Quick definition
An export limit caps how much power a system can send to the grid, but doesn't necessarily forbid export entirely. Zero export takes this further, the strictest possible version of an export limit: it's an export limit set to exactly zero, meaning no solar power is permitted to flow onto the grid under any circumstances, not even a small amount.
This configuration is typically required by the utility as a condition of connection, most often in locations where local grid infrastructure genuinely can't accommodate additional solar export, rather than being a choice the system owner makes independently. Enforcement is often genuinely strict: Craighead Electric Cooperative's published interconnection guidelines, as one real example, require a non-export system to maintain an absolute zero on its received meter register and disconnect automatically if continuous inadvertent export exceeds 30 seconds.
At a glance: a zero export system is still fully connected to and can draw power from the grid; it simply can't send power back, a meaningfully different and less restrictive setup than being fully off-grid.
Why it matters
Understanding zero export matters most for anyone in an area where local grid constraints make it a real possibility, since it genuinely changes what a solar system can financially deliver. Without the ability to export surplus production for credit, the entire value proposition of a zero export system rests on self-consumption: using generated power directly rather than banking it with the utility for later credit. These constraints often connect to a system's own electrical design limits too, since the National Electrical Code, NFPA 70, sets rules like its 120% rule governing how much combined generation and utility supply a panel's busbar can safely carry, a separate but related constraint from a utility's own grid capacity concerns.
This is exactly why battery storage plays such a central role in zero export system design. Without a place to store midday surplus, a zero export system without a battery often has to curtail production it simply can't use in that moment, representing real, avoidable lost potential energy. A battery gives that surplus somewhere to go, capturing production that would otherwise be wasted and making it available for later use instead.
Zero export requirements are also worth understanding early in the planning process, before finalizing system size, since sizing a system appropriately for actual on-site usage patterns, rather than assuming any surplus can simply be exported, becomes genuinely more important under a zero export constraint than it would be under a typical grid-tied setup with normal export allowed.
Where you'll see this
The grid export cap calculator helps understand export limit configurations, including the zero export edge case, for a specific project.
Since battery storage helps offset a zero export constraint, the self consumption battery size calculator sizes storage around maximizing on-site use of production.
This term comes up in interconnection agreements for grid-constrained areas, in system sizing conversations for properties facing export restrictions, and any discussion of how solar economics change when export credit isn't available at all.
Frequently asked
This often comes down to local grid capacity constraints. In an area where the grid infrastructure can't easily absorb additional solar export, or where interconnection studies show export could create issues, a utility may require zero export as a condition of connection, rather than denying the connection outright.
It can, if production exceeds what the property can use in that moment. Without a battery to store the surplus, a zero export system typically has to curtail, or throttle down, production it can't use and can't send anywhere else, representing real potential energy that goes unused.
A battery gives surplus production somewhere to go besides the grid, storing midday excess for later use rather than needing to curtail it. This is exactly why battery storage is often paired with zero export systems, to capture and use more of the production that would otherwise go to waste.
No. A zero export system is still connected to and can draw power from the grid; it simply can't send power back to it. An off-grid system has no grid connection at all, a genuinely different and more restrictive setup.