RICHFIELD — Some 16 miles northeast of Shoshone, farmland sprawls between houses, and sheds protect irrigation pumps along canals. Abandoned vehicles sit crumpled and rusted while cows graze in a field nearby.
Just beyond one of the ranch buildings, a power line ends abruptly. At its base, a chain-link fence protects the 72 south-facing panels soaking up the sun’s rays.
What are these solar panels doing out in the middle of Idaho’s desert? Here, at the end of the line, they’re helping to maintain voltage for 13 farm and ranching customers — a solution that’s the first of its kind in Idaho, and possibly anywhere.
“We’re able to provide voltage supply by generating energy locally,” said Patrick Perry, one of the electrical engineers for Idaho Power Co. who helped get the project in place. “In this situation, it works because we’re out of alternative solutions.”
The power line here runs 26 line miles from the nearest substation, north of Magic Reservoir. It’s unusually long for a “feeder line,” which typically serve only 10 to 20 line miles of customers, Idaho Power spokesman Dan Olmstead said.
Just like a garden hose, the longer a power line is, the less pressure (or voltage, in this case) is at the end, he said. That’s partly because of the resistance of the overhead line itself.
In this case, the older conductor, Perry said, has a relatively high resistance in it. As a result, voltage wasn’t staying up to the company’s quality standards.
If it gets below a certain level, it can have adverse effects — particularly during peak usage in the summer, when the irrigation pumps are running.
“It’s not as efficient for that pump to run on a lower voltage,” Olmstead said.
To deal with irregular voltage, Idaho Power normally installs voltage regulators along particularly long lines. These can bring the voltage up and down based on demand, Perry said. But in this case, there were already three regulators along the line — the maximum number the company could install without them counteracting each other.
The next option would have been to build an entirely new line with wire that has less resistance. But lava rock covering the ground makes drilling new poles a costly solution.
So instead, Idaho Power sought out a way it could generate the voltage needed for those remote customers.
“It’s a bit of an experimental thing,” Olmstead said. “But it makes a lot of sense to do it this way.”
The company had already been looking at local generation as a solution for this kind of situation, but hadn’t identified an area where it was needed and could be implemented. Phil Anderson, another electrical engineer for the company, had been watching the prices of solar panels drop.
Perry helped identify the site for the project, and the panels were installed in October 2016.
“This solar project cost much less than that reconductoring project,” he said.
That includes the cost to extend the line a short way over private property — to get the panels installed on less than an acre of land. The maintenance of the system is also not expected to be excessive.
Perry has been analyzing the system over the past year to see if it’s doing what it should.
“We’ve got some pretty definitive metrics that say it has increased the voltage out there to those 13 customers,” he said.
The 18-kilowatt project supplies enough power to maintain voltage, but the power usage from those customers still exceeds that production.
“We didn’t want a lot of backflow, we just wanted enough to solve the low voltage,” Perry said. “The name of the game isn’t to power the whole area.”
The local power generated by this photovoltaic system decreases the current that transports the energy, which raises the voltage, Perry said.
It’s a non-traditional solution that so far, seems to be working just like it should. Idaho Power is already looking at another potential site in the state where this might work.
“This is the first time it’s ever been done, to my knowledge,” Perry said. “It took a lot of convincing ourselves and management that this was something we needed to move forward with.”