Electricity + Control January 2017

STANDBY + BACK-UP

ROUND UP

Flexible aero-derivative power generation solutions

The importance of renewable power generation technologies such as wind, solar and tidal cannot be questioned. But what happens when there is no wind or sun and there are low tides? Siemens aero-derivative gas turbine technology is a flexible, economical and efficient alternative to around-the-clock generation, be it for peaking, mid-merit or base load operation – writes Andreas Pis- tauer, Senior Vice President for Power and Gas Sales Sub-Saharan Africa at Siemens. Siemens aero gas turbines are derived from turbojet/turbofan technologies, designed for civil and military aircraft, and are relatively new to the African power generation sector, which is accustomed to industrial gas turbines. Overall, Siemens aero gas turbines have a simple cycle efficiency that is typically 1~3% better than traditional industrial gas turbines. The technology is a multi-spool design – where each spool rotates at its own optimal rpm for maximum efficiency across its operating range. Siemens aero gas turbines boast exceptionally high cycle capability, and can be started up in less than ten minutes (or less, if required) with no lockout timers after a shutdown (be it a normal or emergency shutdown). Electrical start-up is 500 kW, the equivalent of a small site back-up generator.

These features bring the power closer to the operator, which is able to respond instantaneously and follow load requirements, with no impact to the equipment’s maintenance cycle and no increase to its maintenance costs. How is a jet engine converted into a gas turbine? The Siemens fleet of Rolls Royce aeroderivative products can be used as an example. The Aero Trent 800, which has more than 24-million flying hours in civil aviation applications, can be con- verted into the power plant specific Industrial Trent gas turbine, by simply replacing the fan with a two stage low-pressure compressor with matched flow capacity. The Industrial Trent features three shafts (HP, IP, LP) that rotate independently and is environmentally friendly, as it is available in dry low emissions and wet low emissions cycle operation, and flexible maintenance solutions are available to ensure maximum return-on-investment. Another important aspect of aero gas turbine technology is reli- ability and endurance under stress.The IndustrialTrent requires no engine overhaul, as hollow shafts eliminate rotor bow and high nickel casings eliminate stress. Titaniumusage also reduces weight, thereby allowing for a higher power density. Operational expenditure is further reduced thanks to anti-friction bearings that require less lubrication.The ball bear- ing design is also lightweight with low oil flow and consumption. Siemens aero gas turbines are therefore a low risk economic solution ideally suited to peak, mid-merit and base load applica- tions, which can be used in open cycle, cogeneration and combined cycle power plants, with the key emphasis on having a power

plant which offers greater operational flexibility. Andreas Pistauer is the Senior Vice President for Power and Gas Sales Sub-Saharan Africa at Siemens. Enquiries: Jennifer.naidoo@siemens.com

Andreas Pistauer, Siemens.

Growth opportunities in power generation

Promising solutions include chemical looping combustion and an in- tegrated gasification combined cycle.The relatively high efficiencies and production rates of renewable energy sources are highlighting the need to make coal-based technologies clean and more effec- tive. Coal-based power production accounts for approximately 41 percent of global electrical energy produced, and will continue to dominate the market for the next two decades. Government funding and private participation are already bringing promising coal-based power generation technologies to the forefront. “Efficient oxygen carriers and combined cycle plant techniques are propelling the power generationmarket forward,” saidTechVision ResearchAnalyst Guhan Sriram RV. “Within the next five years, the development of efficient materials for chemical looping combus- tion (CLC), along with improvements in reliability of integrated gasification combined cycle (IGCC) plants and carbon sequestration efficiencies, can be expected.” Power GenerationTechnologies of the Future, analysis from Frost & Sullivan’sTechVision Energy &

Utility subscription, offers continuous tracking and monitoring of both technology and product developments.The study also covers advancements, market and technology trends and predictions that will result in the creation of new markets, products and services, business models and even new industries within the energy and utility sector. Beyond 2020, CLC will begin to take over as - similar to CO2- based power generation technologies – it is approaching the com- mercialisation phase. Coal fired magnetohydrodynamic (MHD) is another promising technology; although it is still in the early stages of development. “For now, IGCC will dominate clean power production,” noted Sriram. “The technologies that IGCC are based on, like gasification and steam turbine based power production, are quite well estab- lished and any development in these technologies can be easily incorporated to IGCC to improve its performance.” Enquiries: Samantha James. Email samantha.james@frost.com

Electricity+Control January ‘17

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