A new electricity consumption rating tool - which, if widely adopted, could set in motion the creation of a national energy-efficiency benchmark database of South Africa's building stock - was unveiled on Wednesday night, together with the identities of some of the country's top-performing corporate head offices and shopping centres.

The so-called ‘Energy Barometer' is the product of five years of research and development, undertaken by Energy Cybernetics.

Energy Cybernetics cofounder and director Prof L J Grobler, who is also a professor of mechanical engineering at North West University, tells Engineering News that five doctoral and master students participated in the design of the tool, which provides a "bird's-eye view" of a building's energy key drivers and benchmarks this performance against similar buildings elsewhere in the country.

In its inaugural year of operation, some 16 early adopters have had their buildings audited, with the Oriental Plaza, west of Johannesburg, the Centurion Mall, of Tshwane, and Canal Walk, of Cape Town, having emerged as leaders in the shopping centre category, while Exxaro, AngloGold Ashanti, and Barloworld topped the rankings of the head offices assessed.

The results were generated through an analysis of a building's utility bills over a period of a year, as well as from responses to a two-page questionnaire, which is designed to tease out a facility's main energy drivers. The data are then applied to a model that "normalises" the results for locational and/or climatic idiosyncrasies to create a "baseline" for the period under review, in this instance 2009.

The average of the normalised year energy use for all the participating categories of buildings surveyed in 2009 has been used to calculate a "base year" for the barometer, and has been assigned a rating of 100. Therefore, a rating of 120 implies that a building uses 20% more energy, on average, than what similar types of buildings consume. By contrast, a rating of 70 implies that a building uses 30% less than the average of similar types of buildings.

In 2011, the model, which will be based on 2010 consumption patterns, will be extended to hotels, corporate buildings and office parks.

Energy Cybernetics has won support for the instrument, which draws lessons from the US's Energy Star initiative, from South Africa's State-owned Central Energy Fund and it is hoping to convince government to adopt it as a national programme. Meanwhile, government's ‘Save It!' energy efficiency campaign has given the barometer its official support.

The Energy Star energy-efficiency labelling initiative, by comparison, is a joint programme of the US Environmental Protection Agency and that country's Department of Energy. Among other things, it measures the current energy performance of more than 130 000 buildings across the US.

But even if Energy Cybernetics fails to garner official government sanction, Grobler is certain that the concept will continue to gain traction, particularly given South Africa's current state of electricity distress, which is also associated with strongly rising tariffs, which are set to double over the next three years.

In this context, building operators are keen to understand not only what their assets are consuming, but also where they are positioned relative to similar buildings, either within their own portfolios, or those held by other property managers. Therefore, Energy Cybernetics will continue with a baseline certification process for the remainder of 2010, despite the fact that it has already named its top performers for the year.

Grobler says that, as opposed to a green building-type rating, which focuses on the efficiency of the overall design, the barometer seeks to measure actual operational efficiency. He says that, during the course of its recent audits it has been surprised to find that some older buildings are often more energy efficient than the newer ones, even those built to modern principles. This is particularly true of buildings where the windows could be opened, which could lead to far lower use of air-conditioning than is the case with fully enclosed modern buildings.

But Grobler stresses that the programme is entirely confidential and that, while participants gain insight into the functioning of their own assets, the benchmark itself is generic in nature, as there is no intention to "name and shame".

"Primarily, we hope this will be a tool that increases awareness of a buildings energy footprint, which, in turn, will enable property owners to improve the efficiency of their assets over time," he explains.

But he also anticipates that it may reach a point where property companies begin displaying their Energy Barometer certificates at the entrances of their buildings, or where consumers or tenants begin demanding that shopping complexes and office parks display their results on a yearly basis.

Energy Cybernetics is, therefore, also keen for government buildings to adopt the protocol, including key buildings such as public hospitals, and for the auditing systems to eventually spread into other sectors, including industry and mining.