PRPA to add more green power this summer

FORT COLLINS — In another month, barring inability to meet in person, the board of the Platte River Power Authority will be asked to weigh in on its choice of one of four options to help the wholesale electrical utility reach 100 percent non-carbon generation by 2030.

A goal that just a few short years ago seemed audacious if not impossible now appears within grasp due to improvements in technology and declining costs to implement green sources for electrical power.

This year, PRPA, which generates and supplies wholesale electricity to Fort Collins, Loveland, Estes Park and Longmont, will reach 50 percent carbon free in its portfolio. Non-carbon sources of power are hydro power from federal dams, wind and solar from owned or contracted PRPA developments, and some purchased from other utilities.

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How Platte River Power Authority is accelerating its energy transition

Platte River Power Authority, the community-owned wholesale electricity provider for Northern Colorado, has a history of bold initiatives.

Two new non-carbon developments will be ready to come on line for the utility this month and next. A Tesla battery installation to accompany one of them, the Rawhide Prairie Solar field, will help utility operators test how battery storage of wind and solar power will fit in the mix. The battery unit will be operational by late summer, said Pat Connors, vice president of power supply for PRPA. 

“All the portfolios [options for the board to consider] contain a battery component. We have to understand the technology. We have to know how to charge and recharge the batteries or we’ll burn them out,” he said. 

Customer demand within the member cities of PRPA has resulted in the effort to devise a plan that will result in less usage of coal and natural gas to generate electricity and more use of renewable energy.

The four options under consideration as part of the utility’s integrated resource plan are:

Option 1 — Continuity. Here, PRPA will continue to add non-carbon energy generation as it is economical, maintain reliability and retire coal-fired generators when it’s advantageous. This plan will not reach 100 percent renewable energy by 2030 but will result in the lowest increases in costs to member cities at 2.2% annually. 

Option 2 — No coal-fired generation by 2030. This plan would add more renewable energy sources than Option 1 but continue to use natural gas-fired generators to manage electrical loads. The utility would reach 90 percent non carbon generation by 2030. Wholesale rates would increase 2.6% annually. 

Option 3 — 100% non-carbon generation by 2030. This plan eliminates all existing coal and natural gas generators and substantially increases solar,  wind and battery storage capacity. Rates are projected under this plan to increase 8.7% annually to member cities, and utility operators are unsure whether the system’s current reliability can be maintained.  The utility would need to rely upon electrical markets outside of the PRPA to gain higher reliability. 

Option 4 — Integrated utilities. This option requires greater integration between transmission and distribution networks so that electric vehicle use and dispersed rooftop solar generation can be supported. Rawhide coal generation would be phased out by 2035 or, perhaps, that coal generator, which is cleaner than most coal plants, could be used to eliminate dirtier coal plants elsewhere in the west. Reliability could be maintained and wholesale rate increase would be about 2.8% annually.

The PRPA portfolio

The utility has a variety of generating units located north of Fort Collins and in western Colorado at Craig, for a total summer capacity of 1,017 megawatts.

The units are:

• Coal-fired Rawhide Unit 1, a 280 megawatt generator that has served as the backbone of the utility’s network since 1984. It’s the lowest cost generating resource in the portfolio.
• Craig units 1 & 2, also coal-fired, are rated at 151 megawatts. These units are scheduled for decommissioning first.
• Rawhide natural gas units A, B, C, D and F, which are primarily used to handle peak loads. They can jointly generate 388 megawatts of power.
• Federal hydropower, 90 megawatts, comes from dams across the west.
• Medicine Bow Wind Project, a six megawatt installation at Medicine Bow, Wyoming. 
• Spring Canyon Wind Energy Center, a 60 megawatt installation near Peetz.
• Silver Sage Windpower Project, a facility near Cheyenne, Wyoming, delivers 12 megawatts of energy to Platte River. 
• Rawhide Flats Solar, a solar field built in 2016 on 185 acres adjacent to the Rawhide plant that contains 117,120 panels and is rated at 30 megawatts.
• Rawhide Prairie Solar, opening for test energy in July and commercial use in September, will stretch over 150 acres and is rated at 22 megawatts. A battery installation to store two megawatt hours will be included in this project.
• Roundhouse Wind, which is ahead of schedule, will start to produce power in early to mid June. It stretches over 14,000 acres 10 miles north of Rawhide and generates 225 megawatts. It will use the distribution capacity available at the existing Rawhide plant. 

Platte River’s non-carbon resources emphasize wind over solar. Part of the reason for that has to do with its power sharing arrangements with other utilities.

The western alliance

Wholesale power providers don’t operate alone. They are part of a grid in which excess capacity in one area can be tapped to help meet loads in another.

Platte River has a joint dispatch agreement with three other regional utilities to share power resources. Those partners, Xcel Energy, Black Hills Colorado Electric and Colorado Springs Utilities, had been evaluating whether to join an even larger alliance. In December, they settled on the Western Energy Imbalance Market operated by the California Independent System Operator. The new arrangement is intended to save costs and bring more non-carbon sources of power into the Colorado network of utilities.

PRPA will become part of the new imbalance market in April 2022, Connors said. 

“There’s more solar out west, and more wind in Colorado,” Connors said. “We’re relying on each other’s resources to extend capacity. When solar in California is strong, we can use that,” he said.

Platte River wants to have its new integrated resource plan completed by December. Until the COVID-19 pandemic put a stop to in-person hearings, It had gathered comments from listening sessions in the member communities. It continues to gather information from members online.

It delayed the board decision on options because board members wanted to meet in person to debate the direction they will give to utility executives.

The board, composed of the mayors and utility managers from each member community, plan to have that meeting in July. 

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