Solmar Insights
Tesla has signed a long-term power purchase agreement with ContourGlobal to secure close to 1 terawatt-hour (TWh) of renewable energy annually from the Sterling Project, a hybrid solar and battery storage facility located in Arizona. The deal, targeting around 90% of the project’s output bundled with renewable energy certificates (RECs), is among the largest of its kind for a single US site and represents a significant supply for Tesla’s growing energy needs.
Key figures
1TWh/year PPA for Tesla
Project Sterling rated 509MWp/450MWac solar + 360MW/1.4GWh storage
90% of plant output under contract
Deal structure and terms
The PPA stipulates Tesla’s purchase of approximately 90% of the annual output from the Sterling Project, with energy volumes bundled with RECs for renewable power claims. The contract duration and pricing terms were not disclosed, but the scale of the deal places it in the upper echelon of US corporate renewable agreements. The plant will deliver consistently firmed-up renewable power, leveraging onsite battery storage to meet hourly and profile demands for Tesla’s offtake obligations.
ContourGlobal, which acquired Sterling during development in December 2024, customized the project’s design to fulfill Tesla’s specific requirements. The hybrid configuration targets better capacity factors and stable delivery, positioning the plant to meet both regulatory and commercial offtake standards. The agreement underscores the maturation of hybridized PPA structures that are increasingly favored by large corporate buyers demanding reliability in renewables procurement.
In addition to locking in firm renewable supply, the bundled REC structure ensures regulatory compliance and supports Tesla’s sustainability reporting. The structure is aligned with trends toward greater granularity in energy sourcing, as buyers move to match clean energy consumption on an annual and hourly basis. The contract is further reinforced by transmission access and physical transfer rights into high-demand Western US markets.
The ability to secure a PPA for nearly the entire output of a major new build solidifies both parties’ positions: Tesla guarantees long-term renewable supply at a controlled cost basis, while ContourGlobal secures bankable project revenues and financing certainty on a flagship asset.
Hybrid project design and capabilities
The Sterling Project combines 509MW peak (MWp) of solar photovoltaic generation and 450MW alternating current (MWac), paired with a 360MW battery system capable of storing up to 1.4GWh. This coupling of large-scale solar with high-capacity storage enables delivery of firmed renewable power during grid peaks and reduction of curtailment risk. Hybrid projects like Sterling are growing in prominence as utilities and corporate buyers seek uninterrupted renewable profiles.
Locating the project on the Western Area Power Administration grid, with firm transmission rights into the California Independent System Operator (CAISO) market, broadens revenue opportunities for ContourGlobal. The grid access arrangement allows for optimized market participation, including price arbitrage and ancillary services, while increasing the resilience of Tesla’s contracted supply.
The combination of high-capacity storage with substantial PV output also enables the plant to participate in shifting load-serving obligations and providing reliability services to the broader Western US power system. This infrastructure is essential as more variable renewable energy enters the grid: advanced hybrid design reduces intermittency and aligns renewable output to both load and market demands.
The scale of storage integrated into Sterling positions it among the largest hybrid assets in the region, and reflects continued utility and commercial trendlines: new builds are favoring combined solar-plus-storage as the default, rather than standalone assets.
Execution timeline and project development
ContourGlobal acquired Sterling near the end of 2024 while it was still in the pre-construction phase. Since acquisition, the project design was refined in collaboration with Tesla to ensure alignment with power delivery and certification needs. Major off-site construction components commenced in 2025, notably including procurement of principal equipment in June that year. On-site construction is scheduled to begin later in 2026.
The commercial operation date for Sterling is anticipated in 2028. This timeline reflects a multi-year construction and commissioning process typical for large-scale, hybrid renewable projects. ContourGlobal’s progress from acquisition through development and major contract signature demonstrates the capital efficiency and project execution capabilities required in today’s competitive renewables landscape.
Upon completion, Sterling will stand as ContourGlobal’s largest renewable asset globally, marking a milestone not only for the company, but also for the growing trend of gigawatt-hour-scale hybrid deployment in the US Southwest. The focus on the Western grid and California ISOs positions the facility to capture premium pricing intervals and to supply a region with rapidly expanding clean energy consumption.
The execution risks remain typical for projects of this scale, including equipment delivery, labor, permitting, and grid interconnection milestones, all of which are mitigated by the creditworthiness and scale of both parties involved.
Market context and buyer trends
The Sterling PPA underscores the sustained rise of large-scale, multi-year renewable procurement by major corporate offtakers in the US energy sector. As corporates face mounting sustainability targets and electricity demand from industrial, digital infrastructure, and manufacturing expansion, securing dedicated renewables supply through PPAs is now core business strategy. Deals on this scale contribute noticeably to buyers’ total decarbonization goals while insulating them from market price volatility.
For developers like ContourGlobal, offtake agreements with blue-chip corporates offer substantial risk mitigation, support for project financing, and validation for subsequent project pipeline growth. The willingness to tailor projects to customer requirements, such as hybrid configurations and REC structures, marks a new era where developer flexibility and customer-centric design distinguish market leaders.
This transaction also highlights growth in the Western region, where grid constraints, policy direction, and surging demand from the technology and transportation sectors spur new high-capacity project builds. The use of storage is now a must for utility interconnection, market participation, and contract competitiveness. As regulatory frameworks adapt, these deals set new benchmarks in scale, design, and buyer-seller alignment.
Additionally, the deal is part of a broader trend where buyers like Tesla aggregate PPAs across regions and technologies to build a reliable, scalable, and truly renewable load portfolio.
Additional procurement by Tesla
In a related development, Tesla has agreed to a new PPA for the entire output of the 140MWac Lumen Farm solar plant in northeast Texas, with construction expected to begin in 2027 and operations by 2029. This builds on earlier agreements, such as a 57MWac deal with Zelestra for projects in Spain’s Castilla-La Mancha region, illustrating Tesla’s proactive renewable energy strategy.
By committing to multi-region renewable PPAs, Tesla can manage a diverse supply portfolio, improve redundancy, and match its operational load to renewable output across geographies. This approach gives Tesla the flexibility to balance its on-site generation, regulatory obligations, and emerging load growth from corporate operations, manufacturing, and data infrastructure.
The rapid cadence of procurement activity signals both growing demand and increasing sophistication in structuring utility-scale deals. The company’s willingness to embrace new technologies and partner with developers globally further cements its standing as a premier corporate buyer in the renewable space.
With parallel activity such as Meta’s PPA for the Palmera Solar Plant in Texas, the market for large-scale renewable procurement is becoming more competitive and dynamic, with lead buyers driving innovation in contract models, risk sharing, and grid integration.
What this means for buyers
This agreement highlights the increasing expectation for large-scale energy buyers to secure hybrid renewable assets able to deliver reliable, firmed supply through advanced storage integration and robust transmission rights. Sellers should anticipate greater demand for custom-designed, multi-service projects, while buyers must prioritize guarantees on both hourly profiles and compliance instruments. Projects like Sterling and Tesla’s growing portfolio raise the bar for project scale, complexity, and regional diversification in corporate energy procurement across the US.
