Energy Generation
Although some rural schools in East Africa have virtually zero energy needs, this is changing, with an increasing requirement for wireless routers, smartphones and computers. While electric lighting can be avoided during the day with strategic natural daylighting design, all schools require energy for cooking and water heating. Connecting to the national grid is a costly option for urban locations, with standby generators often being implemented during power cuts. For rural schools with limited budgets and increasing energy requirements, it is recommended to utilise smart energy saving principles and tried and tested appropriate technology applications.
Solar PV
Photovoltaic panels are reducing in cost and small power uses for lighting, mobile phone and computer charging can easily be met by a local installation.
A photovoltaic (PV) system consists of solar panels, an inverter and batteries, which convert solar radiation into electricity. Solar panels should be positioned to maximise sunlight exposure. On the equator, sunlight is directly overhead, but panels should still be mounted at 15 degrees to ensure that they self-clean. It may be beneficial to mount panels facing east towards the morning sun as batteries can accept the most charge when they are at their lowest. A PV system can be used for charging phones or computers and provide lighting with energy-efficient light bulbs.
Costing for a standard solar PV installation for a 50sqm classroom block with lighting, phone and laptop charging capabilities.
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Solar Thermal
Solar energy can provide low cost hot water using anything from a black plastic pipe to glazed solar collectors.
Solar thermal technology or solar water heating uses free, renewable energy from the sun to warm water, using a solar thermal collector. At its most sophisticated, a solar collector is a type of solar panel containing tiny tubes of water that are heated by the sun. However, it is possible to create a collector using any material that conducts heat, such as a black hosepipe or a glass topped metal box. Heated water is piped to a storage tank via heat driven convection for use in the kitchen or WC facilities.
A professional solar thermal installation consisting of an evacuated tube solar water heater
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Firewood
Burning wood for cooking is an expensive and polluting use of energy. Carefully designed eco-stoves can reduce smoke inhalation and improve efficiency.
Generally, either eucalyptus or pine is used as fuel wood for cooking in schools. Unless part of a sustainably managed plantation, this can contribute towards deforestation and increase a school's operational carbon emissions. Cooking stoves are often inefficient and unsealed, allowing heat and dangerous gases to escape into unventilated kitchens. Eco-stoves reduce heat loss by burning timber in a sealed and insulated chamber, while channelling dangerous gases away from the user.
COF Primaries A well ventilated kitchen contains fuel-efficient hybrid eco-stoves with the ability to burn both biogases and firewood
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Biogas
Biogas from a biodigester or bio-latrine system is a sustainable alternative to fuel wood that can also be used as a heat source for the school kitchen.
Biogas consists primarily of methane, which is produced through anaerobic decomposition of waste. Biogas can be produced from raw material such as manure, sewage and food waste, which are fermented in a closed system, known as a biodigester. Biogas can be used in a gas engine to produce electricity but in schools the most appropriate application is for cooking fuel. A hybrid eco-stove is recommended where a cast-iron gas hob is inserted into the traditional firewood-fuelled stove.
AWF Primaries The eco-stoves are fuelled with bio-gas supplied through a locally-made cast iron hob.
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Biofuel
New research has revealed cassava and banana peel as valuable raw materials that can be used as fuel instead of timber or charcoal.
There are currently various research streams into utilising agricultural and food waste in the production of biofuels and chemical additives. Cassava peel for instance has no mainstream use and its disposal can cause environmental issues. Research by BAM has been undertaken into potential uses for this waste, among which is the use of residual peels as fuel. Similarly, banana or matooke peelings can be converted into briquettes and used as an alternative to charcoal.
Green Bio Fuel has engaged communities and taught them to make briquettes from waste matooke peel