The Siemens startup SeaFloat has developed concepts for floating combined cycle power plants. The first one shall go into operation in spring 2021.
by Bernd Müller
The global population is growing – about 9.7 billion people will be living on our planet by 2050. Providing all of them with sufficient clean water and electricity will be a daunting task. Today there are already 1.2 billion people who have no access to electricity, and almost 800 million suffer from a shortage of drinking water. If today’s infrastructures are already unable to fill these basic needs for everyone, what will the situation be like in 2050? Perpetuating the status quo will not be enough. New concepts must be developed.
Offenbach is the home of the SeaFloat competence center, which is part of Siemens "Power and Gas". A handpicked team of Siemens employees at the competence center have joined together with the intention of revolutionizing electricity production. Their basic idea is that power plants should be built on ships or floating platforms, i.e. barges, instead of being erected on land. This would have a number of advantages. The operators would save valuable construction space and wouldn’t need to transport the power plant components on roads, because the power plants could be completely assembled in a shipyard, and on their floating foundations they could be pulled by tugboats across oceans or up rivers. As a result, the power plants could, for example, quickly supply remote coastlands with electricity after an earthquake or a tsunami. They could also offset the breakdown of an old power plant. When the power plants were no longer needed, they could simply be towed to another location.
The idea of floating power plants arose after the devastating tsunami in Japan in 2011. In recent years the SeaFloat team has developed the concept to the point of readiness for series production, with the assistance of colleagues from other Siemens locations all over the world working together, all of the participants optimized the technology to the point where it can also operate on ships or floating platforms. Combined cycle power plants actually need to be based on a firm foundation. Being on board a barge at sea exposes turbines to increased stress due to the swell. As a result, the engineers took a wide variety of measures to adapt supports, bearings, and other components that would dampen these wave-induced movements. Another challenge the engineers faced was the need to comply with standards that can vary from country to country and from harbor to harbor. Gas turbines operating on ships and oil platforms are nothing new. However, to date their types have been limited in power output the concept from Siemens is moving into completely new territory. The first planned facilities will be equipped with industrial gas turbines such as the SGT-800 from Finspang, which have an output of 140 megawatts. Even the large Siemens SGT-8000H-class gas turbines will be made seaworthy in the future.
For combined cycle power plants, outputs of up to 1,200 megawatts are possible. Once a power plant is docked the simplest option is to supply it with natural gas from land. If the facility is located further offshore, it can also be supplied with liquid natural gas from ships. To make this possible, additional platforms have to be set up where ships can dock. These platforms would be equipped with the technology that is needed to convert the liquid fuel into a gaseous one.
In order to be able to react quickly and flexibly to growing demand, SeaFloat is working together with several shipyards.
Siemens’ part of the business will consist of providing seaworthy power plants. The company is not planning to create its own fleet, but Siemens Financial Services can help if necessary by providing 20 to 30 percent in equity capital. This will open up interesting business models for customers, who can buy power plants and/or then lease them to the actual operators – for example, in order to support reconstruction after a war or a natural catastrophe or as a backup system in case a power plant on land breaks down. By contrast, energy providers in developing nations that have many islands or long coastlines could buy their own power plants in order to build up their infrastructure over the long term. They would not have to buy a huge amount of land for this purpose, the permit processes would be much shorter, and there would not be any soil-related risks or any need for the complex construction of foundations and buildings. Energy providers in industrialized countries could use floating power plants to replace old coal-fired power plants that are harmful to the environment. Flexibility is the strong point of the SeaFloat concept. In several business cases e.g. areas where land prices are high, the floating version may even be more cost-effective.
In order to be able to react quickly and flexibly to growing demand, SeaFloat is working together with several shipyards. The first floating platform will be equipped with a combined cycle power plant. This “marriage” will be a spectacular event, because cranes will heave the entire power plant, which may weigh as much as 4,000 tons, onto the platform in one piece. Once that is done, the mobile power plant will begin its journey across the world’s oceans to its operation site. If a hurricane threatens, the hawsers, cables, and pipelines will simply be disconnected and the barge will be pulled out to sea, where the swell is not as high as it is near land. Hamed Hossain, business owner of SeaFloat Power Plants, says, “The response time will be long enough to transport the power plant to safety.”
The first order for a barge equipped with two SGT-800 gas turbines was signed in autumn 2018 (see infobox). The floating power plant in the Dominican Republic shall start its operation in spring 2021.
Siemens and the marine arm of ST Engineering in Singapore have jointly received an order for a barge-mounted power plant from Seaboard Corporation subsidiary Transcontinental Capital Corporation (Bermuda) Ltd., an Independent Power Producer (IPP) with operation in Dominican Republic. The project Estrella del Mar III, based on a SCC-800 2x1C SeaFloat Type, shall start its operation in Santo Domingo in Spring 2021.
Under a turnkey plug and play concept, Siemens as team leader will provide a Siemens’ combined cycle power plant with a capacity of 145 megawatts (MW). ST Engineering will be responsible for the engineering design, procurement and construction of the floating power barge, the balance of plant and the installation of the floating power plant. Siemens will also deliver its innovative hybrid SIESTART solution, combining a flexible (gas turbine) combined cycle power plant with a battery energy storage system. The SeaFloat concept completed in the shipyard will provide the customer with a quality proven power plant at a lower cost and with an increased plant size in comparison to a similar land-based power plant.
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