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All power plants under capacity
- Thread starter CathJ
- Start date
Does anyone know how many power stations we have and how many are operational? Why are those that are not working, not working?
I remember when I used to work at Sasol in the eighties, they shut down for 2 weeks and overhauled the whole plant - and it aint no daisy. If they could do that in 2 weeks, Eskom should be able to do the same in a lot less time, because a power station is much smaller than Sasol 2. What is going on? Don't they have preventative maintenance schedules?
That is one of the main reasons for the black-outs.
The demand has increased, which is simple to plan for, and as you point out the actual generating capacity has gone backwards due to shoddy or zero maintenance and some Megatwatt thought he'd be clever and severed ties with the coal mines that fed coal directly by conveyor to the power plants built on the mines, choosing to buy on the spot market and favoring BEE deals which in turn saw a major price increase and the mines were already down-sizing at that time.
The demand has increased, which is simple to plan for, and as you point out the actual generating capacity has gone backwards due to shoddy or zero maintenance and some Megatwatt thought he'd be clever and severed ties with the coal mines that fed coal directly by conveyor to the power plants built on the mines, choosing to buy on the spot market and favoring BEE deals which in turn saw a major price increase and the mines were already down-sizing at that time.
Eskom has similar outage program's, but due to a lack of skills and poor work ethic the standard of the work that gets done during these outages is shoddy and incomplete causing many trips between their outage dates.
Eskom units in the past held international records for mean time between trips, and typically stayed online without trips or forced load reduction between their scheduled outages.
VanZan
Senior Member
These are very significant figures. This means that 25% of Eishkom's installed capacity is not working. This is way beyond the acceptable norm where 15% is the maximum proportion of capacity that should be down for maintenance. It really means that there are some serious problems with the primary generating equipment. It looks as if reliability and availability of generating plant in Eishkom is much worse than what is actually being said in public.
Interesting but also very worrying. Although I suppose the one positive is that if Eskom could run all existing equipment at max capacity we'd be in a better situation. That shouldn't be too hard to do but will they?
You also have to wonder if they're not doing this in some misguided attempt to save money on expensive coal.
Robin Hood
Expert Member
VanZan
Senior Member
AFAIK. Most (if not all) SA coal power stations are designed to run at about 100% capacity. That is the maximum rated power output for a specific plant design to achieve a specified life expectancy which is minimum 30-40years. (Similar to CPU's to give most forumites a terms of reference.) All quoted figures are based on those values. It is possible to 'overclock'
the unit marginally but with a severe penalty in reduced life-expectancy (and I mean severe as in logarithmic relation) and reliability. By reducing the output on a plant a significant drop in efficiency is experienced and the unit cost of electricity production is actually increased. So normally the optimum operation of a unit is also close to maximum rated capacity. Problems such as wet coal, etc can however reduce the capacity of the boilers to generate thermal energy and thereby reduce the electrical output of the turbine/generator part of the unit.AFAIK. Most (if not all) SA coal power stations are designed to run at about 100% capacity. That is the maximum rated power output for a specific plant design to achieve a specified life expectancy which is minimum 30-40years. (Similar to CPU's to give most forumites a terms of reference.) All quoted figures are based on those values. It is possible to 'overclock'
Are they running at 100% capacity? The impression I get is that at the moment they aren't. Even if they are then only some of them are, plenty of them are down for maintenance etc.
Plenty of them are down for unscheduled maintenance, and that's creating major problems.
As VanZan points out, the units have a guaranteed MCR (Maximum Continuous Rating) and life span, but many of them cannot operate at MCR due to technical load limiting problems once again due to lack of skills and work ethic leading to poor maintenance and unreliability.
semiautomatix
Honorary Master
During summer it is normal to have anywhere between 10%-15% of power plants down for maintenance before the peak winter season. However, this is done assuming that the remaining stations are at 100% capacity for that period (obviously this works on a rotational basis for the whole summer season).
Furthermore, Eskom now acts as though it has never seen rain before. It rains every summer, and has done so and will continue to do so. What makes this summer so spectacular that the coal is too "wet" to burn? Furthermore, certain comments made have shown that it is no more difficult to burn wet coal than dry coal.
Lies! Lies! Lies!
Furthermore, Eskom now acts as though it has never seen rain before. It rains every summer, and has done so and will continue to do so. What makes this summer so spectacular that the coal is too "wet" to burn? Furthermore, certain comments made have shown that it is no more difficult to burn wet coal than dry coal.
Lies! Lies! Lies!
VanZan
Senior Member
Sorry I wasn't clear. Most new generation Eskom power stations is a six unit station. Each unit functions almost independent. If a unit operates it does so at about 100% capacity. Alternatively it is shut down and off the grid. From other threads it seems as if there is about 4000MW shortage (from installed capacity) due to maintenance (planned and unplanned) or reduced load operation due to coal problems.
Ok so they if they reduce generation they'd shut down for instance 2 out of the 6 units.
VanZan
Senior Member
Yes something like that. To operate a unit under stable and efficient conditions they try to run it as close as possible to optimum output. Alternatively they would prefer to shut down - but it is also expensive to start and stop a unit so integrated and preemptive planning is very important. So they won't shut it down for a short term cycle, but reduce the supply by a small % on each unit across a number of units for a short period. They could also supply power to one of the water storage schemes and regenerate hydro power later when peak demand kicks in.
Makes sense. Its just ridiculous they can't even get coal supplies right.
Moederloos
Honorary Master
I have been out all day, and reading various papers between meetings.
Not sure where I saw the article, but Eskom is producing 1000MW less today than it was on Friday.
I *think* it was in the Business Report.
Not sure where I saw the article, but Eskom is producing 1000MW less today than it was on Friday.
I *think* it was in the Business Report.