The Energy Blog
Bolivian Heat Recovery: The Technology Powering an Energy Renaissance
Just three kilometres southwest of Bolivia’s remarkable Salar de Uyuni salt flats (an 11,000 square kilometre expanse of brilliant white salt and rock formations) is an evocative sight: a steam train “graveyard” where the skeletons of disused locomotives rust away in the corrosive salty winds, at the end of an equally neglected train line.
If these steam-powered machines represent Bolivia’s past, the steam-powered future is taking shape in this ambitious nation, with 11 cutting edge Heat Recovery Steam Generators (HRSGs) made by Siemens’ NEM – the Netherlands-based leader in heat transfer technology – beginning to arrive in Bolivia after a journey of over 20,000 km from their factory in China.
They are being supplied as part of a commitment by Siemens and NEM (alongside Spanish consortium partner TSK) to increase the installed power generating capacity of Bolivia's National Interconnected System by 66% - in part through the conversion of existing simple cycle gas turbine (“SCGT”) power stations to combined cycle (“CCGT”); a more complex and powerful form of generation that can boost power output by a third for the same fuel costs.
Simple to combined cycle – a client journey
Conversion involves not just HRSGs and 14 of Siemens’ SGT-800 gas turbines but 11 SST-400 steam turbines with condensers, cooling towers, additional generator step-up transformers, and water treatment systems, along with a SPPA-T3000 control system to convert Bolivia’s Termoeléctrica del Sur, Termoeléctrica de Warnes and Termoeléctrica Entre Rios –ultimately adding a substantial 1GW to Bolivia’s electricity generation capacity.
It’s a process of growing complexity and power that mirrors Bolivia’s own evolution in recent years – and increasing appetite for both technological advance and capacity to drive the kind of economic and social expansion it seeks as South America’s fastest growing economy each year since 2014. And it involves the evolution of an already close partnership.
As NEM’s project manager Han Wijnands puts it: “We’ve been working closely with our customer to deliver this equipment and support their understanding of its technology and use, with a delegation visiting both the factory in China, our safety valve supplier in the UK and also undergoing operational training on the ground. Building that local skills base and operational capacity is at the heart of any good relationship.”
The overall NEM project scope for the combined cycle power plants includes the engineering, manufacturing and delivery of the 22 vertical double-pressure reheat once-through HRSGs – chosen for their small footprint, rapid and flexible start-up and modularity. As Mr Wijnands adds: “The benefits of this solution are its highly modular nature: each HRSG has a relatively low quantity of piping and equipment, and the boiler main body is delivered in just half a dozen parts; the inlet duct, two boiler modules, an outlet duct and the stack (in two parts).”
Bridging the gap
HRSGs use the energy in the hot exhaust gas of a gas turbine to generate steam for electricity production or for various industrial processes; ramping up the output and efficiency of existing power stations.
Each HRSG contains 2,700 single tubes of 12 metres in length but the equipment has been delivered in six primary modules for rapid assembly. Yet modularity or no modularity, the logistics challenges to bring this additional capacity – quite literally – to market are substantial.
Each HRSG module, for example, weighs some 154 tons and is being carried on a trailer that alone weighs 70 tons itself. With two core modules per HRSG, each requires a convoy that includes two service cars supporting four mechanics, as well as an advance team that includes a structural engineer to ensure that the myriad bridges on Bolivia’s roads over the Andes are sound enough to support the weight of this load – and can be reinforced with steel girders when they are not.
With – at the time of publication – the first two HRSG’s having left Chile’s Arica port and begun their journey, Siemens’ and NEM’s project teams are eagerly anticipating their arrival; sites are cleared, prepped and ready and Bolivia’s operational team are waiting for the moment of magic when the technology comes to life. Lights, probably a few cameras, certainly steam, and a great deal of action await.