# Natural reservoirs: What to track

Droughts, melting glaciers and the pumped storage boom

Source page: https://www.materialinsights.org/energy/e_natural_stores/tracking/

What this tab covers The attributes worth tracking regularly, with the latest value, the direction of travel and why each matters.

Track hydrology and climate signals as closely as prices; the store's size is set by nature.

| Category | Attribute | Latest | Trend | Why it matters |
|---|---|---|---|---|
| Techno-economic | **LCOS trajectory (hydropower LCOE as proxy)** | USD 57 per MWh (2024), up from 44 in 2010^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2025/Jul/IRENA_TEC_RPGC_in_2024_Summary_2025.pdf) | ↘ worsening | Best remaining sites are costlier. |
| Technical | **Capacity fade and state of health (hydrology, sedimentation, glacier and snowpack loss)** | Severe droughts in 2025 in parts of South America, South and Central Asia and Europe^[1](https://www.hydropower.org/news/year-of-the-water-battery-global-pumped-storage-capacity-surpasses-200-gw) | ↘ worsening | Climate change shrinks and shifts natural storage. |
| Supply chain | **Critical mineral cost and geopolitical concentration** | Not applicable; constraint is sites and water rights^[10](https://digitalcommons.mtu.edu/cee-fp/106) | → stable | Transboundary rivers carry geopolitical risk instead. |
| Market | **Ancillary service market saturation** | Over 500 negative-price hours in at least six European countries (2025)^[1](https://www.hydropower.org/news/year-of-the-water-battery-global-pumped-storage-capacity-surpasses-200-gw) | ↗ improving | Bigger price swings raise the value of stored water. |
| Regulatory | **Safety and environmental compliance** | Reservoir emissions about 0.8 Gt CO2e a year; dam safety rules^[3](https://dare.uva.nl/id/6fe8a425-ca11-48ae-a045-9e913f8198b6) | → stable | Methane and ecological flow rules affect operation. |
| Impact | **Lifecycle carbon intensity (payback proxy)** | Median 24 g CO2e/kWh, range 1-2,200^[12](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf#page=7) | → stable | Site choice decides whether a reservoir is low-carbon. |
| Market | **Pumped storage pipeline (charging natural reservoirs)** | 201 GW installed, 621 GW pipeline (2025); India from about 3.5-5 GW to as much as 100 GW by 2035^[1](https://www.hydropower.org/news/year-of-the-water-battery-global-pumped-storage-capacity-surpasses-200-gw) | ↗ improving | Turns natural reservoirs into rechargeable stores. |
| Market | **Largest seasonal reservoir store (Norway)** | over 87 TWh, about half of Europe's reservoir capacity^[15](https://energifaktanorge.no/en/utskrift/) | → stable | Sets how far northern hydro can firm European wind and solar. |
| Technical | **Ground heat storage uptake** | over 2,800 aquifer stores, over 2.5 TWh a year of heating and cooling^[7](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf) | ↗ improving | Shows how the ground is used as a seasonal store. |

#### Sources

1. [Year of the water battery: global pumped storage capacity surpasses 200 GW (2026 World Hydropower Outlook)](https://www.hydropower.org/news/year-of-the-water-battery-global-pumped-storage-capacity-surpasses-200-gw) International Hydropower Association, 2026
2. [Renewable Power Generation Costs in 2024: Summary (Table S1)](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2025/Jul/IRENA_TEC_RPGC_in_2024_Summary_2025.pdf) IRENA, 2025
3. [Greenhouse gas emissions from reservoir water surfaces: a new global synthesis (Deemer et al., BioScience 66)](https://dare.uva.nl/id/6fe8a425-ca11-48ae-a045-9e913f8198b6) University of Amsterdam repository, 2016
4. [Innovation Outlook: Thermal Energy Storage](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf) IRENA, 2020
5. [Mapping the world's free-flowing rivers (Grill et al., Nature 569)](https://digitalcommons.mtu.edu/cee-fp/106) Michigan Technological University repository, 2019
6. [Climate Change 2014: Mitigation, Annex III Technology-specific cost and performance parameters](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf#page=7) IPCC, 2014
7. [Electricity production: Key facts about the Norwegian energy sector (data from NVE)](https://energifaktanorge.no/en/utskrift/) Energy Facts Norway (Norwegian Ministry of Energy; data from NVE), 2025

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_natural_stores/index.md)
- [Overview](https://www.materialinsights.org/energy/e_natural_stores/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_natural_stores/correlation/index.md)
- [Science and technology](https://www.materialinsights.org/energy/e_natural_stores/sg-sci/index.md)
- [Engineering and performance](https://www.materialinsights.org/energy/e_natural_stores/sg-eng/index.md)
- [Economics](https://www.materialinsights.org/energy/e_natural_stores/sg-econ/index.md)
- [Impact and additionality](https://www.materialinsights.org/energy/e_natural_stores/sg-impact/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_natural_stores/links/index.md)