There has been a strange but interesting batch of ESKOM press releases recently.
The first argued that SA had saved from the retrofit of 43.5m CFLs, “1800MW of electricity power” and that that is “1/3 of Medupi or Kusile”. What a load of rubbish! Let’s assume that a 60W bulb was replaced with an 11W CFL. Then the saving is 49W WHEN THE BULB IS RUNNING. 89W x 43.5m bulbs = 2100 MW, close enough to the 1800MW argued. But how many hours is the average lightbulb on? Let’s be conservative and say 5 hours a day, although in reality it is probably less. A coal power station probably runs 23 hours a day on average. Thus a 1800MW power station will produce 41 GWh of electrical energy a day, while 1800MW of lightbulbs will consume only 9 GWh per day. So in reality, the lightbulbs are only 1/14 (7%) of a Medupi or Kusile! It is the classic mistake of confusing POWER (MW) with energy (MWh).
Another example of this is the argument that South Africa’s proposed IRP will lead to “SA’s electricity generation in 2030” being sourced “from coal (48%), renewable energy (16%), nuclear (14%) and a combination of imported hydro, gas and pump storage (22%).” But again, these are the peak POWER figures of the power stations. Coal & Nuclear run at a much higher capacity factor than solar or wind (i.e. more average equivalent full-time hours of operation every day). Thus if you calculate the ENERGY figures, it gives a very different story:
- · COAL and other: 70%
- · RE: 7%
- · NUCLEAR: 23%
That is a pathetic target for 2030! Just 7% of electrical energy from renewables.
Then to ESKOM target of installing 925,000 SWH by 2013. Over the last 2 years or so, they have installed 33 000. At a rate of 16500 per year, we will have 82,500 SWH installed by 2013…. (Good Luck!) They also say that 6.4 GWh of electricity has been saved by SWH. Simply dividing that by 33000 SWH equals 193 kWh/SWH. That’s about 4000 litres of hot water per SWH. Or about 45 baths per SWH.
Maybe people are bathing less because the lights are too dark…
Frank
PS: Off to Lesotho next week to install a met mast at 3300m! Wish us luck…
