The giant Medupi Power Station near Lephalale in Limpopo. Picture: AdobeStock Eskom says it has effectively switched off 13 675MW of generating capacity “due to excess capacity and lower demand during the holiday season”. This capacity, primarily comprising coal power stations, is available to the grid but is not currently operating.
To get this started and brought back online will typically take hours. The amount of capacity in cold reserve is equivalent to nearly three Medupi power stations, which has a nameplate capacity of 4 800MW. While the stunning turnaround in the generation performance at Eskom over the last 18 months remains remarkable, that it is able to remove this amount of capacity from the system temporarily is both a demand and supply story.
On Friday (1 January), it said the evening peak demand would be 19 545MW – a nearly 4 500MW reduction from the same Friday a year ago (23 983MW). Commercial users, particularly large ones, have installed solar and inverter systems to reduce their consumption from the grid. The maths makes sense, with some real estate investment trusts (Reits) reporting payback periods of four to six years.
Read Full Article on The Citizen
[paywall]
This alternative generation has effectively nearly permanently removed this demand, with the grid only being relied on during very rainy or overcast periods. This is one of the reasons Eskom wants to overhaul its tariffs to reflect the reality of it needing to be an always-available ‘back-up’ supplier (which is tricky to do with a base of large coal-fired power stations that take hours to ramp up and ramp down capacity). Eskom estimates a total rooftop photovoltaic solar base of 7.4GW across commercial, industrial and residential users, compared to 7.6GW from all other renewable energy independent power producers who have contracted their supply to the utility.
The former figure overtook the latter in August last year, but additional utility-scale renewables projects have since come on stream. The peak generation from solar, which is from midday into the afternoon, poses a real challenge to Eskom and the system operator – under the National Transmission Company of South Africa (NTCSA) – as it needs to remove supply from its coal fleet over that time.
[/paywall]
