September 15, 2006

Nova Scotia Power's Point Aconi plant overcomes CFB design problems to become rock of reliability

Dr. Robert Peltier, PE

Back on top

The first full year that Point Aconi operated with all modifications was 2005. That year, the unit's DAFOR was 1.28%—a huge improvement over the 30% of 1999. Capacity factor likewise improved to a very admirable 92%, from 50% in the mid-1990s and 75% in 2001. Total generation increased from 700 GWh in 1995 to 1,365 GWh 10 years later. The unit's rated capacity was increased to 192 MW (gross) and has been maintained while firing 80% pet coke. Hot loop ash surging has been eliminated.

Results of the Point Aconi revitalization program. Source: Nova Scotia Power

Even more significantly, there were no boiler tube failures in 2005; in the worst year, 1996, there were 18 such incidents (Figure 8). The table and the three bar charts of Figure 9 detail the most significant improvements in performance achieved since 2001, when the revitalization program began.

8. Hole in the wall gang. Historical trend of boiler tube failures at Point Aconi. Source: Nova Scotia Power

9. Steady improvements. Historical trends of Point Aconi's generation, derated adjusted forced outage rate, and capacity factor. Source: Nova Scotia Power

The additional revenues produced by these large gains in reliability and performance have easily justified what it cost NSPI to achieve them: a little over $20 million. Today, thanks to years of effort by the boiler revitalization team (Figure 10), Point Aconi is one of the most reliable power plants not just in Canada, but in the world. Because it burns one of the cheapest fuels on the planet—petroleum coke—it is one of the lowest-cost power producers as well. For Nova Scotia Power, the long journey to excellence in operations was well worth it.

10. Intelligent design. The original Point Aconi boiler revitalization project team consisted of (from left to right) Gerry Currie, James Taylor, Paul Warren, Bill Small, and John Roper. Missing from the photograph is Mark Savory. Earlier this year, the team was awarded the Nova Scotia Power CEO award for Excellence in Innovation for its work on the revitalization project. Courtesy: Nova Scotia Power