POWER [October, 15 2006]

Cover Stories

Apply the fundamentals to improve emissions performance

The O&M staff of AES Westover Station wisely took a holistic approach to optimizing combustion within Unit 8's boiler in order to reduce its NOx emissions while maintaining acceptable levels of carbon-in-ash content. The results of major modifications—centered on the addition of a fan-boosted overfire air system—were a 60% reduction in NOx levels, improved unit reliability, and a project payback period measured in months rather than years. As this project proved, the whole is more than the sum of its parts.

Designing and upgrading plants to blend coal

Fuel flexibility isn't free. Whether you're equipping a new power plant to burn more than one type of coal or retrofitting an existing plant to handle coal blends, you'll have to spend time and money to ensure that all three functions performed by its coal-handling system—unloading, stockout, and reclaim—are up to the task. The first half of this article lays out the available options for configuring each subsystem to support blending. The second half describes, in words and pictures, how 12 power plants—both new and old—address the issue.

Expert systems optimize boiler performance, extend plant life

Slagging and fouling of furnaces and boilers' convective pass top the list of costly coal plant O&M problems. Although sootblowing is a tried and true solution, running sootblowers too often can erode boiler tubes. Lehigh University's Energy Research Center has developed an "expert" sootblowing system that has outperformed experienced operators' "seat of their pants" sootblowing procedures on two head-to-head field tests.

Features

Meeting utility industry challenges through innovation

In 2005, Xcel Energy fully implemented its unique Utility Innovations initiative to encourage its IT vendors to work together. One pilot project completed under the UI umbrella confirmed that tighter integration of predictive and analytical systems and data can optimize preventive maintenance intervals, reducing costs and downtime while increasing profits and productivity.

Monitoring key gases in insulating oil keeps transformers healthy

Large T&D-sized transformers age as quickly as generating assets do. But preventing transformers from failing is difficult because they have no moving parts and are sealed up. Tracking the concentrations of certain gases—the more, the better—that are dissolved in a unit's insulating oil is a proven way of detecting damage before it causes a costly problem.

Shaving load peaks from the substation

The first megawatt-class sodium sulfur (NaS) battery placed in service in North America was installed this June in Charleston, W.Va. The 1.2-MW system—comprising the battery and a bidirectional inverter—can be discharged during the day to provide 7.2 MWh of on-demand power for shaving peak loads and be recharged at night. It's no longer true that electricity can't be stored, except in small quantities.

Technology options for capturing CO2

Concerns about global climate change have prompted interest in reducing or eliminating the carbon dioxide (CO2) emissions of fossil fuel-fired power plants. Here's a guide to the technology and economics of three CO2 capture methods: postcombustion separation of CO2 from flue gas (applicable to existing plants), and oxygen-fired combustion and precombustion capture (suitable for new coal-fired capacity, including IGCC plants).

Utilities split on readiness of IGCC

For some gencos, the dearth of operating experience for integrated gasification combined-cycle plants adds too much uncertainty to the risk/reward equation for new-capacity technology options. For others, the possibility of being able to comply with air pollution limits as far out as 2018, as well as to meet all-but-certain CO2 caps, makes IGCC well worth investing in—now.

Departments

Commentary

Turning the corner on global warming

In his keynote speech this May to the Global Roundtable on Climate Change, held in Iceland and hosted by the Earth Institute of Columbia University, Ólafur Ragnar Grimsson—the president of…

New Products

Legal & Regulatory

Restricting bids for new capacity raises costs, lowers reliability

Most sponsors of bid solicitations seek to attract the maximum number of high-quality bids. Basic economic principles tell us that the greater the number of respondents to a solicitation, the…

Focus on O&M

Focus on O&M (October 2006)

Upgrading to digital--twice / Lower-cost turbine monitoring / Pros and cons of remote process control / Nuts about Superbolt

Global Monitor

Global Monitor (October 2006)

First live superconducting cable / Biggest CO2 storage project / Largest hydrogen-fueled plants / Record run for fuel cell cogen system / Largest PV plant still in Bavaria / Luz returns to U.S. / POWER digest

Speaking of Power

Balancing risks and rewards

More top utilities are making plans to add one or more integrated gasification combined-cycle (IGCC) plants to their generation portfolios over the next decade. Some 25 separate projects are on…

GBR Reports