Proper system design and installation are the first steps required for sustainable on-site health facility energy systems. Off-grid energy system design is quite complex and should typically be done by a trained professional. This page does not attempt to teach the user how to do a design and installation, but rather covers some general principles and lessons learned.

General Principles

First, it is important to emphasis the importance of doing a design! One-size fits all approaches to health facility energy system procurement are rarely effective.
A proper design must be done by a professional, include input from several stakeholders, and should be reviewed after system installation to check if assumptions were correct.
Consider using the energy audit template to collect information for the design process and use the optimization tool to compare different technology choices.
Professional installation of energy equipment is critical for proper operation. Several donor programs have been observed in the field which provide a health facility with energy equipment, but do not cover installation costs. The results are often that the health facility lets the equipment sit idle, or that they use a local technician without the training for proper installation of the equipment.

Key Lessons Learned

Evaluation of energy system cost based only upon initial cost discourages the choice for RE sources. Life cycle costs should be used and can be calculated using the online homer tool
Perceptions are often inaccurate or over simplified. Common misperceptions are that RE power systems are unaffordable, are a viable option for the entire load of large hospitals, or that they require no maintenance.
Anti-theft measures should be considered in all design plans.
“Maintenance free” gel seal batteries are a good option for health facilities.
Professional installation with proper labeling is critical for long term system operation.
Battery-based systems designed for and dedicated to a specific load (e.g. computer, vaccine refrigerator) have the highest success rate. Duplicate systems should be considered for a given facility (e.g. a stand alone isolated system for different critical loads).
For solar PV systems, annual average PSH values should only be used for locations with very little month to month variability.
Oversizing battery banks to provide multiple days of autonomy often results in continuously discharged batteries unless the size of the solar array is also increased or a generator is added to the system.
In order to recharge batteries and reduce system size and cost, Diesel/PV hybrid systems are recommended for all but the smallest health centers (as opposed to solar only systems).
Invertors which easily allow users to override low voltage cutoff are not recommended. Low voltage cutoff settings should often be increased from factory set default values to prolong battery life in developing country settings.
Access to locally available spare parts should be a consideration in initial equipment procurement.

United States Agency for International Development: U.S. AID from the American People

Energy System Design Considerations

Designing off-grid energy systems can be complicated and should be done by a trained professional. First, it is important to emphasis the importance of doing a design! One-size fits all approaches to health facility energy system procurement are rarely effective. A proper design must be done by a professional, include input from several stakeholders, and should be reviewed after system installation to check if assumptions were correct.

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Last updated: September 28, 2011

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