ENERGY: Eskom Puts Theory Into Practise
Recent Western Cape Business News
WITH a nationwide focus on improving and optimising energy consumption driven by the need to be more responsible with a limited resource, Eskom has itself applied many of the recommendations it has made for reduced electricity usage. As a consequence, it has reduced its energy consumption by an estimated 10-18% at its largest facility, Megawatt Park, in the process reducing operational cost by over R3 million per annum.
This initiative has enabled Megawatt Park in Johannesburg to consistently reduce the energy it consumes.
“Substantial and ongoing reductions in its energy use has been achieved at Megawatt Park through the introduction of a strategy for electricity management which is underpinned by several tactical measures. Outside of computing – Eskom’s main data centre is located at Megawatt Park and accounts for about 33% of the total energy consumed by the building, with lighting and air-conditioning being the major energy consumers in a commercial building such as Megawatt Park,” says Feizal Mangera, Eskom’s property manager.
From quick – and obvious interventions which were initiated in 2007, Megawatt Park has embarked on a process of engaging specialist consultants to assist with a detailed study of the building.
Perhaps the greatest lesson which has emerged from the energy-saving strategy is that it takes very little in terms of additional expenditure. Meaningful reductions can be achieved if all staff members change their behaviour and approach towards electricity usage even slightly, while more advanced initiatives contribute to further reductions in energy requirements.
Like any good business plan, initiatives to reduce power consumption at Megawatt Park started with a sound strategy. This strategy would revolve around two pillars: replacing inefficient electrical products and appliances, and modifying human behaviour.
Prior to November 2007, the building management already initiated measures to reduce electricity usage by targeting simple yet effective interventions. The immediate aim was to reduce the power used by at least 10%.
These simple interventions (which businesses and consumers nationwide were also encouraged to apply) included:
• Replacement of lighting ballasts. Newer ballasts using electronic technology (rather than magnetic) reduces power consumption by up to 20%.
• Installation of variable speed drives in the air-conditioning units. Variable speed drives reduce electricity consumption as they can be calibrated to address the task at hand, rather than being switched on using full power.
• Replacement of all incandescent bulbs with CFL lamps. Incandescent bulbs operate by heating a filament in a vacuum. This creates substantial resistance by generating heat and consuming excess electricity. CFLs operate at much cooler temperatures, consuming less power.
• Removal of hot water geysers in the Eskom section of the building.
Following these initial ‘quick hit’ solutions, more detailed initiatives were undertaken. That included a complete energy audit, which includes virtual modelling of the building, which is intended to yield maximum energy efficiency. That includes examining the external ‘fabric’ of the building and gauging its thermal properties, redesigning the lighting systems throughout and redesigning the air-conditioning system.
In terms of the exterior, with a substantial area of glass, a good deal of heat exchange occurs. The glass permits sunlight to shine through, thus translating into heat coming through, rendering climate control inside Megawatt Park somewhat difficult. The building was designed some decades ago, so energy efficiency was never a consideration for Megawatt Park; the result is that moving it to a lower consumption requires substantial interventions. This thermal performance has a direct impact on the requirements in terms of air-conditioning.
Chilled beam air-conditioning is currently being piloted. A recent innovation, the chilled beam system uses water (instead of circulating cold air) to remove heat from a room. Chilled beams are best suited to locations where the humidity can be controlled.
In terms of lighting, Eskom is going one step further than just replacing incandescent bulbs with CFLs. By removing baffles around each fluorescent tube, the distribution of the light can be increased. As a result, the number of tubes can be halved without impacting the light quality. This action, which reduces the number of fluorescent tubes by some 8 000 units, results in a saving of 18MWh per month, or nearly 1GWh per year.
In a world where electricity was previously inexpensive and freely available, it was an inevitable consequence that wastage would occur. Modifying entrenched behaviour is recognised by industrial and clinical psychologists as a substantial challenge given the human propensity to resist change. However, Eskom committed to achieving its target of reduced power consumption through the following activities:
• All lighting in the building is turned off between 19h00-05h00. Where cleaning was formerly performed overnight under artificial lighting, it is now done during normal working hours to make use of natural daylight
• The lighting level in the parking areas has been reduced to the minimum legal requirement during the day, and is turned off at night after the building lights have been turned off
• All non-essential lights are turned off
• Lighting in the basement is halved, with the removal of at least 400 fluorescent tubes
• During the summer months the extraction fans are turned on at around 04h00 to draw cold outside air through the building to cool down the structure. This enables the air conditioning chillers to be switched on about three hours later in the morning. The average temperature in the building has been changed to 23°C as opposed to the previous 22°C
• In winter, retained heat built up during the day is used to keep the structure warm in the morning. This minimises the use of boilers. The temperature inside the building is now maintained at 22°C rather than the previous 24°C that was experienced during preceding winters.
Cumulatively, the initiatives underway at Megawatt Park have a substantial impact. In a building which houses some 2 500 people, energy consumption has been reduced by an estimated 18% in 2009 from the baseline levels recorded in 2006.
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