New discoveries of natural gas resources in Mozambique, Botswana, Namibia and South Africa have made the use of natural gas to provide heating, cooling and electricity in Southern Africa more viable, says German energy systems company MTU Onsite Energy sales manager Georg Herz.

Finds in Mozambique are expected to yield more than 120-trillion cubic feet of natural gas and there is potentially more than 400- trillion cubic feet of shale gas in South Africa. The development of coal-bed methane gas reserves in Botswana and proven natural gas production in Nigeria also provide sources of natural gas.

“Natural gas is the cleanest fossil fuel and generators do not currently require exhaust gas treatment systems because the exhaust gases contain few residual contaminants. A standard cubic foot of natural gas contains 48 MJ of energy and one-trillion cubic feet can be used to produce 1 000 MW of power for 25 years.”

The clean high-temperature exhaust gases from natural gas generators can be used to provide process heat for industrial applications and the heat can also be used to provide cooling by means of an absorption chiller.

“Producing only electricity from natural gas fuels uses about 40% of the energy in the fuel. If heat and electricity are produced, more than 90% of the energy in the gas can be used,” says Herz.

However, gas generation requires infrastructure to pipe the fuel, which is a key consideration. Currently, the high cost of gas in South Africa is a barrier to increased adoption.

New finds in Southern Africa will help increase the availability of natural gas that will lead to more applications of natural gas electricity-generation technologies in future to provide distributed and off-grid generation.

“Gas has a big role to play in future power generation in Southern Africa. Further, the variety of gas sources leads to broader applications using natural gas to provide heat, cooling and electricity for commercial and industrial applications, as well as biogas from sewage treatment plants, landfill sites and farms.”

Sewage treatment works can be modified to produce biogas to provide combined heat and power not only for their own processes; landfills also produce and can use their own gas and farms can produce biogas using an anaerobic digester as well as enrich greenhouses with the cleaned carbon dioxide produced as fertiliser.

Combined heat and power applications are also efficiently used to provide electricity, heat and cooling in office buildings, shopping malls, healthcare facilities and industrial applications that require heat or steam.

“There is already a reticulation network and gas is available in Johannesburg. Owing to the cleanliness and economics of natural gas fuel, gas can ideally be used for continuous power generation once the availability further increases. The new discoveries throughout Southern Africa will only accelerate this development,” concludes Herz.

Herz was a keynote speaker at secure power company Master Power Technologies’ Data Centre and Secure Power roadshow in July.