While driving down Interstate 5 during the last two years, Lodi residents have watched a towering structure rise near White Slough wastewater treatment plant.
The looming, metal metropolis of twisting pipes, 800,000 yards of wiring and a control center with a long panel of screens will be supplying the city of Lodi with a steady stream of electricity starting this fall.
The Lodi Energy Center is a natural gas power plant that will generate 300 megawatts of power, which is enough to power a little less than 300,000 homes on average, said Kevin Cunningham, the plant's general manager. Lodi will receive 30 megawatts.
The plant will have its opening in early August, but it will not be fully operational until the fall, after a series of tests, Cunningham said. Workers still have to finish electrical work, insulation, small bore piping, painting and paving.
The entire project costs $452 million and will be paid for through bond financing. Lodi Electric Utility users will pay down the utility's $41 million share of the bond debt in their electric utility rates.
The $140 million power island was purchased from Germany-based Siemens Energy.
The Northern California Power Agency will construct, own and operate the plant, and it will pay the city of Lodi to rent the land and to use Lodi's wastewater in the plant.
The combined-cycle power plant is designed to start up in two hours, which is much quicker than the typical six to eight hours of most plants. That means there are less emissions, Cunningham said.
"It's much more efficient than the old fossil fuel-style plants. ... It's the cleanest, most efficient power plant in the country," he said.
When the plant is running, there will be several different processes going all at the same time. Natural gas is fed into plant, and then it is combined with air that has gone through a large filter, similar to the air filter in a car. When they combine, it creates combustion, just like a jet engine, and that turns a turbine. The process happens in a room that is filled with a large circular piece of metal covered in heavy insulation to keep any heat from escaping.
To use all of the resources, the plant then captures the remaining heat, which is around 1,000 degrees, and feeds it into a building filled with tubes that then boils water to power a steam turbine running at 9,000 reps per minute. The water will come from the city of Lodi's wastewater treatment plant, and NCPA will clean it even further to the point of almost being distilled, Cunningham said.
From near the top of the 150-foot boiler-stack, the entire plant's 4.4 acres and the green fields surrounding the plant are visible.
Once the water has gone through the steam turbine, it is put into a large cooling tower that funnels it through to bring the temperature down from 130 degrees to 80 degrees Fahrenheit.
It then goes through another cleaning process and then is injected 5,000 feet into the ground, where Cunningham says it actually improves the water supply.
NCPA will employ 23 employees to work at the plant, though that number will drop down to 21 in a year. At its peak, the plant had 260 employees ranging from carpenters, boilermakers, electricians, pipe fitters, operating engineers and laborers working at the site.
Ten of NCPA's 17 members and four other public power agencies are participating in the power plant.
The plant has an advantage because when renewable power, like solar or wind, are not producing, the plant can fill in the gaps. But if there is enough power being provided, especially during the spring of good hydro years, the agency can temporarily shut down the plant.
"We can supply our own electricity and we can play the market to provide for the cities," Cunningham said.
The city already has a power plant on the site, which made it ideal for the Lodi Energy Center construction. There are no neighbors, it already had a Pacific Gas & Electric gas line, the city had wastewater to be used for the steam turbine and to cool the plant, and there were already PG&E electrical lines to send out the power.
In the future, there could even be a Lodi Energy Center II, Cunningham said.
"Everything we needed was here and we had a supportive community," he said.