In a recent Q&A with the American Public Power Association, Brad Koehn, the new General Manager of California public power utility Turlock Irrigation District, detailed TID’s plans for adding power supplies in the years ahead.
“I feel like TID is pretty unique. We're what I would consider probably a medium-sized utility, but we are our own balancing authority…a decent portion of our generation is internal generation within the district,” said Koehn, who became GM of TID in June of this year.
He noted that the utility has “quite a few small hydro facilities,” as well as the Don Pedro Hydro Project.
“We have wind in the Northwest, we have solar inside the district, we have solar down in Southern California. We are part of a geothermal plant,” Koehn said, as well as a combustion turbine fleet “that also helps us maintain our balancing authority and as far as power mix goes, our power mix annually does vary due to the hydro year because of Don Pedro and the hydro facility there and so we range between about 50 to 75% of our of our annual mix being carbon free.”
TID is “currently looking at adding renewable energy both inside and outside of the district and we're pretty agnostic to the type of renewable energy. But again solar, wind, geothermal -- they're all in the mix, but we will be adding those in the years to come and are currently involved in some negotiations that will bring those online in the next couple of years,” Koehn said.
He made his remarks in a recent episode of APPA’s Public Power Now podcast.
Koehn noted that a TID long term planning effort called the energy road map looks out to 2045. “Here in the West, we have a very aggressive path to carbon free energy. And this energy road map is really analyzing all options and paths that can get us there,” he said.
“This is inclusive of even pumped hydro, even nuclear we’re assessing and really the filter we're looking at all of these paths through is reliability and affordability, which is the mission of TID and that is the key focus. All of these options are being looked through that lens,” he noted.
“And I think that this plan will be unique because I think many of the plans that we see and within the industry sometimes lack those cost projections, and therefore that affordability metric sometimes is muted or sometimes even missed and so we're really excited to see what this plan shows and depending on what it shows, we're going to use it heavily in what our statement is and moving forward, like I said, it's a very aggressive path to carbon free,” he said.
“The one thing that's front and center is that we have to remain reliable and we have to remain affordable as a district.”
In the interview, Koehn was also asked to discuss how resource planning has changed.
The proliferation of renewables in the West “has definitely changed, but one thing specifically that it's changed is load shapes,” the TID General Manager said.
“The daily load shape -- everybody's familiar with what we call the duck curve and what that duck curve shows is that as solar gets more and more common here in the West, when that solar comes off and when the sun goes down, it's creating this steep curve and a later peak -- it's pushing the peak later in the day, and it's creating a pretty steep curve, which just means we need to rely more on fast acting generation and so that shows value in some of our fast acting combustion turbine fleet.”
Batteries “are things that we're looking into. They're also fast acting. They're just pretty expensive still and so really that's some of the things we're seeing as far as load shape goes.”
The other thing “that's really changing resource planning is how the markets are changing here in the West – the Energy Imbalance Market -- the district’s been part of that for probably about six years now, seeing huge benefits in being able to gain access to energy, when it's at its lowest value, being able to import more energy when it's cheap and being able to sell some of our excess capacity into that same market when it's highly valuable. Also there's another product called EDAM. It's the extended day ahead market which is really moving the benefits of EIM even to the day ahead time frame,” he said.
“And so that's not quite a fully formed market yet, but we are involved in that and plan on continuing to keep that on the front of our minds because participating in these markets really offsets the cost of these renewables to our customers and that's really our goal -- to optimize every part of our business that we can to really maintain that affordability for our customers.”
Don Pedro Life Extension Project
He also provided details on the utility’s Don Pedro Life Extension project. “Don Pedro is our large hydro facility on the Tuolumne River and it was built in the early 70s. It's currently in the relicensing stage and the life extension project is exactly that. It is a refurbishment or replacement of basically all components of the project to completely extend the life of this hydro facility,” Koehn said.
“That includes increasing the capacity. It's currently a 203 MW capacity and because of more efficient turbines and generators will increase that to over 260 megawatts,” he noted.
Unique Solar Project
Koehn also provided details on TID's Project Nexus, which calls for the installation of solar panel canopies over various sections of the utility’s irrigation canals.
“We have had more media coverage on Project Nexus than I think anything in the history of TID, including international coverage, so really excited to be part of something that has become such a covered project,” he said.
“It's extremely unique. It's a public-private academic partnership, DWR and TID are the public entities.”
Solar Aquagrid is the private entity and the UC system is UC Merced – “the academic piece of the puzzle. So that's a unique partnership to start.”
The project has been funded by the state of California “and really the goals at the highest level are install solar panels over the top of a water conveyance system and study all things you can to determine what are the costs? What are the benefits? How does the project perform all to support how this could be scaled in the future.”
He pointed out that there are “a lot of water conveyance systems in California. And is this a solution that can be scaled large scale and become a solution as we transition to carbon free energy as a state?”
Koehn noted that there have been “claims of solar generation is increased when it's in a more humid or cooler state. How much evaporation is saved by shading the canal? We're really interested in what happens to aquatic growth when you remove sun from the equation.”
TID spends “a lot of money as a district cleaning our canals because of aquatic growth, and I think there could be some real maintenance savings by shading the canal system. And in general this is a solution that is installed on property that TID already owns.”
In comparison to a typical ground mount solar farm – “you're buying hundreds of acres within the district. And because of our water reliability, our land value is significant here. We're [$50,000] to $60,000 an acre. You start doing the math on a large scale solar project and it becomes very, very cumbersome cost wise to be competitive.”
And so “this has a unique ability to be placed on property we already own. It's our canal banks and also TID is a unique project participant because we are an integrated utility as well, so we are the water provider and the electric provider. And so that builds some efficiencies in interconnections, et cetera."
