Taqueria Poncho is the first solar powered street vender cart to do business on the streets of Oaxaca, Mexico. The inventor of the system is swiss engineer, Michael Götz. The vendor who operates the cart is Alfredo Garcia Martinez.
A parabolic trough reflector is mounted above the cart, creating a strip of light focussed onto a copper tube filled with water. This tube sends the water, when heated to 130°C, to a pump. Water vapor is produced, goes directly to the steamer. This allows the broth, tortillas, and beef barbeque to continue cooking and be kept at a constant temperature.
The system is designed to follow the sun. As the sun changes position, the reflector will automatically adjust to maximize solar exposure. Garcia Martinez mentions that when the system is in use, he will typically save 60-70% of the natural gas he normally uses. Götz feels these systems will help relieve the gas shortage Mexico will face in the coming years. The country is beginning to import natural gas, and prices will rise. An interesting side benefit is noted by Rodrigo González Illescas, Comptroller of Oaxaca de Juarez. He said the municipality's interest in this type of project is primarily civil protection, as it is known that there are frequent ambulance trips within the city, many caused by the explosions of gas cylinders. Hence the local government is sympathetic to allowing the solar powered carts to be tried.
Of course there are disadvantages to the system as well. It works during the day, but the cart converts to gas for evening use. Rainy days, and working in shady areas also require using gas. Another drawback is the size of the solar griddle. It is about 65cm x 100cm x 65cm, and exceeds the space available to many street vendors. However, due to the potential savings of gas and as a civil protection measure, it is likely these disadvantages will be overcome. The future will see more carts in Oaxaca like the one operated by Garcia Martinez.
News: Since spring 2013, Taquería Poncho is using a new foodstall. It is larger and made with a lot of stainless steel. The new reflector has more power, its size is 180cm x 150cm.Try the solar tacos every morning from 9 AM to 1 PM at the corner of Escuela Naval and Gardenias in Colonia Reforma of Oaxaca!