Tuesday, September 09, 2014

Electricity Supply Situation

Eskom’s Supply System Status Bulletins, released twice a week and freely available on its website at http://www.eskom.co.za/Pages/Landing.aspx, provide an overview of the system status for the previous five days and a forecast for the next week. Bulletins 273, 274 and 275 published at the end of August 2014 carry fairly consistent messages that `The system is expected to be tight over the evening peak tonight and………’.. They also:

 

  • ….urge customers to reduce their electricity usage, especially in the early evening (17:30 to 18:30), as the power grid is expected to be under severe pressure during this time; and

  • ....calls on all consumers to pull together to help beat the peak over the next few months by using electricity sparingly particularly from 5pm to 9pm. We request all electricity customers to save at least 10% of their electricity usage and sustain these savings. Residential and commercial customers can make the biggest difference by switching off geysers and pool pumps during peak hours (5pm – 9pm); switching off non-essential lights; using space-heating efficiently and responding to the Power Alerts messages.

Engineering News Online reported in an article published on 30 July 2014 that the interim Eskom CEO, Collin Matjila, had presented a five-point Eskom generation recovery plan to the Parliamentary Portfolio Committees on Energy and Public Enterprises that was being introduced in a bid to place its underperforming power station fleet on a “sustainable path”. Eskom had cautioned that an additional 7 400 MW of capacity would be required this year to provide the cushion it required to enable it to deal with its maintenance requirement – a maintenance-capacity shortfall that would persist until 2019, but at a lower level as new capacity was introduced.

Eskom also indicated that the recovery plan was premised on recommitting to and delivering on Eskom’s ‘80-10-10’ operating model, which implied 80% plant availability, 10% planned outages and 10% unplanned events across a period of a year. In 2013/14, the group’s unplanned capacity loss factor rose to around 11%, while its energy availability factor fell to 75.1%. The article also said that it had been confirmed that former mining executive and Energy Intensive User Group chairperson Mike Rossouw had been appointed on a one-year assignment to initially focus on the finding remedies to the performance problems being experienced at the power stations.

In the 14 August 2014 edition of Engineering News Online, it is reported in an article titled `Eskom outlines blackout scenario, won’t be challenged on load-shedding’ that `Eskom will make no apologies for its unpopular load shedding measures, saying `…. that the long-term sustainability of the group and the security of the national power grid remained “at the heart of everything we do”.

Eskom group executive for sustainability Dr Steve Lennon told a media and stakeholder information session that the company had recently made a “step-change” in its approach to align security of supply with increasing demand. He said that `… one of the critical functions of Eskom was to maintain the power system at a frequency level of 50 Hz to prevent a blackout, which would be averted through the implementation of scheduled load-reduction measures when necessary.’

“Eskom will only instruct load reduction measures when there is an imbalance between the electricity demand and the supply that it can provide at a particular time.
 
“This is done either through load curtailment, when Eskom asks big business to reduce their load by up to 25% to help free up pressure on the grid, and load shedding, where the focus shifts to residential and commercial customers,” outlined Eskom National Control Centre manager A’Louise van Deventer.

 
Lennon added that people should not appeal to the utility to stop load shedding.
 
“We want people to understand why we do it. We have to be prepared to respond to a blackout threat. You can’t tell Eskom not to load-shed, as that’s a recipe for disaster,” he cautioned.


Copies of the full Engineering News Online articles are available at http://newsletters.creamermedia.co.za/servlet/link/14/62683/141325/1572713 and
http://newsletters.creamermedia.co.za/servlet/link/14/62989/141325/1590814 respectively (Source: Creamer Media’s Engineering News at www.engineeringnews.co.za).
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