Research

With electricity consumption growth in the electrification (residential) sector expected to be over 15% p.a. over the next ten years, the implications for Eskom, the supplier are profound. New plant would need to be constructed to meet this new load type i.e. generation plant capable of running for relatively short periods during the day and only for a few months of the year. The capacity utilisation of this new plant would thus be extremely low compared with the currently installed capacity.
The role of DSM in meeting rapid (low load factor) growth.

In considering the cost implications of new generation capacity provision to the country and its electricity consumers, DSM becomes an extremely attractive alternative. Although SA currently has surplus generation capacity, the lead times for new plant construction are lengthy (up to 10 years for pumped storage hydro capacity) and a decision to build new capacity had to be taken by 2002.

If DSM can be used to limit residential demand growth or mitigate the impacts through the provision of incentives for industry/commerce to move load out of the peak periods, substantial benefits for all customer groups could be derived. Inevitably high price increases would be avoided through the deferment and probable avoidance of certain generation capacity construction.

The Eskom generation capacity position and long term maximum demand forecast (moderate growth scenario) is shown in Figure 2 below, including a 15 % reserve margin and current interruptible load agreements (treated as supply-side resources for modeling purposes).

Figure 2 As is evident, new capacity is only required in 2007 under the moderate forecast. Current Generation performance however, with plant availability in the order of 90 % could reduce reserve margins thus further deferring the need for additional capacity.

The extent of Eskom's surplus capacity is thus clearly evident. Not withstanding the long lead times for new generation plant construction, a had to be taken by the end of 2000, assuming that a "high growth" electricity sales growth scenario materialises. The potential therefore exists to substantially defer any supply side generation construction decision through DSM until well into the next millennium. With enough suitable DSM, permanent avoidance of certain new plant may well be achieved.

The DSM provision in Eskom's current Integrated Electricity Plan includes 7300 MW of peak load reduction, broadly classified in the Table below. The targets outlined are viewed as being extremely conservative, with recent work showing that over 11 000 MW could be achieved within the same time period at costs significantly below the equivalent supply-side costs.


Table 1. Eskom DSM load reduction targets