Brennan Spellacy Took the Long Way Back to Climate

Brennan Spellacy chose chemical engineering because he wanted a job in lower-carbon energy. Hydroelectric power appealed to him. So did nuclear. Then the job market supplied its own punchline: the opportunities coming his way were in oil and gas in Western Canada. An education acquired to help change the energy system had made him employable in the system he hoped to change. The equations, it turned out, were quite accommodating about whom they worked for.

He became a programmer at Shopify instead. Later came product and engineering work at the hospitality startup Flatbook, which became Sonder. Patch, the company he co-founded with Aaron Grunfeld in 2020, brought him back to the problem that had sent him to McGill University. The route was circuitous, but it left him with an unusually useful combination: an interest in the physical world and experience making software businesses work.

His career invites a question that hangs over the company he now runs. How much climate progress is waiting for a new invention, and how much is waiting for somebody to connect the inventions, customers and capital already available? Spellacy has placed his working life on the second question. There is considerable ambition in it, even when the daily expression of that ambition involves a contract.

Two colleagues, ten pages

At Sonder, Spellacy and Grunfeld had already tested their working relationship. They launched teams together, including a supply chain team, and found they liked the work of building something from its beginnings. When they considered going out on their own, they had evidence that they could collaborate. Their partnership preceded their startup idea. That sequence is less cinematic than two strangers discovering a shared destiny over coffee, and probably more useful.

Their experience also gave them a way to look at a disorderly market. Carbon projects needed access to buyers. Buyers faced scattered information, uncertain prices and a thicket of separate relationships. Spellacy and Grunfeld recognized a distribution problem. Their earlier work in hospitality had acquainted them with the difficulty of organizing supply that existed in the world before it was conveniently available on a screen.

They left Sonder with a ten-page pitch deck. The early argument was that reducing emissions and removing carbon both needed attention, while carbon removal lacked the momentum already visible in renewable energy and electric vehicles. Patch would help demand reach that neglected side of the equation. The founder who had gone into software was returning with software as his instrument.

Even at that early stage, Spellacy could be playful about the inevitable comparisons. Asked to locate Patch alongside familiar financial infrastructure companies, he reversed the usual flattery: “But I like to think of Plaid as the Patch for banking.” A young company is allowed a little cheek. It also reveals how he saw the business: infrastructure that could become ordinary enough to disappear into somebody else’s product.

The climate option inside the app

An API lets one software system use another. For Patch, that meant carbon purchases could sit inside a travel product, a payment experience or another company’s sustainability software. The commercial logic was straightforward: people already had places where they booked, bought and managed money. An additional destination introduced an additional reason to stop. Patch wanted the climate option to be available where the activity was already happening.

Afterpay supplied a concrete example. Its shopping app incorporated a carbon emissions dashboard and a way for customers to purchase credits. The experience brought the market into an existing consumer relationship. Spellacy’s work was several steps removed from a forest or a carbon removal machine, but the distance was deliberate. Software could connect an ordinary transaction to a project without requiring each shopper to negotiate with a developer.

The public conversations around Patch also reveal a founder interested in the machinery of marketplaces. In an Everything Marketplaces discussion, he covered supplier onboarding, trust, sales, monetization and the challenges of an API approach. These are the subjects that determine whether a useful idea becomes a functioning business. The planet may be the motivation; someone still has to finish onboarding the supplier.

A tonne needs a paper trail

Carbon, however, presents a peculiar customer experience. A ride ends when you arrive. A parcel can be opened. A carbon credit represents an outcome involving an invisible gas, a particular project and a period of time. Spellacy has repeatedly treated that gap between purchase and proof as part of the business problem. Easier transactions are valuable only if the buyer can understand what has been purchased.

He has argued for separating the marketplace from independent verification, and for working with external carbon accounting providers. In his account, the company selling credits should avoid deciding how many credits a customer needs. The position makes partnerships central to Patch’s model. It also places a limit on the attractive software-company instinct to put every adjacent service under one roof.

For suppliers, the operational challenge led to CarbonOS, launched in April 2023. Patch described developers managing credits through spreadsheets and separate systems while trying to handle inventory, sales and delivery. CarbonOS brought those tasks together. Estimates could be distinguished from verified issuance. Reserves could be set. A delivery schedule could accompany a sale. This is the kind of detail that rarely survives a stirring climate speech, though a business built around selling future outcomes has considerable need of it.

At launch, Patch said suppliers were using its platform to manage and ultimately deliver more than 130 million tonnes of credits. That was a measure of inventory and expected delivery being managed, rather than a claim that Patch had already removed that quantity of carbon. The distinction matters. The attraction of the software lies partly in keeping such distinctions legible.

The business grows a longer to-do list

Patch raised a $55 million Series B in September 2022, led by Energize Ventures. Its backers also included Andreessen Horowitz and Coatue. Spellacy and Grunfeld’s announcement emphasized a team capable of turning the initial concept into working infrastructure. The money offered room to expand the company’s technology and reach. It did not make the atmosphere easier to account for.

By April 2025, Spellacy was describing a wider task. Patch’s new platform combined data, software and human expertise across strategy, sourcing, diligence, purchase and management. The company’s research had found that only 15 of the largest 100 carbon credit buyers had teams dedicated to carbon. The intended customer had a substantial responsibility and a surprisingly small amount of specialized capacity.

That finding helps explain the role of experts beside the software. A sustainability leader needs to define a strategy, compare projects, understand risk, secure agreement internally and keep track after a purchase. Patch was offering help across that sequence. Workday, Autodesk, Bain & Company and Deutsche Telekom were among the customers Spellacy named as having used the platform before its public launch.

“Where Patch started isn’t where we are today,” he wrote. The observation is useful because it gives the company permission to learn. His original insight about access remained relevant, while the practical work expanded around it. A purchase can be quick. Deciding what deserves to be purchased, and following it through, has a rather longer calendar.

The less romantic arithmetic

By October 2025, the arithmetic of running Patch had become a story of its own. Spellacy said the company was planning toward profitability rather than assuming another venture round would be available. He described eight months of declining monthly cash burn alongside strong annual growth. Those were his reports of the business at the time, and the direction he wanted it to take.

He also described a carbon technology sector that had received too much funding in 2021 and 2022. Patch had benefited from that period. Now investors had other destinations for their money, particularly fast-growing AI companies, and the comparative appeal of a climate startup had changed. The founder had to think about remaining useful to customers through a less generous funding environment.

The deadlines of corporate customers offered another clock. In 2025, a 2030 climate commitment had entered the territory of a five-year business plan. Spellacy described growing interest in strategic partnerships and potential acquisitions as other participants looked for exits. His account combined confidence in demand with caution about capital. That combination is revealing: a market can need what a company sells while the company still has to earn its own survival.

“Where Patch started isn’t where we are today.”

Brennan Spellacy / April 2025

Back to the energy problem

His July 2026 writing widened the frame again. Spellacy identified friction as a central obstacle to climate progress: fragmented standards, difficult pricing, lengthy coordination and repeated work. He argued that AI could reduce the cost of dealing with that complexity, while human experts retained the consequential judgments. He also acknowledged AI’s growing energy demand. In his proposed operating model, the tool and its environmental cost have to be considered together.

A second July essay argued for coordinating carbon credits, renewable energy certificates, sustainable aviation fuel certificates and virtual power purchase agreements. Each instrument serves a different purpose. His point was that companies should manage the relationships among them, rather than assemble isolated purchases through separate vendors. The ambition had moved beyond a carbon button toward a coordinated program of environmental procurement.

That brings his story back within sight of its beginning. The McGill student imagined working directly on lower-carbon energy. The Patch founder is trying to help organizations navigate the decisions and transactions that support climate work. The technical vocabulary has changed, and the work includes more procurement than his younger self might have expected.

There is a temptation to make a detour sound inevitable once it produces a company. Spellacy’s route is more interesting with the contingency left in. A field of study did not deliver the job he wanted. Software offered another place to learn. A colleague became a co-founder. The original purpose survived the changes in occupation. Now the test is whether all that practical experience can make it easier for somebody else to act on a climate ambition of their own.