Energize Inbox, May 2015

May 14th, 2015, Published in Articles: Energize

re: Power ships: a real solution to South Africa’s short-term energy needs

Our winning letter

Sir

The power ships article published on the Energize website on 20 April 2015, and now on page 20 of this issue of Energize, refers.

In 2006 I was with RMB and we were part funders for the AES Lagos barge power station. RMB was responsible for the technical portfolio so I visited the plant. It consists of nine barges, each fitted with a GE Frame 6 open cycle gas turbine, moored next to each other. This arrangement, which is supplied by an on-shore gas source, generates 270 MW of electricity.

Eskom was offered a similar solution in 2007. The offer was rejected, and three months later the lights went out.

Powerships or barges are a sound, proven approach to supply temporary power – or, as in the case of Lagos, Nigeria, a permanent one – and there is another one in Ghana.

To be of use in South Africa these ships need to generate more power than the ones used in Lagos, and would only be of value if we got between five and ten of them.

The GDF Suez/Mitsui project uses 6 x 170 MW turbines. Delivery time is 24 to 30 months, which is probably in the same range as a ship, and possibly a little cheaper.

I read recently that the DOE is considering power ships because they can produce power at half the cost from “heavy fuel oil”. But the Eskom peakers can probably also run on it with some burner modification.

The Eskom V94.2 turbines are specifically built (and bought) to be fuel flexible (at the direct loss in thermal efficiency as against axial combustors). The turbines have radial combustion chambers which enables longer combustion times, i.e. allows low CV gas and liquid fuels can be used. My thinking is that we should just double-up on our plant and do the gas and finally closed cycle gas turbine (CCGT) conversions as planned, sooner rather than later.

Koos Smit

Energize-November-2014.indd


Sir

The powership solution is just a nice dream.

From your article above: “Four 500 MW power ships, moored at different harbours around the country, would supply the grid with an additional 2000 MW – equivalent to stage two loadshedding which has been frequently imposed by Eskom in recent times.”

According to the company’s website, its complete fleet consists of eight power plants with a total installed capacity of 925 MW. The largest powership in the world, the Kaya Bey, has a output capacity of 232 MW.

So, Sir, where are you going to get four powerships with a total combined output of 2000 MW?

Pieter Venter

Editor’s note: Thank you for your letter. The company tells me that it is in the process of buying additional hulls onto which larger (500 MW) power stations will be built. The first of these is the “Osman Khan” which is shown in Fig. 7 in the article.


Sir

In the South African context, the powerships would need to have generating licences and be grid code compliant. They would also be subject to environmental authorisation. If there isn’t a suitable substation and/or power line on the quay, a high voltage line will need to be built, which is also subject to environmental approval, etc.

All in all, without significant political willpower and a “bending of the rules,” like with the 2010 FIFA World Cup it is unlikely that a powership can be connected in less than 18 months.

“Temporary” installations may have lest strict requirements, but I am not an environmental practitioner so I can’t comment.

Someone, please prove me wrong!

Wayne Kitching

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