WattWitness

Who it's for

Australian home-battery owners enrolled in VPPs (AGL VPP, Origin Loop, Tesla Energy Plan) or on wholesale pass-through (Amber Electric); today they cope with the retailer's opaque monthly credit line, manual CSV exports from their inverter app, and Whirlpool forum threads where they paste screenshots to compare payouts.

The problem

Payment, concretely: the VPP credit line cannot be checked against what the exported kWh were worth at the 5-minute wholesale interval, and warranty-eating discharge cycles into negative or bottom-quartile prices are invisible — the household loses real money per month and cannot prove it to the operator or an ombudsman.

How to build it

Read-only web app: ingest meter data via AEMO Consumer Data Right (with retailer CSV upload as fallback), battery telemetry via Tesla/Sungrow/BYD read-only APIs, joined to public NEM 5-minute prices; outputs a monthly audit PDF, a per-event ledger, negative-price cycling alerts, and a dispute-letter generator. No battery control, no automation.

How it makes money

Households pay $49/yr (or $8/mo) for the running audit and alerts — trivial against the thousands-per-year bill variance this cohort actively arbitrages — and they pay because no free option does the CDR-plus-telemetry-plus-price join: retailer apps deliberately stop at the credit line, and the raw-data plumbing is precisely what free tools don't maintain.

Why it doesn't exist yet

Incumbents skip it because opacity is the margin: VPP operators' apps show the credit they paid, never the counterfactual wholesale value, and comparison sites only model tariffs, not telemetry. The indie gap: CDR energy data becoming machine-readable, AEMO's public 5-minute price feed, and documented battery local APIs only became simultaneously joinable recently, and gluing three ugly Australia-specific data sources for one country's niche is exactly the unglamorous plumbing no platform will bother with.

First users

Amber Electric power users on Whirlpool's energy forums already spreadsheet this exact comparison by hand and post their results; one well-placed thread in the VPP-payout megathread, plus the r/australian energy-nerd cohort, delivers the first 10 because the tool automates a chore they are publicly doing manually today.

Build size

2 people x 10 weeks. Included: CSV-first meter ingest with CDR as stretch, NEM 5-min price join, Tesla+Sungrow+BYD read-only adapters, monthly audit PDF and dispute letters. Excluded: any battery control or real-time dispatch, WA's WEM market, solar-only households without batteries.

Biggest risk

Amber Electric or a comparison site (e.g., WATTever) ships a native credit-vs-wholesale breakdown inside its own app for free, removing the paid wedge before the indie tool reaches the forum cohort.

Conditions for a hit (all 3 required)

• For a connected household, the monthly audit lists every battery discharge event >=1 kWh with the matching NEM 5-minute interval price and the dollar gap versus the VPP credit applied to that energy, checkable against public AEMO data.
• The app flags and totals any month in which at least one discharge occurred during a negative-price interval, showing event count and kWh cycled.
• Generates a per-event dispute/switch letter citing timestamps, public AEMO interval prices, and credited amounts, exportable as PDF.

How it's judged (in 6 months)

Product Hunt daily top 5 within the window, or a public status page showing >=500 connected households, or 1,000+ stars on its open-source NEM/CDR ingest adapter(judgment date 2027-02-15)

AI self-confidence 50/100 — self-reported likelihood of meeting the criterion, not a business success rate