This work aims to show how sustainability and renewable energies could benefit a rural area of Africa (in São Tomé) by means of using solar energy and biogas. Applying these technologies requires ingeniousness and little founding, the favourable outcomes are becoming less dependent of fossil fuels (wood, coal and gasoline) while saving time and, more importantly, the forest. We have taught how to design, build and operate systems for cooking, lighting and water-heating that use renewable sources of energy.

The Petri-dish where this study has been conducted is ‘Escola de Artes y Oficios Diogo Vaz’ (association Natcultura) located in the roça Diogo Vaz, 36 km away of São Tomé city. This roça is a rural area in where approximately five hundred people sustain their living from cacao cultivation.

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Problem statement

The increasing use of natural resources and the emission of higher amounts of contaminants to the atmosphere, rivers, seas and soils have sown, once more, the necessity of using our sources of energy in a sustainable way. That is, the sustainment and development of our civilization must be based on a responsible mode of consuming the raw materials, in a way that this will not induce to their extinction. In other words, the idea is to consume at the same rate nature can produce. Moreover, the emissions generated from the mentioned consumption should have the lesser impact on the environment and human beings in order to sustain life and progress. 

The upcoming depletion of fossil fuels (oil and gas) joins to the fact that the population of the world is constantly increasing. This population have equal right to use energy since it is one of the pillars to nourish the development, enhancing the quality of life of the society.   In this manner, renewable or sustainable energies are gaining importance nowadays, to mention some; solar, wind, hydraulic, geothermic or tidal energy. Additionally there is a strong investment of money, time and ideas in order to produce gas and liquids from renewable sources as algae, plants-crops, wastes (forestall, agricultural, wooden, animal…), wood or coal. All of them to incorporate the term bio- to indicate the renewable source: biogas, biofuel, biodiesel, etc.

São Tomé and Principe is the second smallest country in Africa, situated in the gulf of Guinea, posses around 150,000 inhabitants from which ca. 60 % of them live from agriculture-fishing. The electricity is obtained both by hydroelectric plants and from fossil fuels as petroleum or gas. Interestingly, the immense majority of the kitchens operate by combusting wood and charcoal (made by rudimentary methods from wood) and therefore, representing a threat for the fragile ecosystem that exists in this country. The humid equatorial climate alternated with periods of strong solar radiation has leaded to a fauna and flora that has evolved separately from continental Africa, creating a rainforest which is unique in the world. It is hence important to propose initiatives for protecting this ecosystem. The source of energy in São Tomé cannot come from agricultural-land since the amount of crops produced from it is barely able to feed the population and exportation of cacao.

The education of sustainability is the main point of concern, as long as this is the long-term road for giving the African people tools for developing their own ideas and technology. The approach is investing in their education first to further devote money for infrastructures of sustainable energy.

This work aimed to teach sustainability and renewable energies to the community of Diogo Vaz and particularly to the internal students of the school, and show at the same time how these technologies could benefit their life. We will set first the objectives of the work based on the limitations of founding and environment (temperature, solar radiation, access to raw materials...), selecting the appropriate technologies to develop in the area. We will explain the workshops undertaken, giving appropriate data for building replicas. Finally we will explain the results and what we all have learn. Additionally we will provide with some pictures of the devices built and useful references.


The main targets of the project can be divided in (i) educational and (ii) practical. The educational targets consist in teaching what sustainability is, what renewable energies are, raise the concern of the students on the peculiar ecosystem in where they live, how fragile it is and what actions, if any, are required to protect it. 

The practical objectives consist in a series of workshops in which we had built systems to use renewable sources of energy for cooking, lighting and the sanitarian showers. Although electrification is imperative in the area, due to the limited time and founding we decided to concentrate our efforts for saving wood in the kitchen, and among all the available technologies we selected a number of them based on the conditions of the area, that is, temperature, humidity, availability of raw materials (manure, clay, and solar radiation among others), etc. The selected sources of energy for the school of Diogo Vaz were solar and biogas.

Besides the educational targets above mentioned we described a little of the science behind the workshops. As we taught these principles the students, might be able to master the design-operation of the units for a given set of conditions.