New research shows hospitals with electricity available at least 22 hours a day had inpatient mortality about 41% lower than those without.
The study examined 303 hospitals and reference health centres across North Kivu, South Kivu and Haut-Katanga in the Democratic Republic of the Congo (DRC). Published in the Proceedings of the National Academy of Sciences (PNAS), it is one of the first to directly link a facility’s power quality to patient survival.
In an exclusive interview with the report co-authors, ESI Africa unpacks what the numbers mean
From connection to survival
Researchers already know that electricity shapes what a clinic can do. The missing piece, says lead author Ryan McCord, a postdoctoral researcher in energy economics at Duke University, was the link to patient deaths.
“These studies have looked at things like service availability, equipment use, patient volumes and other measures of facility performance. There has been much less evidence directly connecting the quality and reliability of electricity to patient mortality,” he says.
So what does a 41% reduction look like on the ward? In the study sample, inpatient mortality fell from roughly 4.4% to 2.6%. “That is about 18 fewer deaths for every 1,000 patients admitted,” McCord explains.
But what is the practical lesson?
“Knowing whether a hospital has an electricity connection is not enough. A connected hospital may still lose power for hours at a time, or it may have some electricity without enough capacity to run all of its wards and equipment. Those differences appear to matter a great deal for patients.”
Sufficient and reliable power
The study deliberately separates two tests. Sufficiency asks whether a facility has enough capacity to run everything it needs. Reliability asks whether that power is there most of the day. A facility can pass one and fail the other.
“A small solar system might reliably power lights and a few basic loads, [but] it is insufficient to run oxygen concentrators or other clinical equipment that is critical for patient care,” McCord says. “A large generator may provide plenty of power when it is running, but fuel shortages or breakdowns can leave the facility without electricity for long periods of time.”
When the team relaxed the test to require only one condition, the effect shrank and lost statistical significance. “It really seems to be the combination of these two things that makes the difference.”
Why 22 hours a day
The reliability bar of more than 22 hours a day, or 91.7% uptime, began as a practical choice. It lined up with how the World Health Organisation (WHO) asks health facilities about electricity reliability.
“We did not know beforehand that 22 hours would turn out to be where the mortality relationship appeared,” McCord says.
The researchers re-ran their analyses at thresholds from about 20 to 23 hours a day. Across the full sample, mortality reductions began to appear at around 21 hours. In 18 facilities fitted with power sensors, the relationship appeared at around 22 hours. Beyond those points, extra hours brought no clear further drop.
McCord cautions against treating 22 hours as a universal target, as the result may be specific to the DRC. “What is useful is that we have at least the first starting point in an effort to identify the level of reliability at which health outcomes change,” he says.
“We think it’s really important that we set these kinds of reliability targets tied to the outcomes we actually care about, in this case patient outcomes.”
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The most exposed wards
The largest falls in mortality came in internal medicine and paediatric wards. The data cannot trace the clinical pathway from an outage to an individual death, but McCord points to plausible explanations.
“Patients in paediatrics and internal medicine wards are often very sick and may depend on things like oxygen that cannot be disrupted when the power goes out without severe consequences to patients,” he says.
There is also a question of priorities. “Hospitals may also protect some areas, such as operating theatres, with dedicated backup power, while general inpatient wards are more exposed to outages.”
More patients, more nurse days
The benefits reach beyond survival. Facilities with good power saw 17% more outpatients and 24% more nurse working days.
“The staffing result was particularly interesting to us,” McCord says. It could reflect working conditions, whether services actually operate, or how the facility can organise care.
Patients appear to respond too. “People may be more willing to seek care from a facility if they expect it to be open and functioning, and if they know that the services they need are likely to be available and of a high quality.”
Taken together, he says, the results suggest “reliable electricity affects the functioning of the facility quite broadly, not only whether a particular piece of equipment can turn on.”
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Reading the 41% figure
How should programme designers use the headline number? Laura Kwong, assistant professor of environmental health sciences at the University of California, Berkeley, and McCord stress that it captures electricity “as it exists in these facilities, with all the other things that come alongside it”, including equipment, staffing and management.
“I would not take our estimate and say that installing a particular solar system at any hospital will automatically reduce mortality by 41% overnight,” Kwong says. “Many other things might need to change – equipment may need to be purchased, new services might need to be offered, and staff trained on how to do them.”
Short-term reliability still counts. In the sensor-monitored facilities, power was fairly reliable on average, yet mortality rose in months when reliability dropped. “So even in the places that maybe have made all of those other investments, there are consequences to poor reliability, even in the short-term.”
Their message to programme designers is to ensure that the power is there, that it is reliable and stays reliable over time. “At the end of the day, electricity is a service provided by infrastructure. It must come with other things to have the kinds of transformational benefits we see in this paper,” maintains Kwong. ESI
Assess the research paper: Impacts of sufficient and reliable electricity in low-resource healthcare facilities
Ryan McCord, Samuel B Miles, Jackson M Mughuma, Daniel M Kammen & Laura H. Kwong (2026) Assessing the impacts of sufficient and reliable electricity in low-resource healthcare facilities, Proceedings of the National Academy of Sciences, 123, e2538126123.
