1.Suitability for Biogas

Temperature

The plains round Kendu are very suitable for biogas, as the daily temperature range is within the optimum range. Higher parts of Kenya are less suitable as night time temperatures fall below the range that the bacteria prefer. (I have tried biogas in Kakamega district where night time temperatures cause the process to slow down at night).

2. Materials

Before starting any biogas project people should identify the materials they will be using. There needs to be a supply of animal wastes to provide nitrogen and phosphorus. Such sources would be: cow dung, for example from cattle kept overnight in a boma. Other sources are pig manure, chicken manure from chickens kept in cages or other intensive rearing unit. Horses and goats also provide manure.

If there is a lack of animal manure human manure can be used. However, advice on health should be sought as to prevent infection the materials will need to be kept safely away from people while the process operates. At the end the waste products - liquids and solid - should be safe as all pathogens should be dead by that time.

The other source is vegetable products. These include: banana trunks after the fruit has been harvested, maize stalks, coffee wastes, water hyacinth, grass cuttings and so on. In areas where grass is burned during the dry season it may be suitable to use this grass in a biogas plant instead

3. Water

A supply of water is essential. This water need not be of drinking quality.

4. Uses for the gas

There is no point in making biogas before one knows what people are going to use it for, and who is going to use it.

Some possible uses are described in my paper on a Water Hyacinth project.

A small biogas plant can supply a family for cooking. A larger one can provide energy for such uses as small scale industries or crafts.

5. Uses for the other products

The solid and liquid products of a biogas plant are at least as valuable as the gas itself, and may even be considered as being more valuable. A biogas plant can be thought of as a device which bribes people with gas into making the valuable compost.

The fertilising outputs can be used to improve crops. If supplied to an enterprise growing for sale they could lead to classification as Organic Producer. Coffee is a good example of this, as Organic Coffee sells for a higher price than ordinary coffee.

Before setting up a large gas plant the uses for the output should be identified. It may be appropriate to get contracts for the use of the products.

In monetary terms the sale of the fertiliser would be essential for the overall profitability of the process. Even if they are used in a cooperative or family without money changing hands the value of these products should be emphasised.

These energy sources should also receive Carbon Credits from the Carbon Exchange market. For this purpose there should be an Association of Carbon free Energy producers, open to the smallest producers.