Women in Guatemala cook with a solar oven that they built themselves. Credit: Tom Cogill

At 4 a.m., Eunice in El Jobo, Nicaragua, puts a fistful of madero de madura (seasoned firewood) in her mud and brick oven. The wood catches flame; a cloud of smoke and ash rises, resting beneath the metal roof. Eunice launches into a coughing fit. Her daily routine has started.

Around the world, 3 billion poor people like Eunice cook over unventilated wood, coal or dung fires. About 4 million deaths a year are associated with inhaling the smoke1. Hours spent gathering wood or biomass fuel robs families of time and energy needed for education and work. Deforestation degrades soil and destroys habitats.

Massive efforts are under way to introduce cleaner ways of cooking, such as with solar ovens. Most of these attempts are too narrowly focused. Stoves are replaced without channelling women's time savings and health improvements into community development.

Women who must cook with solid fuels face many other obstacles, such as poor health and malnutrition, lack of transportation, illiteracy, ingrained social attitudes about their roles and potential, and resistance to change from beneficiaries of the status quo.

More-holistic approaches can address a constellation of difficulties, as shown by our long experience with the Central American Solar Energy Project (CASEP, of which W.F.L. is president and L.S.B. is programme coordinator). CASEP is a private foundation funded mainly through family donations. For nearly 25 years, it has provided financial and technical assistance to thousands of poor, rural women for the construction of solar ovens in Guatemala, Costa Rica, Nicaragua and Honduras. CASEP weaves into its programmes opportunities for women to break gender barriers and receive education on health, human rights, leadership and community engagement.

Our modest programme is a worked example of the kind of on-the-ground change that is needed more broadly at the nexus of international development, clean-energy markets and sustainable technologies. We call on decision-makers in these fields to reframe their work around supporting women to adopt clean cooking by following four key practices (see ‘Four steps to clean cooking’). These steps encourage individual, household and community development while reducing carbon emissions.

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Wider benefits

Solar-cooking initiatives face challenges. Critics emphasize the difficulty of developing financially sustainable markets for solar ovens. The most durable stoves are expensive and difficult to manoeuvre or repair. Cheap ovens are insubstantial and easily stolen. Solar cookers that are designed to focus the Sun's rays with parabolic mirrors are vulnerable to wind damage and require constant repositioning to catch sunlight. Opportunities for generating profit are limited — no one sells sunshine.

Distributing subsidized solar ovens also has drawbacks. International-development programmes are results-driven and focus on easily measurable impacts. They do not draw connections between women's cooking needs and their other needs. The focus is the stove, not the people who use it.

The most prominent clean-cooking effort is the Global Alliance for Clean Cookstoves. Launched five years ago by then-US secretary of state Hillary Clinton, the alliance counts 1,000 government, non-profit, academic and business groups as partners. Its goal is to convert 100 million households to clean cooking fuels by 2020 and to establish a thriving market for clean stoves, with a focus on eight countries: Nigeria, Kenya, Uganda, Ghana, Guatemala, Bangladesh, India and China. Solar power is not a focus: of 278 stove designs promoted, only 13 are sun-powered.

CASEP has a different approach. Zero greenhouse-gas emissions and free fuel make solar ovens the cleanest and most accessible option for many poor households, costing around US$300 each in materials and workshop costs (see go.nature.com/pvweju).

When CASEP was launched in 1991, local tradesmen built the ovens and presented them to their wives. The women took the gesture as criticism — what was wrong with how they had cooked all those years? The ovens gathered dust. So we put women at the heart of the programme.

Keeping momentum

Today, at solar-cooking demonstrations, we identify 10–20 women who wish to build an oven. We train some as instructors and provide materials. The women invest a lot of work and time, spending up to three full-time weeks or ten weekends working on the stoves.

Women construct them from plywood, glass, aluminium and metal. They use hammers, hand saws, shears and sealant guns — items they had considered 'men's tools'. Participants complete each step of the construction process by rotating among several work stations. Building the ovens collectively and in stages nurtures a spirit of solidarity.

The focus of international-development programmes is the stove, not the people who use it.

The workshop serves as a proving ground for leadership skills. Participants elect a leadership team to manage the workshop finances, meals and interpersonal issues. Once the ovens are complete, graduates celebrate in public at the clausura, a solar banquet with music and festivities. “This oven that we women have made with our very own hands is a source of pride for me ... it's a great advantage,” said Maria Francisca, a workshop graduate in Nicaragua. Adequate follow-up is key to the adoption of solar cooking. Ongoing support is provided for at least two years by CASEP staff in each country.

Women who use solar ovens tell us that they save the time spent on gathering firewood and the money spent on fuel; are able to leave their meals to cook unattended; and enjoy clean indoor air and improved health. And the benefits go further.

Women apply their new skills to advocate for themselves and others. They form solidarity groups, feeding programmes and micro-loan enterprises. They develop ecological household systems for water and waste, organic community farms and urban agriculture programmes. “They emerge as new women: women without limits, who value themselves, who have rights, who refuse to be limited or violated by anyone,” said Fatima, a participant in Costa Rica2.

CASEP's affiliate group in Honduras, the Association of Women Defenders of Life, manages a micro-loan programme, leads efforts to prevent maternal and child malnutrition and facilitates leadership and civic-engagement programmes for women and young people.

In Costa Rica, CASEP gave rise to Casa del Sol (House of the Sun), a demonstration centre for household solar applications such as cooking, water purification and lighting. And Sol de Vida (Sun of Life), which constructs solar ovens, works for gender equality and engages in ecological activism.

In Nicaragua, the Solar Project Foundation for Nicaraguan Women won the 2013 Energy Globe World Award in the air category, for its construction of solar ovens in rural and semi-urban communities.

There have been setbacks. Some women's associations have stopped. Ovens have been abandoned. Programmes have ceased owing to corruption and lack of leadership. Finding and retaining skilled female leaders is CASEP's biggest challenge. Many of the programme's beneficiaries become local community leaders and advocates; few want to develop the professional skills needed to lead an international organization.

The difficulty of adapting lifestyles to cook with sunlight is also a challenge. Although a CASEP solar oven is simple to repair, long-lasting and large enough to cook a full meal for a typical family, it requires longer cooking times that depend on the weather. Households that use solar cooking need to change how and when they prepare food, and need ongoing support.

Leaders in public policy, sustainable technologies, emerging energy markets and international development should focus on encouraging women to adopt clean cooking practices. Conversion efforts towards cleaner stoves that leverage savings in women's time and resources for the common good will amplify the benefits and create community change.