A comprehensive ESG report from a sustainability consultancy (JLL, CBRE, or specialist firms) typically costs £50,000–£100,000+ per year for a full advisory engagement, while AI-powered ESG reporting tools deliver comparable report quality for £5,000–£25,000 per year — but the right choice depends on whether you need strategic advisory (consultancy) or compliant documentation (tool), and at what portfolio scale you're operating.
This is not a simple "AI is cheaper, therefore better" comparison. Consultancies and AI tools serve different primary functions, and understanding where each adds genuine value is essential for making the right procurement decision.
What Consultancies Provide That AI Tools Don't
A sustainability consultancy provides strategic advisory — they help you decide what to do, not just document what you've done. This includes developing the ESG strategy itself, advising on retrofit prioritisation based on site-specific knowledge, navigating complex regulatory situations (CSRD transition plans, EU Taxonomy technical screening criteria), managing stakeholder engagement, and providing professional opinions that carry institutional weight in LP meetings and board presentations.
For a fund that does not yet have a sustainability strategy, is entering new regulatory territory (first CSRD report, first Article 8 classification), or faces complex, asset-specific challenges (listed building retrofit, contaminated land remediation), a consultancy engagement is likely the appropriate choice.
What AI Tools Provide That Consultancies Don't
AI-powered ESG reporting tools provide speed, consistency, and scalability. They generate compliant documentation (GRESB submissions, SFDR disclosures, RICS valuation inserts) at a fraction of the time and cost, with standardised methodology that produces consistent output across reporting cycles and portfolio assets. They are strongest when the strategic direction is already set and the need is for efficient, high-quality documentation of existing performance.
| Sustainability Consultancy | AI Reporting Tool | |
|---|---|---|
| Annual cost | £50,000–£100,000+ | £5,000–£25,000 |
| Time to report | 6–12 weeks | Days to hours |
| Strategic advisory | Yes — core value | No — documentation only |
| Consistency across cycles | Varies by team | Standardised methodology |
| Scalability | Linear cost increase | Marginal cost near zero |
| Best for | Strategy development, complex situations | Compliant documentation at scale |
The hybrid model: The most cost-effective approach for many funds is a hybrid: use a consultancy for strategy development and complex advisory (every 2–3 years), and use an AI tool for the annual reporting cycle, quarterly updates, and valuation-level inserts. This captures the strategic value of consultancy without paying advisory-level fees for documentation work.
Plinthos was designed specifically as the documentation layer — generating investor-grade ESG reports, GRESB submissions, and RICS valuation inserts built on analysis of 136 UK REIT sustainability reports. It complements rather than replaces strategic advisory, delivering the "last mile" between ESG data and professional documentation at a fraction of consultancy cost.