~ Eskom has recently changed its thinking about load shedding and, with the blessing of the National Energy Regulator of South Africa (Nersa), households rather than industry will bear the brunt going forward. It is also by design that load shedding occurred during the weekend, when it is less disruptive to the economy. “It is the lesser of two evils,” Eskom spokesperson Andrew Etzinger said. Moneyweb reported in September that Eskom applied to Nersa for amendments to the load shedding protocol in order to limit the damage to the economy. The application entailed that households rather than industry would be the first port of call when it became necessary to reduce demand in order to protect the electricity system from total collapse. Etzinger confirmed on Monday that the application was granted and two instances of countrywide load shedding in November were the result of the new approach. Etzinger said Eskom does not expect load shedding to be a regular occurrence going forward, but if it happens, it will preferably be over weekends and residential customers will be affected before industry. On Sunday Eskom did call on its industrial customers to reduce demand by 10% over and above the stage 2 load shedding already implemented countrywide. The declaration of an emergency at the same time was not an indication that the situation deteriorated beyond control. It is a requirement when industrial customers are called upon to reduce demand, Etzinger said. Nersa also granted Eskom permission to take over the direct control of load shedding in cases where municipalities struggle or fail to manage the process as required. This means that Eskom will simply go ahead and switch off the feed to that municipality for the required period. If the municipality has more than one feeding point, it may accordingly switch off one or more feeds in order to achieve the required savings, Etzinger said. If there is only one feed, the total supply to the municipality will be cut. He said in certain cases municipalities have requested Eskom to take over. Eskom has to account to Nersa after each load shedding incident and has to explain each decision in detail. Its actions with regard to these newly acquired powers will form part of such reports and will be scrutinised by the regulator, Etzinger says. Pump storage schemes Etzinger said that Eskom has been running its pump storage and diesel plants extraordinarily hard since the collapse of the coal silo at its Majuba power station on 1 November. In the past, the two pump storage schemes – Palmiet in the Western Cape and Drakensberg in KwaZulu-Natal – were run for only a few hours at a time. The units generate electricity when water is released from a high level. The force of the falling water turns the turbine that effects the generation. The water collects at the bottom of the system and has to be pumped back to continue generating electricity. For every hour of pumping the plant can provide two-thirds of an hour of release, or put differently, for every ten hours of electricity generation 15 hours are needed to pump the water back. In the past the plant was run for short periods and there was enough time to pump the water back every night. In the past three weeks, however, the schemes were run virtually from 6:00 to 20:00. Towards the end of the week Eskom ran out of water to release, since there wasn’t enough time to pump it back. The decision was taken to take the units offline and pump back over weekends, when the damage to the economy was less than during the week. With regard to the open-cycle gas turbines, Eskom planned to utilise the diesel gobbling units 11% of the time, measured over a week. Due to the tightness of the system this increased to 37%, which placed pressure on the diesel stock and the supply chain towards the end of the week. Etzinger said Eskom conducts load shedding countrywide and does not require bigger sacrifices from certain areas or towns. The required savings are determined in proportion to the demand from those customers. He says over the weekend Eskom escalated its load shedding from phase 1 to phase 2. Some customers did not realise that and did not update the information they got from their load shedding schedules. In some cases that created the impression that load shedding schedules were not being followed. While Eskom sticks to its published schedules, it is clear that some municipalities are struggling, Etzinger said. Eskom is trying to assist municipalities in this regard. Customers can at any time go to loadshedding.eskom.co.za/ to check whether Eskom is load shedding and, if so, what stage of load shedding is being implemented. The website also contains a link to Eskom and municipal distributors’ load shedding schedules. Some of the bigger metros like the City of Tshwane, City of Cape Town, and Johannesburg’s City Power also use Twitter to update customers regularly. Source: Moneyweb
Posted on: Wed, 26 Nov 2014 08:35:02 +0000