Agriculture: Delivering Water with Sunlight
Photo credit: Courtesy: Center on Food Security and the Environment
Agriculture: Delivering Water with Sunlight
Innovative multi-year project shows promise of economically and environmentally sustainable solar irrigation systems This story is part of a series about Stanford researchers developing solutions to water supply and access challenges affecting billions of people.
Innovative multi-year project shows promise of economically and environmentally sustainable solar irrigation systems
This story is part of a series about Stanford researchers developing solutions to water supply and access challenges affecting billions of people.
In northern Benin, West Africa, the dry season between rains can last six to nine months at a time. Because most of Benin’s smallholder farmers rely on rain-fed agriculture for their food supply and income, the dry season can foster not only food insecurity, but poverty, illness and malnutrition. Groundwater is often too deep for traditional wells to reach, and the high price of fuel makes it difficult to rely on electric irrigation pumps.
In 2007, Stanford’s Center on Food Security and the Environment (FSE) joined with the Solar Electric Light Fund (SELF), to bring solar power to villages in Kalalé, Benin. The Stanford Woods Institute’s Environmental Venture Projects provided initial funding for the collaboration. SELF helped the villages install solar arrays to power drip irrigation pumps, which farmers now use to grow high-valued crops in “solar market gardens.” This work expands on the African Market Garden project pioneered by the International Crops Research Institute for the Semi-Arid Tropics.
“The economic benefits of these irrigation systems are clear, but the health benefits are also very encouraging,” said FSE Director Rosamond L. Naylor, the William Wrigley Professor in the School of Earth, Energy & Environmental Sciences.
The solar arrays, which are paid for by SELF and installed and maintained by villagers, use the sun’s energy to power water pumps that tap into deep wells. The pumps deliver water to plants through a system of rubber hoses with small perforations, so that water drips onto the roots of individual plants throughout the day, reducing water waste and improving plant growth. In the dry season these crops provide a steady food source, better nutrition and higher household incomes as families sell extra produce at nearby markets.
Working with a local women’s farming cooperative, Naylor and FSE fellow Jennifer Burney designed a multi-year survey to measure the impacts of a small pilot subset of solar market gardens. Naylor is a senior fellow at the Stanford Woods Institute and the Freeman Spogli Institute for International Studies.
The project, which recently expanded to eight more villages, is looking more closely at specific health indicators like children’s height, weight, anemia rates and frequency of illness. “We know that solar market gardens provide families with more food and more diverse diets,” Naylor said. “Now we want to understand exactly how this is improving overall health.”
Naylor and Burney looked at how the new irrigation systems affect farming households’ food security, income, health and well-being during the dry season. They found that solar irrigation technology yields substantial and significant benefits in the form of higher household income and nutritional intake. They also found that the technology is cost-competitive in the medium term, especially where fuel supplies for other types of pumps are unreliable. (See "An Alternative Development Model: Assessing solar electrification for income generation in Benin.”)
Preliminary results of the ongoing study highlight several key impacts of the solar market gardens:
- Food insecurity dropped 17 percent and nutrition security improved in households with access to the solar irrigation system
- Families with solar market gardens were able to spend an average of $0.69 more per day (per person), primarily on food and especially during the dry season
- Solar irrigation systems made it easier for households to meet their daily water needs
- Farmers with solar market gardens spent less time working on their plots and were much more likely to report that their overall family well-being had improved in the first year of the project
- Within a year, the village with the first pilot installation developed an elementary school curriculum to teach children about solar irrigation technology and high-value crop production
Looking Ahead and Scaling Up
Naylor and Burney are optimistic about the potential for this technology to scale up, to improve regional and national food security and economic development in Benin, and beyond. In 2014 the project expanded to eight new villages, and our surveys expanded to measure household health indicators in much more detail. A goal of this phase of scale up is to create a regional market and learning center for the technology, so that it can be replicated in other areas of West Africa. The goal is to provide careful evaluation of the solar market garden system using a randomized, control-study approach at each phase of the scale up.
As the world struggles to cope with a changing climate, the Stanford project’s data could help shape the debate on how best to promote environmentally friendly development in the poorest and most vulnerable nations.
A version of this story originally appeared on the website of the Center on Food Security and the Environment.