# Grid Flexibility

> Open analysis of US wholesale electricity markets across 7 ISOs (CAISO, ERCOT, PJM, NYISO, ISO-NE, MISO, SPP). Where prices spike, where the grid is constrained, what data center buildout means for grid planning, and how demand flexibility creates value.

Grid Flexibility (gridflexibility.fyi) is a research site analyzing US electricity markets with a focus on demand flexibility and the cross-ISO comparison of wholesale prices, capacity values, ancillary services, and grid constraints.

## Pages

- [Dominion Virginia: Data Centers, Rising Bills, and Who Pays](https://gridflexibility.fyi/case-studies/dominion-virginia): A primary-source case study reconstructing why Dominion Energy Virginia residential bills rose about 38% from 2021 to 2025 (commercial about 35%, large-load about 34%), how data-center growth drives the generation and transmission buildout (a roughly 70 GW connection-request queue, nearly three times the grid's all-time peak), and why billing by peak demand puts the largest share of cost on households (about 53 to 55% of transmission cost and 40% of generation cost) rather than the flat data-center load behind the growth. Sources: Virginia SCC dockets (PUR-2025-00058 biennial review, PUR-2026-00011 large-load queue), PJM, EIA, and JLARC. Covers the GS-5 large-load rate class (effective 2027), the DOM-zone winter peak record (25.2 GW), the largest 2025 real-time price increase of any PJM zone (about 51%), and where demand flexibility changes the outcome.

- [Case Studies](https://gridflexibility.fyi/case-studies): Primary-source case studies on US electricity markets, rates, reliability, and demand flexibility, starting with Dominion Energy Virginia.

- [Data Centers and the US Grid](https://gridflexibility.fyi/data-centers): Where data center load is concentrating across US ISOs, why interconnection queues stall buildout (4.5-year US median per LBNL 2025), and how developers and states are responding. Sections cover national load growth (166 GW projected per Grid Strategies 2025), geographic concentration, grid bottlenecks, behind-the-meter generation, compute flexibility, state policy responses (VA SCC GS-5 rate class, AEP Ohio tariff, Oregon POWER Act, PA PUC tentative).

- [Wholesale Electricity Markets Across US ISOs](https://gridflexibility.fyi/markets): Wholesale electricity prices across 7 US ISOs. Critical-hours value concentration, price spikes, regional patterns. (Page in progress.)

- [Demand Flexibility Value Across US ISOs](https://gridflexibility.fyi/value): How US wholesale markets pay for flexible loads: energy arbitrage, capacity, ancillary services, transmission deferral. Cross-ISO comparison. (Page in progress.)

- [US Grid Constraints: Cross-ISO Stress Analysis](https://gridflexibility.fyi/stress): Where transmission is binding, where retirements are concentrated, and where the interconnection queue is stalled across US ISOs. (Page in progress.)

- [Methodology, Data Sources, and Reproducibility](https://gridflexibility.fyi/methodology): How we collect, validate, and analyze data across US wholesale electricity markets. Sources, schema, and code paths. (Page in progress.)

## Open datasets

Free, primary-source, CC BY 4.0 derived datasets (the raw hourly/nodal panel is available on request). Catalog: [Grid Flexibility open datasets](https://gridflexibility.fyi/data).

- [Critical-Hours Value Concentration Across US ISOs](https://gridflexibility.fyi/data/critical-hours-value-concentration): How concentrated wholesale value is in a few hours, measured as each hour's price deviation from the annual median (the arbitrage a flexible load can capture), by ISO and year, day-ahead and real-time. Across the 7 US ISOs (2018-2025), the 1% of hours with the largest deviation hold a median 10% of the year's arbitrage value and the top 5% hold a median 27% (most concentrated: ERCOT at 41%). Coverage: CAISO, ERCOT, ISO-NE, MISO, NYISO, PJM, SPP.

- [Locational Avoided Capacity and Transmission Cost Across US ISOs](https://gridflexibility.fyi/data/locational-avoided-cost): The consumer-side avoided cost: what a consumer avoids in capacity-plus-transmission cost by cutting one kilowatt of demand at the coincident peak, by ISO zone and year (2018-2027). Ranges from about $1 to $214 per kW-year (median about $60), highest in PJM (BGE about $170, DOM about $162 for 2026) and ERCOT. Coverage: ERCOT, ISO-NE, MISO, NYISO, PJM.

## Differentiators

- **Cross-ISO scope**: most public analysis is single-ISO focused (PJM-only, ERCOT-only). Grid Flexibility covers all 7 US ISOs with a consistent approach, enabling cross-market comparison of wholesale prices, capacity values, and demand-flexibility revenue streams.

## Audience

The site is primarily useful for:
- VPP operators and demand-flexibility startups
- Data center and infrastructure developers (locational electricity costs, grid interconnection)
- Regulators and utility-side analysts
- Researchers and academics
- Journalists and policy writers

## Contact

Author: Corey Balgeman.
Site: https://gridflexibility.fyi