Glossary

Net kW is the headline number every downstream metric depends on — miner count, hashrate, mining revenue, capex sizing. We start from the LHV energy content of the gas, apply the engine’s electrical efficiency, then subtract every derate the engine OEM will quote against.

Each derate is independent and multiplicative. A site at 4,000 ft with 90 °F ambient and 800 ppm H₂S can lose 25–35% of nameplate before any parasitic load. Always size the gen-set against the worst-month derated output, not the nameplate.

Hashprice is the single best summary statistic for mining profitability. It collapses BTC price, network difficulty, block subsidy and fee market into one number ($/TH/day) you can multiply by your fleet hashrate to get revenue.

Industry trackers (Hashrate Index, Luxor, CoinMetrics) publish hashprice daily. As of late 2024 it has ranged $40–$60/PH/day (~$0.04–$0.06/TH/day). The calculator defaults reflect that band; use Bear/Bull BTC price scenarios to envelope hashprice volatility.

Difficulty adjusts every 2,016 blocks (~2 weeks) to keep block time at 10 min. If BTC price stays flat but global hashrate grows, hashprice falls. Conversely, fee spikes (ordinals, congestion) lift hashprice even at constant BTC price.

Gross hashrate is purely a function of Net kW divided by per-miner power draw, multiplied by per-miner hashrate. Floor-divide — partial miners don’t exist.

The calculator assumes a single miner SKU. Mixed-fleet deployments (S19j Pro + S21 + M60S) need to be sized against the modal SKU or modeled in spreadsheet rather than this tool.

Effective uptime drives every revenue line — both mining and carbon. A 95% mechanical uptime sounds high until you subtract 12 days/yr of planned maintenance and a few weeks of summer derate, leaving real delivered uptime closer to 88–90%.

The calculator solves IRR by bisection (10–80% search window). Cashflows include the decline-curve multiplier from year 2 onward, so a project with a steep early-year decline will show meaningfully lower IRR than a flat-revenue calculation would suggest.

Compare IRR against the project hurdle rate (default 20%). Green means the project clears the hurdle; red means it doesn’t. A bisected IRR is sensitive to the cashflow shape — short-life, back-loaded projects can have multiple sign changes; this tool assumes a conventional outflow-then-inflow shape.

Discounted payback is stricter than the simple-payback heuristic (capex ÷ year-1 cashflow) because it credits later cashflows less. For a flat 20-year project at 10% discount, the gap between simple and discounted payback is typically 1–3 years.

The Investor Payback shown on the Deal tab is a static, undiscounted months figure (capex ÷ year-1 monthly investor share) intended for quick conversation — use the Decline-tab payback for full lifecycle numbers.

NPV is the rigorous answer to “is this project worth doing?” IRR tells you the rate; NPV tells you the dollar value created at your chosen cost of capital. The two metrics agree on accept/reject for conventional cashflow patterns and can disagree on ranking between mutually-exclusive projects.

The calculator reports both Lifetime Revenue NPV (top-line, before opex/capex) and Project NPV (bottom-line, after everything). Use the first for sizing royalty negotiations; use the second for go/no-go decisions.

Methane traps about 80× more heat than CO₂ over 20 years but breaks down in the atmosphere within a decade. CO₂ persists for centuries. GWP collapses that time profile into a single multiplier — but the choice of horizon (20 vs 100 years) substantially changes the headline tCO₂e number.

IPCC AR6 raised GWP-100 to 27.9 (and 29.8 with carbon-feedback adjustment). The calculator stays at 28 for parity with all major registries; flip GWP-20/100 to see the policy-vs-issuance gap.

Additionality is the bar a project must clear to be eligible for credit issuance under any reputable registry. Three common tests:

• Regulatory: The action is not already required by law (e.g., open landfill venting may be permitted in some jurisdictions but mandated to be flared in others).
• Financial: The project IRR without carbon revenue falls below the hurdle rate. Carbon revenue tips it over.
• Common-practice: The technology is not yet the standard approach in that geography or sector.

Methane-to-hash projects on stranded gas (small landfills, orphan flares, ventilation-air methane) usually clear all three tests easily. Projects on already-flared sources need to argue marginal destruction efficiency improvements.

When a project sells “1,000 tCO₂e of credits”, the atmospheric benefit was actually larger — the registry held back a fraction in a shared buffer pool. If any project in that pool later reverses (the engine breaks, the host vents the gas), the buffer credits are retired to compensate.

For methane destruction the reversal risk is mostly equipment failure or operational discontinuity (project abandoned). Buffer contributions are typically 10–20% depending on the methodology (VCS VM0041, ACR, CAR Methane). The calculator applies a default 15% combined haircut covering both buffer pool and verification cost; tune in the Carbon tab.

Always state which counterfactual you are claiming against. “vs Vent” is appropriate only where venting is legally permitted today and there is no flare in place. “vs Flare” is the registry default for any site with existing combustion controls.

The mining pathway itself emits some CO₂ — both the small CH₄ slip through the engine (0.3–1%) and the combusted CO₂ from the oxidized methane. CO₂ from biogenic methane (landfill, manure digester) is typically considered short-cycle and excluded from the tCO₂e tally; CO₂ from fossil methane (flare gas, CMM) is counted.