Opinion

The Role of the ‘Negawatt’ in Easing the Power Crisis

Jonathan Skeen

The proven technology of cogeneration offers a simple solution with big gains.

In 1989, an American named Amory Lovins coined the term ‘Negawatt’ to describe a unit of electricity that wasn’t created, but conserved, through improved energy efficiency. In recent times the term has become particularly relevant South Africa, as Eskom have battled an ongoing power shortage, and made huge investments in new infrastructure in order to increase capacity.

At the recent National Energy Summit, Eskom requested a staggering 60% increase in their tariffs as a response to rising fuel prices, and as a means to fund their upgrades to an ageing and underpowered national grid. The request was, unsurprisingly, rejected. Nonetheless South Africans are set to receive a substantial increase in their electricity bills in the coming months.

Under these circumstances, the need for improved energy efficiency is obvious. Improvements can be achieved in a range of different ways, with a variety of technologies, but one of the best ways to save large amounts of energy is through the application of cogeneration on large developments and industrial plants.

Put simply, cogeneration is the combined use of thermal and electrical power from a single fuel source. Any generator unit that relies on the input of fuel to produce electrical power, such as a gas-turbine, or a reciprocating diesel engine, will produce both shaft power (which is converted to electrical power) and heat, in the form of hot exhaust gases or engine cooling water.

In a cogeneration plant the thermal energy in the exhaust gases or cooling water is used to provide heating for an industrial or domestic application. The result is a saving in the cost of electricity or additional fuel that would ordinarily have been used as the energy source. The overall fuel efficiency of a cogeneration plant can be as much as 40% higher than a plant that draws all of its power from the local grid. This increased efficiency equates to lower costs and reduced emissions of harmful by-products, such as greenhouse gases.

On the face of it, it seems that cogeneration should be an obvious part of the solution to the South African power crisis. It is a simple concept, which does not involve the use of new technology, and has been successfully applied on various plants around the world for decades. The inherent potential of cogeneration technology to produce financial savings, decrease loads on the national grid, and reduce environmental impact is large. Consequently, Eskom’s recent invitation for tenders for new cogeneration plants received a strong response from a number of private organisations.

So what holds the development of cogeneration back? Largely, it is the policies applied by government and Eskom towards independent power producers. As a parastatal, Eskom has enjoyed an almost complete monopoly on the power generation industry and has made it difficult, if not impossible, for private entities to produce their own power in an economical manner.

An example of this is the price that utilities like Eskom will pay for independently produced power. Cogeneration plants are often made profitable by selling the excess power that they produce to the local grid. However, until recently, this advantage was negated by the fact that Eskom would only pay about half of their own selling price for such power. This is one of many issues, including unclear policies and complicated procedures, which make it difficult for private investors to gauge the viability of cogeneration projects.

Added to this is the fact that South Africa has traditionally had some of the cheapest electricity in the world, and the need for improved efficiency has not been a pressing issue. This is set to change, with the unavoidable impact of higher fuel prices, Eskom’s capacity shortage, and an increasing concern over the effect of inefficient industry on our environment. Resultantly, a number of private companies have appealed to government to create conditions that are more conducive to the successful development of cogeneration plants and private power stations.

A lack of foresight and poor management has damaged Eskom’s ability to produce a surplus of electrical power at a low cost, and there is now a mad and expensive rush to increase capacity as quickly as possible. Those responsible for ‘load-shedding’ and the imminent increases in electricity tariffs would do well to welcome the ‘Negawatt’ as a responsible and long-term supplement to the unrestrained development of more generating capacity.

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Jonathan Skeen is an electro-mechanical engineer based in Johannesburg with a strong interest in environmental and energy issues. He is currently based at Tenova-Pyromet.

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