Power Sources

Study lays out path for Platte River zero net carbon portfolio

A study completed by Pace Global LLC concludes that a zero net carbon, or ZNC, energy portfolio for the Platte River Power Authority owner communities of Estes Park, Fort Collins, Longmont and Loveland in Colorado can be achieved.

But the study also said that a ZNC for Platte River would require significantly more renewable generating capacity than what Platte River calls for in its current, long-range integrated resource plan.

On Dec. 7, the Platte River Board of Directors and public learned that a ZNC energy portfolio for Estes Park, Fort Collins, Longmont and Loveland can be achieved by 2030, Platte River noted in a news release.

Jason Frisbie, CEO of Platte River, said Platte River’s leaders had two primary objectives concerning the modeling effort: 1) the lowest cost generating model that would result in carbon neutrality and; 2) system reliability be maintained at currently high levels.

During a community meeting sponsored by Platte River, participants received a briefing on the ZNC study from Pace Global.

Platte River is a not-for-profit wholesale electricity generation and transmission provider that delivers energy and services to its owner communities of Estes Park, Fort Collins, Longmont and Loveland, Colorado for delivery to their utility customers.

Study assumptions

Pace produced the study assuming the need for more renewable energy resources, the retirement of all coal-fired generating resources by 2030 while retaining combustion turbines, retention of existing hydro power positions and the potential need for new natural gas resources.

The study concludes a ZNC energy portfolio for Platte River would require significantly more renewable generating capacity than what Platte River calls for in its current, long-range IRP.

Modeling also considered the need for firming capacity that would be used to integrate intermittent renewable energy onto the grid, provide backup for any load loss and maintain needed reserve margins.

Under the least-cost model, Platte River would serve approximately 75 percent of its customer load with renewable energy resources and 25 percent with natural gas-fired resources.

Platte River would offset the fossil-fuel generated electricity by selling excess renewable energy to the market on an annualized basis, thereby reaching carbon neutrality.

To achieve a ZNC energy portfolio, Pace estimated the need for 600 megawatts of new solar, 350 MW of wind and 286 MW of natural gas combined cycle generating capacity be placed on Platte River’s system by 2030, the year when the coal-fired Rawhide Unit 1 would be retired.

Lithium-ion battery storage was considered by Pace but determined to be less cost effective, with less capacity than traditional resources at this point in time.

“We estimate Platte River’s energy production costs to achieve a zero net carbon portfolio would be approximately 20 percent higher in 2030 than they would be under current forecasts within Platte River’s current IRP,” said Gary Vicinus, a managing director for Pace Global.

Although risks to system reliability are largely addressed through the addition of natural gas-fired generating capacity, market access and price risks may rise as more utilities build renewables and sell excess power into the marketplace.

Vicinus noted that Platte River may need to sell renewable energy into the market at lower rates than anticipated, for example, to meet the requirement of achieving zero net carbon emissions throughout a given year.

RTO participation

The Pace study indicates that Platte River participation in a regional transmission organization (RTO) could reduce costs of achieving carbon neutrality.

Platte River is part of the Mountain West Transmission Group. Mountain West is an informal collaboration of electricity service providers that formed in early 2013 to evaluate an array of strategic options to adapt to the changing electric industry. Options evaluated ranged from a common transmission tariff to RTO membership.

Southwest Power Pool, an RTO, notes on its website that following recent public meetings, it will facilitate negotiations regarding the terms and conditions of Mountain West’s membership among its staff and existing member companies and the members of the Mountain West Transmission Group. Current assumptions anticipate full integration of Mountain West as members of SPP in late 2019.

Meanwhile, the Pace Global study said additional cost and risk mitigation includes the flexibility to use battery storage should technologies advance to make it more cost effective, and the continued use of Platte River’s existing combustion turbines to meet intermittent load needs.

Value of storage

The Pace Global study said the capability and price of energy storage continue to improve, making it an increasingly viable component for power systems.

“Battery energy storage economics have improved both as a standalone technology and in combination with solar and thermal resources, although the total market penetration remains relatively low,” the study noted.

Pace Global noted that a storage study completed by consulting firm HDR and commissioned by Platte River indicated that lithium-ion battery energy storage costs are expected to decline by approximately 20% over the next five years. (The storage study is available here.)

“Much of the recent utility scale battery energy storage applications were driven more by mandates and the desire for utilities to gain experience with this technology. With improving economics, the installations and roles for batteries are expected to continue to expand,” Pace Global said.

Pace Global said that for the ZNC portfolio analysis, battery storage (four-hour duration) was considered as a long-term capacity expansion option. Based on Platte River’s study and expertise, the battery energy storage peak credit was assumed to be 75% for a long-duration battery. “Based on the hourly modeling conducted for this study, battery storage resources proved uneconomic relative to other resources such as intermittent renewables and thermal generation capacity. Other sources of value for storage that would require intra-hour modeling, (e.g., fast ramping, frequency, and voltage control) were not analyzed,” Pace noted.

As storage technology matures and there is wider adoption, battery storage can also be considered a part of the portfolio mix for ancillary service needs, the Pace Global study said.

Platte River’s board supports purchase of new wind power capacity

Following the presentation, Frisbie announced the Platte River Board of Directors supported the purchase of 150 MW of new wind power capacity.

In early 2017, Platte River requested proposals for 50 megawatts of new capacity and received several favorable proposals.

“If we move forward with 150 megawatts of new wind, we will have a generating portfolio that is nearly 48 percent carbon-free,” Frisbie said. “Even though we would be years ahead of the current IRP, we will not be done. We will continue to look for opportunities to provide added value to our owner municipalities.”

ZNC modeling effort emerged from separate initiative

The ZNC modeling effort emerged from a Platte River initiative to study customized resource plans, or CRP, providing cost and feasibility concerning a range of energy resource options available to meet individual community goals.

In July, the Platte River board approved a study of even higher levels of non-carbon resources, with a focus toward modeling a 100 percent noncarbon resource scenario for all four municipalities.

With both the CRP and ZNC modeling efforts, Platte River said it will develop a full range of options for consideration by its owner communities.

Additional details about the ZNC study are available here, while additional details about Platte River’s carbon-free resources are available here.

Colo. executive order addresses statewide greenhouse gas emissions

In July, Colorado Gov. John Hickenlooper signed an executive order that declared it to be the goal of the Colorado to achieve the following: (1) reduce statewide greenhouse gas emissions by more than 26 percent from 2005 levels by 2025; (2) reduce carbon dioxide emissions from the electricity sector by 25 percent by 2025 and 35 percent by 2030 from 2012 levels; and (3) achieve electricity savings of two percent of total electricity sales per year by 2020.

The state also committed to, among other things, work strategically with any interested utility or electric cooperative on a voluntary basis to maximize use of renewable energy without increasing costs to taxpayers and create a statewide electric vehicle plan by Jan. 1, 2018.

Tags
Topics