Vietnam Decree 243: Rooftop Surplus Sales Lifted to 50%

Vietnam’s rooftop solar rules have spent the past couple of years oscillating between enthusiasm and constraint. Self-consumption was encouraged. Export was tightly capped. Developers learned to design for the rulebook as much as for the roof.

On 26 June 2026, the government issued Decree No. 243/2026/ND-CP, amending provisions of the earlier Decree 57/2025 (DPPA mechanism) and Decree 58/2025 (renewables / self-generation detail under the Electricity Law). One change is already travelling widely in local and international legal briefings: the surplus electricity that eligible self-produced, self-consumed rooftop solar systems may sell rises from 20% to 50% of electricity generated at the inverter output under available solar irradiance.

A month on, the decree is less a rumour and more a design input. That is when project models start to move.

What changed

EVN English-language summaries and law-firm notes (including Watson Farley & Williams, VTN and Partners, and LNT Partners briefings) converge on several operational points:

• Higher default export headroom. Parties may agree surplus sales up to 50% of inverter output under irradiance — up from the previous 20% cap in Decree 58/2025.
• Time-boxed flexibility above 50%. From the decree’s effect until 31 December 2030, parties may agree to trade more than 50% where the local grid at the interconnection point has adequate hosting capacity and safe operation requirements are met.
• Storage-aware surplus. Surplus can include energy discharged from a battery charged by the rooftop system, not only instantaneous PV export — important for how hybrid sites are metered and contracted.
• Pricing discipline. Purchase price references remain tied to prior-year average market electricity price concepts published by the market operator, with caps linked to regional ground-mounted solar ceiling frameworks (excluding BESS-specific ceiling constructs in the summaries above).
• Buyer set expansion. Beyond EVN Power Corporations, certain private grid owners / licensed distribution or retail entities meeting ownership and licensing tests are discussed as eligible purchasers in the amended framework — relevant for industrial parks and cluster retail models.
• Grid refusal and safety valves. EVN’s ability to refuse surplus where low- or medium-voltage networks would be overloaded remains part of the practical picture; “zero-export” style control concepts appear in implementing discussion for keeping sites inside agreed ratios.

Other Decree 243 themes — DPPA participant expansion, offshore wind survey mechanics, and related Electricity Law implementation — sit beside the rooftop surplus headline. For household and C&I rooftop markets, the 20%→50% shift is the immediate lever.

Why it matters

A 20% surplus cap pushes system design toward heavy self-consumption and conservative sizing. That can be rational on constrained feeders. It also leaves energy on the table when roofs are large, daytime loads are thin, or weekends empty a factory.

Lifting the cap to 50% changes the optimisation. More projects can justify capacity that matches roof and inverter economics rather than only the strictest on-site load shape. Allowing batteries to participate in the surplus definition encourages hybrids that shift solar into evening peaks and still monetise controlled export.

None of this removes distribution physics. A higher legal cap without hosting capacity is a permission slip, not a connection. The decree’s own above-50% window is explicitly conditional on grid absorption and safety — a useful honesty clause.

For Vietnam’s industrial energy transition, the interaction with DPPA reforms matters. Direct procurement and behind-the-meter generation are complementary tools. Factories evaluating rooftop plus storage plus possible park-level private wire arrangements now have a slightly less punitive export rulebook than in 2025.

What to watch

Implementing circulars and local practice. Decree text is the floor. Provincial Power Corporations’ interconnection practice will decide how fast the new ratios show up in signed agreements.

Hybrid uptake. If BESS attachment rises with the storage-inclusive surplus definition, Decree 243 will have done more than move a percentage.

Hosting-capacity transparency. The 2030 above-50% window only works where grids can take energy. Watch for clearer public data on feeder constraints in high-rooftop provinces.

Mixed-use and non-rooftop nuances. Briefings note different residual caps for some non-rooftop or mixed-land cases. Developers should not assume the 50% rooftop rule generalises to every self-consumption configuration.

Decree 243 does not make Vietnam an open net-metering market. It does something more Vietnamese and more useful: it widens the self-consumption bargain, keeps safety gates, and gives storage a clearer role in surplus maths. Roofs will notice.

Sources: EVN English summary of Decree 243/2026/ND-CP; legal briefings from WFW, VTN and Partners, and LNT Partners; Vietnamese press explainers on the 50% surplus ratio (late June 2026).