TL;DR

• Carbon credits are a core instrument in any serious sustainability program, and for most companies, the right place to start. But they're one tool in a set of increasingly scarce environmental resources, and a program built on carbon alone leaves significant scope 2 and scope 3 exposure unaddressed.
• The most effective programs are built on a portfolio of instruments: carbon credits, Renewable Energy Certificates (RECs), Sustainable Aviation Fuel certificates (SAFc), and in some cases Virtual Power Purchase Agreements (VPPAs). For companies with specific scope 3 exposure related to gas consumption or certain materials categories, emerging instruments like Renewable Natural Gas certificates (RNGc) and book-and-claim materials certificates may also be relevant, though these markets are still maturing.
• Diversification across instruments is how you manage stability, not just compliance.
• The portfolio lens changes how you procure. You're optimizing the whole program for cost, integrity, and risk, not treating each instrument as a separate purchase.
• Companies building this infrastructure now will have a structural advantage over those who start in 2027-28, when compliance pressure significantly raises the floor.

Carbon credits are where most programs start. The best programs don't stop there.

Environmental resources, including carbon, renewable energy, and sustainable aviation fuel, used to occupy a special category of corporate spending. They were discretionary, often disconnected from operational planning, and managed separately from the resources companies actively hedge against.

That's changing. The sustainability teams making the most progress are starting to treat these instruments the way a portfolio manager would treat any scarce resource: with attention to supply risk, price exposure, and diversification across the full program.

Carbon credits address residual greenhouse gas emissions across scopes (such as scope 1 from direct operations and scope 3 categories beyond business travel) that can't yet be eliminated through operational changes. They come in two broad forms: avoidance credits, which prevent emissions from happening, and removal credits, which pull carbon out of the atmosphere.

RECs address scope 2 emissions tied to the electricity you purchase. SBTi's net-zero standard requires companies to source 80-100% of their energy via RECs or VPPAs by 2025 or 2030. If you have an SBTi scope 2 commitment or an RE100 membership, that requirement is structural; carbon credits can't substitute. RECs are broadly accepted for market-based accounting, but they don't fund new renewable capacity. For companies where additionality matters, that's what pushes the conversation toward VPPAs.

If your electricity footprint is large and concentrated, a VPPA may be the most appropriate long-term instrument. VPPAs finance new renewable capacity and provide scope 2 coverage, with price hedging and a supply commitment that RECs alone don't offer.

Business travel is often one of the most visible scope 3 categories for employees and stakeholders. SAF certificates are the instrument built for it, addressing scope 3 Category 6 through a Book-and-Claim system. With CORSIA tightening the supply available to corporate buyers, this is an instrument worth prioritizing before the market gets harder to access. Carbon credits can't substitute here.

Most companies care about their full footprint. The harder problem is that procurement workflows weren't built to coordinate across these instruments at once. Carbon became the default because it was the most accessible market. The others developed later, in separate vendor relationships, on separate reporting cycles, with separate diligence requirements.

Closing that fragmentation is what separates a mature program from a reactive one.

What each instrument does, and what it doesn't

The most common instruments enterprise sustainability teams work with are carbon credits, RECs, SAFc, and VPPAs. Each addresses a different emission scope, operates in a different market, and requires different diligence. Managing them separately creates sprawl. You can't optimize them as a portfolio until you understand what each one actually does.

Carbon credits are transacted in the voluntary carbon market. Each credit represents one metric ton of carbon dioxide equivalent (tCO2e) avoided or removed. Integrity standards from organizations like the Voluntary Carbon Markets Integrity Initiative (VCMI) and the Integrity Council for the Voluntary Carbon Market (ICVCM) govern which credits meet corporate climate claim requirements.

RECs and I-RECs are the standard instruments for scope 2 market-based accounting. Each certificate represents 1 megawatt-hour (MWh) of renewable electricity generated and fed into the grid. In North America, they're called RECs. In international markets, including most of APAC, they're called I-RECs. RE100 and SBTi scope 2 targets require market-based accounting, which means RECs are how those commitments get fulfilled. That said, RECs attribute existing generation to your electricity use; they don't fund new renewable capacity. For companies raising the bar to require additionality on their electricity footprint, that's where VPPAs come in.

VPPAs are long-term financial contracts with renewable energy developers, typically 10 to 15 years, that finance new renewable capacity and provide scope 2 coverage. They're most relevant for companies with large, concentrated electricity footprints, like data centers and manufacturing facilities, that need additionality and price certainty beyond what RECs provide.

SAF certificates address scope 3 aviation emissions through a Book-and-Claim system. Sustainable Aviation Fuel is blended into the aviation fuel supply; the corresponding environmental attribute is registered and can be purchased by any company, regardless of which flights used the fuel. It's the same underlying logic as RECs, applied to aviation. CORSIA has made SAFc a compliance requirement for airlines, which tightens how much supply is available to corporate buyers. With only ~47 million confirmed eligible emissions units against a Phase 1 demand floor of 90 million or more, that supply gap is significant and growing faster than current production can close it.

A note on emerging instruments. For companies with scope 3 exposure related to natural gas consumption or certain materials categories, instruments like Renewable Natural Gas certificates (RNGc) and book-and-claim materials certificates are beginning to appear in enterprise sustainability programs. These markets are still developing, and methodologies vary significantly across providers and registries. They may be worth tracking, particularly if your scope 3 profile includes categories these instruments address, but they require careful diligence before inclusion in formal reporting claims.

How mature buyers are thinking about this now

The enterprise buyers who are furthest ahead aren't managing carbon, RECs, and SAF as separate line items with separate vendors. They're treating their environmental program as a portfolio, optimizing across instruments for cost, integrity, risk, and reporting coherence, the way a CFO manages a financial portfolio.

A recent call with a CSO reinforced how I'm thinking about enterprise-grade sustainability strategy. For years, their team had allocated budget by carbon mechanism: nature, durable removals, avoidance, each one its own line, each one its own internal owner. This year they collapsed all of it into a single flexible budget they can move across categories as the market shifts.

The reason was complexity. Keeping track of offtakes, contracts, and exposure across mechanism-specific budgets had become unmanageable. They were starting to think about their book the way a portfolio manager would: NPV, diversification, how the whole thing performs together, not how any single piece scores in isolation.

The CSOs I talk to most often aren't asking which credits are good. They're asking how to construct a strategy that holds up across the next three to five years of policy, science, and supply risk. That's a different conversation, and most of the market isn't set up to have it yet.

The mechanics of portfolio construction follow a logic that will be familiar to anyone who manages financial assets:

Match instruments to obligations. RECs for your SBTi scope 2 target. SAFc for scope 3 aviation — one of the most visible emission categories a company can address, and one where supply is tightening. Carbon credits for your ongoing emissions responsibility across all scopes. Under SBTi's OER framework, coverage expectations increase as you progress — from a 1% floor at the Engaged tier to 100% at Leadership — and the instrument mix shifts from avoidance toward removal credits as you approach your net-zero year. VPPAs when your electricity footprint justifies a long-term supply commitment and you need additionality, not just attribution.

Optimize the whole program, not each line item. Buying the cheapest carbon credits alongside the cheapest RECs doesn't mean you've built the best program. Quality, vintage, additionality, and geography all affect whether instruments hold up under scrutiny. One practical approach: start with the budget you have, establish internal quality criteria and raise them over time, and invest in high-integrity instruments rather than maximizing tonne volume from a budget that's too small to buy well. A portfolio lens means thinking about how these decisions interact across the whole program.

Sequence for materiality. Start with what's most material to your footprint. For most companies, that's scope 2 through RECs alongside carbon credits for ongoing emissions across scopes. OER defines the coverage expectation at each level of ambition, starting at a 1% floor for Engaged companies and scaling to 100% for Leadership. Business travel is often a more visible category than residual scope 1 for employees and stakeholders; SAFc belongs in the conversation early, not as an afterthought. Model VPPAs when your electricity footprint crosses the threshold where a long-term supply commitment makes structural sense.

Build for the policy scenarios that are coming. The most valuable thing you can do right now is build supplier relationships before the market forces you to. Companies locking in forward agreements and multi-instrument partnerships today will be in a meaningfully different position heading into 2027 and 2028, when compliance pressure in Europe and voluntary markets tightens supply and drives prices higher. The companies best positioned won't be the ones who respond fastest at peak pressure — they'll be the ones who established supply access and locked in favorable pricing before it got competitive.

What a mature multi-EAC program looks like in practice

A mature multi-EAC program consolidates sourcing, diligence, and reporting across all instruments into a single coordinated workflow, rather than running carbon, RECs, and SAF through separate vendors with separate reporting cycles. This reduces cost, closes reporting gaps, and makes it possible to optimize the whole program rather than each piece in isolation.

Operational consolidation solves four problems:

Diligence. Every instrument requires quality checks before purchase. Carbon credits require registry verification, vintage assessment, and integrity standard alignment. RECs require geography verification and certification standard review. SAFc requires pathway and CORSIA-eligibility assessment. Running these separately creates duplicated work and inconsistent standards.

Reporting. CDP, GRI, SBTi, and ISSB all require coordinated disclosure across scopes. When instruments come from different vendors on different cycles, reconciling them into a coherent report is a significant operational burden. A consolidated program closes that gap structurally.

Vendor management. Multiple vendor relationships mean multiple contract negotiations, multiple onboarding cycles, multiple renewal timelines. Consolidation reduces not just cost, but the administrative overhead that makes scaling a multi-instrument program operationally difficult.

Cost. A portfolio view creates opportunities to optimize across instruments. Volume commitments, forward agreements, and coordinated sourcing can reduce per-unit cost across the program in ways that aren't available when each instrument is managed separately.

This is not a future aspiration. The operational infrastructure to run a coordinated multi-EAC program exists today. The question is whether your team builds toward it intentionally, or waits for circumstances to force it.

For a breakdown of how RECs specifically fit into a multi-EAC strategy, including the geography rules that determine whether your REC purchases will hold up in CDP and SBTi submissions, see our guide to renewable energy certificates for enterprise sustainability teams.

Frequently Asked Questions

Are carbon credits and RECs the same thing?

No. Carbon credits offset greenhouse gas emissions, typically residual emissions across scope 1 and applicable scope 3 categories that can't yet be eliminated through operational changes. RECs address scope 2 electricity consumption by attributing renewable energy generation to your electricity use. Most enterprise sustainability programs need both, alongside SAF certificates for aviation emissions.

What is a multi-EAC procurement strategy?

Multi-EAC (Environmental Attribute Certificate) procurement means coordinating your purchases of carbon credits, RECs, SAF certificates, and potentially VPPAs as a single portfolio, rather than buying each instrument separately through different vendors. Enterprise companies are moving in this direction to reduce sprawl, improve reporting, and optimize their whole environmental program for cost and integrity.

When should a company add SAF certificates or RECs to their carbon program?

When your scope 2 or scope 3 aviation emissions are material and you have SBTi or RE100 commitments requiring market-based accounting. For most enterprise companies, RECs should be addressed alongside carbon from the start — they cover different emission scopes and can't substitute for each other. SAF certificates belong in the conversation early too: business travel is one of the most visible scope 3 categories for employees and stakeholders, and supply is tightening as CORSIA creates compliance demand from airlines.

What is a VPPA and who needs one?

A Virtual Power Purchase Agreement is a long-term financial contract with a renewable energy developer, typically 10 to 15 years, that funds new renewable capacity and provides scope 2 coverage. VPPAs are most relevant for companies with large, concentrated electricity footprints, like data centers and manufacturing facilities, that want additionality and price hedging beyond what RECs provide.

Why are companies rethinking their environmental procurement now?

A few things are converging. Voluntary market standards are rising, SBTi and RE100 requirements have made multi-instrument programs a structural necessity for companies with meaningful scope 2 and scope 3 commitments, and supply across several instrument categories is tightening ahead of 2027 and 2028 compliance deadlines. The companies in the best position won't be the ones who respond fastest when pressure peaks. They'll be the ones who built supplier relationships, established supply access, and locked in favorable pricing before the market got competitive.