority of Wellington Airport’s commercial tenants now enter data directly into BraveGen smart forms each quarter or six-monthly cycle. The team now rarely manually emails tenants, chases responses, or rebuilds spreadsheets, and the data lands in a structure that’s already audit-ready.
Created a digital twin of a fluid, evolving airport
The platform’s location structure mirrors how Wellington Airport actually operates: a precinct where retailers come and go, tenants change, properties are bought, sold, demolished and built. Capital projects are tracked as locations alongside operational sites, allowing emissions to be tracked against capital expenditure. End-dating handles changes cleanly, so historical data tells a true story rather than getting tangled with the current state.
“The organisational benefit is probably underappreciated by anyone still living in spreadsheet land. All your documentation follows a logical structure, you can customise it to fit how you actually operate, and it becomes one stop shop: invoices, data, notes, organisational structure, all in the same place. We’re a fluid organisation. Retailers come and go, we buy and sell property, we demolish and build. Mirroring that in BraveGen is great.”
Josh McIvor, Sustainability Manager, Wellington Airport
Key features in use
- Smart forms for automated tenant data collection across the precinct
- Location hierarchy used as a digital twin of the airport, including capital projects
- File upload, smart forms, and limited manual entry across data sources
- Bulk emission factor updates aligned with MfE releases
- Invoice-level documentation with notes, end-dating and full audit history
- One source of truth shared with auditors and ACA verifiers
Impact
A complete inventory, no extra time, and confidence in every number
Wellington Airport tripled the scope of its emissions reporting in the same year it adopted BraveGen, without adding headcount, and while spending less time on the inventory than before:
- Tripled Reporting Scope Without Adding Headcount
Wellington Airport significantly increased the number of tenants included in its GHG inventory in the same year it adopted BraveGen, while reducing total time spent on data collection, preparation, and follow-up. - Freed the Sustainability Team for What Actually Matters
Inventory preparation no longer dominates the start of the year. What previously occupied the sustainability manager near full-time for the first three months is now a fraction of that effort, freeing capacity for the practical initiatives that advance the airport’s broader sustainability targets. - Faster, Lighter Audit and Verification
Auditors now access source documentation directly within BraveGen. Questions have shifted from tracking down invoices to substantive methodology discussions, a significant change in how verification time is spent and a direct reduction in the team’s audit preparation burden. - Industry-Leading ESG Performance
Wellington Airport scored 98/100 in GRESB FY25, with the team actively targeting 100/100 in FY26. The same underlying BraveGen inventory simultaneously supports ACA Level 4+ Transition renewal preparation, sustainability-linked loan assurance, and voluntary climate disclosures. - Higher Confidence in Every Number
Calculations no longer depend on the integrity of cross-linked spreadsheets. With a single system of record, every figure is traceable, documented, and ready for scrutiny. That matters when the same numbers are tested across multiple independent assurance processes. - Foundation for Future Scope 3 Targets
With FY27 marking the end of Wellington Airport’s current sustainability-linked lending arrangements, new Scope 3 targets will be required. The data flowing through BraveGen will be the direct foundation against which those targets are set and verified.
Any sustainability manager can tell you there’s so much you actually want to spend time doing, and you have to be hands-on, because you don’t have an army of people. The less time I spend in spreadsheets following up on data, the more I can actually do that. This year I prepared the inventory while still being able to progress other important sustainability initiatives. Without BraveGen, I would have just blocked out a few months for the inventory alone.
Josh McIvor, Sustainability Manager, Wellington Airport
Wellington Airport’s experience demonstrates that getting the data foundation right is what allows a small sustainability team to operate at the maturity level that ACA, GRESB, and assurance providers now demand. As ANZ airports increasingly move up the ACA levels, the infrastructure required at Level 4 and above quickly outgrows what spreadsheets can carry, making a purpose-built system of record a prerequisite for sustained performance, not a luxury.
In their own words
We significantly increased the number of tenants we were collecting data for, at the same time as we brought BraveGen on. So I’m spending less time on it than before, while covering significantly more tenant data. It’s a fraction of the time spent requesting data from tenants.
Auditors can explore the BraveGen system themselves. The questions we get now are about calculation methodology and bespoke things like passenger commuting, not ‘where’s this invoice, what was that?’ That’s been one of our biggest benefits.
BraveGen is a great product. It’s been great for us. We’re loving it.
Josh McIvor, Sustainability Manager, Wellington Airport
