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World Bank ESMAP Nepal Solar and Wind Resource Measurement

World Bank ESMAP's Nepal solar and wind measurement programme and ground-station resource evidence.

Page status
Verified core
Updated
2026-05-11
Last reviewed
2026-07-19
Review due
2027-07-19

Open in the interactive explorer and map

Summary

The ground-measured solar and wind resource dataset for Nepal. Operated 2015–2019 under the World Bank ESMAP Renewable Energy Resource Mapping & Geospatial Planning programme, implemented on the ground through AEPC with technical delivery by Vaisala / 3TIER (solar) and DNV GL (wind).

This is the only authoritative measured-data source for Nepal solar resource at the station-hour resolution — every satellite-derived estimate (including Global Solar Atlas (Nepal coverage)) is calibrated against and cross-validated with this dataset.

What the source covers

  • 14 solar measurement stations deployed across Nepal's representative zones
  • 4 wind measurement towers (lower priority; wind is constrained in Nepal)
  • 10-minute and hourly meteorological and radiation data
  • GHI, DNI, DIF, temperature, wind speed, humidity — the full solar-meteorological stack
  • Validation campaign against Global Solar Atlas and MERRA-2 satellite datasets
  • Open-data release through ESMAP Global Solar Atlas portal and AEPC national reports

Station network (solar — representative)

Station (approximate) Zone Elevation (m) Measurement period GHI mean (kWh/m²/day)
Jumla E / A-border 2,370 2015–19 ~5.2
Nepalgunj B3 150 2015–19 ~5.1
Simara / Birgunj B1 130 2015–19 ~4.9
Biratnagar B2 80 2015–19 ~4.9
Pokhara C2 820 2015–19 ~4.5
Kathmandu C1 1,340 2015–19 ~4.3
Dhankuta C3 1,100 2015–19 ~4.4
Surkhet C4 700 2015–19 ~4.8
Jomsom (Mustang) A 2,730 2015–19 ~6.0
(+ 5 additional stations, detail in final report) various

Specific station coordinates, exact measurement periods, and precise GHI means require cross-reference with the ESMAP final report tables; the values here are representative.

Key findings (composite, from ESMAP final report)

  • Nepal country-weighted GHI: 4.7–5.0 kWh/m²/day
  • GHI range across stations: 4.3 (Kathmandu Valley) to 6.0+ (Jomsom / Mustang)
  • Strongest seasonality in: mid-hill stations (Pokhara, Dhankuta) with 35–45% monsoon penalty
  • Weakest seasonality in: trans-Himalayan stations (Jomsom) with 5–15% monsoon penalty
  • Station-satellite validation: Global Solar Atlas is within ±5% of measured GHI at all stations; trans-Himalayan stations had largest satellite underestimate (~5–8%)
  • Wind resource: limited utility-scale potential; best pockets in Mustang (annual mean >6 m/s at hub height) and selected Koshi gaps

Why this source matters

For the wiki specifically

For Nepal solar planning in general

It is the dataset that moves Nepal solar discussion from "we think Nepal has good sun" to "we measured it for four years across 14 representative sites and here is the spatial and seasonal structure." This is the empirical floor under NEA Solar Award Tariffs Undercut the Standard Small-RoR Blended Tariff and the LCOE arguments downstream.

Data access

  • Raw 10-min / hourly station data: ESMAP portal (historically), AEPC national archive (partial)
  • Derived products: Global Solar Atlas tiles, Nepal national solar atlas (AEPC), IRENA REmap modelling
  • Station reports: ESMAP Nepal final report (~2019–2020)

Relevance to project

Primary source for:

Validation source for:

Data-quality notes

  • Station data is high-quality pyranometer-grade, calibrated, Vaisala-instrument-based.
  • Spatial coverage is thin (14 stations across a country of Nepal's complexity); satellite products fill the interpolation gap but with systematic biases in high-mountain terrain.
  • Temporal coverage (2015–2019) pre-dates the 2021–2024 atmospheric-aerosol shifts; there is a case for a refresh campaign, especially in the Indo-Gangetic-plain-adjacent Terai where dust aerosol has intensified.
  • Post-2019 data is patchy; some stations continued under AEPC operation, others were decommissioned.

Gaps we would like

  • A 2024/25 refresh campaign across at least 8 of the original 14 stations, to capture atmospheric-aerosol evolution.
  • Publication of a per-station 10-year climatology with percentile bands (not just 10-year mean).
  • Integration with cloud-cover indices (MODIS, Himawari) for operational forecasting value.

Limitations

  • Spatial coverage thin. 14 stations across Nepal's terrain complexity leaves substantial interpolation gaps. Satellite products fill the gap but with systematic biases in high-mountain terrain.
  • Temporal cutoff at 2019. The measurement campaign ended in 2019, pre-dating the 2021–2024 atmospheric-aerosol shifts. Terai stations in particular may now face dust-aerosol conditions not captured in the dataset.
  • Post-2019 data patchy. Some stations continued under AEPC operation after 2019; others were decommissioned. There is no uniform post-campaign dataset.
  • Station values are representative, not precise. The GHI means in the station table are approximate; exact values require cross-reference with the ESMAP final report tables.

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