Diligent ESG alternatives: Diligent carbon accounting after the Persefoni move, and an invoice-first option

This page is built from Diligent's own newsroom releases, its product and pricing pages on diligent.com, and the Diligent One Platform help documentation, all read in September 2026, plus Persefoni's announcement of the same deal. It is not built from a vendor roundup. No dollar figures appear for Diligent or Persefoni, because neither publishes a price list and an invented number is worse than none. Where Diligent is stronger than we are, this page says so. If you want to see the alternative approach on your own data first, run our carbon accounting software on a few invoice lines in the panel below.

Diligent ESG is a carbon, energy and sustainability reporting platform sold by Diligent, the New York company best known for board portal and governance, risk and compliance software. Its carbon engine came from Accuvio, an ESG data and reporting company headquartered in Limerick, Ireland, which Diligent acquired on August 10, 2021. At the time, Diligent said Accuvio covered "2,000+ types of emissions sources (including waste, water, transport, business travel, commuting, and supply chain) using more than 62,000 emissions factors," and its named clients included The Hartford and Ocean Spray alongside Irish and UK public bodies.

Today Diligent describes a "purpose-built carbon calculator" that produces "auditable submission-ready reports," with more than 70,000 emissions factors across 120+ countries, 2,000+ fuels and business activities, 80 pre-built audit-ready reports and nine methods of data capture, including utility data integration, surveys and APIs. Diligent says the platform can "collect key information from tens of thousands of employees, suppliers and other stakeholders."

The help documentation is more specific about the calculation. The software "accepts inputs in the form of fossil fuel and energy consumption data" and calculates the resulting emissions using the GHG Protocol Corporate Standard, ISO 14064-1, the UK DEFRA greenhouse gas guidelines and GRI indicators. Scope 3 category 3 (fuel and energy related activities) is calculated by default from Scope 1 and 2 inputs, and the documentation notes that the platform "currently only accounts for the Greenhouse Gases under the Kyoto Protocol." In other words, it is an activity-data engine at heart: meter readings, fuel volumes, travel and waste records go in, emissions come out.

Yes, that is what Diligent announced. On October 22, 2025, Diligent and Persefoni announced a strategic partnership under which "Diligent will transition its carbon accounting clients to Persefoni's market-leading platform" and Diligent will "take an equity position in Persefoni." Diligent's general manager for compliance, Amanda Carty, cited Persefoni's "advanced technology, compelling roadmap, and top-tier NPS among sustainability vendors."

What neither company published is a timeline. The releases we read give no migration date, no detail on how historical inventories, emission factor choices and audit trails move across, and no statement on what happens to the non-carbon ESG reporting that sits inside Diligent. When we read Diligent's carbon accounting pages in September 2026 they were still live and still described the 70,000-factor engine. So the practical step for a current customer is simple: ask your Diligent account team which platform your next inventory will be calculated on, and when. We set out the questions to ask, and the options if you would rather choose your own platform, in Persefoni Diligent migration: your carbon accounting options.

A comparison that only lists a rival's weaknesses is no use to you. Three Diligent strengths are real, and we do not attempt the first one at all.

It sits next to the board. Diligent says 700,000 directors use its governance software. If your audit committee already reviews materials in Diligent and your risk, audit and compliance teams work in the Diligent One Platform, ESG data lives in the same governance system that oversees it. For a public company whose board wants climate oversight evidenced alongside every other risk, that is a genuine advantage. We are carbon inventory software and nothing else.

The factor library is global. Seventy thousand factors across more than 120 countries matters if you run sites in dozens of jurisdictions and need a local grid or fuel factor for each. A US-centered company rarely needs that breadth, but a multinational with plants in Asia and Latin America does.

Reporting outputs are mature. Eighty pre-built reports and a long history with established frameworks (Diligent states its calculations are certified by CDP, GRESB, GRI, SASB and DJSI) reflect more than a decade of Accuvio and Diligent work on sustainability disclosure.

Diligent does not publish pricing for Diligent ESG or any other product. Its pricing page says "Pricing built around your needs" and invites you to "Get a package tailored to your organization's size and stage of growth," then asks for a form. Persefoni does not publish a price list either. Any exact figure you see in a listicle is a guess.

What is worth understanding is the shape of the bill. Diligent ESG is typically bought as one module of a wider Diligent relationship, so the price depends on which other Diligent products you hold, the number of entities and sites in the inventory, and which report packs you need. After the Persefoni announcement there is a second question: whether your carbon accounting will be billed through Diligent, through Persefoni, or both, and whether today's terms carry across. Get that in writing before a renewal. Our own plans are on the pricing page, and how carbon accounting quotes are built across the category is on carbon accounting software cost.

If your board, audit and compliance workflows already run in Diligent, staying keeps governance evidence in one place, and the vendor-led move to Persefoni is the path of least resistance. Your history and reporting relationships are carried by the two companies rather than rebuilt by your team.

It is also the better choice when your organization looks like Persefoni's core customer: a large, multi-entity company or financial institution with a sustainability data team, reasonable-assurance ambitions and a procurement process built for enterprise platforms. Persefoni publishes guidance on California SB 253 and SB 261, and Diligent chose it specifically for Scope 3 supply chain capability and "AI-powered disclosure readiness." Our separate Persefoni alternatives page compares it with the rest of the enterprise field.

And it is the better choice if your inventory is dominated by global energy and fuel data across many countries, where a large international factor library does the heavy lifting.

The fit changes when your footprint is mostly Scope 3. Diligent's own documentation describes an engine fed with fuel and energy consumption data. For most US companies outside heavy industry, though, the largest share of the inventory is purchased goods and services, which lives in accounts payable as vendor names, GL codes and dollar amounts. We start there. The classifier reads the AP or GL export you already produce, proposes a scope and one of the 15 Scope 3 categories for every line with a confidence level and a stated reason, and a person reviews the uncertain tail instead of the whole file. Every figure keeps a link to the invoice line behind it, which is the trail an assurance provider samples.

The second difference is the calendar. A company that clears the $1 billion revenue threshold for California SB 253 has to report Scope 1 and 2 by November 10, 2026, with Scope 3 following in 2027, and a CDP request from a large customer arrives on its own timetable. On the Diligent ESG pages we read in September 2026 we did not find SB 253 named. We document the US calendar page by page: SB 253 reporting software, CDP reporting software and EPA GHG reporting for the October 30 GHGRP window.

The third difference is how you start. You can run our classifier on your own data on this page before an email address changes hands, and our pricing is public. Diligent's and Persefoni's entry points are a demo request and a pricing form. Neither approach is wrong, but if a platform change is being made for you anyway, testing the alternative on your own ledger costs you ten minutes.

If Diligent is on your list because governance and disclosure sit together in your company, the closest comparison is Workiva carbon accounting alternatives, where the report is assembled and filed. For enterprise platforms built on site and energy data, see the IBM Envizi alternative, Schneider Resource Advisor alternatives and the EHS suites on Sphera carbon accounting alternatives and Cority carbon accounting alternatives. If your ERP vendor is driving the shortlist, see Microsoft Sustainability Manager alternatives.

For carbon-first platforms, compare Persefoni alternatives and Watershed alternatives at the enterprise end. The whole field is on best carbon accounting software, and if supplier data is the part you cannot evidence, start from supplier emissions reporting software.