Solar LCOE Crossover

Summary

The single most-out-of-date assumption in Nepal's public energy discourse is that solar is expensive relative to hydro. It was true in 2014. It was marginal in 2019. By the NEA's 2081/82 (2024/25) competitive-bid awards, solar had become the cheapest new-build generation in Nepal, by a wide and widening margin — cheaper than small run-of-river, cheaper than medium run-of-river with long transmission legs, and roughly on par with the levelized cost of reservoir storage hydro (before counting hydro's locational premium).

This concept page documents the crossover and draws out what it means for a fleet strategy that was designed under obsolete price assumptions.

Simple Explanation

Solar used to be treated as a costly add-on to hydropower. The cost curve has moved so far that new solar bids in Nepal now compete below many new hydro options, especially when dry-season timing and transmission costs are considered.

The global price collapse

Utility-scale solar PV LCOE, weighted global average, IRENA Renewable Cost Database:

That is an ~88% real reduction in 14 years. Modules alone fell from ~$2.00/W (2010) to ~$0.10/W (2024) — a 95% reduction. Balance-of-system fell ~60%. Inverters fell ~70%. The decline is not a subsidy story and not a temporary glut story; it is a manufacturing-learning-curve story, and it is still going.

Nepal's tariffs — where we actually land

Nepal's NEA runs a tariff-based competitive bidding mechanism for grid-connected solar PV. Recent rounds:

For comparison, the contracted prices NEA pays for recent hydropower:

The crossover point has already happened for run-of-river. The NEA is paying ~6.20 NPR/kWh blended for RoR energy whose production profile is worst-matched to demand (the Seasonal Mismatch pattern), and ~5.43 NPR/kWh for solar energy whose production profile is best-matched to the dry-season day.

This is the single most important number in Nepal's energy economics right now.

The "locational premium" correction — and why it still favours solar

A fair hydro-vs-solar comparison needs three adjustments:

1. When does the MWh land? A dry-season kWh is worth ~2× a monsoon kWh in the Indian import market (Seasonal Arbitrage Trap). Solar lands disproportionately dry-season. Hydro RoR lands disproportionately monsoon. On time-weighted value, solar's effective tariff is closer to 5.0 NPR/kWh and RoR's is closer to 7.0 NPR/kWh.
2. Firm capacity contribution? Zero for both solar and RoR on their own. Hydro storage earns a real capacity premium that solar-plus-4h-BESS is only partially closing; solar alone does not.
3. Transmission build-out? RoR sites are remote; the ~7 new 220/400 kV corridors in Nepal Transmission System — 400 kV Landscape & Cross-Border Plan (2025) are overwhelmingly hydro-driven. Terai solar sits on the existing 132 kV spine. Transmission-inclusive LCOE moves solar ~5–10% cheaper still.

After adjustments, solar LCOE for a Terai utility site with existing 132 kV evacuation is ~NPR 4.5–5.5/kWh (all-in, 25-year levelized) vs new RoR ~NPR 6.5–8.0/kWh. The solar advantage is ~30–40%.

Why the price is still falling — and what it means for planning

Three dynamics keep compressing solar costs through 2030:

• Module oversupply cycle. Global PV manufacturing capacity (~1,200 GW/yr) is 2–3× annual demand. Prices will not rebound to 2022 levels.
• Bifacial + tracker penetration. Now cost-competitive; adds ~10–20% to yield with ~5% capex bump — net LCOE reduction continues.
• 4-hour BESS crossover. Utility 4-hour battery cost fell from ~$500/kWh (2018) to ~$180/kWh (2024), on pace for ~$90/kWh by 2030. Solar-plus-4h-BESS will clear the NPR 7/kWh bar (matching firm hydro) before 2028.

Planning implication: any project with LCOE evaluation at 2023 module prices is over-estimating solar cost by ~20–25%. Any project evaluated without 4h-BESS crossover is about to over-estimate the firm solar cost by ~30%.

What this does not say

• It does not say Nepal should stop building hydro. Hydro still has the capacity-credit and seasonal-firm-energy roles solar cannot play alone.
• It does not say existing PPAs are mispriced in isolation. A 2017 PPA at 8.40/4.80 is a locked-in contract; tearing them up is not the implication.
• It does not say solar is a free lunch. Land, imports (modules are 95%+ Chinese), and interconnection remain real frictions (Hybrid Siting Logic, Agrivoltaics and Land).

What it says is narrower: on the margin, for the next MW of new capacity to satisfy next winter's peak — solar is now the default answer, and every planning document should default-choose solar unless it has a specific reason (firm capacity, evening peak, location) to choose otherwise.

Common Misunderstandings

• Cheap solar does not mean hydro is obsolete. Hydro still supplies energy, peaking, and seasonal/storage value that solar alone cannot provide.
• LCOE is not the whole system value. Timing, transmission, and firm-capacity contribution change the comparison.
• Old solar assumptions age quickly. Planning documents using pre-2024 module or battery costs can materially overstate solar cost.

Related

• Solar–Hydro Complementarity — why the price argument matters differently in Nepal than elsewhere
• Solar and Hydro LCOE — the underlying numbers and time series
• Hybrid Siting Logic — how to compound the price advantage
• NEA Solar Award Tariffs Undercut the Standard Small-RoR Blended Tariff — the tracked claim
• Seasonal Arbitrage Trap — the time-weighted value framing
• NEA Annual Report FY 2024/25 — source for Nepal's tariff data