Tag: medupi

Day 501 – New thing go bang

Posted on

It’s only been a week (note the literal “7 days ago” on the screenshot below) since our occasionally electricity-generating parastatal Eskom proudly, officially added a new big, dirty, coal-fired power station to its big, dirty, coal-fired power station collection:

And it was last night at around 11pm that Unit 4 at Medupi exploded after a hydrogen leak was apparently not dealt with correctly. Hydrogen is used as a coolant [why? Well, see Hydrogen Cools Well, But Safety Is Crucial], some of it leaked and instead of flushing the area with CO2 as per the standard procedure, some air was used at the wrong point and that exploded the place a bit. Here’s Sikonathi Mantshantsha (you may remember him from the proud “it’ll last 50 years” quote just above) again:

“The incident occurred during the activity to displace hydrogen with carbon dioxide and air respectively, for the purposes of finding an external leak. Following the power station preliminary investigation, it appears that while performing this activity air was introduced into the generator at a point where hydrogen was still present in the generator at sufficient quantities to create an explosive mixture, which ignited and resulted in the explosion.”

“It also appears that there was a deviation from the procedure for carrying out this activity.”

Here are some photos: Oops.

I know that it’s deeply uncool (literally) to use coal to make electricity these days, but in South Africa’s defence, two things:
Firstly, coal is plentiful, local, and wonderfully cheap and easy to heap into Mpumalanga power stations, and we simply don’t have the money or the technology for anything else at the moment (shout at me all you want, I get it, but like it or not, you’re going to need a billion* wind farms to match the 4.8GW capacity that each of Kusile or Medupi provides (when they are working), and secondly, two units at Medupi aren’t using any coal at the moment because one has exploded and another has tripped because the one next door exploded.

Another win for the environment.

We’re probably looking at a few more billions of Rands and a couple more years before this 800MW generator is back online, which given our continuing precarious relationship between supply and demand of the sparky stuff, is not good news.

And who knows how long it will last next time? Hopefully a bit longer than a week.

* back of a fag packet calculation

Carbon dioxide emissions in US drop to 20 year low. Why?

Posted on

I mentioned this article from Slate.com briefly yesterday, but it’s worth putting on here as well as it does rather poke a bit of stick into the ribs of the local environMENTALists currently going nuts over the SA Government moratorium on fracking being lifted.

Carbon-dioxide emissions in the United States have dropped to their lowest level in 20 years. Estimating on the basis of data from the US Energy Information Agency from the first five months of 2012, this year’s expected CO2 emissions have declined by more than 800 million tons, or 14 percent from their peak in 2007.

The cause is an unprecedented switch to natural gas, which emits 45 percent less carbon per energy unit. The U.S. used to generate about half its electricity from coal, and roughly 20 percent from gas. Over the past five years, those numbers have changed, first slowly and now dramatically: In April of this year, coal’s share in power generation plummeted to just 32 percent, on par with gas.

It is tempting to believe that renewable energy sources are responsible for emissions reductions, but the numbers clearly say otherwise. Accounting for a reduction of 50 Mt of CO2 per year, America’s 30,000 wind turbines reduce emissions by just one-10 the amount that natural gas does. Biofuels reduce emissions by only 10 megatons, and solar panels by a paltry three megatons.

All of which further demonstrates the benefits of shale gas, not just for the South African economy, but also for the environment. And with Eskom currently building the  largest dry-cooled coal fired power station in the world at Medupi in Limpopo, which will burn through almost 15 million tonnes of coal each year for the next 40 years, it would be nice to have a safer, cleaner, more efficient yet viable alternative.