AI Tool Usage & Costs

NZIPL Clean Value Chain Explorer — March–May 2026

Author
Affiliation

Oriol Vallès Codina

Net Zero Industrial Policy Lab, Johns Hopkins University (SAIS)

Published

May 20, 2026

Purpose

This document summarises AI and software tool subscriptions used during the development of the NZIPL Clean Value Chain Explorer (CVCE) and related research, covering March 6 – May 20, 2026. It is intended to support cost-sharing discussions between personal and institutional accounts, and to document the transition to a stable workflow configuration.


Current Workflow Setup (May 2026)

The subscription stack has stabilised into two distinct tiers:

Tier Tool Purpose
NZIPL Claude Code (Team Pro) Primary AI coding environment for all CVCE/NZIPL work — reads/writes R, JS, Python; manages git; builds data pipelines; debugs and edits interactive dashboards
Personal DeepSeek API Cost-efficient API for personal research and scripting tasks outside NZIPL scope
Personal Qwen (local model) Offline personal assistant; zero marginal cost
Personal (occasional) Claude Pro Occasional personal queries via web interface

ChatGPT Plus — cancelled April 2026. No longer in the subscription stack. Usage was consolidated into Claude, which handles all the tasks ChatGPT was previously used for (academic writing, reasoning cross-checks, equation formatting).


Cost Summary: Lab Period (August 15, 2025 – May 20, 2026)

Service Period Months Per month Total (EUR/USD)
Claude / Claude Code (Anthropic) Mar 6 – May 20, 2026 ~3 EUR 18–46/mo EUR 427.60
ChatGPT Plus (OpenAI) Aug 17 – Apr 17, 2026 $21.63 $194.67
Windsurf Pro (Exafunction) Sep 4 – Mar 4, 2026 7 $16.22 $113.54
Posit Connect Cloud Sep 27 – Feb 27, 2026 6 $20.54 $123.24
DeepSeek API May 2026 – ongoing pay-as-you-go Personal only
Qwen (local) May 2026 – ongoing $0 Personal only
TOTAL (institutional scope) ≈ $885²

1 Lab period only (Aug 2025 – Apr 2026). Pre-lab months (Jan–Jul 2025, 7 × $21.63) excluded as personal. 2 EUR 427.60 @ 1.08 USD/EUR = $461.81 + $431.45 USD tools = ~$893. ChatGPT cancelled Apr 2026.

Anthropic invoice detail (all receipts)

Invoice Date Amount Type Project
NJJAFZLE-0001 Mar 6 EUR 21.78 Claude Pro – month 1 CVCE setup
NJJAFZLE-0002 Mar 23 EUR 6.05 Extra usage LEEDS_MODEL
NJJAFZLE-0003 Mar 31 EUR 6.05 Extra usage LEEDS_MODEL
NJJAFZLE-0004 Apr 1 EUR 24.20 Extra usage LEEDS_MODEL
NJJAFZLE-0005 Apr 2 EUR 24.20 Extra usage LEEDS_MODEL (submission)
NJJAFZLE-0006 Apr 2 EUR 24.20 Extra usage LEEDS_MODEL (submission)
NJJAFZLE-0007 Apr 6 EUR 21.78 Claude Pro – month 2 CVCE
NJJAFZLE-0008 Apr 8 EUR 46.28 Team Pro prepaid CVCE
NJJAFZLE-0009 Apr 15 EUR 46.28 Team Pro prepaid CVCE
NJJAFZLE-0010 Apr 28 EUR 46.28 Team Pro prepaid CVCE + CONSERVATION
NJJAFZLE-0011 Apr 29 EUR 46.28 Team Pro prepaid CVCE + CONSERVATION
NJJAFZLE-0012 May 6 EUR 21.78 Claude Pro – month 3 (personal) Personal
NJJAFZLE-0013 May 7 EUR 46.28 Team Pro prepaid CVCE Phase II
NJJAFZLE-0014 May 11 EUR 46.28 Team Pro prepaid CVCE Phase II
Total EUR 427.60

May 2026 additions: EUR 114.34 (invoices 0012–0014) — reflecting continued intensive Phase II development (Generic Country Atlas builder, Global Atlas, panel system, color mode toggle, SHAP-RCA scatter).


Project Attribution

Based on git commit history and session logs through May 20, 2026:

Project Claude share Claude (EUR) Evidence
CVCE / NZIPL ~72% ~308 Phase I (Apr): Global Atlas, Chile/Brazil Atlases, Intelligence Report. Phase II (May): Generic Atlas builder, 7-country atlases, 13 Global Atlas sheets, category drums, color mode toggle, SHAP-RCA scatter, data summaries
LEEDS_MODEL ~15% ~64 8 commits Apr 2 (submission sprint); zero after Apr 3
CONSERVATION papers ~8% ~34 Files modified Apr 22–30 (sraffa_acs, econ_thermo, conservation_PhysicaA)
Personal (misc.) ~5% ~22 May 2026 personal queries via Claude Pro (NJJAFZLE-0012)
Total 100% 427.60

Activity timeline

Period Activity Project
Mar 6–22 Claude Pro starts; workplan, render scripts, deploy setup CVCE
Mar 23 – Apr 3 MRIO equations, paper editing, submission sprint LEEDS_MODEL
Apr 3 Paper submitted to Ecological Economics SI
Apr 8–20 type→role rename; Global Atlas v1; Chile/Brazil Atlases CVCE
Apr 20–27 Intelligence Report; ecoclassical.github.io restructure CVCE
Apr 22–30 Conservation papers parallel with CVCE CVCE + CONSERVATION
Apr 28–30 ChatGPT cancelled; Windsurf ended; stack simplified
May 1–11 Generic Country Atlas (all countries × 10 techs); Global Atlas fixed; Phase II panels CVCE
May 11–20 SHAP-RCA scatter (bug fixes); category drum + color toggle; legend redesign CVCE

Subscription Status (May 20, 2026)

Service Status
Claude Code Team Pro (Anthropic) Active — primary NZIPL tool; prepaid usage billing
Claude Pro (Anthropic, personal) Active — occasional personal use only
DeepSeek API Active — personal research; pay-as-you-go, negligible cost
Qwen (local model) Active — personal; zero cost
ChatGPT Plus (OpenAI) Cancelled April 2026 — replaced by Claude
Windsurf Pro Cancelled March 2026
Posit Connect Cloud Cancelled February 2026

Productivity Impact

Claude Code (adopted March 6, 2026) replaced a four-tool stack (ChatGPT + Windsurf + Posit + manual workflows). Git commit frequency increased 5.8× within the first eight weeks and has remained elevated through May 2026.

Repository Before Claude Code After Claude Code Increase
CVCE / NZIPL 6.4 / week 21.5 / week +3.4×
LEEDS_MODEL 0.6 / week 3.6 / week +6.0×
All repos combined 7.5 / week 44.0 / week +5.8×

Before: Aug 15, 2025 – Mar 5, 2026 (28 weeks). After: Mar 6 – May 20, 2026 (~11 weeks).

Notable Phase II deliverables (May 2026, NZIPL scope):

  • Generic Country Atlas — single build_country_atlas.R covering all countries × 10 techs
  • 7 country atlases deployed (Brazil, India, Japan, South Korea, Vietnam, Mexico, Spain)
  • 13 Global Atlas sheets with SHAP-RCA scatter panel
  • Category-aware drum wheels — Stage → Role → Category → Product cascade filter
  • Color mode toggle — global SR / Category coloring across all panels
  • 2-column SR legend + HS Category legend — compact 2+1 header layout

Note

PDF receipts (invoices NJJAFZLE-0001 through NJJAFZLE-0011) archived in docs/receipts/pdf/. Invoices 0012–0014 (May 2026) are in Gmail — download manually from invoice+statements@mail.anthropic.com and save as Anthropic_2026-05-06.pdf, Anthropic_2026-05-07.pdf, Anthropic_2026-05-11.pdf.

Full ledger: docs/receipts/subscription_costs.csv