GWH Stock: Insider Activity, Filings & Research
ESS Tech, Inc. (GWH) — Drillr’s hub for GWH insider activity, SEC filings, earnings signals and AI research. Over the trailing 3 months, GWH insiders filed 0 open-market buys and 4 sales (SEC Form 4).
GWH insider trading activity (SEC Form 4)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| Jun 2, 2026 | WELLMAN ALEXIdirector | Grant | 13,513 | — |
| Jun 2, 2026 | Quarls Harrydirector | Grant | 13,513 | — |
| Jun 2, 2026 | Nijhawan Sandeepdirector | Grant | 13,513 | — |
| Jun 2, 2026 | Hossfeld Richdirector | Grant | 13,513 | — |
| Jun 2, 2026 | Garabedian Raffidirector | Grant | 13,513 | — |
| May 26, 2026 | Goodman Kelly F.officer: SEE REMARKS | Sell | 2,751 | $0.93 |
| May 26, 2026 | Suhadolnik Kate Eileenofficer: Chief Financial Officer | Sell | 1,735 | $0.92 |
| May 26, 2026 | Suhadolnik Kate Eileenofficer: Chief Financial Officer | Sell | 1,922 | $0.93 |
| May 26, 2026 | Goodman Kelly F.officer: SEE REMARKS | Sell | 2,482 | $0.92 |
| Feb 26, 2026 | Suhadolnik Kate Eileenofficer: Chief Financial Officer | Sell | 741 | $1.54 |
| Feb 26, 2026 | Suhadolnik Kate Eileenofficer: Chief Financial Officer | Grant | 137,500 | — |
| Feb 26, 2026 | Goodman Kelly F.officer: SEE REMARKS | Grant | 137,500 | — |
| Feb 26, 2026 | Goodman Kelly F.officer: SEE REMARKS | Sell | 2,269 | $1.54 |
| Jan 29, 2026 | Buckley Drew Pdirector, officer: CEO | Grant | 550,000 | $1.68 |
| Nov 21, 2025 | Goodman Kelly F.officer: Interim CEO | Tax | 4,513 | $2.40 |
Source: GWH SEC Form 4 filings, latest Jun 2, 2026. For informational purposes only — not investment advice.
ESS Tech, Inc. company profile
Overview
ESS Tech, Inc. (NYSE:GWH) is an energy storage company founded in 2011 and headquartered in Wilsonville, Oregon. The company went public in January 2021 and specializes in designing and manufacturing iron flow batteries for commercial and utility-scale energy storage applications. ESS Tech has positioned itself as an alternative to lithium-ion battery technology, focusing on long-duration energy storage solutions that can store and discharge electricity for extended periods ranging from 4 to 12+ hours.
Business
ESS Tech operates in the rapidly growing energy storage industry, which serves as a critical component of the modern electrical grid. The company manufactures iron flow batteries, a type of electrochemical energy storage system that uses iron, salt, and water as its core components. Unlike lithium-ion batteries that store energy in solid materials, flow batteries store energy in liquid electrolytes contained in external tanks, allowing for the independent scaling of power and energy capacity. The company offers two primary product lines. The Energy Warehouse is a behind-the-meter solution designed for commercial and industrial customers who want to reduce electricity costs, provide backup power, or achieve energy independence. The Energy Center represents the company's front-of-the-meter solution, designed for utility-scale applications where electric utilities and independent power producers need grid-scale energy storage. More recently, ESS Tech introduced the Energy Base product, which targets extended duration applications of 12+ hours and potentially up to 22 hours by 2027. Flow battery technology offers several advantages over conventional lithium-ion systems. These batteries can operate safely across wide temperature ranges without risk of thermal runaway, have virtually unlimited cycling capability without degradation, and use abundant, non-toxic materials. The technology is particularly well-suited for applications requiring long-duration storage, where electricity needs to be stored for many hours and then discharged over extended periods to balance supply and demand on the electrical grid. The company's revenue streams are currently modest, with 2024 full-year revenue of $6.3 million primarily derived from equipment sales (approximately 65%) and site preparation services (35%). ESS Tech is still in the early commercialization phase, having delivered systems to customers including utilities in Florida, Portland General Electric, and international customers like Schiphol Airport in Amsterdam.
Revenue model
ESS Tech generates revenue primarily through direct product sales of its iron flow battery systems to utilities, commercial customers, and industrial users. The company operates on a project-based business model where it designs, manufactures, and delivers complete energy storage systems tailored to specific customer requirements. Revenue is recognized upon delivery and commissioning of systems, though the company has experienced delays in revenue recognition due to project timing and customer financing challenges. The company's customers include electric utilities seeking grid-scale storage solutions, commercial and industrial facilities looking to reduce energy costs or ensure power reliability, and specialized applications like airports and data centers. Recent wins include a 50 MWh pilot project with an Arizona public utility and ongoing deployments with Portland General Electric and Florida utilities. Several factors significantly impact ESS Tech's margins and profitability prospects. On the positive side, the company has achieved substantial cost reductions, cutting Energy Center product costs by nearly 50% through manufacturing improvements, in-house electrode production (35% cost reduction), and electrolyte reformulation (50% cost reduction with 20% energy output increase). The Inflation Reduction Act provides substantial tax incentives for energy storage projects, improving project economics for customers. Growing electricity demand driven by data centers and artificial intelligence applications creates expanding market opportunities. However, margin pressures persist from intense competition with lithium-ion battery systems, which continue to experience rapid cost declines. The company faces high fixed manufacturing costs while operating at low production volumes, creating negative gross margins. Supply chain challenges and the need for specialized components add cost volatility. Additionally, the nascent state of the long-duration energy storage market means customer adoption remains slow, limiting the company's ability to achieve economies of scale. ESS Tech expects to remain gross margin negative through 2025 due to overhead costs and low production volumes.
Competitive moat
ESS Tech's competitive moat is relatively narrow and still developing. The company's primary differentiation lies in its iron flow battery technology, which offers superior safety characteristics, unlimited cycling capability, and the ability to operate in extreme temperatures without degradation. This technology advantage is most pronounced in applications requiring 8+ hour duration storage, where lithium-ion systems become less economically viable due to capacity fade over time. The company benefits from being one of the few commercial-scale iron flow battery manufacturers, giving it a first-mover advantage in this specific technology segment. ESS Tech has also built relationships with strategic partners like Honeywell, which provides both investment capital and potential market access. The company's focus on domestic manufacturing (98% of components sourced domestically) positions it well for projects requiring American-made content due to government incentives and supply chain security concerns. However, the moat faces significant challenges. The core iron flow battery technology is not proprietary to ESS Tech, and several other companies are developing competing flow battery solutions. More critically, lithium-ion battery technology continues to improve rapidly in both cost and performance, potentially eroding the duration-based advantage that flow batteries currently enjoy. Large, well-capitalized battery manufacturers could potentially enter the long-duration storage market with hybrid or alternative technologies. The company's small scale and limited financial resources also constrain its ability to invest in research and development or manufacturing capacity at the pace of larger competitors. Without achieving significant scale and cost reductions, ESS Tech risks being marginalized by larger players or alternative technologies. The competitive moat is currently weak and depends heavily on successful execution of the company's cost reduction and scale-up initiatives.
Risks & safety
ESS Tech faces significant financial challenges with a narrow margin of safety. • Cash burn and solvency risk: The company burned $19 million in free cash flow in Q1 2025 and $79.5 million for full year 2024. With only $8.4 million in cash and short-term investments as of Q1 2025, the company faces immediate liquidity concerns and is actively pursuing capital raising options including ATM offerings and Export-Import Bank financing. • Debt levels: Debt-to-equity ratio remains manageable at 0.11, indicating low leverage, though this reflects the company's difficulty accessing debt markets rather than conservative financial management. • Valuation metrics: Trading at 2.3x book value with negative earnings and EBITDA. The company's enterprise value to EBITDA is negative due to losses. Current ratio of 1.07 indicates tight near-term liquidity. • Other considerations: The company has access to a $50 million Export-Import Bank loan facility, though this requires maintaining minimum capital levels. Management is exploring strategic partnerships and additional financing alternatives to extend the cash runway into 2026. The margin of safety is extremely thin, with the company facing potential solvency issues without successful capital raising in the near term.
Recent development
Over the past few years, ESS Tech has undergone significant strategic and operational evolution. The company has shifted from its original Energy Warehouse focus toward utility-scale applications with the Energy Center product, and most recently introduced the Energy Base platform targeting 12+ hour duration storage applications. This strategic pivot reflects management's recognition that the greatest market opportunity lies in long-duration utility-scale storage rather than behind-the-meter commercial applications. Manufacturing capabilities have expanded substantially, with the company achieving 800 megawatt-hours of annual production capacity and developing a second automated production line to reach 1 gigawatt-hour capacity by 2025. Significant cost reduction initiatives have yielded impressive results, including nearly 50% cost reductions for Energy Center products, 35% savings through in-house electrode production, and 50% electrolyte cost reductions while simultaneously improving energy output by 20%. The company has secured several landmark customer relationships, including partnerships with Sacramento Municipal Utility District for 2 gigawatt-hours of storage, Portland General Electric for grid-scale deployments, and international customers like Schiphol Airport. A recent 50 MWh pilot project win with an Arizona public utility represents a significant validation of the technology's competitiveness against lithium-ion alternatives. Strategic partnerships have become increasingly important, particularly the relationship with Honeywell, which has provided both investment capital and technology development collaboration. The company has also secured access to Export-Import Bank financing, reflecting confidence in its export potential and domestic manufacturing capabilities. However, revenue growth has disappointed, with 2024 full-year revenue of $6.3 million falling short of guidance, primarily due to customer financing delays and project timing issues.
GWH company profile · for informational purposes only — not investment advice.
Track GWH with Drillr
SEC filings, earnings calls, insider activity, alt-data signals — all queryable through Drillr's AI terminal and MCP API.
Try Drillr for free