Amid the damage and disruption caused by Hurricane Ida in New Orleans, a bright spot stands out. The New Orleans Power Station (NOPS), a 128-megawatt reciprocating engine power generating facility designed and built by Burns & McDonnell, performed as designed. The NOPS was the first local plant back online, thanks to black start capability that brought power back to many sections of the city well before grid repairs were complete.
The value of black start capability in reciprocating engine facilities is becoming increasingly important as more regions of the country experience extended outages due to extreme weather events. All of the reciprocating engine configurations in plants designed by Burns & McDonnell have black start capability.
What Black Start Means
The process of getting a large, completely idle power generating plant back online — commonly called a black start — relies either on electricity from the surrounding grid or power from an on-site generator for the initial energy needed to fire up the main plant. For a combustion turbine plant, a freestanding black start unit is typically fueled by diesel or natural gas and must be available on-site to provide as much as 10-12 megawatts (MW) of initial power needed by the plant until the primary turbines kick in.
For a reciprocating engine plant, much less initial energy is needed for the black start. An auxiliary generator as small as 500 kilowatts can quickly bring up the first reciprocating engine, which in turn brings up all the remaining engines in a rapid-fire sequence that can get the entire plant running at full capacity to support starting the grid.
Why It Works So Well
At the NOPS, seven Wärtsilä 18V50SG engine generating sets were installed under an engineer-procure-construct (EPC) contract that began with a notice to proceed in 2018. Reciprocating engine technology with black start capability was chosen by Entergy New Orleans in anticipation of future grid disruptions caused by severe weather events. With the devastation caused by Hurricane Katrina in mind, the utility wanted to incorporate more resilient, reliable technology on its local grid while also achieving the flexibility to support the addition of more renewable generation from solar and wind installations.
The Wärtsilä engines were selected by Burns & McDonnell because they can provide continuous efficient operation even when operating below 25% of the plant’s rated output.
Passing the Test Elsewhere
The NOPS is one of several reciprocating engine power facilities that have performed well during recent severe weather or other unusual events.
In February, when winter storm Uri knocked out much of the Texas grid, the Denton Energy Center, a 225-MW reciprocating engine facility serving the City of Denton, Texas, remained online providing much-needed power. The Denton Energy Center is powered by Wärtsilä 18V50SG reciprocating engines and was designed and built as part of the Denton Municipal Electric plan to convert its system to renewable energy. Since it was first energized in 2018, the DEC has been recognized as one of the power industry’s most flexible and efficient generating stations because it can quickly ramp up or down with little deviation from peak efficiency ranges.
In addition, a reciprocating engine plant designed by Burns & McDonnell for Matanuska Electric Association withstood a magnitude 7 earthquake that struck south-central Alaska near Anchorage in 2018. Designed and built as a source of peaking capacity for this cooperative electric utility, it served as an important source of power until an outage affecting the wider region was resolved.
Introducing Hydrogen Into the Fuel Mix
Reciprocating engine technology is one of a number of use cases currently being explored for development of hydrogen as a clean energy fuel source. Several manufacturers now have units available that can burn a blend of up to 25% hydrogen and 75% other fuel such as natural gas, and all are developing technologies that can burn 100% green hydrogen or ammonia produced from renewable power sources.
As utilities transition toward more renewables and clean energy sources in the resource mix, and as extreme weather and other events cause disruptions to service, reciprocating engine technology will be increasingly leaned on to provide the flexible and reliable balancing power needed by a much more dynamic grid.
As more intermittent renewables are added to the grid, reciprocating engine plants continue to gain momentum among utilities nationwide.
