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Electricity was named as the most beneficial new technology of the 20th Century. It is clean, convenient and versatile, and the backbone of every modern economy. However, South Africa, like many other countries, is running out of generation capacity. Some say we need more power stations which in turn are the biggest carbon producers. What energy source should we use: coal, hydro, nuclear, oil, wind, solar or biogas? Some folk believe that humanity’s profligate consumption of fossil fuels is an insignificant contributor to global warming when measured against “perfectly natural” cyclical phenomena. The same people think Al Gore's movie - An Inconvenient Truth- doesn’t deserve a Nobel Prize for his work. For the record, most scientists believe no such thing. But no matter what our standpoint on the issue, just about everyone agrees on one thing: global warming is bad news. Greenhouse gases are affecting our planet’s weather patterns in ways we have yet to fully understand, and there’s strong evidence to suggest that we won’t like the long-term effects. US president George W Bush wrote to senators in 2001 explaining his administration’s views on global climate change: “As you know, I oppose the Kyoto Protocol because it exempts 80 per cent of the world, including major population centres such as China and India, from compliance, and would cause serious harm to the US economy. The Senate’s vote, 95-0, shows that there is a clear consensus that the Kyoto Protocol is an unfair and ineffective means of addressing global climate c hange concerns.” (www.whitehouse.gov) British Prime Minister Gordon Brown committed the UK to reducing carbon dioxide emissions by 60 per cent before 2050. The Climate Change Bill will make Britain the first country to put carbon emissions reduction targets into law. In South Africa, some forward-thinking individuals are adopting new, planet friendly technologies with an enthusiasm that occasionally borders on obsession though they make us proud. Starting small, and doing much of the work themselves, they’re designing, installing and exploiting myriad forms of “alternative” energy with the express intention of minimising their carbon footprints and living off the grid. Biogas digesters In effect, the technology provides environmentally savvy homeowners with a three-pronged solution to their power and waste management needs – energy production, a waterborne sanitation system, and an organic kitchen and garden waste recycling opportunity. Renewable power options such as solar arrays and wind turbines make sense in the domestic environment if the requirement is primarily for lighting and sufficient power for entertainment devices such as a radio or TV. But solar and wind power have serious limitations when it comes to power-hungry applications such as water heating and cooking. Consequently, most homeowners striving for independence rely on bottled liquid petroleum (LP) gas, as it’s the most practical option. However LPG is still a fossil fuel, and with an escalating oil price, it’s an increasingly expensive option. Biogas, unlike LPG, is considered a green energy source because it’s not derived from crude oil. Instead, it’s created in the here-and-now from black water (raw sewage), kitchen scraps, garden waste and animal dung. The average domestic biogas digester is – on a technological level, anyway – simplicity itself. It comprises an airtight container with an inlet for the solid waste, an outlet for the nutrient-rich outflow, and a gas line to the kitchen. Inside, anaerobic (requiring no oxygen) bacteria break down nutrients in the organic matter. The final stage in the process is the production of methane and carbon dioxide, making up two thirds and one third respectively of the total gas produced. One cubic metre of biogas provides at least two hours’ cooking time, or an electrical output of about 1,5 kWh. Biogas digesters are nothing new, having been developed in the 1950s. Today, over 14 million biogas systems are operating worldwide, with China, India and Nepal leading the way. But they are less common in the West, and virtually unknown in South Africa. AGAMA Energy, Cape Town, hopes to change all that. Watch this space for more information! |
