There are reported to be more than 50 FPPs in use around the world. The biggest is a 220-MW unit at Mangalore in south-west India; built in South Korea, it is moored in a lagoon, and its design allows this FPP to rise vertically by about 5 m to cope with the dramatic increase in the water level during the monsoon season. And a 520-MW FPP is planned for New York City, which has no affordable land available for a new power station, but plenty of water on which to float one.

An FPP is basically a power station mounted on a barge, and FPPs are generally constructed by shipbuilders. Interestingly, from a South African perspective, they are most favoured by developing countries experiencing rapid economic growth, yet suffering from inadequate investment in the maintenance and/or expansion of their terrestrial power generation infrastructure. Thus FPPs have been, and are, successfully employed by countries in the Caribbean, South America and South-East Asia (especially the Philippines), in addition to India. Nor are they necessarily short-term options – one of the first such FPPs, a 30-MW unit named Impedence, was still in operation 50 years after it was built.

FPPs can be built very quickly. If the necessary power generation plant is available, a 100-MW unit could be assembled (the barge designed and built, the generation plant installed) and delivered to the required location, in six months, according to Waller Marine Incorporated pre-sident David B Waller.

Interestingly, Eskom is known to have acquired a power generation turbine from General Electric (GE) – this was built by GE for another customer who then cancelled the order, allowing the South African utility to snap it up. But now Eskom is pondering where to put it and how to provide its fuel supply – pipeline, railway tanker, or road tanker? Putting it on a barge would speed things up considerably and solve the fuel supply problem – it could be delivered by hose from product tankers (that is, tankers that transport refined fuels, not crude oil).

Also relevant to the South African situation is that FPP projects in rapidly growing emerging market countries have often involved State-owned utilities turning to private-sector companies to supply both the FPP and the financing for the project. This is done by signing power purchas- ing agreements with the private-sector (often foreign) investors, using either build-own-operate or build-own-transfer arrangements.

A fascinating aspect of FPPs is that they are legally equivalent to ships, not to terrestrial power stations. Each FPP is a legal entity, with a home port, a country of registration, and a flag, opera- ting under maritime law, and in compliance with international regulations – hence, the fact that the 50-year-old 30-MW FPP mentioned earlier has a name.

To date, FPPs have all employed petroleum- based or natural-gas fuels, but in the last few years, coal has been under consideration for 100-MW units intended for deployment in the US. Hitherto, FPPs had to be moored in sheltered locations, protected from wave action or strong currents (tidal rises and falls are no problem), which suggests that places like Durban Bay, Saldanha Bay, and Richards Bay might be the most suitable locations for FPPs in this country. However, designs are under way for FPPs that can be deployed in the open ocean, up to 200 nautical miles offshore and in water as deep as 9 000 m, which would eliminate the wave problem.

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