After close collaboration for years by Portland, OR-based utilities NW Natural and Portland General Electric (PGE), a unique natural gas storage service is closer to becoming a reality in the Pacific Northwest in response to an evolving electric-gas sector relationship that has become more critical with renewables growth.
NW Natural CEO David Anderson earlier this month told financial analysts on a quarterly earnings conference call that completion of the $128 million expansion of the North Mist gas storage field is on track to begin operations before the start of the 2018-2019 winter heating season. Critical engineering, construction and testing work, however, still awaits the project in the next nine to 12 months.
Two years ago, PGE formally asked NW Natural to move ahead with expanding capacity at the Mist underground gas storage facility northwest of Portland to serve PGE's nearby gas-fired electric generation plant, Port Westward.
Mist's expansion includes developing a reservoir to provide up to 2.5 Bcf of storage, a compressor station to increase injection/withdrawal capacities by 120 MMcf/d, and a 13-mile pipeline connected to the generation plant.
Anderson said all the wells have been drilled, the compressor station is being built off site, and the pipeline should be in place late this fall.
"We continue to expect that the majority of the project's construction and dollars will be spent and completed this year," Anderson said. "The project is on track to be in service for the winter of 2018-19."
With the increased reliance on intermittent renewable sources of power, the need for back-up generation sources that can be ramped up and down in minutes is increasingly critical for the power sector, which was the impetus behind the utilities seeking a unique no-notice storage arrangement.
To get the expansion into service, NW Natural, as the storage field operator, has to slowly inject up to 1 Bcf of base gas supplies into the new reservoir, said NW Natural’s Dave Weber, who heads the project.
"We inject the base gas very slowly because this reservoir produced over many, many years so we want to push back the water and gas slowly so as to produce a nice round bubble, so this reservoir can be viable as a storage facility for the next 80 to 100 years," Weber said.
Eventually, PGE would buy supplies of working gas that would be injected before rigorous injection/withdrawal tests are run to ensure the electric utility can get the supplies it needs to provide load-balancing power.
"Once all of that is successfully completed, we should be well underway in the September/October timeframe next year," Weber said. "This is a unique facility.” It’s a “no-notice service, so it is not like a traditional gas storage facility. PGE's generation plant can turn on in six minutes, and when it does we need to put gas in that pipeline, so that means that the facility testing is critical to show that we can make that quick turnaround."
NW Natural reported net income of $2.7 million (10 cents/share) in 2Q2017, compared with $2 million (7 cents) a year ago.