Zero Terrain · McWilliams Energy
Where UPS is buildable (flat terrain, crystalline basement at 500–2,000 m) and needed (fast-growing renewables, storage gap). Adjust the score weights, scan the map, shortlist, then drill into a country.
Screening basis: McWilliams, The Global Need for Underground Pumped Storage Hydro (Aug 2025). Data: Ember 2026 · IRENA 2026-H1 · province-level geology screen.
Hover for detail · click a country to open its profile
Storage need vs geological suitability · bubble size = projected 2035 VRE · blue = current top 12 by score
Ranked by opportunity score — click headers to sort, rows to open
| # | Country | Region | Score | Need | Build | Gap ’35 GW | VRE ’35 GW | CAGR | Geo | Terr | Seismic | Conf |
|---|
The score operationalises the screening logic of McWilliams, The Global Need for Underground Pumped Storage Hydro (McWilliams Energy, Aug 2025): a market is attractive where long-duration storage is needed and Zero Terrain-style UPS is buildable. The paper proposes no formal country ranking — this model is our construction from its stated thresholds, and every weight is adjustable in the panel.
| Sub-score | Definition (0–100) | Paper basis |
|---|---|---|
| Storage gap 2035 | log-scaled gap to a storage fleet = 15% of projected 2035 VRE capacity (100 ≈ 300 GW gap) | storage need scales with vRE build-out; 15% ≈ today’s leading flexible systems (CN 14%, US 19%, AU 13%) |
| VRE growth | 5-yr wind+solar CAGR, capped at 40%/yr | value rises with vRE growth |
| VRE share | ramp from 5% to 35% of generation | storage need becomes material past ~20–25% vRE penetration |
| Market scale | log-scaled projected 2035 VRE (100 ≈ 500 GW) | market must absorb ≥500 MW / ≥8 h units (~US$2 bn per 1,000 MW / 8,000 MWh) |
| Geology | curated geology suitability score: crystalline basement reachable at 750–2,000 m, low permeability | competent rock at depth; SBR shafts to 120 MPa UCS, SBC to 250 MPa; groundwater studies gate |
| Terrain need | flatness + absence of conventional PSH resource | “zero terrain” — flat land is where UPS’s location-agnosticism has most value |
Combination. Need is a weighted mean of its sub-scores. Buildability is a weighted geometric mean of geology and terrain, so flat terrain cannot compensate for missing rock. The final score is the geometric mean of the two axes, so failing either axis fails the screen (the Netherlands has the need but not the rock; Norway the rock but not the need). Penalties: seismicity (high ×0.6, moderate ×0.85), a grid-scale gate (a proxy for absorbing a 500 MW unit, using projected VRE + hydro), and a flexible-hydro discount (reservoir fleets like Brazil’s or Norway’s substitute for storage). Deliverability — market structure, financing, EPC+F/FELT readiness — has no global dataset and is out of scope; read the geology notes and confidence flags alongside.
Capacity by technology and country, 2000–2025: Ember Yearly Electricity Data (2026 release; 2024 baseline for 191 of 207 countries). Pumped storage and mixed (pump-back) hydro: IRENA ELECSTAT 2026-H1. Grid batteries: curated 27-market table (NEA/CNESA, EIA, GOV.UK/Modo, Ember Europe, IEA GER 2026; ~96% of global fleet) — other countries treated as ~0 GW and flagged. 2030/2035 projections are decaying-growth extrapolations (r₀ = 5-yr CAGR capped at 25%/yr, decaying 20%/yr): conservative for policy-driven markets — India, Germany and Saudi Arabia project well below stated targets, so their gaps are lower bounds. The storage-gap benchmark (power = 15% of VRE) is a screening heuristic, not a system adequacy study: it ignores duration (GWh), interconnection and demand response.
Country-level scores curated from geological-province literature (Precambrian shields and cratons, platform basement-depth maps, GSHAP/GEM seismic hazard), terrain ruggedness (Nunn & Puga TRI) and mean elevation, with an adjustment for conventional pumped-hydro resource (ANU RE100 atlas). Country means hide sub-national reality — the “key regions” text in each country profile carries the district-level story (e.g. the USA’s national ~32 hides an excellent Upper Midwest; India’s Deccan pediplains vs the dead Indo-Gangetic plain). Scores are province-level expert judgement, not a basement-depth grid — the confidence flag marks the weakest entries. Water availability and market structure are out of scope (noted qualitatively where decisive).