Optimising mini-grid efficiency in Ghana: A techno-economic analysis of hydrogen production from redundant solar energy for fuel cell power generation

Abstract

Rural mini-grids in Ghana often experience substantial midday solar PV generation surpluses due to mismatches between peak production and local demand, with excess energy (redundant energy) frequently curtailed once batteries are fully charged. This underutilisation limits the socio-economic benefits of renewable electrification and highlights the need for alternative long-duration storage solutions. This study investigated the techno-economic feasibility of converting excess PV energy from a 54 kWp mini-grid in Aglakope, Ghana, into hydrogen via electrolysis, storing it, and reconverting it to electricity using fuel cells. Redundant energy generation was quantified using measured PV output and load consumption and validated using statistical error metrics (R² = 0.955). Hydrogen production and recovery potential were modelled for different electrolyser technologies, and system performance was evaluated using round-trip efficiency (RTE), levelized cost of hydrogen (LCOH), and levelized cost of storage (LCOS), with comparative analysis against additional battery capacity. The results yielded an average monthly excess energy of about 2250 kWh, convertible into 43–53 kg per month of hydrogen depending on electrolyser type. The proposed hydrogen-fuel cell pathway yielded a RTE of 44.4 %, LCOH of $4.97/kg, and LCOS of $0.249/kWh, which is about 13 % higher than lithium-ion storage benchmarks. The study findings demonstrate that hydrogen storage can complement batteries, offer seasonal and multi-day storage capability, and reduce renewable curtailment. Therefore, wider adoption could be supported by cost reductions, efficiency improvements, and enabling policies, positioning hydrogen-based storage as a viable pathway for resilient, low-carbon rural electrification in off-grid contexts.