Solar Green Hydrogen Thermal Analysis

What this research found

India's National Green Hydrogen Mission favours high-irradiance desert sites, which raises the question of whether the heat that comes with the sunshine cancels out the advantage. An hourly year-long simulation of a 1 MW solar array feeding matched alkaline and proton exchange membrane (PEM) electrolysers at Jodhpur, Rajasthan, found that the answer depends on the technology: thermal penalties consume 113.6% of the solar gain for alkaline, erasing it, but only 48.1% for PEM.

• For alkaline electrolysis the thermal offset ratio reaches 113.6%, so heat-driven losses slightly exceed the benefit of Rajasthan's stronger sunlight. For PEM the ratio is 48.1%, leaving roughly half the solar advantage intact.
• Over 20 years PEM returns 2.97 times the net benefit of alkaline — 74,397 kg of additional hydrogen against 25,027 kg, measured against an average-India reference — despite beginning with lower efficiency, 59.6% versus 62.0% on a lower-heating-value basis.
• The divergence traces to operating temperature. Alkaline runs at 70.3°C for an Arrhenius acceleration factor of 1.83, or 83% faster ageing, while PEM runs at 60.3°C for a factor of 1.03, a 15-fold difference in thermal impact.
• The photovoltaic array itself gives up 7.42% of its annual energy to heat relative to standard test conditions, about 170 MWh forgone on a 1 MW system.
• First-year output is nearly identical between the two technologies, 40,050 kg of hydrogen for alkaline against 39,255 kg for PEM, but the ranking inverts over the full horizon: 703,664 kg cumulative for alkaline against 708,189 kg for PEM.

How it was done

A typical meteorological year for Jodhpur, Rajasthan (26.24°N, 73.02°E) was synthesized with the pvlib library using the Ineichen clear-sky model, producing 8,760 hourly values of irradiance, temperature and wind: annual global horizontal irradiance of 2,091 kWh/m², a mean temperature of 26.1°C and a 43.6°C peak, with cloud conditions applied to 15% of hours. That series drove an hourly model of a 1 MW photovoltaic array coupled to matched 1 MW alkaline and PEM electrolysers, with efficiency and stack degradation made temperature-dependent through Arrhenius kinetics using activation energies of 55 kJ/mol for alkaline and 65 kJ/mol for PEM. Output was projected across 20 years and compared against an average-India reference case at 85% irradiance, 3% photovoltaic loss and 60°C operation. The work was published as a 19-page two-column paper with 19 figures and more than 60 references, plus a 9-slide deck.

Data sources

• Synthesized typical meteorological year for Jodhpur, Rajasthan — 8,760 hourly records generated with pvlib's Ineichen clear-sky model
• Garcia-Navarro et al. (2024) on PEM stack degradation and Bonanno et al. (2024) on elevated-temperature PEM operation
• IEA levelised cost of hydrogen maps (2024) and the European Hydrogen Observatory
• Sharma & Sagar (2024) policy analysis of India's National Green Hydrogen Mission

Figures from this analysis

What this would have cost

This session was one of 67 audited against what a qualified specialist would spend producing the same deliverable alone, at mid-market US consulting rates.

Order-of-magnitude estimates (±30%) by design. The human baseline assumes one specialist working full-time without queueing or meetings, and excludes data and software licensing. The K-Dense figure is the credits a session consumed, valued at the Plus rate. What you are actually charged is capped per run — $9 at Standard, $29 at Pro — so the real gap is wider than shown. Full methodology.