Access to reliable, affordable and sustainable energy is essential for improving living standards, development and economic growth. From a healthcare perspective, energy is a critical parameter for delivering and improving healthcare services and life-saving interventions in the Global South. This review provides an estimation of the energy needs of different healthcare facilities as a function of patient capacity and services provided. It also presents the strengths and limitations of several energy sources that can be used to meet these needs. The review focuses on energy provision in off-grid scenarios and for satisfying peak demands of grid-connected hospitals.

The initial key observations are that fossil-fuel generators are the main energy source because of their low investment costs. However, this technology can no longer compete with the energy produced from renewable sources in terms of levelized cost of electricity (LCOE). Photovoltaics (PV) has an LCOE of 0.09 USD/kWh, versus an average 0.25 USD/kWh for diesel generators. Moreover, PV is a modular technology that can efficiently meet energy demands in an environment-friendly way. Wind turbines share many strengths of PV and yet both technologies suffer from intermittent energy sources. They must therefore be coupled with a storage system that provides continuous and stable electricity. Today, energy is mainly stored electrochemically, in the form of lead-acid batteries. However, this review shows that nickel-metal hydride (NiMH) should be used when possible for their higher energy density (200 Wh/l versus 80 Wh/l), non-toxicity, safety and simple maintenance. Alternatively, lithium-based batteries should be used when the energy density and number of cycles is a priority. Other energy production means (e.g., hydropower) and storage technologies (e.g., flywheels) are reviewed as well.

In conclusion, the optimal energy solution for medium-to-large healthcare facilities, especially for those in off-grid settings, is a hybrid system wherein the strengths of a renewable energy source coupled with efficient batteries is combined with a diesel generator to minimize the LCOE.