Fund the rooftop solar — or solar plus battery — on your balance sheet. Arcus Energy originates, builds, and operates the system under a long-term O&M contract. You own the equipment, the electricity, the I-RECs, and the upside. 10–13% unlevered USD project IRR on cash; 15–18% equity IRR with 55% Vietnamese bank debt layered in. As Vietnam's energy market matures and load management becomes the lever, the same balance-sheet structure funds a solar+BESS package — solar today, storage layered behind the same meter as the integrated answer for managed-load factories.
On 22 April, MOIT extended Vietnam's evening peak to a single continuous 5-hour block from 17:30 to 22:30 Mon–Sat — 66% wider than the old 17:00–20:00 window. The morning peak is abolished; off-peak now runs 00:00–06:00 daily. The VND/kWh rates in Decision 1279/QĐ-BCT are unchanged. The change is the shape of the day, not the price of a kWh.
For a self-invested factory rooftop on the manufacturing tariff, the economics are near-untouched. Roughly 95% of solar kWh self-consumes against the standard rate during the working day — that band is unchanged, and the 10–13% unlevered IRR / 5–7 year simple payback hold. What has shifted is the market structure underneath: Vietnam's two-part tariff pilot started 1 July 2026 for the largest manufacturers and is expected to broaden over the following ~12 months. As load management becomes the lever rather than just energy cost, the balance-sheet case scales from solar to solar+BESS — capacity-charge management as the additive layer on the same owned asset, with both savings flowing to your P&L rather than an investor's.
Direct ownership of a 25-year cashflow asset. Every VND of saving flows to your P&L, not an investor's.
When you self-invest, the economic return stays with you. A well-sited factory rooftop in Vietnam earns 10–13% unlevered USD IRR over 25 years against today's EVN manufacturing tariff. Layering 55% Vietnamese bank debt lifts equity IRR to 15–18%. No investor margin, no PPA spread, no split of savings.
The rooftop solar system sits on your balance sheet, capitalised and depreciated over its useful life. When you sell the facility, the solar asset transfers with the site and adds real value. When you refinance the group, the asset contributes to collateral. No buyout schedule, no end-of-term transfer, no investor claim on the equipment.
When you own the asset, the environmental attributes are yours automatically. I-RECs issue directly to your registered account. A 25 MWp rooftop generates roughly 20,000 tCO₂e of avoided Scope 2 emissions annually at Vietnam's 2024 grid emission factor of 0.681 tCO₂e/MWh — the same supplier-audit claim Apple, Nike, Samsung, LG, H&M and Uniqlo require from their factories.
EVN has raised manufacturing tariffs at roughly 5% per year since 2020 and plans to continue through 2030. When grid tariffs rise, your self-generated electricity becomes more valuable — the saving compounds against an escalating grid price. Under a PPA you share that uplift with an investor. Under Self-Invest you don't.
Self-Invest is not a financing product. It is the default: you buy an asset, you operate it, you keep the economics. Financing decisions — cash versus debt — sit inside that choice. The same balance-sheet structure scales to solar+BESS: solar cuts the energy charge today; capacity-charge management via storage becomes the additive layer as Vietnam's two-part tariff pilot broadens beyond the July 2026 launch.
Two configurations for factories. Solar on its own clears most of your daytime consumption. Solar plus battery captures the evening peak too.
The standard configuration. Solar panels on the factory roof displace daytime EVN consumption. System size scales with roof area and daytime load — typically 1–25 MWp for a mid-size Vietnamese factory.
Best fit: factories with strong daytime load, enough south-facing roof area, and a view that electricity is a long-term cost line worth reducing.
Rooftop solar plus a battery sized to capture Vietnam's evening peak window. Solar covers daytime; the battery stores surplus generation and discharges across the new 17:30–22:30 Mon–Sat evening peak under Decision 963 — a single continuous 5-hour block, 66% wider than the pre-963 window. Adds the Decision 988 BESS tariff premium.
Best fit: factories with evening shift operations, high peak-rate exposure, or a supplier ESG target that benefits from Scope 2 reduction plus peak demand shaving.
These are both self-invest configurations. The financing decision — cash versus 55% bank debt — applies to either. Increasingly, solar+BESS is the integrated factory answer rather than a sequential one: as Vietnam's two-part tariff broadens beyond the July 2026 pilot, BESS sized to the site's load profile (rather than to a wide arbitrage spread) earns directly on the capacity charge alongside solar's energy-charge saving. Factories where the operating data already supports peak-shaving — evening shift work, high registered Pmax, or a supplier ESG target — typically commission solar+BESS as a single project; factories with simpler load profiles still pair solar-only with debt financing on the first project, and add BESS once site data confirms the case.
Typical timeline from signed purchase order to a commissioned rooftop: 4–6 months. Grid connection approval is the longest pole.
Arcus reviews your electricity bills, roof structural survey, and load shape. You receive an engineering report, a bill of quantities, a capex number, and an IRR model you can take to your board or bank.
You approve internally and issue the EPC purchase order. If debt-financing, the bank mandate runs in parallel — Vietnamese lenders typically close on 55% gearing in 6–8 weeks for well-structured SPVs.
Arcus develops, procures, installs and commissions the system. Grid connection approval runs in parallel. Factory operations are not disrupted.
The system generates. You consume. You pay the O&M fee. I-RECs issue annually to you. Arcus operates the asset for its full useful life under a long-term O&M contract.
Self-Invest is three contracts — EPC, O&M, and (optionally) a senior loan. Each is a standard Vietnamese commercial document your counsel has seen before.
Unlike a PPA, the asset sits on your balance sheet from commissioning. That means you capture the upside if the system outperforms expectations, and you carry the downside if a component fails outside warranty. Panel manufacturers warranty 25 years at ≥80% output; inverters 10–12 years. Arcus insures the asset under the O&M contract — operational risk is managed, not transferred.
The O&M fee is a fixed annual charge indexed to Vietnamese CPI — not a percentage of savings. Arcus handles monitoring, preventive maintenance, insurance claims, inverter replacements, and performance reporting. The contract runs for the full asset life, renewable, with defined SLAs on availability and yield guarantees. If performance falls below contracted availability, Arcus pays a fixed penalty.
If you want to fund the project with 100% cash, Self-Invest works from day one. If you want to layer in Vietnamese bank debt — typically 55% of project cost over 8 years — that negotiation happens in parallel with the EPC purchase order and closes before financial completion. Most Vietnamese lenders are familiar with C&I solar project finance and move in 6–8 weeks on a clean structure.
You can fund Self-Invest entirely from cash, or you can layer in Vietnamese bank debt. Most of our factory clients who have done this more than once lean toward debt — not because they need the liquidity, but because project-level gearing frees up balance-sheet capital for higher-return deployments in their core business.
Vietnamese commercial lenders — VietinBank, BIDV, Vietcombank and others — routinely finance rooftop solar at roughly 55% of project cost, over an 8-year tenor, secured against the project SPV and the electricity receivables. DSCRs typically target 1.3–1.5× in base case, and lenders want a demonstrable history of group solvency more than they want complex completion guarantees.
The equity arithmetic is where this gets interesting. On a USD 13.9 million project (25 MWp rooftop, all-in), your equity cheque is USD 6.3 million rather than the full capex. The unlevered 10–13% project IRR becomes a 15–18% equity IRR, and simple payback on the equity cheque compresses from 5–7 years to 3–4 years. The debt service is paid out of the operating savings themselves, not from group cashflow.
Arcus does not arrange debt. We model the senior-lender case alongside the equity case so you can take both to your treasury desk, and we work alongside whichever bank you appoint during the EPC phase. Most of our factory clients run the bank mandate in parallel with the purchase order — the two processes close within a week of each other.
This is the model for buyers whose cost of capital is below the project's return, and who value balance-sheet ownership.
Self-Invest is not the right model if your group's capex approval cycles are long or fragmented, or if you treat electricity as an operating line rather than a project investment. For that profile, a Zero Capex PPA removes up-front capital and balance-sheet impact entirely while still locking a 10–30% discount to EVN's tariff (by site location, driven by irradiance). That choice is detailed on the Zero Capex page.
We develop the same underlying project under all three structures. The right choice depends on your cost of capital, your capex authority, and your appetite for balance-sheet ownership — not on which model is objectively better.
A factory self-investing in rooftop solar in Vietnam typically earns a 10–13% unlevered USD project IRR over the 25-year asset life. Southern factories earn toward the top of that range (irradiance is higher); Northern factories toward the bottom.
Adding a battery layer for arbitrage across the new Decision 963 evening peak (17:30–22:30 Mon–Sat, in force from 22 April 2026) and the Decision 988 BESS tariff premium lifts unlevered IRR to roughly 11–14%. The IRR uplift is real but modest on factory manufacturing tariffs — for solar-led sites the headline lever is still the daytime energy charge, not the spread. As Vietnam's two-part tariff broadens beyond the July 2026 pilot, BESS earns increasingly on the capacity charge rather than the arbitrage spread, and solar+BESS becomes the integrated factory answer rather than a sequential one.
Simple payback on a self-invested rooftop solar system in Vietnam is 5–7 years for factories on the manufacturing tariff, faster in the South (5–6 years) and slower in the North (6–7 years). Solar plus BESS is 6–8 years — the battery adds capex but captures arbitrage across the new Decision 963 evening peak window (17:30–22:30 Mon–Sat, a single continuous 5-hour block from 22 April 2026 — 66% wider than the pre-963 window).
With 55% Vietnamese bank debt layered in, equity payback compresses to 3–4 years because the debt is serviced from the operating savings themselves, not from your equity cheque. Over the full 25-year asset life, the levered case generates materially more cash-on-cash return.
Approximately USD 555,000 per MWp all-in installed, inclusive of VAT, for a utility-scale factory rooftop. This covers panels, inverters, mounting, DC and AC cabling, SCADA, grid connection works and commissioning. A 25 MWp factory rooftop therefore sits at roughly USD 13.9 million capex.
Adding BESS costs USD 190 per kWh usable capacity for behind-the-meter C&I deployments. A typical hybrid configuration pairs solar capacity with a battery sized to discharge across the 5-hour Decision 963 evening peak (17:30–22:30 Mon–Sat) — typically 10–20% of solar capacity — enough to capture the wider arbitrage window without overbuilding storage. As the two-part tariff broadens, BESS sizing tilts toward load-management (Pmax shaving) rather than arbitrage capacity.
Yes. Vietnamese commercial lenders — VietinBank, BIDV, Vietcombank and others — routinely finance rooftop solar at roughly 55% of project cost, over an 8-year tenor, secured against the project SPV and the offtaker's electricity receivables. DSCRs typically target 1.3–1.5× in base case.
Equity IRR lifts from the unlevered 10–13% range into 15–18%. Equity payback compresses from 5–7 years unlevered to 3–4 years on the equity cheque. Arcus does not arrange debt directly, but we model the senior-lender case alongside the equity case so you can take both to your treasury desk.
Arcus Energy operates and maintains the system under a long-term O&M contract, typically 25 years matching the asset life. You own the equipment and the performance risk — panel degradation, inverter replacement at year 12–15, insurance — but Arcus carries the operational work.
The O&M fee is a fixed annual charge indexed to inflation, not a percentage of savings. The contract includes defined SLAs on availability and yield; if performance falls below contracted availability, Arcus pays a fixed penalty. This is the same O&M structure used on every utility-scale solar project in Vietnam.
Yes. When you own the asset, you own the environmental attributes automatically — International Renewable Energy Certificates issue directly to your registered account each year. No transfer is required; ownership of the asset is ownership of the claim.
Under Vietnam's 2024 grid emission factor of 0.681 tCO₂e per MWh, a 25 MWp rooftop generating 30 GWh annually produces roughly 20,000 tCO₂e of avoided Scope 2 emissions — the same supplier-audit claim Apple, Nike, Samsung, LG, H&M and Uniqlo require from their factories.
Typically 4–6 months from signed purchase order to commissioned rooftop. Feasibility and the internal purchase-order approval are 4–8 weeks combined. Build and grid connection approval run in parallel for 3–4 months.
A factory ordering in Q2 2026 commissions in Q4 2026 and starts depreciating the capitalised asset in the same financial year. If debt-financing, the bank mandate runs in parallel with the EPC purchase order and closes within a week of financial completion.
No obligation, no hard sell. We'll tell you the indicative system size, the unlevered and equity-levered IRR, the simple payback on both structures, and whether Self-Invest or Zero Capex is the better fit for your balance sheet.