Fluence and Invenergy partner on 1,900MWh Arizona solar-plus-storage project

July 28, 2025
LinkedIn
Twitter
Reddit
Facebook
Email

Lithium-ion battery storage system integrator Fluence and independent power producer (IPP) Invenergy will be partnering on the 475MW solar and 1,900MWh energy storage Hashknife Solar Energy Centre in Navajo County, Arizona, US.

According to Fluence, Hashknife will be one of the largest solar-plus-storage facilities in Arizona, and will use the company’s Gridstack and Gridstack Pro lithium-ion energy storage solutions.

The project will be built in two phases. Hashknife I entered construction in 2024 and is expected to begin commercial operations in 2026. Hashknife II is expected to begin construction this year and will begin commercial operations in 2027.

Invenergy’s 2024 construction update for Hashknife I indicates that both phases have signed power purchase agreements (PPAs) with utility Arizona Public Service (APS) and are included in APS’s biggest portfolio of projects obtained through a request for proposals (RFP).

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

The company also says the project will support 450 construction jobs during peak construction and create 16 full-time jobs. Invenergy expects the total economic investment to be US$53 million.

Fluence launched the Gridstack series in 2020, claiming it to be a highly customisable yet mass production modular battery energy storage system (BESS) solution. Gridstack Pro followed in 2023, which Fluence said at the time was aimed at the largest and most complicated projects its customers are undertaking.

At the beginning of the year, the company launched SmartStack, an integrated AC block with balance-of-plant (BOP) components housed underneath the battery stacks. By essentially making the units taller while increasing energy density, the company aimed for a smaller footprint on the ground.

Invenergy recently lost federal funding for its Grain Belt Express project, which aims to connect four US grid regions with a single transmission line. The company states that this would enhance energy affordability and reliability. Moreover, consumers linked to this grid and neighbouring grids would benefit, even if their utility does not buy power from Grain Belt Express.  

The company also claims it would have the ability to power 50 data centres, create an estimated US$52 billion in energy cost savings over 15 years, and create approximately 22,300 jobs during the construction of the line and new generation.

The US Department of Energy’s (DOE) Loan Programs Office (LPO) announced on 23 July that it had cancelled a US$4.9 billion loan guarantee for the Grain Belt Express Phase 1 project.

Several sources have claimed that lawyers at the LPO advised that the action was illegal. Invenergy has said it expects to find private funding for Grain Belt.

24 March 2026
Dallas, Texas
The Energy Storage Summit USA is the only place where you are guaranteed to meet all the most important investors, developers, IPPs, RTOs and ISOs, policymakers, utilities, energy buyers, service providers, consultancies and technology providers in one room, to ensure that your deals get done as efficiently as possible. Book your ticket today to join us in 2026!

Read Next

January 9, 2026
Jointly owned by Masdar and Igneo Infrastructure Partners, independent power producer (IPP) Terra-Gen’s Lockhart CL I and II battery energy storage system (BESS) projects have reached commercial operations in San Bernardino County, California, US.
Premium
January 9, 2026
Javier Savolainen of Wärtsilä explains how Australia’s battery storage and pumped hydro fleet have been impacted by the current heatwave.
January 9, 2026
Yanara has appointed Gamuda Australia as the project delivery partner for the early contractor involvement (ECI) phase of the Mortlake Energy Hub in Victoria.
January 8, 2026
H.I.G. Capital-backed energy platform, Greenflash Infrastructure, has Safe Harboured more than 10GWh of lithium-ion (Li-ion) energy storage capacity.
January 7, 2026
A roundup of updates on BESS projects from SolarMax, Energy Vault, Engie, and Spearmint in the Electric Reliability Council of Texas (ERCOT) market.