Harnessing the Power of the Sun to Fight Malaria

Sub-Saharan Africa’s tropical climate makes it an ideal breeding ground for mosquitoes, which contributes to the region experiencing the world’s highest rate of malaria transmission and deaths. But one aspect of the region’s climate is now being leveraged to accelerate the fight against malaria-carrying mosquitoes: the power of the sun.

The U.S. President’s Malaria Initiative (PMI) partners with 24 countries in Sub-Saharan Africa to combat malaria. An important tool for controlling malaria is indoor residual spraying, which treats the inside walls of homes with long-lasting insecticides that are safe for humans but kill mosquitos.

Historically, the electric grid and generators powered cooling systems for insecticide storerooms and charged electronic devices that collect the data needed to implement effective campaigns.

With support from PMI, communities are finding that solar power can provide the required electricity, cheaply and more reliably.

Adapting to High Temperatures in Madagascar

With almost all regions of Madagascar receiving more than 2,800 hours of sunlight per year, the country is an ideal location for solar power. However, the island’s weather can also create challenges for malaria prevention programs.

“One of the major concerns in Madagascar is the impact of climate change like high temperatures and violent storms,” said PMI VectorLink’s Regional Environmental Compliance Manager Tahina Masihelison. “These interfere with the storage conditions of the insecticides because either the storerooms are not electrified, or the power is cut for several days after the passage of storms.”

The maximum recommended storeroom temperature for IRS insecticides is 35°C (approximately 95°F). Higher temperatures can make the insecticide less effective or cause the insecticide containers to degrade. In Betioky District, in southwest Madagascar, temperatures can reach 42°C (approximately 107°F) even in the shade.

The PMI project in Madagascar tested the use of a solar-powered cooling and ventilation system in the Tongobory insecticide-spraying operations site in the southwest region of Madagascar. The ventilation system comprises a solar panel that can produce 500 watts of electricity, a battery, an AC/DC inverter, a humidifier, and a fan. The battery stores the energy collected by the solar panel and powers the fan and humidifier when the sun is not shining. The ventilation system keeps the storeroom cool and distributes the air evenly, eliminating hot spots.

After the solar powered system was installed, the storeroom temperature decreased by 12°C on average. If the outside temperature was 40 – 44°C (approximately 104 to 111°F), the temperature inside the storeroom was cooled to between 28 and 32°C (approximately 82 to 90°F).

The advantages of solar power over generators are significant. In Madagascar, a 500-watt solar installation with a humidifier costs around $430 to run eight hours a day for 30 days, while a generator costs around $730. While generators are widely available and easy to install, their fuel pollutes the environment, they require recurring fuel costs, and they are bulky and noisy. Solar panels, in contrast, are quiet and light making them easier to transport and install.

The new technology supports electrification of the central storerooms beyond a single spray campaign, as the expected lifetime of a battery is four years while a solar panel may function for 20 years. Trained storekeepers are responsible for maintaining the equipment so that insecticide can be ordered in advance of campaigns and stored year round.

Reliable Power for Data Collection in Tanzania

Beyond their use for cooling storerooms, solar panels can be used to charge devices for mobile data collection. Use of mobile devices increases the effectiveness of insecticide spraying campaigns by enabling same-day processing of data to track progress: structures visited, areas covered, and populations protected. Previously, data was recorded on paper and manually entered into a data system, a time-consuming and labor-intensive process that could result in delayed availability of data for day-to-day decisions.

For mobile data collection to be possible, mobile devices need to be charged. In the past, the project rented generators and purchased fuel, power stabilizers, and extension cables to charge the devices, and used electricity at sites where it was available. However, maintenance issues and frequent power cuts resulted in the electricity supply being unreliable. In addition, electricity is not available in some hard-to-reach communities. The portability of the solar chargers enables a smooth reallocation of the panels across different operational sites.

In 2020, PMI piloted the use of solar panels for charging mobile devices in Tanzania and in 2021, the project scaled up the use of solar panels to transition to fully mobile data collection. The solar panels provide a reliable power source for the mobile devices so that key data is available to spray campaign planners and implementers as soon as they need it.

Using solar panels also cuts costs. While electricity costs less in the short-term for areas on the grid, approximately $4,152 per spraying campaign, the grid does not reach many rural settings, which have relied instead on generators to provide the necessary electricity. Solar power is more cost effective than generators—with an upfront cost of around $12,300 for the solar panels compared to a cost of around $34,000 for generators to power a campaign.  Currently, the Tanzania team has 532 solar panels and enough phone chargers for 1,325 active devices.

“The rollout of solar charging systems enhanced the quick availability of data that helped timely decision-making and adjusted field supervision priorities among operations sites. Spray operators were able to operate with charged phones every day, establishing a stable synchronization process at the end of the spray day,” stated Ditrick Novat, PMI VectorLink Tanzania’s Monitoring and Evaluation Officer.

The solar panels are available to Tanzania’s National Malaria Control Program, if needed. Scaling up these systems can help significantly with a spray campaign’s reach and enable malaria services to remain resilient, particularly in more remote or harder to reach locations.

Combating the Impacts of Climate Change

With the impacts of climate change becoming more extreme, countries are increasingly concerned with how climate change will affect the prevalence of malaria as warmer, wetter, and more extreme weather makes it easier for malaria-carrying mosquitoes to breed and spread their disease. Hotter and more extreme weather can also cause disruptions to malaria programming. Transitioning to solar power enables malaria services to remain resilient against shocks like climate change while reducing carbon emissions, a key aim of the U.S. Agency for International Development’s (USAID) Climate Strategy 2022-2030.

As the experiences in Madagascar and Tanzania have shown, transitioning to solar power can make the fight against malaria more effective, cheaper, and less damaging to the environment, while bringing renewable power and a more promising future to even the remotest communities.

Cover photo: Spray operators spraying a practice wall while a supervisor watches. Photo credit: Arnaud Rakotonirina, VectorLink Madagascar