Behind-the-meter battery storage arbitrages Vietnam's peak tariff, eliminates capacity charges, and delivers one of the cleanest economic fits for commercial BESS in Asia.
These are budget numbers for a standard 22 kV business tariff hotel profile. Actual savings vary by load shape and will be confirmed by a full site survey. Want a detailed payback — 22-year cashflow, DSCR, debt-structured IRR? Run the full calculator →
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; the $/kWh rates in Decision 1279/QĐ-BCT are unchanged. The change is the shape of the day, not the price of a kWh.
For hotels this is structurally favourable. Hotel evening load — check-in surge, AC ramp, F&B service, function rooms, late departures — lines up almost perfectly with the new 17:30–22:30 window. A BESS charges off-peak between 00:00 and 06:00 and discharges across the full evening peak. The hours that just got more expensive become the hours your hotel runs on stored energy. The arbitrage spread is unchanged at 3.1×; the window over which it earns has expanded.
Scope: this page applies to hotels on Vietnam's commercial tariff. Rooftop solar is an optional add-on where roof space permits — most urban hotels have limited roof, so BESS is usually the primary move. Manufacturing-tariff sites (factories, large production facilities) follow a different logic — see /solutions/factories.
Vietnam's business tariff at 22 kV (Decision 1279/QĐ-BCT) sets peak electricity at VND 5,025/kWh and off-peak at VND 1,609/kWh. Under Decision 963/QĐ-BCT (effective 22 April 2026), the peak window runs 17:30–22:30 Mon–Sat (5 hours continuous) and off-peak runs 00:00–06:00 daily. A 3.1× spread is one of the most arbitrage-favourable retail tariffs in Asia. BESS charges off-peak, discharges during peak — the spread is the revenue.
Factories cycle five or six days. Hotels cycle seven. An extra 50+ cycles per year translates directly to roughly 15% more lifetime revenue — same capex, same battery, more dispatches.
Air-conditioning, hot water, function rooms, F&B service, and check-in surges create a load curve that lines up almost perfectly with Vietnam's peak tariff window — now 5 continuous hours from 17:30 to 22:30 Mon–Sat under Decision 963/QĐ-BCT. Hotels don't need complex dispatch optimisation. They need storage between off-peak and peak.
For hotel groups and asset managers, BESS isn't a property-level capex decision — it's a portfolio-wide treasury decision. Each property has its own load profile, its own tariff voltage, its own retrofit constraints. What you need is a partner who can survey your portfolio once, rank properties by payback, and roll out in a phased programme.
That's how we work. We take a portfolio of six, ten, twenty properties, prioritise by monthly bill size and tariff voltage, and deliver the first four within nine months. The rest follow on a predictable schedule. Your finance team sees one set of IRRs, one capex curve, one M&V methodology — not twelve ad-hoc procurement exercises.
Single-project EPC contractors can't do this. Pure financiers can't 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), and deliver the asset.
The minimum viable hotel for BESS economics is roughly 60+ rooms, full AC, pool, and a monthly EVN bill above $1,500. Below that, the capex doesn't earn its keep. Above $2,500/month, the economics become genuinely strong.
Everything on this page assumes a 22 kV business tariff connection — the voltage band for mid-sized hotels. If your property is on a lower voltage (6–22 kV or below), the tariff is higher and the spread is slightly wider, which generally improves the case. A 10-minute call with our team will tell you definitively.
The mini-calculator at the top of this page runs the same engine as our full calculator — same Excel model, same tariff data. The headline shown here is an all-equity case: no debt, cleanest single number. The full calculator lets you overlay VietinBank debt at 50% gearing, run TOU breakdowns, and stress-test every assumption. Use the mini-calc to sanity-check the economics; use the full calculator when you're ready to audit them.
We don't push one over the other. The right answer depends on your balance sheet and your risk appetite.
For owners who want the electricity bill solved, not a new asset class to manage.
For hotel groups with cash on balance sheet looking for yield — not a discount.
Not sure which fits? Our team will model both against your portfolio and show you the numbers side by side.
HorecFex Vietnam (20–21 August 2026) is the primary industry engagement point. Active outreach through the Da Nang Hotel Association.
The highest hotel density on the Vietnamese coast. Strong tariff-voltage fit for 4–5 star resort economics.
Active pipeline on the south coast — resort properties on 22 kV business tariff with strong peak-hour AC load profiles. Directly connected to our Vietnam GM's local network.
High concentration of 4–5 star properties. USD-denominated room revenue against VND electricity costs creates strong FX tariff exposure BESS cleanly hedges.
Arcus Energy operates nationally in Vietnam. These are just where current hotel pipeline activity is concentrated. Any property anywhere in Vietnam on business tariff 22 kV will work — the economics travel.
For a hotel on 22 kV business tariff, the BESS is sized to shave the peak tariff window — roughly 5 hours per day, Monday through Saturday. We size the battery power to 80% of the average load during peak hours in the property's lowest-consumption month. Sizing to the lowest month guarantees the battery is fully utilised every month of the year — no oversized capacity sitting idle in low season.
Energy capacity is typically two hours of discharge. That means a hotel with a 300 kW peak load is sized at roughly 240 kW / 480 kWh — one outdoor liquid-cooled container, connected at low voltage.
Our standard supply is CFGE containerised liquid-cooled LFP at 92% depth-of-discharge and 90% round-trip efficiency. Cycle life is 8,000 cycles — at one cycle per day across the new 5-hour evening peak (17:30–22:30 Mon–Sat under Decision 963/QĐ-BCT), that's roughly 25+ years of useful life on the cells alone. The container is outdoor-rated, footprint roughly the size of a shipping container, and slots behind your main switchboard with a single connection point.
Three specific forces are tightening the economics of BESS in Vietnam this year. All three work against the operator who waits.
Battery-grade lithium carbonate nearly doubled between December 2025 and January 2026 — roughly +95% in two months, per Fastmarkets. S&P Global's 2026 outlook forecasts the global lithium surplus narrowing into a deficit, driven by grid-scale storage demand. Cell and system prices have followed upstream costs higher. The "prices fall every year" assumption that held through 2023–24 has reversed. Capex locked in today is cheaper than capex locked in next quarter.
Decision 963/QĐ-BCT (effective 22 April 2026) replaced the old 3-hour evening peak (17:00–20:00) with a single continuous 5-hour block running 17:30–22:30 Mon–Sat — a 66% wider peak window. The morning peak is abolished. For commercial customers paying the 22 kV business tariff, this means more peak-rate hours per day, every day. For BESS, it means a longer discharge window across a tariff band where the spread is unchanged at 3.1× off-peak. The arbitrage opportunity got bigger overnight, and it's not going to get bigger again any time soon.
A 200-room hotel pays roughly $2,500 per month more than it has to, every month a BESS isn't installed. Twelve months of delay is $30,000 in recoverable margin, permanently given to EVN. Add rising capex on the install side (lithium reversed in Q1 2026) and an evening peak that just got 66% wider, and the regulatory tailwind has already arrived — every month of delay is a month of the new wider arbitrage window paid to EVN instead of recovered against your asset. Nothing about waiting makes the numbers better.
BESS is sized to 80% of the average load during peak tariff hours in your lowest-consumption month, with a 2-hour discharge duration. A rough rule of thumb is that a mid-size hotel on 22 kV business tariff needs approximately 0.15 MWh of BESS capacity for every $500 of monthly electricity bill.
A 10-minute load review with our team gives the exact number for your property. The mini-calculator at the top of this page gives an indicative answer in 30 seconds.
Roughly 60+ rooms, full AC, pool, monthly EVN bill above $1,500. Below that, the capex doesn't earn its keep.
Above $2,500/month the economics become genuinely strong. Above $5,000/month BESS is often a clear yes before a site survey even begins.
No. BESS makes money on tariff arbitrage with or without solar. If you already have rooftop solar, BESS also recovers approximately 10% of annual yield that currently curtails — effectively free money on top of the arbitrage savings.
If you don't have solar, BESS still pays back on peak/off-peak arbitrage alone. Solar is additive, not a prerequisite.
Business tariff, 22 kV, under EVN Decision 1279/QĐ-BCT (effective 10 May 2025): peak VND 5,025/kWh, standard VND 2,887/kWh, off-peak VND 1,609/kWh. Under Decision 963/QĐ-BCT (effective 22 April 2026), the evening peak runs 17:30–22:30 Mon–Sat (5 hours continuous) and off-peak runs 00:00–06:00 daily. The 3.1× peak-to-off-peak spread is one of the most favourable retail tariff spreads in Asia.
BESS charges at off-peak rate and discharges at peak rate. The arbitrage margin is the revenue.
The two-component tariff — separating a capacity charge (VND/kW/month) from an energy charge (VND/kWh) — rolls out to manufacturing pilot customers from July 2026 at ≥200,000 kWh/month, ≥22 kV.
Business tariff customers (hotels) are not in the pilot. Broader rollout is 2028–2030.
When it does reach hotels, BESS becomes more valuable, not less — because shaving peak kW directly cuts the capacity charge, on top of the arbitrage revenue already modelled.
Decision 963/QĐ-BCT, effective 22 April 2026, restructures the time-of-use windows under Circular 60/2025/TT-BCT. The morning peak (09:30–11:30) is abolished. The evening peak now runs as a single continuous block from 17:30 to 22:30 Mon–Sat — 5 hours, up from 3 hours under the old regime, a 66% wider peak window. Off-peak is 00:00–06:00 daily. Sunday has no peak. The $/kWh tariff levels under Decision 1279/QĐ-BCT are unchanged.
For hotels this is structurally favourable. Hotel evening load — check-in surge, AC ramp, F&B service, function rooms, late departures — lines up almost perfectly with the new 17:30–22:30 window. A BESS charges off-peak between 00:00 and 06:00 and discharges across the full evening peak. The hours that just got more expensive become the hours your hotel runs on stored energy.
Practical implication: the arbitrage spread is unchanged at 3.1×, but the window over which it earns has expanded by two hours per day. The regulatory tailwind has arrived.
For a single property: 4–6 months from contract signature to commissioning. The long pole is grid connection approvals, not civil works.
For a portfolio, we phase deployment so the first four properties commission in 8–9 months and the rest follow on a predictable schedule.
Ten-minute conversation. We'll tell you whether your property or portfolio fits — and what capex looks like at this week's supplier pricing, not next quarter's.