MOIT's 13 February 2026 guidance under Circular 60/2025 reclassified third-party data centres from manufacturing tariff to commercial tariff — a ~50% blended cost increase that started hitting operator bills within weeks. Behind-the-meter battery storage arbitrages the commercial-tariff peak/off-peak spread back into the P&L.
These are budget numbers for a standard 22 kV business tariff 24/7 data centre profile. Actual savings vary by IT load shape, cooling regime, and PUE, 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; 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 data centres this is structurally favourable. A 24/7 baseload dispatches every peak window and never idles — so a wider peak window converts directly into more arbitrage revenue per battery, with no behavioural change required. The 6-hour 00:00–06:00 off-peak window gives a clean charging runway, and the 5-hour 17:30–22:30 evening peak gives a clean discharge runway. The hours that just got more expensive become the hours your data centre 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 data centres on Vietnam's commercial (business) tariff — the classification that covers the vast majority of colocation and enterprise data centres in the country. The BESS described here sits behind the main incoming switchboard, upstream of the UPS and genset chain — it arbitrages tariff, it does not carry critical load. Manufacturing-tariff sites (factories, 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. For third-party data centres reclassified onto this tariff under Circular 60/2025, the blended all-hours rate is roughly 50% higher than it was on the old manufacturing treatment — so the absolute spread BESS captures is meaningfully larger than it was three months ago.
A factory cycles five or six days. A hotel cycles seven. A data centre runs 365 days and never idles — every peak window is dispatched. That's ~310 peak arbitrage windows per year at full utilisation, the ceiling of what's possible on a Vietnamese commercial connection. Same capex, same battery, maximum cycles.
Data-centre load is ~90–95% of peak average even in off-peak hours — IT draw is continuous and cooling tracks it almost linearly. That eliminates the forecasting risk that constrains BESS sizing at other segments. The battery is sized to a known, stable load, not to a variable one. Dispatch optimisation is trivial: charge at off-peak, discharge at peak, repeat.
For operators with multiple sites — colocation providers, enterprise data-centre groups, integrated telco/cloud operators — BESS isn't a facility-level capex decision. It's a group treasury decision. Each site has its own HV/MV topology, its own load profile (IT density, cooling regime, PUE), and its own commercial constraints. What you need is a partner who can survey the estate once, rank sites by payback, and roll out in a coordinated programme.
That's how we work. We take an estate of three, five, ten facilities, prioritise by monthly bill size and connection voltage, and deliver the first facility within nine months. The rest follow at approximately two-month intervals. Your finance team sees one set of IRRs, one capex curve, one M&V methodology across the estate — not multiple ad-hoc procurement exercises negotiated separately.
Single-project EPC contractors can't deliver 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 data centre for BESS economics is roughly 500 kW continuous IT load with a monthly EVN bill above $4,000. Below that, the container-scale minimum capex doesn't earn its keep on a single-site basis. Above $10,000/month (around 1.2 MW continuous draw) the economics become genuinely strong. At MW-scale, the absolute savings are large enough that the business case typically closes on a 15-minute load review.
Everything on this page assumes a 22 kV business tariff connection — the voltage band for most Vietnamese enterprise data centres. If your facility is on 110 kV or above, the tariff is lower and the spread is narrower, which slightly dilutes the arbitrage case but does not eliminate it. If you're on 6–22 kV, the tariff is higher and the spread is slightly wider, which improves the case. A 10-minute call with our team gives a definitive answer.
The mini-calculator at the top of this page runs the same engine as our full calculator — same Excel model, same tariff data, same data-centre load profile (17% peak / 50% standard / 33% off-peak, reflecting 24/7 baseload operation). 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 your actual TOU breakdown, 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 operators who want the electricity bill solved, not a new asset class to manage.
For operators with cash on balance sheet looking for infrastructure-grade yield — not a discount.
Not sure which fits? Our team will model both against your estate and show you the numbers side by side.
Home to most of Vietnam's enterprise, telco, and state-owned data centres. VNPT, Viettel IDC, and CMC all operate flagship facilities in and around the city. Commercial tariff connections at 22 kV dominate. Highest density of BESS-addressable load in the country.
The northern industrial corridor: Samsung, Foxconn, and a growing band of hyperscale and regional colocation operators serving Hanoi and the export-manufacturing belt. 22 kV commercial tariff is the norm, with 110 kV for the largest facilities.
The government's designated target for Vietnam's next wave of hyperscale investment. New projects announced through 2025–2026 by domestic and regional operators targeting low-latency central-coast connectivity. Early-stage market — BESS retrofits available on existing facilities; new-build integration ideal.
The commercial capital and the largest concentration of private-sector and foreign-operator data centres in Vietnam. HCMC and surrounding Bình Dương / Đồng Nai industrial zones together account for more than half of the country's IT load. All on commercial tariff; most at 22 kV.
Arcus Energy operates nationally in Vietnam. These are just where current data-centre load is concentrated. Any facility anywhere in Vietnam on business tariff 22 kV will work — the economics travel.
For a data centre on 22 kV business tariff, the BESS is sized to shave the peak tariff window — roughly 5 hours per day, Monday through Saturday. Because data-centre load is continuous and baseload-dominated (IT draw is essentially flat, cooling tracks it almost linearly), the peak-hour load is very close to the average load. We size the battery power to 80% of the average peak-hour load in the facility's lowest-consumption month, with a 2-hour discharge duration.
For a facility with a continuous IT draw of roughly 1.2 MW — a typical mid-scale enterprise or colocation site — the BESS sizes at approximately 0.96 MW / 1.92 MWh. That translates to two outdoor liquid-cooled containers, each around the size of a standard shipping container, connected at medium voltage via a dedicated step-up transformer. Larger facilities scale linearly: a 4 MW site sits at roughly 3.2 MW / 6.4 MWh across six to seven containers.
Critically, this BESS is electrically and operationally separate from the UPS and genset backup chain. It sits behind the main incoming switchboard, upstream of the critical load distribution. It charges during off-peak hours, discharges during peak hours, and never carries IT load. It is not a reliability asset — it is a bill-reduction asset — and it does not need the Tier III/IV redundancy engineering that governs the UPS. Commissioning is non-disruptive to the critical load.
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. Footprint is compact by data-centre standards: a 2 MW / 4 MWh installation occupies roughly the space of three parking bays.
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. Off-peak runs 00:00–06:00 daily, giving a clean 6-hour charging runway. For commercial customers paying the 22 kV business tariff, this means more peak-rate hours per day, every day. A 24/7 data-centre baseload captures every one of them — a wider window converts directly into more arbitrage revenue per battery, with no operational change required. The arbitrage opportunity got bigger overnight, and it's not going to get bigger again any time soon.
MOIT's 13 February 2026 guidance letter under Circular 60/2025/TT-BCT reclassified third-party data centres from manufacturing tariff to commercial tariff — roughly a 50% blended cost step-up, unoffset, and hitting bills from the first post-reclassification cycle. Viettel, VNPT, FPT Telecom, CMC and VNG have all petitioned MOIT to reverse it; MOIT has declined. A 1.2 MW data centre on commercial tariff now pays tens of thousands of dollars more per month at peak than it did on manufacturing. BESS is the mechanism that reclaims a large share of that delta. Each additional month of delay is margin given to EVN that BESS could have recovered. Rising capex on the install side, the Decision 963 evening peak now 66% wider on the operating side — the regulatory tailwind has already arrived, and the base-rate hit compounds underneath.
BESS is sized to 80% of the average load during peak tariff hours in the facility's lowest-consumption month, with a 2-hour discharge duration. Because data-centre load is continuous and baseload-dominated, peak-hour load is typically 90–95% of average draw, so BESS scales almost linearly with IT load.
A rough rule of thumb: every 1 MW of continuous IT draw on commercial tariff supports approximately 1.4–1.6 MWh of BESS capacity. A 30-minute load review gives the exact number.
No. The arbitrage BESS on this page sits behind the main incoming switchboard and operates independently of the UPS and diesel gensets. It does not carry IT load. It does not participate in failover. It does not need the reliability engineering of a Tier III/IV UPS chain.
It charges at off-peak rates, discharges at peak rates, and never sees the critical load. Electrically and operationally it is a separate system from the backup chain. Commissioning is non-disruptive to the IT load.
Commercial (business) tariff at 22 kV under EVN Decision 1279/QĐ-BCT. Rates: peak VND 5,025/kWh, standard VND 2,887/kWh, off-peak VND 1,609/kWh.
The peak-to-off-peak ratio is 3.1×. Third-party data centres were moved onto this tariff under Circular 60/2025/TT-BCT following MOIT's 13 February 2026 guidance — a blended cost increase of roughly 50% versus the previous manufacturing-tariff treatment. BESS arbitrages the 3.1× spread that the reclassification puts you on the wrong side of.
Data centres run 24/7, so a larger share of total consumption falls in off-peak and standard windows where the arbitrage spread is smaller. A hotel concentrates more of its load in peak hours via air-conditioning and kitchens.
On a percentage-of-bill basis, typical hotel savings are 30–50%; typical data-centre savings are 25–40%. In absolute USD terms, data-centre savings are much larger because the bills are much larger — a 2 MW facility saves multiples of what a 60-room hotel saves.
The two-component tariff — separating a capacity charge (VND/kW/month) from an energy charge (VND/kWh) — launched for manufacturing pilot customers from July 2026 at ≥200,000 kWh/month, ≥22 kV. Commercial tariff customers including data centres are not in the pilot.
When broader rollout reaches commercial tariff, BESS becomes more valuable, not less — shaving peak kW (Pmax) directly cuts the capacity charge, an additional revenue stream on top of the arbitrage already modelled. Pmax benefit is deliberately excluded from the mini-calculator headline; treat it as upside.
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 VND/kWh tariff levels under Decision 1279/QĐ-BCT are unchanged.
For data centres this is structurally favourable. A 24/7 baseload captures every peak window and never idles, so a wider peak window converts directly into more arbitrage revenue per battery, with no behavioural change required. A BESS now charges across the 6-hour 00:00–06:00 off-peak window and discharges across the full 5-hour 17:30–22:30 evening peak. Same capex, same battery, longer earning window, spread unchanged at 3.1×.
Our model now runs at one cycle per day by default — one off-peak charge, one peak discharge — across the new 5-hour evening peak. The dual-cycle scenario is preserved in the calculator engine as an Advanced-panel override (set Phase 1 cyc/day=2 and Phase 1 years=3) for any future regulatory shift that reintroduces a morning peak window. At one cycle per day, the 8,000-cycle CFGE LFP supply gives roughly 25+ years of useful life on the cells alone — comfortably ahead of the 22-year financial model.
For a single facility at MW scale: 5–7 months from contract signature to commissioning. The long pole is grid connection re-approval at the incoming HV/MV switchgear, not civil works or battery delivery.
For a multi-site operator, deployment is phased to allow the first facility to commission in 7–9 months, with the balance following at approximately two-month intervals. Commissioning is non-disruptive — the arbitrage BESS sits upstream of the UPS and can be brought online without a facility outage.
Fifteen-minute conversation. We'll tell you whether your facility or estate fits — and what capex looks like at this week's supplier pricing, not next quarter's.