There are several ways of beating the current hike in fuel prices. One of such ways is to switch to a different, cheaper, type of fuel.
Some vehicles are purpose made to run on gas – liquid petroleum gas (lpg) or compressed natural gas (cng). Even those that are not manufactured to run on gas can be fitted with a gadget which enables them to run on gas or on petrol/diesel. Many motorists in Kenya and Tanzania, among other African countries, have had their vehicles converted to gas propelled ones.
What makes gas attractive is that it is cheaper than traditional fuels – petrol or diesel. The current prices of diesel, petrol and lpg are K1,920 per litre, K1946 per litre and K2,726 per gram, respectively. A kilogram of lpg is equivalent to nearly 2 litres. Therefore, if we convert the price of lpg so that it is expressed in litres (to make it comparable to those of petrol and diesel), it will be K1,363 per litre. This is markedly lower than the price of petrol or diesel.
All is not rosy with gas propelled vehicles though. There are a few potential drawbacks to this solution. Perhaps the biggest of the drawbacks is the high cost of the conversion. The vehicles we use in Malawi are not compatible with gas and need to be fitted with a conversion gadget to enable them utilize gas. When I last checked, the price of conversion was the equivalent of USD1,000 in Kenya. Unless the vehicle is one with high usage, spending upwards of one million Kwacha on it just to make it compatible with gas would be prohibitive. It may not be worth it for vehicles whose usage is low, as they would hardly payback the investment.
Additionally, a vehicle running around with a container of highly inflammable gas is potentially a mobile bomb. If the fuel system developed any leakages, which is not a great impossibility under African conditions, the tiniest of sparks near the leakage would cause an explosion. Insurers would therefore be reluctant to extend insurance cover to such vehicles, for understandable reasons.
What is more, the energy density of gaseous fuel is lower than that of traditional fuels. Put in layman’s language, this means that a litre of petrol or diesel will take you a longer distance, albeit by a small margin, than a litre of gas. The statement that gas is cheaper than traditional fuel for running vehicles, therefore, needs to be qualified properly.
Be that as it may, there is one type of gas that would be economically interesting in countries which do not produce natural gas, like Malawi. This is biogas. Biogas can be obtained by anaerobically digesting practically any organic waste. By anaerobic digestion is meant the digestion of matter by bacteria in the absence of oxygen. Special tanks called digesters are made to facilitate this process. The feedstock to the digester is simply organic waste such as that which can be collected from produce markets or from homes. Cow dung is excellent material for anaerobic digestion, as is human excreta. It is amazing how much value can be gleaned from what is normally considered waste. Waste is not waste until it is wasted.
The digester is an airtight tank with a tube attached to one end to act as an outlet for the resultant gas. The gas, which is typically a mixture of methane, CH4, carbon dioxide, CO2, and other trace gases, is collected in an appropriate container for storage and subsequent use as a fuel. Because of the methane content, biogas is readily flammable and is normally used for lighting or cooking.
In its purest natural form biogas will contain roughly 80% methane, otherwise the methane content can be as low as 50%. It can be made purer by absorbing the carbon dioxide in a bath of hot water, a process known as upgrading. Upgraded biogas is essentially identical to natural gas and can be compressed to yield what is known as compressed natural gas (cng). Like lpg, cng can be used as fuel in gas compatible engines.
Like it is said, “wakufa saopa kuola (he who is dead cannot be scared of decomposition),” Malawians should not be scared of trying out some of these solutions to our chronic energy problems. The beauty about biogas is two-fold: it can be locally made, and the feedstock for its synthesis is all over the place. With our low and still dwindling foreign exchange reserves, use of locally made fuel would be a great relief to the enormous pressure on forex. Let us begin searching within Malawi for alternative fuels.