Case study: a self-serve project calculator

Return on investment

22New leadsGenerated in the first two weeks after launch.

44Engineering hours savedNot spent building feasibility estimates by hand, in the first two weeks.

0Leads missedEvery enquiry is captured the instant it's submitted, with no wait on an available engineer.

An instant answer, not a queued one

Prospects get a credible CAPEX and P&L estimate the moment they ask — with no engineer or salesperson on the other end.

Background

Complex calculations every customer needs

Onnu Engineering builds and sells CarboFlow, a pyrolysis technology that converts biomass into biochar, carbon credits and recoverable heat. Its customers are prospective plant operators: landowners, agribusinesses, waste handlers and consultants who want to build a biochar plant and need specific answers on cost, technology and production before they can take a project forward. Those answers are not generic. They depend on the feedstock, the site, the energy the operator wants back and how the project is financed. Every one of them used to be worked out by hand.

Two Onnu CarboFlow pyrolysis units in the fabrication workshop

The challenge

Every enquiry needed an engineer before it could be qualified

Every serious enquiry, “what would a CarboFlow plant cost and return for my feedstock and site?”, required manual engineering and sales effort: feedstock analysis, building a CAPEX estimate, and modelling a P&L, all before anyone knew whether the lead was even qualified. Spreadsheet-based versions of this work existed, but each one had to be run and interpreted by an engineer for every prospect individually.

01

Slow, high-touch sales cycle

Even exploratory prospects, many of whom would never convert, consumed engineering time before anyone could tell whether the lead was worth having.

02

No self-serve entry point

A prospect could not get a rough but credible number without first getting on a call, which capped how many leads the business could engage with at once.

03

Qualification by gut feel

Once a lead did arrive, judging it meant reading the submission and deciding. Different people weighted feedstock volume, site readiness and financing differently, and none of it was written down.

04

No way to interrogate a decision

A lead was either followed up or it was not. Nobody could ask why one looked stronger than another, or what was missing from it, without going back through the whole submission by hand.

Mainspring solution

A tool that answers the prospect and assesses them at the same time

A guided, self-serve calculatorEight steps from feedstock to a sized plant, with CAPEX, a full P&L, mass energy balance and plant specification at the end. No engineer, no sign-up, no wait.
Dynamic scoring across every signalAI scores each lead on feedstock volume and consistency, site readiness, financing posture, how far they got and what they supplied. The weighting reflects what has actually predicted real projects rather than a fixed rule set, and every score carries the reasoning behind it.
Both sides can askProspects question their own estimate in plain language and get answers from their own figures. The sales team asks why a lead scored what it did, what is missing and what to ask first, and gets the same grounded answer rather than a number to take on trust.

See it in actionPick a screen, use the arrows, or tap the cards behind

01Easy to use02Multiple options03Usable output04Lead dashboard

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01

Easy to use

A guided, eight-step flow takes a prospect from “about you” to a sized plant in one sitting. Each answer updates the live project summary above the form, so they watch the plant take shape as they go.

8 guided stepsLive summaryNo sign-up

calculator.onnuengineering.com/carbon

Plant size, unit count and footprint are computed from feedstock alone, before any contact details are asked for.

02

Multiple options

Feedstock type, site location, heat use and currency all feed the model. Choose on-site hot water and power generation drops out; change feedstock and the plant resizes. Every prospect gets a plan for their project, not a brochure figure.

FeedstockHeat useCurrency

calculator.onnuengineering.com/energy

Heat choices reshape the model live: selecting on-site hot water removes power generation and reprices the plant.

03

Usable output

The results page states the units required, CAPEX, a full P&L, payback, mass-energy balance and plant specification. Every assumption is a slider with a reset, and prospects can ask about any of it in plain language, getting answers drawn from their own run and the model’s assumptions, with the chat saying plainly when something needs an engineer.

CAPEXFull P&LAsk your own numbers

calculator.onnuengineering.com/pnl

Every assumption is a slider, so prospects stress-test their own P&L instead of waiting on an engineer.

04

Lead dashboard

Every run lands in Onnu Engineering’s dashboard scored out of 100, with the factors that lifted or held it back shown alongside. The sales team can question any score directly, asking what is weak, what is missing and what to raise on the first call. Figures are recomputed server-side, and partial runs are kept and scored on what was completed.

Scored 0–100Reasoning shownAsk the score

leads.onnuengineering.com

Every submission is scored server-side and triaged. Partial, abandoned runs still land as leads.

The outcome

Engineers freed, and leads that arrive already assessed

The Project Assessment Tool changed how Onnu Engineering's pipeline runs, and what the team knows about a lead before they pick up the phone:

Engineering time goes to real projects. 44 hours in the first fortnight were not spent building estimates by hand, because prospects produce their own.

Nothing waits for a human. Every enquiry is captured, costed and scored the moment it is submitted, including the ones that arrive at 2am.

Qualification is consistent and explainable. The same criteria apply to every lead, and the sales team can ask why any score landed where it did before picking up the phone.

Prospects answer their own questions. What used to be a call is now a conversation with their own estimate, and what they ask tells the sales team what the lead actually cares about.

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