Biomass renewable energy can ensure a sustainable future

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The Department of Energy (DoE) is now seeking the consensus of the National Energy Regulator of South Africa (Nersa) for the procurement of an additional 6,300MW of renewable energy.

Biomass, a lesser known but very viable form of renewable energy, entered the REIPPPP in Window 3 with the first biomass project being awarded and an investment of R1,061m ($108m) allocated to it. Last month in Window 4, the Ngodwana Biomass Energy Project was selected as a successful renewable energy bidder. Financial close for this project will take place later this year.

However, Rodrigue Kamba, project engineer for EES Africa, advocates an increased allocation and investment in biomass in South Africa going forward.

Organic material

Biomass energy is renewable energy that comes from organic material. It includes energy from both plant and animal matter and is derived from the reaction between carbon dioxide, water and sunlight, via photosynthesis.

One of the key advantages of biomass is its versatility. Not only can it be burned directly to produce heat and energy, but it can also be converted into a gas or oil to generate electricity (bio-power) and heat, or converted into liquid fuels (bio-fuels) for transportation needs.

"Biomass can be converted into electric power through several methods. The most common is direct combustion of biomass material, such as agricultural waste or woody materials," says Kamba.

Other options include co-firing, gasification, pyrolysis and anaerobic digestion. "Co-firing involves burning biomass, along with coal, in traditional plant boilers. Gasification produces a synthesis gas with usable energy content by heating the biomass with less oxygen than needed for complete combustion. Pyrolysis yields bio-oil by rapidly heating the biomass in the absence of oxygen. Anaerobic digestion produces a renewable natural gas when organic matter is decomposed by bacteria in the absence of oxygen," Kamba explains.

Sugar cane

He cites electricity from sugar cane as a typical example of biomass energy. "Sugar cane bagasse is the pulp or residue left after sugar cane is crushed, with the juice being used to make sugar. The bagasse is then burnt to generate electricity.

"Biomass has a significant role to play in renewable energy generation, overcoming global warming and ensuring a sustainable future. If biomass energy is generated and produced correctly in ways that enhance and protect the environment it can be sustainable for generations to come," Kamba concludes.