For Vietnamese manufacturers whose buyers — Apple, Nike, Samsung, Uniqlo, H&M — now require a credible decarbonisation trajectory, on-site solar under a Power Purchase Agreement is the shortest path to a verifiable Scope 2 reduction and a 25-year hedge against a rising manufacturing tariff. Decision 963's proposed ToU restructure will harden pure-solar economics when it takes effect; pairing the array with a small battery offsets some of the reduction in returns and keeps solar viable.
All-equity basis. Pre-tax simple payback.
Discount sized on a typical developer return on investment. Savings shown at the mid-point of the range.
The TOU window restructure that took effect 22 April 2026 marginally reduces solar PPA returns for factories on day-shift load profiles — more of the displaced consumption now sits in the standard-rate band rather than catching peak hours. Returns remain firmly economic. A rooftop PPA is still the single most effective lever a Vietnamese manufacturer has to cut electricity cost and produce I-RECs for Scope 2 reporting.
EVN's broader trajectory points the other way: standard-rate tariffs — which factories on day shift hit hardest — are expected to rise faster than peak rates as the gap narrows. That strengthens the hedged-PPA case rather than weakens it. Rate levels under Decision 1279/QĐ-BCT are unchanged; only the hours each rate applies shifted.
Scope: this page applies to Vietnamese manufacturing sites on EVN's manufacturing tariff, typically connected at 22 kV or 110 kV. Under Decision 1279/QĐ-BCT (effective 10 May 2025), the manufacturing tariff at 22–110 kV is VND 3,398/kWh peak, VND 1,833/kWh standard, VND 1,190/kWh off-peak. Peak hours will run 17:30–22:30 Mon–Sat under Decision 963/QĐ-BCT (issued 22 April 2026, applies from the next EVN average retail tariff adjustment); rate levels themselves are unchanged. For commercial-tariff sites — hotels, data centres — see /solutions/hotels and /solutions/data-centres, where BESS economics dominate.
Apple, Nike, Samsung, LG, Uniqlo, H&M and every major electronics and apparel brand now embed decarbonisation trajectories into supplier agreements. A rooftop solar PPA produces International Renewable Energy Certificates (I-RECs) that transfer to the factory, reducing reported Scope 2 emissions under the GHG Protocol market-based method. For a 25 MWp rooftop generating roughly 30 GWh/year, that is approximately 20,000 tCO₂e avoided annually at Vietnam's 2024 grid emission factor of 0.681 tCO₂e/MWh (MONRE, 2025).
A standard rooftop PPA prices electricity at a 10–30% discount to the prevailing EVN manufacturing tariff, with the specific range driven by geographical location and site characteristics. The discount is fixed for the 25-year contract term, with an optional utility floor clause protecting the first 20 years. Vietnam's manufacturing tariff has escalated at roughly 5% per year since 2020, and EVN's own planning assumes continued 3–5% annual escalation through 2030 — with the standard-rate band, which factories operating on day shift hit hardest, expected to rise fastest as EVN narrows the gap to the peak rate. The 25-year PPA converts a rising, uncontrolled operating cost into a fixed, hedged one.
Under the Zero Capex model, a third-party investor funds and owns the rooftop system. The factory pays nothing up front, enters a PPA at the discounted rate, and the I-RECs transfer to the factory for Scope 2 reporting purposes. Factories with cash on balance sheet can alternatively self-invest for the full IRR — typically 17–23% unlevered USD, 25–35% equity-levered — but the majority of Vietnamese manufacturing rooftop deployments today are Zero Capex, because capex-avoidance lets CFOs preserve dry powder for production capacity and automation.
"Five years ago, a Vietnamese factory bought rooftop solar for the electricity saving. Today, more than half of the manufacturers we speak to lead with Scope 2. The electricity economics are still real, but they're no longer the reason on the front of the request-for-proposal — the buyer's sustainability clause is."
— Rob Santler, Founder, Arcus Energy
15+ years in Vietnam C&I solar. Previously founder of SPUC Vietnam (Dragon Capital JV), MD BECIS Vietnam & Cambodia, CEO CN Green Roof Asia (Norfund-backed portfolio).
For manufacturing groups with multiple production sites — whether two flagship factories and three satellites, or twelve sites across Bắc Ninh, Bình Dương and Đồng Nai — solar is not a site-by-site capex decision. It is a group-level decarbonisation and treasury decision. Each site has its own roof area, its own connection voltage, its own structural constraints, and its own bill size. What the group needs is a partner who audits the estate once, ranks sites by payback and by Scope 2 impact, and deploys in a phased programme.
That is how we work. We take an estate of four, ten, twenty sites, prioritise by monthly bill size and usable roof area, and deliver the first three within nine to twelve months. The rest follow on a predictable schedule. Your finance team sees one set of IRRs, one PPA template, one I-REC transfer methodology, and one consolidated Scope 2 number — not twelve ad-hoc procurement exercises. Your sustainability team sees a single group-level emissions reduction report that rolls up to the parent.
Single-project EPC contractors cannot do this. Pure financiers cannot either — they need a developer to originate and execute. Arcus Energy sits in the middle: we originate the project, arrange the finance (Zero Capex via third-party investors; Self-Invest via VietinBank or similar; Self-Invest + Debt for larger sites), and deliver the asset.
The minimum viable factory for a rooftop solar PPA in Vietnam is roughly 3 MWp of installable capacity — about 24,000 m² of usable single-storey roof area — and a monthly EVN manufacturing bill above $15,000. Below that, the fixed costs of permitting, interconnection and PPA legal work dominate the economics. Above a monthly bill of $25,000, the economics become genuinely strong. Above $50,000/month, rooftop solar is almost always the cheapest marginal megawatt-hour the factory can procure.
Everything on this page assumes connection at 22 kV or 110 kV — the manufacturing tariff voltage bands. If your facility is on a lower voltage band, the manufacturing tariff is modestly higher and the PPA discount is slightly wider in absolute VND terms, which generally improves the case. A 10-minute site review will tell you definitively.
What you are buying is not a solar system. You are buying three things bundled: a 25-year electricity price hedge, a verifiable Scope 2 reduction instrument in the form of I-RECs transferred to you each year, and a roof-level asset that does not disturb production, does not require land, and uses space that is otherwise generating no revenue. The right structure for your group depends on whether you want to own the asset (Self-Invest) or purchase the electricity (Zero Capex PPA) — detailed in §6.
Anonymised at the customer's request. Numbers are from the project's live financial model — not an illustrative template.
This is a live project, not an illustrative template. The 25 MWp rooftop was commissioned in 2025 on a single-site electronics manufacturer in Vietnam, delivering approximately 29.3 GWh of electricity at a 20% discount to the prevailing 22 kV manufacturing tariff. The financing structure uses 55% senior debt at 7.0% all-in USD (via VND at 8.5% p.a.), sculpted to a minimum DSCR of 1.15×, with an 8-year tenor against the 25-year PPA.
A four-year Vietnam corporate income tax holiday applies (standard for large manufacturing solar investments under the Law on Investment), after which the standard 20% rate kicks in. CIT is one of several levers that can be optimised for specific factory profiles — export tax-incentive zones, VAT refund claims on capex, and the specific commissioning year all affect the headline economics.
Your numbers will differ. This worked example reflects one executed site. Your economics depend on roof area, connection voltage, monthly consumption profile, whether you pay the PPA or self-fund, your sector-specific tax treatment, and the year you commission. A site assessment produces your specific numbers, not a range.
We don't push one over the others. The right answer depends on your balance sheet, your tax position, and whether you want to own the asset or buy the electricity.
The dominant structure for Vietnamese rooftop — ~70% of executed projects use this.
For manufacturers with cash on balance sheet looking for long-tenor yield.
For larger sites where 55% gearing works cleanly with VietinBank or equivalent.
Not sure which fits? Our team will model all three against your site and show you the numbers side by side.
Vietnam's electronics manufacturing capital — Samsung's flagship complex, Foxconn, Canon, and tier-one suppliers to the global consumer-electronics supply chain. Large single-storey production roofs, 22–110 kV connections, and strong brand pressure on Scope 2 trajectories.
The northern port-adjacent industrial corridor — LG Electronics, LG Display, Bridgestone, and a concentration of automotive parts and heavy industry. New-build facilities commissioning solar-ready at lowest marginal cost.
The southern industrial belt north of Ho Chi Minh City — footwear, apparel, furniture, and a concentration of tier-one suppliers to Nike, Adidas, IKEA and similar. Export-heavy sectors with explicit Scope 2 reduction clauses in supplier agreements.
The southern export-processing belt flanking HCMC — food and beverage processing, chemicals, plastics, and apparel. High concentration of facilities already on the Decree 06/2022 mandatory GHG inventory list.
Arcus Energy operates nationally in Vietnam. These are the four industrial clusters where our current factory pipeline is concentrated. Any site anywhere in Vietnam on manufacturing tariff 22–110 kV with 30,000+ m² of usable roof will work — the economics travel.
For a factory on the 22 kV manufacturing tariff, the rooftop system is sized to cover 30–50% of annual electricity consumption — typically the daytime load when production is running and air-conditioning or process cooling is at its heaviest. In Central and Southern Vietnam, specific yield runs 1,150–1,300 kWh/kWp/yr; the Luxshare worked example uses 1,206. A 25 MWp system on 200,000 m² of roof produces roughly 30 GWh in Year 1, declining at 0.4% per year for the first 25 years under standard panel degradation curves.
The installation does not disturb production. Panels mount to standardised rails bolted or ballasted to the existing roof structure; inverters sit on a perimeter platform; the connection to your main switchboard is a single cable run and a single synchronisation breaker. A 5 MWp rooftop installation completes in approximately four months from financial close to commissioning. A 25 MWp installation completes in six to nine months. No production downtime is required beyond a single shift for the final grid tie-in.
Our standard supply is Tier-1 bifacial monocrystalline modules (Trina, JinkoSolar, LONGi or equivalent) at 580–620 W per module, paired with string inverters at 150–350 kW per unit. The mounting system is Vietnam-engineered specifically for high-wind-load coastal environments and for the concentrated rain loads of the August–October season. Module warranty is 25 years to 85% performance; inverter warranty is 10 years, standard-extended to 15 or 20 years at the owner's option.
What about BESS? Standalone BESS still doesn't earn its keep on the manufacturing tariff — the 2.0× peak/off-peak spread at 22 kV (VND 3,398 peak vs VND 1,190 off-peak; peak window 17:30–22:30 Mon–Sat per Decision 963/QĐ-BCT) is too thin for grid-charge arbitrage to pay back, in contrast to the 3.1× commercial-tariff spread that drives hotel and data-centre BESS economics.
A small BESS paired with the solar array is a different proposition. Decision 963 will cut the share of solar generation that monetises at peak from ~25% to ~0.5% when it takes effect, lowering solar-only revenue by ~24%. A battery sized to mop up daytime overspill — charged for free from the array, discharged across the new evening peak — offsets some of the reduction in returns and keeps solar viable on the manufacturing tariff. The calculator above sizes both layers from your roofspace.
When the two-component tariff reaches the manufacturing segment at broader scale (2028–2030 per EVN's published rollout plan), the case broadens further by adding a demand-charge revenue stream BESS can monetise directly. For the BESS-led segment pages, see /solutions/hotels and /solutions/data-centres.
Customer audit cycles, a re-carbonising grid, and Vietnam's activated carbon exchange — all working against the manufacturer who defers.
Apple's Supplier Clean Energy Program has required 100% renewable electricity for direct Apple production across its entire supply chain since 2020. Nike, H&M, Uniqlo, Samsung and LG have followed with variations of the same requirement. Supplier audit cycles run on 12–18 month clocks; a PPA signed today delivers its first I-REC at commercial operation plus roughly 90 days, meaning a manufacturer contracting in Q2 2026 has verifiable Scope 2 reduction evidence in hand for 2027 audits. A manufacturer contracting in 2027 does not.
Vietnam's national grid emission factor rose to 0.681 tCO₂e/MWh in 2024, a 3.2% increase on the 2023 figure of 0.6592 tCO₂/MWh, per MONRE's Department of Climate Change in collaboration with Hanoi University of Science and Technology. The driver is a 17.7% surge in coal-fired generation, which reached 49.5% of the national mix. Vietnam is one of the few countries in Asia where grid CO₂ intensity is rising rather than falling — and where the per-MWh displacement value of on-site solar is therefore increasing year on year. Every year a manufacturer defers, each unsolarised megawatt-hour embeds more CO₂e in their Scope 2 reporting, not less.
Decree 29/2026/NĐ-CP, issued 19 January 2026, establishes the operational framework for a centralised domestic carbon exchange. The pilot runs through 31 December 2028, with full commercialisation from 1 January 2029. Facilities on the Decree 06/2022 mandatory inventory list — the ≥3,000 tCO₂e threshold — will be allocated emission quotas for 2026–2030. A manufacturer who deploys solar today positions the site to sell surplus quotas into the domestic exchange from 2029. A manufacturer who defers positions the site to buy shortfall at whatever the 2029 clearing price turns out to be. These two outcomes are not symmetrical.
Yes. Under the GHG Protocol Corporate Standard, renewable electricity procured through a Power Purchase Agreement reduces Scope 2 emissions under the market-based method, provided the environmental attributes — typically issued as International Renewable Energy Certificates (I-RECs) in Vietnam — are transferred to the offtaker.
In a standard Vietnam rooftop PPA, the I-RECs issue to the host factory, not the investor, which means the CO₂ reduction counts toward the factory's reported Scope 2 number. A 25 MWp rooftop producing roughly 30 GWh per year avoids approximately 20,000 tCO₂e annually, based on the 2024 Vietnam grid emission factor of 0.681 tCO₂e/MWh.
Any facility emitting 3,000 tCO₂e per year or more is required to conduct a biennial GHG inventory under Decree 06/2022/NĐ-CP, expanded by Decree 119/2025/NĐ-CP. The first reporting cycle covered 2024 data, with reports due to provincial People's Committees by 31 March 2025.
Decision 01/2022/QĐ-TTg lists approximately 1,900 named facilities in the industry and trade sectors subject to the requirement. A typical 22 kV manufacturing site consuming 30 GWh per year — roughly what a 25 MWp solar system would offset — already exceeds the 3,000 tCO₂e threshold by a factor of six at current grid intensity.
0.681 tCO₂e/MWh for 2024, published by MONRE's Department of Climate Change in collaboration with Hanoi University of Science and Technology and the Ministry of Agriculture and Environment.
This is 3.2% higher than the 2023 factor of 0.6592 tCO₂/MWh, driven by a 17.7% surge in coal-fired generation that brought coal to 49.5% of the electricity mix in 2024. The implication for manufacturers is that every megawatt-hour of grid electricity consumed in 2024 carried more embedded CO₂ than in 2023, and the per-MWh displacement value of on-site solar has increased year on year.
A rooftop PPA is a behind-the-meter arrangement: solar is installed on the factory's own roof, the factory consumes the electricity directly, and any surplus is exported to the grid under EVN's prevailing rules.
A Direct PPA (DPPA) is an off-site arrangement where a separate renewable generator — typically a utility-scale solar or wind farm — contracts directly with a corporate offtaker through the private-wire or virtual-DPPA mechanism established under Decree 57/2025/NĐ-CP.
For most factories with usable roof area, rooftop PPAs are faster to deploy (6–9 months versus 18–24 months for DPPAs), require no corporate credit rating disclosure, and capture the full retail tariff discount rather than a wholesale-linked price.
Roughly 8,000 m² of usable, unshaded, structurally sound roof area per MWp installed, allowing for access walkways, plant and edge setbacks. A 3 MWp minimum viable system therefore needs around 24,000 m² of roof.
Most tier-one industrial-park factories in Bắc Ninh, Bình Dương, Đồng Nai and Long An have 40,000–200,000 m² of single-storey production roof — well above threshold. Multi-storey facilities need a structural review before sizing.
New-build factories commissioned solar-ready are 20–30% cheaper per kWp installed than retrofits, because cable routing and roof penetrations are designed in rather than added on.
Under a Zero Capex PPA, the factory pays no up-front capital and purchases electricity from the investor-owned solar system at a 10–30% discount to the prevailing EVN manufacturing tariff for the voltage band. The discount is typically fixed for the 25-year PPA term, with an optional utility floor clause for the first 20 years.
Under Self-Invest, installed all-in capex at Vietnamese rooftop scale runs approximately $0.50/Wp pre-VAT, $0.55/Wp post-VAT, or $500,000–$555,000 per MWp. For a 25 MWp system, that is roughly $14 million all-in total investment cost.
Typical unlevered project IRR on a Self-Invest solar+BESS rooftop project sits between 17% and 23% in USD terms, with 55% debt gearing lifting equity IRR into the 25–35% range.
Standalone BESS, no. The 22 kV manufacturing peak/off-peak spread is approximately 2.0× (VND 3,398 peak vs VND 1,190 off-peak; rates per Decision 1279/QĐ-BCT, peak window 17:30–22:30 Mon–Sat per Decision 963/QĐ-BCT), too thin for grid-charge arbitrage to pay back. The commercial tariff that hotels and data centres run on has a 3.1× spread; that's the regime where BESS-only earns its keep.
A small BESS paired with rooftop solar, yes — and the case has just got stronger. Decision 963 will cut the share of solar generation that monetises at peak from roughly 25% to ~0.5% when it takes effect (operational data confirms the briefing's worst-case framing), lowering solar-only revenue by ~24%. A battery sized to mop up daytime overspill — charged for free off the array, discharged across the new 17:30–22:30 evening peak — offsets some of the reduction in returns and keeps solar viable on the manufacturing tariff.
The BESS sized this way is small relative to the solar array (typically 2–5 MWh against a 5–25 MWp rooftop), and it does not require a separate site, separate planning approval or a separate interconnect. The calculator above sizes both layers from your roofspace and shows you what each delivers under self-invest and zero capex.
The two-component capacity tariff arriving in 2028–2030 will broaden the case further by adding a demand-charge revenue stream BESS can monetise directly.
Fifteen-minute conversation. We'll tell you whether your site or estate fits, what size system the roof supports, and what a Zero Capex PPA looks like at current tariff levels.