The construction that will be a common, and continual, sight at OPPD’s North Omaha Station in 2016 has already begun.
For the more than 60-year-old coal-fired plant, 2016 will be a year like few others. A number of large projects are underway that will dramatically transform North Omaha Station (NOS), and ensure its compliance with tighter clean-air rules.
The 648-megawatt station first came online in 1954 as a single coal-fired unit. Four more units were added by 1968. The plant has long been a workhorse in the fleet, particularly during the historic flood of 2011, when flood waters threatened Fort Calhoun and Nebraska City stations.
The work at NOS, the oldest of OPPD’s four main baseload plants, stems from the 2014 decision to reshape the company’s generation plan.
OPPD, through its stakeholder process, decided to put a greater focus on renewable energy sources as well as decrease demand by 300 megawatts through demand side management programs by 2023. The result was a commitment to 33 percent of retail load to come from renewable sources by 2018.
Some of that work started last year. On the west side of the plant, construction crews are installing four silos that will store dry sorbent and activated carbon, which will be injected into the flue gas stream of Units 4 and 5. The injection process will reduce acid gases and mercury emissions below the limits established by the Boiler MATS (Mercury and Air Toxics Standards) rule, which OPPD must comply with by April 16. Testing on the injection system will begin next month.
Units 1, 2 and 3 will stop burning coal in April of this year. Units 1 and 2 will be retired at that time and Unit 3 will remain operational until the end of 2016 burning natural gas and then retired.
Units 4 and 5 will then be retrofitted to be natural gas-fired units in 2023. The remaining three units will be retired in April.
Dave Wetrosky, NOS plant manager, said the work is on schedule and going well.
Wetrosky said there is a lot of work to be done on those three units after they are retired to make them safe for personnel. The work includes cleaning all the remaining coal out of the bunkers, draining water and oil out of equipment and storage tanks and eventually disconnecting any interconnected piping between the operational units and the retired units.
John Wichman, senior production operations engineer, said that along with the cleaning, work on the three retiring units includes many complicated, and often interconnected, mechanical and electronic systems.
“One thing that has struck me is that when these units were designed and built, it doesn’t seem that they accounted for decommissioning or retirement,” Wichman said.
Wichman said the three units will stop burning coal by April 16, either on a staggered schedule over several weeks or over a period of five days leading up to April 16, depending on a number of factors, including current market prices.
Other projects will also be done in support of changes at NOS, including modifications to the coal handling process and auxiliary steam systems. The auxiliary steam modifications will provide a heating option and start-up source for Units 4 and 5 once the three units are retired.
With the unit retirements came the need for staff reductions. An early commitment was made that no employees would be let go due to the decisions affecting NOS. As of late January, only four of the 48 workers displaced by the unit retirements still needed different positions.
“It is a big year,” Wetrosky said. “A lot of employees have put a lot of their time and effort into these units over the years and have a great deal of attachment to them. We plan on having a ceremony in June honoring all of the work done and the tremendous role these units have played for the district. It will be an emotional time.”