On September 20, 2022, Stem Inc. (NYSE: STEM) and InCharge Energy announced a strategic partnership to deliver integrated solar, storage, and EV charging solutions. The partnership combined Stem's Athena AI energy optimization platform with InCharge's InControl charging management system.
The technical integration enabled battery storage systems to charge from excess solar generation and discharge to EV chargers when solar wasn't available. The combined platform provided EV load management with clean energy sources, utility bill optimization, grid constraint mitigation, and ESG (Environmental, Social, Governance) performance tracking.
Target markets included EV fleet charging depots and high-power fast charging hubs—locations where energy costs, demand charges, and grid capacity constraints significantly impact operational economics. The partnership's stated value proposition was helping customers navigate complexity, manage costs, and integrate distributed energy resources (DERs) without requiring in-house expertise in energy management.
Stem brought expertise in AI-driven energy optimization and demand charge management. InCharge provided fleet charging management software with knowledge of EV charging patterns, vehicle requirements, and depot operations. The integration required API development to enable bidirectional communication between the two platforms: Athena needed real-time charging demand forecasts to optimize battery dispatch, while InControl needed available power limits from the energy management system to schedule charging sessions.
The announcement emphasized reducing complexity for fleet operators who otherwise would need to manage separate systems for solar monitoring, battery control, and EV charging while also tracking utility rate structures and demand response requirements.
The Build vs. Partner Decision
This partnership reveals a specific product boundary choice: when to build capability internally versus integrating with specialized external platforms.
InCharge could have developed energy optimization algorithms for managing solar and battery storage alongside EV charging. The charging management system already handled power allocation across chargers; adding solar and battery dispatch would extend existing capabilities. But Stem had already built Athena with sophisticated AI models for utility rate optimization, demand forecasting, and battery cycling algorithms refined across thousands of commercial energy storage deployments.
Building that capability internally would have required hiring energy market specialists, developing utility rate parsers for multiple jurisdictions, creating battery health optimization models, and validating the system across diverse deployment scenarios. The development timeline would be measured in years, not months. Meanwhile, Stem had already solved these problems and had a commercial platform in production.
The product decision was to remain focused on fleet charging optimization—understanding vehicle schedules, state of charge requirements, charger availability, and depot operations—while integrating with a partner that specialized in the energy management layer. This preserved development resources for core charging capabilities rather than building adjacent technology that others had already commercialized.
The integration created a new constraint: the combined system's reliability now depended on both platforms maintaining API compatibility and coordinating software updates. If either company made breaking changes, the integration would fail. This is the hidden cost of partnership strategies—you gain capabilities faster but increase system coupling and coordination overhead.
The ESG tracking component also signals market requirements in 2022: large fleets and commercial charging operators needed verifiable sustainability metrics for corporate reporting and grant compliance. Neither platform alone could provide complete renewable energy utilization data, but the integration enabled tracking solar generation, battery cycling, and charging consumption in ways that satisfied auditors and grant administrators.
The announcement's focus on "navigating complexity" reflects the actual customer problem: fleet operators wanted to charge vehicles reliably and cost-effectively, not become experts in distributed energy resource management. The partnership abstracted that complexity behind integrated software rather than requiring customers to coordinate multiple vendors and platforms independently.