Some power plant operators take reliability over heat rate

Driving the heat rate down and improving efficiency has been the Holy Grail of the power industry for years, and still is for the most part, but reliability is fast becoming of equal importance, according to operators speaking at Power-Gen International in Orlando. New market rules in the UK will require an emphasis on reliability, according to Derek Cheetham of Innogy Holdings PLC.


Kate Thomas
OGJ Online

ORLANDO-Driving the heat rate down and improving efficiency has been the Holy Grail of the power industry for years, and still is for the most part, but reliability is fast becoming of equal importance, according to operators speaking here at Power-Gen International.

Deregulation has engendered a different culture, especially with respect to older plants, said Derek Cheetham of the UK's Innogy Holdings PLC, formerly the domestic operations of National Power PLC. The integrated energy company operates both coal and gas-fired units.

"The market is moving toward reliability in the UK. We try to make sure the plant is always available when it can make money," he said. "We won't run it unless we can make money."

New market rules in the UK will require bilateral contracts, rather than scheduling all power sales through a pool. If a supplier can't fulfill the contract because a plant is down and has to go into the market to buy power at the last minute, the negative financial effect can be significant, Cheetham explained.

"We are willing to give up a few [heat rate] points for reliability," he said. "But we won't spend the money to make sure the plant is available all the time."

He says that is a change in attitude from a time when high availability at all times was a paramount concern. As the coal-fired units were pushed down into merit order for dispatch, the company switched them to base load for winter business days from November to March and achieved 99% reliability for that period.

Moving down
As the coal plants move even further down the chain, they are being dispatched for peaking needs or what the company refers to as commercial availability, Cheetham said.

Achieving the best results requires extensive investment in instrumentation to avoid overloading or underloading plants, he said. It also means linking the plant to information about fuel cost and the price for power and running this information through the trading desk.

In certain regions of the US market, combined cycle plants are also being used as peaking units, increasing the need for reliability and flexibility, said David Robb of Southern Energy Inc.

"Some OEMs (Original Equipment Manufacturers) have units that will go for 12,000 hr without maintenance," he said. "That's very desirable to us." Most require maintenance at 8,000 hr.

Panelists complained the boom in gas turbine orders is hurting equipment suppliers' reliability. Many said equipment is being shipped without necessary parts and requires extra assembling when it reaches a site. Some equipment is reaching the market without adequate testing, said Richard Weiss, formerly of El Paso International, a unit of El Paso Energy Corp.

"The rate of change is not healthy for the US market," he said, and has led to lawsuits and to changes in the way projects are managed today.

Examining the impact of environmentalism on the electric power industry, US operators noted rules continue to tighten for nitrogen oxide (NOx), sulfur dioxide (2), and the pressure is on to limit carbon dioxide (CO2). Recent 400-year floods in the UK have also heightened awareness of global warming, Cheetham said, and led to calls for CO2 limits.

Not so well known is the effect access to water is having on the electric power industry, said Weiss.

"Water has become a much bigger constraint," he said, than many people realize. As access to water becomes increasingly limited, more plants are using dry rather than water cooling. Because the technology is more expensive, it will make "a difference where you stand in the dispatch queue later on," he said. The best deal is to be the last company to build a water-cooled plant in a competitive region, said Weiss.

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