Solar Baking Under the Sonoran Sun

50 Home Power #59 • June / July 1997

alk down almost any city streetin Sonora, Mexico and you’relikely to see bakeries filled with

sweet breads, empenadas and Mexicancookies. Ciudad Obregon is no different.In a small, poor neighborhood on theoutskirts of Ciudad Obregon (a city of400,000), a group of women havestarted their own bakery. Along the dirtroads of Aves del Castillo and under theheat of the Sonoran sun, this smallgroup of women make and sell theirown breads and empenadas. Thesewomen are taking a differentapproach—they’re baking with the sun.

Two years ago, Ken Olson and I, of Solar EnergyInternational (SEI), had the pleasure of visiting Aves delCastillo. Through the Tucson based Farmer to Farmerorganization and the Sonoran branch of Save theChildren (FAI), we were introduced to a woman’s groupcalled Mujeres Activas (Active Women). And active theyare. These women, from one of the poorestneighborhoods of Ciudad Obregon, have not let theireconomic problems impede their desire for an improvedquality of life. With the help of FAI, Mujeres Activashave held nutrition clinics, started a program to sell soyproducts, learned to build straw-bale houses, and havebeen building and cooking with solar ovens.

There is a great need for employment in Aves delCastillo. The women of Mujeres Activas were lookingfor a micro-enterprise that could help support theirfamilies. Of all the different possibilities presentedbefore them, they felt a solar bakery could best meettheir needs. And having solar cooked for their familiesfor months, they were already hooked on solar cooking.

Laurie StoneSolar Baking Under the Sonoran Sun

©1997 Laurie Stone

WW

51Home Power #59 • June / July 1997

Solar Cooking

For the next two years while we looked for funding, thewomen worked out their plan. They decided who wouldbe involved, what they would bake, and how they wouldadvertise. With the help of the Tides, Greenville, andInternational Foundations, SEI was able to return toCiudad Obregon to help the women with the solar oven.Ed Eaton, Cholla Eaton (Ed’s daughter and our trustyphotographer), Laurie Loeb, and I, all of SEI, headeddown to Sonora to meet the women involved, teachthem to build commercial size solar ovens, and try outnumerous solar baked mexican pastries.

The OvenEd had designed a large commercial size solar ovenwhich we use to bake cookies at our local summer fair.With adjustments to the materials and the angle of theglass we had a great model for the bakery in Sonora.

We built two ovens for the Aves del Castillo bakery. Thefirst one was built at our office in Colorado. We madethis oven into a kit for easy assembly. This made itmuch simpler to teach all the steps involved in buildingthe oven while we helped them put together the kit. Italso made the second oven, built from scratch inCiudad Obregon with local materials, come togetherquicker than we could have ever imagined.

Each oven is 76 by 34 inches to accommodate astandard sized glass pane. They are made of 3/4 inch

plywood and ductboard insulation. The double panetempered glass is angled at 30˚ (the latitude of CiudadObregon is 28˚). There are two side reflectors (40 by 42inches), angled at 60˚, and a back reflector (76 by 42inches) which hinges so it can be adjusted to any angledepending on the season and time of day. Thereflectors are covered with Everbright, a shinyaluminum. The ovens are divided in half with a door onthe back side of each. We have found in our cookiebaking experience that using a fan to circulate the airdoes wonders for cookies and pastries. We includedone PV powered fan in each side of the oven. The fansare run by a 6 Volt, 5 Amp module.

The ovens are on stands with wheels on the bottom toaccommodate easy tracking of the sun. A localcarpenter built the stands along with an adjustable rackto hold the PV panel. When the ovens are not in usethe panel folds down out of the way, and when in use itcan be tilted to varying angles.

Building the ovens couldn’t have gone smoother. Thereare four women involved in the bakery, but on the firstday of the ovenbuilding eightwomen showedup. They told usthey weren’t all

Above: Cutting the wood for the oven frame.

Photo by: Cholla Eaton

Above: Making templates of theoven so it can be easily replicated.

Photo by: Cholla Eaton

Above: The basic oven box.Photo by: Cholla Eaton

Above: Attaching the doors for the oven.

Photo by: Cholla Eaton

Above: Working on the oven box.Photo by: Cholla Eaton

Above: Patricia attaching theEverbright to the reflector.

Photo by: Laurie Stone

52 Home Power #59 • June / July 1997

Solar Cooking

part of the official bakery group but were eager to learnabout building ovens. They asked us if it was okay ifthey helped out. We were ecstatic that more peoplewanted to learn about solar cooking. During the nextfew days many people stopped by to pick up a hammer,sketch out the oven plans, or just watch this huge solaroven being built.

On the first day we had barely pulled out the toolsbefore the women were hard at work. Their energy andenthusiasm made the first oven come together in a dayand a half. We thought that building the second ovenfrom scratch would take much longer, yet the womenknew exactly what to do and were so eager to get theoven built they didn’t want to stop working. One dayafter getting the main box put together and theinsulation put in, we left for our lunch break. When wecame back three hours later (many Mexicans like longlunch breaks to avoid working during the hottest part ofthe day), we were surprised to see that Rosalinda andLupita had not even left for lunch. They had workedstraight through and both of the side reflectors werenow on the oven. At that rate it only took two days forthe second oven to be ready for cooking.

Empenadas and More EmpenadasNow, with the ovens built, came the hard part—learningto run a business. The first thing that needed to be

done was to test out the recipes in the ovens. The nextthree days were spent making empenadas filled withsquash or strawberry jam, cookies, breads, muffins,pizzas, and coyotas (a Sonoran staple, a large flatpastry filled with brown sugar). We, of course, had to bethe tasters to make sure all the recipes were up to par.They were delicious! Every day the women also cookedlunch for everyone in the ovens, making rice, fish,pizza, and steamed vegetables.

During those next days we also discussed the follow-upto the project. We provided the women with a weeklyform to be filled out. The forms are to be used to keeprecords of the bakery and for us to keep track of howthe bakery is doing. It asks questions such as:

• How many of each type of pastry or bread was madeeach day?

• How many customers did you have each day?• How many people worked and how many hours were

worked each day?• How much money was spent on ingredients weekly?• What was the weekly profit?• What problems, if any, did you have with the oven?• What new things were tried?

The women already have an advertising plan workedout. They are going to hang up and hand out flyers

Above: Julia, Guillermina, andRosario working on the oven.

Photo by: Cholla Eaton

Above: Siliconing the oven.Photo by: Cholla Eaton

Above: Attaching the Everbright to the reflector.

Photo by: Cholla Eaton

Above: Rosalinda attaching the sides of the oven.

Photo by: Cholla Eaton

Above: Three of the children working on the doors.

Photo by: Laurie Stone

Above: Everybody working on the oven.

Photo by: Cholla Eaton

53Home Power #59 • June / July 1997

Solar Cooking

throughout the neighborhood and advertise on the localradio station. Dora Elia, a woman working with FAI, isgoing to teach them about accounting. SEI provided thewomen with a loan to buy any baking equipment theymight need such as bread pans and cookie trays. FAI isproviding them with a location for the bakery. Any profitsthey make, after they pay themselves a decent salaryand pay off their loans, will be reinvested in the bakeryto build more ovens, build a nicer space for the bakery,or even expand to open a cafe. They are also thinkingof building and selling smaller family size ovens topeople in Aves del Castil lo and neighboringcommunities.

Solar Baking SignificanceThe bakery was to open at the end of March. Thewomen of the solar bakery will not only be earningmuch needed salaries, they will also be spreading theword about solar cooking. Micro-enterprises like theAves del Castillo solar bakery have far reachingconsequences. Now that the women are earningmoney their children can go to school, they can providetheir families with shoes and clothes, and they don’thave to worry about whether they will be able to putfood on their plates.

This model micro-enterprise also has significance worldwide. The women of Aves del Castillo have proven that

with some will, determination, and sunshine, people canimprove their quality of life. There are people all overthe world who could benefit from a solar business likethis bakery. Although most solar projects in developingcountries focus on rural areas, there is also great needin the cities. Unemployment is high in the developingworld. Often people from rural areas flock to cities insearch of employment, only to find themselves living onthe streets with the rest of the unemployed. Reducingthe appeal of urban life by bringing electricity to ruralareas is one way solar energy can improve people’slives. But creating employment in cities is another wayto better people’s lives which cannot be overlooked.

The Sonoran commercial solar ovens are sure to bakeup hundreds of empenadas and coyotas. However,there is much more to running a successful solarbakery than a hot solar oven. The enthusiasm,competence, and devotion of these women is sure tomake Ciudad Obregon’s (if not Mexico’s) first solarbakery a huge success.

AccessAuthor: Laurie Stone, Oven designer: Ed Eaton, Solar Energy International, PO Box 715,Carbondale, CO 81623 • 970-963-8855Fax: 970-963-8866 • E-Mail: sei@solarenergy.org Web: www.solarenergy.org

Above: Rosalinda and Lupitavarnishing the finished oven.

Photo by: Cholla Eaton

Above: The bakery crew in front ofthe two finished ovens.

Photo by: Cholla Eaton

Above: Making empanadas and coyotas.

Photo by: Laurie Stone

Above: Watching the empanadas bake.Photo by: Laurie Stone

Above: Rosalinda with some fresh baked cupcakes.

Photo by: Laurie Stone

Above: Enjoying the empenadasfresh out of the oven.

Photo by: Cholla Eaton