NTPC moves up the ladder on efficiency
THE HINDU group of publications
Sunday, Jun 07, 2009

Our Bureau

New Delhi, June 6 NTPC Ltd, the country’s largest power generator, is moving up the ladder on efficiency norms for new projects.

The utility, which has already begun the transition shift from conventional boiler units to supercritical units, is now gearing up to adopt ultra-supercritical steam cycle technology.
Choice of technology

Ultra-supercritical power plants, which are fast becoming the system of choice for new commercial coal-fired utilities across China, Europe and the US, operate at higher temperatures and pressures and therefore, achieve higher efficiencies than conventional boiler units, resulting in less coal use per megawatt-hour.

This leads to lower emissions (including carbon dioxide and mercury), higher efficiency and lower fuel costs per megawatt.

“We have commissioned a study for adopting ultra-supercritical technology with efficiency levels of over 41 per cent is in progress.

“Already, the progressive adoption of supercritical technology has raised the cycle of efficiency in the Barh-II project by adopting higher reheat temperature and super heater temperature,” a senior official with NTPC said.
Going higher

Research and development is still under way for ultra-supercritical units operating at even higher efficiencies, potentially up to around 50 per cent.

Conventional coal-fired power plants have efficiency of about 32 per cent.

The introduction of ultra-supercritical technology has been driven over recent years in countries such as Germany, Japan, and more recently in China, in order to achieve improved plant efficiencies and lower fuel costs.

Research is focusing on the development of new steels for boiler tubes and on high alloy steels that minimise corrosion.

According to a Siemens report, just a one per cent gain in efficiency for a 700-MW plant reduces 30-year lifetime emissions by 2.5 million tonnes of carbon dioxide, besides sulphur dioxide, particulates.

China is the biggest adopter of advanced ultra-supercritical units and is now building around 10 similar coal-fired plants using different international manufacturers, and amassing its own design and construction expertise.