"Cooking with Solar Energy"

INTRODUCTION

Cooking by means of solar energy started in the '70s in response to the growing shortage of firewood resulting from chronic deforestation. A solar cooker needed no wood - just sun! With this in mind, dozens of research institutes developed solar cookers.

However, first of all something will be said about problems that may be expected in the introduction of solar cookers; it has become clear that several projects in which solar cookers were introduced were failures because insufficient account was taken of the local population.

SOCIAL ASPECTS

The social aspects of solar cooker introduction schemes can cause important problems, as cooking with solar energy differs radically from other cooking methods. Because of this, solar energy offers only a supplement to other energy sources, and can never provide a 100% replacement. Besides this, buying a solar cooker can cost a lot of money. In practice it is hard to explain that a technique with a limited application can still be economic. The applications are limited because:

the sun does not always shine

not all meals can be prepared in a solar cooker.

To begin with the sunshine: many people cook at dawn or dusk. A solar cooker cannot, therefore, be used. It is often difficult and sometimes impossible to change these cooking habits. Someone who walks an hour to the fields to spend all day there is not going to come home at midday to cook and eat. On sunless days the cooker is also useless.

Not all meals can be prepared in a solar cooker. The more important the meal is, the worse this problem becomes. The cooking box has two serious drawbacks: it cannot be opened during the cooking, to stir a meal or to add ingredients; and food cannot be fried or roasted in it. In the cooking box that will be described here the temperatures are not high enough. There are models which allow for frying and roasting, but they are complicated and less convenient. A cooker using a parabolic reflector is less of a problem but this can heat only one pan at a time.

The purchase price is a problem for the poorer groups especially; the cost recovery time varies widely according to local circumstances and in many instances can be as long as two or three years. The apparatus must therefore be made to a high quality, using accordingly expensive materials. The image of the cooking box also plays a part. In areas where the "modern, western life" is in demand, such a simple appliance may be rejected for vague reasons even when it is economically acceptable.

Finally a few remarks concerning its use. The cooker must obviously be so sited as to receive full sunlight. Children at play can easily damage a solar cooker so it also has to be out of their way; in towns, a flat roof is sometimes a suitable place. The different appliances can be heavy or awkward to move; facilities for an eventual repair should be nearby. Lastly, the users have to learn how to handle the cooker. The cooking technique is so unfamiliar, especially for the cooking box, that guidance during its introduction and afterwards is vital. If its users are at a loss to know how to use it, it quickly falls into disuse.

The problems outlined above are not intended to discourage the introduction of a solar cooker, but to illustrate that careful planning and preparation are a more than usually important aspect of the introduction of this technique.