Why We Need to Schedule Post-Quantum Cryptography Around the Weather

An engineer has released Quant Harvest, an open-source Go control plane that schedules post-quantum cryptography workloads to run only when the electrical grid is cleanest. The tool buffers CPU-intensive PQC operations and defers them when carbon intensity is high, resuming when renewable energy is available, aiming to reduce the carbon footprint of the PQC migration.

The security industry is undergoing one of the largest migrations in history: moving from classical cryptography RSA/ECC to Post-Quantum Cryptography PQC . While algorithms like ML-KEM FIPS 203 are quantum-resistant, they have a hidden cost: they are CPU-intensive . Compared to classical algorithms, key generation, signing, and verification consume significantly more compute. More compute = more electricity. For bulk operations signing millions of docs, encrypting petabytes of backups , this spikes carbon footprint — bad for net-zero goals. What if we schedule these workloads to run only when the grid is cleanest ? Enter Quant Harvest . Quant Harvest is an open-source Go control plane — a carbon-aware deferred-execution queue for PQC workloads. Instead of executing heavy crypto immediately, it buffers workloads and monitors grid carbon intensity gCO2e/kWh . Dirty grid fossil → pause queue. Clean grid solar/wind → resume and harvest. ┌──────────────────────┐ │ Workload Enqueued │ └──────────┬───────────┘ ▼ ┌──────────────────────┐ │ Task Buffered │ └──────────┬───────────┘ ▼ No /───────────────────\ ┌────/ Grid Clean enough? \ │ \ Under threshold / │ \───────────────────/ ▼ │ Yes ┌──────────────┐ ▼ │ Queue Paused │ ┌──────────────┐ └──────────────┘ │ Execute Task │ └──────────────┘ Try it live: https://quant-harvest.onrender.com https://quant-harvest.onrender.com curl -X POST https://quant-harvest.onrender.com/api/tasks \ -H "Content-Type: application/json" \ -H "Idempotency-Key: demo-123" \ -d '{"name":"pqc-batch-signing","payload":"ml-kem-768"}' Watch /api/status — when carbon 200 it defers, when <200 it runs curl https://quant-harvest.onrender.com/api/status | jq modernc.org/sqlite pure-Go driver — busy timeouts, atomic claims, idempotency via Idempotency-Key /metrics qharvest task queue size , qharvest carbon intensity + /healthz /readyz / — real-time grid chart + queue + WAL logs see live demo deploy/ // pqc.go — integration boundary ready for ML-KEM func EnvelopeIdentifier data byte 32 byte { return sha256.Sum256 data // placeholder for vetted ML-KEM/FIPS203 } 2026/08/15 12:01:45 Q-HARVEST listening on :8080 2026/08/15 12:02:00 scheduler: deferring queue at 270gCO2e/kWh 2026/08/15 12:02:15 scheduler: carbon intensity dropped to 145gCO2e/kWh 2026/08/15 12:02:15 scheduler: executing pqc-bulk-signing Green computing is usually "use less." Quant Harvest is "use when clean." Same jobs, shifted to renewable windows — simplest decarbonization win for PQC migration. Apache-2.0. If you're Go/DevOps/crypto, try the live demo and roast the scheduler logic