How the Data Center Index estimates grid and gas impact
From announced megawatts to expected load, energy, gas burn and a 1-to-4 bolt impact rating. Every figure marked “expected” or “estimated” is a Discovery Energy model output, not a reported number.
Scope
- Coverage: data center campuses of 100 MW or more in the US and Canada that entered service since 2021, or are under construction, approved, announced or proposed. Crypto-mining sites converting to AI/HPC are included and tagged by segment.
- Threshold: 100 MW. Below roughly 20 MW the grid effect is minor.
- Data: public sources only: news reports, regulatory and utility filings, grid operator publications, government sites, company releases and public trackers. No paid datasets. Every source is listed in the source log.
- Geography of impact: bill effects follow the grid region and utility a campus connects to. Campuses with on-site gas generation shift the impact from electric bills to the gas system.
Method, step by step
Normalize size
Published MW can be IT load, facility load, utility service, on-site generation nameplate or campus potential. IT load × 1.2 (PUE); generation nameplate × 0.8 (plants are built with spare units); others as published.
Phase to 2030
Horizon factor by facility MW: up to 1,000 MW counts 100%; 1,000 to 3,000 MW counts 60%; above 3,000 MW counts 30%.
Weight by build stage
Expected MW = facility MW × horizon × status probability (table below).
Convert to energy
Average MW = expected MW × 75% load factor. Annual GWh = average MW × 8.76.
Split grid from on-site
On-site gas and fuel-cell campuses count 100% on-site; hybrids are split by on-site nameplate × 0.8 ÷ facility MW.
Estimate gas burn
MMcf/d = average MW × 24 × heat rate ÷ (1,036 Btu/cf × 1,000). On-site uses the on-site heat rate; grid share uses the region's gas share of new supply × 7,500 Btu/kWh. Design-day Dth/d uses a 95% load factor. Check: 1 GW at 6,000 Btu/kWh ≈ 139 MMcf/d, matching Enverus's 140.
Electric bill effect
Where a market monitor quantifies the data center share of capacity cost (PJM): capacity price × 365 × data center share per MW of peak load contribution. For 2028/29: $325 × 365 × 38% = $45,078 per MW-year, or $7.35/MWh at a 70% load factor. Other markets are calibrated from resource plans, rate cases and tariffs in later passes.
Rate the impact
Each campus gets a grid score and a gas score; the rating is the higher of the two (scale below).
Impact rating: 1 to 4 bolts
The rating measures strain on the system, not who pays. Bolts are solid for operating or under-construction campuses and outlined for approved, announced or proposed ones. The label shows whether the grid score, the gas score or both drive the rating.
| Rating | Grid-served load by 2030 | Local design-day gas draw | Typical meaning |
|---|---|---|---|
Gigawatt-class | 800 MW+ | 120,000+ Dth/d | Reshapes regional planning and capacity prices; pipeline expansion territory |
Regional | 400–800 MW | 60,000–120,000 Dth/d | About a large power plant's output; new transmission; may need a new gas lateral |
Utility-scale | 150–400 MW | 25,000–60,000 Dth/d | Dedicated substation and high-voltage lines |
Local | Under 150 MW | Under 25,000 Dth/d | Served by expanding an existing substation |
- Local gas draw = on-site design-day gas + dedicated-plant gas + 50% of regional grid gas.
- Metro rating (sum of a metro's campuses): 2 bolts from 500 MW / 50,000 Dth/d, 3 from 1,500 MW / 150,000 Dth/d, 4 from 3,000 MW / 300,000 Dth/d.
- Current distribution (87 campuses): 4 bolts 23 · 3 bolts 29 · 2 bolts 32 · 1 bolt 3. Drivers: grid 71 · gas 10 · grid + gas 6.
Assumptions
| Parameter | Base | Low | High | Basis |
|---|---|---|---|---|
| PUE (IT → facility) | 1.20 | 1.10 | 1.40 | Discovery Energy assumption for new hyperscale/AI builds |
| On-site nameplate → served load | 0.80 | 0.70 | 0.90 | Redundancy (N+1/N+2) |
| Average load factor | 75% | 60% | 85% | Near-flat 24/7 load; Dominion GS-5 defined around 75% |
| Design-day load factor | 95% | 90% | 100% | Peak-day pipeline sizing |
| Heat rate, grid gas serving new load | 7,500 Btu/kWh | 6,960 | 9,000 | EIA Table 8.2; new CCGTs average 6,960 |
| Heat rate, on-site turbines/engines | 9,500 Btu/kWh | 8,900 | 11,000 | EIA: gas turbines ~11,000, engines ~8,900 |
| Heat rate, on-site fuel cells | 7,000 Btu/kWh | 6,500 | 8,000 | Discovery Energy assumption |
| Gas heat content | 1,036 Btu/cf | 1,030 | 1,040 | EIA average |
| Example large-user load factor | 70% | 50% | 85% | For bill examples |
Build-stage probabilities
| Status | Counts toward 2030 | Meaning |
|---|---|---|
| Operating | 100% | In service, no further phases announced |
| Operating, expanding | 90% | Partly energized; later phases under construction |
| Under construction | 80% | Site work underway |
| Approved | 65% | Utility agreement or power contract, grid allocation, or zoning approval |
| Announced | 35% | Named developer and site, no construction |
| Proposed | 15% | Developer only, no named tenant, power plan unresolved |
| Cancelled / withdrawn | 0% | Kept for history |
Gas share of new supply by region
| Region | Gas share |
|---|---|
| PJM | 60% |
| ERCOT | 55% |
| SPP | 50% |
| MISO | 60% |
| Southeast utilities | 75% |
| West: Mountain/Northwest | 50% |
| West: Desert Southwest | 60% |
| Alberta (AESO) | 90% |
| Alaska | 90% |
| NYISO | 60% |
| ISO-NE | 70% |
| CAISO | 35% |
| Ontario (IESO) | 40% |
| Québec (Hydro-Québec) | 0% |
Version 0 judgment, to be calibrated against utility resource plans. Campuses served by plants built for them use a 100% gas share.
Tariff protection
Share of data-center-driven grid cost assumed to reach other customers: Strong 30%, Partial 60%, None 100%, Under review 100%.
Confidence grades
| Grade | Meaning |
|---|---|
| A | Verified against a primary source |
| B | Several consistent sources |
| C | One secondary source |
| D | Conflicting or estimated figures |
Timeline model
The timeline spreads each campus's expected MW across years by build stage until real dates replace it: operating, all by end of 2025; operating-expanding, 50% by 2025 and 25% in each of 2026 and 2027; under construction, up to 1 GW announced half in 2026 and half in 2027, 1 to 3 GW 40/30/30 over 2027–2029, over 3 GW 30/35/35 over 2028–2030; approved, half in 2027 and half in 2028; announced, 30/35/35 over 2028–2030; proposed, half in 2029 and half in 2030.
Calibration
| Measure | Index | Benchmark | Source |
|---|---|---|---|
| Expected data center load by 2030 | 54.9 GW | 62 GW new, 2026–2030 (Lower 48) | Enverus, July 2026 |
| PJM expected load by 2030 | 16.4 GW | 35.1 GW accepted, 2026–2031 | PJM 2026 load forecast |
| Added gas burn by 2030 | 5.1 Bcf/d | 3–10 Bcf/d | S&P Global, PwC and others |
The index sits inside these ranges while still missing much of the 100 MW to 1 GW tier, so totals will rise. Status probabilities are tightened if the index runs hot.
Limits
- Published capacity figures often conflict across trackers; the index records the basis used and flags conflicts in each campus note.
- The bill-effect calculation is quantified only for PJM so far.
- Metro gas headroom (needed for the gas stress ratio and the ±1 local adjustment) is still being compiled.