A Milestone For Steam Turbines

BY ROBERTA PRANDI

GE Power Services business, in consortium with NGSL (a joint venture of GE and THE Indian utility NTPC Limited), completed a project for the modernization at the Ukai Power Station of Gujarat State Electricity Corp. Ltd. (GSECL) in India. This project is considered by GE as a milestone for India, as it is the first of its kind to be carried out in what the company said is a market with a great potential for retrofits in existing, older coal-fired power plants.

This is also part of GE’s Powering Efficiency Center Of Excellence (COE), which aims to slash the global CO² emissions from the world’s fleet of existing coal plants through a total plant hardware and software solution approach.

In the 1350 MW Ukai plant, GE implemented its Advanced Steam Path (ASP) solution to restore the original output of a 200 MW LMZ steam turbine supplied by Bharat Heavy Electricals Ltd. (BHEL). ASP modernization technology features high-pressure and intermediate-pressure full module upgrades and low-pressure inner block upgrade, and it is part of GE’s Fleet360 portfolio.

Ashok Ganesan, senior executive in charge of steam plant solutions for GE’s Power Services business and global CEO leader, told Diesel & Gas Turbine Worldwide that this is a very important achievement for the Indian market, where an aging fleet of steam turbines operating in coal-fired power plants delivers an average plant efficiency of just 27-28%.

According to Ganesan, the modernization project allowed the overall Ukai plant efficiency to be increased by 5.5.%.

“Implementing our ASP technology in the Unit 4 steam turbine at Ukai consisted of a full shaftline replacement,” Ganesan said. “In practice, the existing LMZ steam turbine was opened and all the internal components removed and replaced. And in this particular case, no changes were made to the existing footprint.

“This successfully implemented upgrade improved the turbine’s heat rate by approximately 14.5%, restored the output to its original 200-MW capacity, and extended the unit life up to 25 years.”

Final tests made at Ukai’s plant showed a more efficient operation, so that the plant will reduce its coal consumption by more than 140 000 tons per year and carbon dioxide emissions by 180 000 tons per year.

“With our Fleet360 portfolio – that includes ASP technology – we can offer comprehensive capabilities to service and upgrade not only GE’s equipment, but also that of other makers. Also, ASP is not limited to the upgrade of turbines in coal-fired plants, but can be utilized for steam turbines in combined-cycle power plants, for example,” Ganesan said. “Actually, ASP has been successfully implemented with a good number of small industrial turbines, where it helped reaching a higher efficiency especially at small loads.

“When it comes to the upgrade of existing coal-fired power plants, we see a big potential in countries such as India, China, Indonesia, and sub-Saharan Africa, to name a few.”

Earlier in 2017, GE announced another ASP modernization project with NTPC Limited in India for three 200 MW Ansaldo steam turbines at the Ramagundam station. According to GE, upgrade projects like these will better position India to meet future energy demands and challenges including enabling to back up renewables. In the country’s New Policies Scenario, electricity demand will more than triple in the next two decades, rising by 4.9% per year on average from 900 TWh in 2013 to almost 3300 TWh by the end of 2040.