How a PLUS Expressway R&R concessionaire used Huawei SUN2000 + LUNA2000 with smart load management to make eight DC fast chargers financially viable without a RM 800k grid upgrade
tCO₂ offset annually
“Adding eight DC fast chargers to a highway R&R sounds straightforward until you find out the grid upgrade to support simultaneous 150 kW chargers would cost RM 800,000 and take two years. Trexon's solar-plus-storage design eliminated that entirely. The LUNA2000 ESS handles the demand peaks from simultaneous charger sessions, and the solar canopy covers the charging bay roof — which our operations team loves because it keeps the cars cool and signals to EV drivers that the power is genuinely green. Two months in, our TNB Maximum Demand charge has dropped by RM 27,000 per month. We're already in conversation with Trexon about Phase 2 for the Segamat and Sungai Besi R&Rs.”
Malaysia's National Energy Transition Roadmap (NETR) targets 10,000 public EV charging points by 2025 and 123,000 by 2030. For highway rest-stop operators, the business case for DC fast chargers is compelling — highway corridors are where range anxiety peaks, charging dwell time aligns with natural rest-stop behaviour (20–30 minutes), and EV penetration along the North-South Expressway is growing faster than the national average as premium EVs from BYD, BMW, and Mercedes-Benz establish their presence in Klang Valley and Johor.
The barrier is not demand. It is grid infrastructure economics.
A single 150 kW DC fast charger requires a dedicated power supply capacity of approximately 180 kVA (accounting for power factor and standby draw). Eight chargers operating simultaneously — a realistic peak-traffic scenario on a busy R&R during festive season traffic — would require 1,440 kVA of dedicated grid supply. For a highway R&R typically served by a C1 or C2 medium-voltage TNB connection designed for a 400–600 kW total facility load, this demand cannot be met without a grid reinforcement project: new cable infrastructure, transformer upgrades, potentially a new TNB substation — a process that costs RM 600,000–1,200,000 and requires 18–30 months for completion.
The project in this case study — a R&R on the North-South Expressway operated by a PLUS Expressway concessionaire — faced exactly this barrier. TNB's grid feasibility study for the proposed 8-charger installation quoted RM 800,000 in grid upgrade costs and a 24-month delivery timeline. The concessionaire needed a different path.
Trexon's proposal reframed the problem. Rather than treating the EV chargers as requiring 1,440 kW of continuous grid capacity, the technical team modelled the actual simultaneous demand profile using EV charging data from comparable R&R sites in Singapore and Thailand.
Key insight: at most R&R sites, peak simultaneous usage of all chargers occurs for at most 4–6 hours per day during peak traffic periods (Friday evenings, Sunday returns from festive travel). For the remaining 18–20 hours, average simultaneous charger utilisation is 1.5–2.5 chargers out of eight — a load of 225–375 kW rather than 1,200 kW. This load profile is precisely suited to solar generation plus battery peak-shaving: a 600 kWp PV array covers the daytime demand contribution from chargers during off-peak periods, while a 400 kWh ESS absorbs the simultaneous-charging demand spikes during busy periods without registering them against the TNB Maximum Demand baseline.
The resulting TNB connection requirement: a 450 kVA service upgrade (versus the original 1,440 kVA) — within the capacity of the existing R&R substation with a standard transformer tap change and no new cabling. Grid upgrade cost: RM 0 (within the existing TNB connection budget). Delivery timeline: standard NEM 3.0 ATAP grid-tie process.
EV Charging Bay Solar Canopy: 350 kWp
The primary solar installation is a purpose-designed solar canopy structure over the dedicated EV charging bay — a 60-bay reconfigured section of the R&R carpark. The canopy provides weather protection for charging vehicles (a premium feature that differentiates the site from competitor charging stations) and a south-facing solar array of 608 Trina Vertex 575W panels, generating 350 kWp of DC capacity.
The canopy structure was designed by a Trexon-appointed structural engineer to accommodate the panel wind loading for the highway corridor's wind exposure category (EN 1991-1-4 WE3 exposure class), using hot-dip galvanised steel columns at 6-metre centres. Column footings were bored to 2.5 m depth to ensure structural integrity in the R&R's compacted gravel subgrade.
Facility Rooftop Array: 250 kWp
435 additional Trina Vertex 575W panels were installed on the R&R's main building rooftop — the food court, convenience store, and toilet facility block — using ballasted racking. This array feeds directly into the facility's general consumption circuits (lighting, HVAC, food preparation equipment), reducing the facility's independent TNB consumption and freeing more grid capacity for the charger operation.
Inverter and ESS Configuration:
Three Huawei SUN2000-150K-MG0 microgrid controllers (150 kW each, total 450 kW AC) were installed in a purpose-built inverter room between the EV charging bay and the main substation. The SUN2000-150K-MG0's grid-forming capability was selected for its ability to maintain charger power quality during grid disturbances — highway R&R grid supply is more exposed to momentary grid events than urban commercial sites, and DC fast chargers are sensitive to voltage sags during active charging sessions.
Two LUNA2000-215 battery units (approximately 400 kWh total usable capacity) were installed in the same equipment room. The LUNA2000's charge-discharge scheduling integrates with Huawei's FusionSolar energy management platform, which monitors real-time charger utilisation via the facility's charger management system Modbus feed and dispatches battery discharge pre-emptively when simultaneous charger demand is projected to spike — a predictive algorithm rather than a reactive one.
The LUNA2000 ESS and SUN2000-150K-MG0 operate within a smart load management framework configured by Trexon's energy management team. The framework implements three rules:
Rule 1 — Solar Priority Charging: During 09:00–16:00 (peak solar generation window), the charger management system signals the LUNA2000 to maintain maximum state-of-charge from surplus solar. EV sessions initiated during this window draw from direct solar as first priority, reducing grid draw to near-zero for low-to-medium simultaneous charger utilisation (1–4 chargers active).
Rule 2 — Peak MD Guard: The system monitors real-time demand via the Huawei SmartLogger 3000A connected to the facility's MDM (Maximum Demand Meter) at the TNB metering point. When instantaneous demand approaches 380 kW (the agreed MD contract threshold), the LUNA2000 begins discharging to cap visible demand at 380 kW regardless of simultaneous charger count. This prevents the simultaneous fast-charger startup spikes (a characteristic of DC fast charger soft-start protocols that can draw 200% of rated power for 3–5 seconds) from registering against the monthly MD.
Rule 3 — Overnight Recharge: Between 02:00 and 06:00 (when charger utilisation is near-zero and TNB grid load is lowest), the LUNA2000 recharges from grid to reach 90% SOC by 06:00, ready for the morning commuter charging peak.
Generation: Average monthly generation: 69,300 kWh — a specific yield of 1,386 kWh/kWp/year, consistent with the P50 design estimate for the highway corridor's irradiance zone.
Savings: Average monthly TNB bill reduction: RM 27,100: - Energy consumption savings: RM 12,900/month (solar displacing grid consumption at C2 tariff rates for the facility's general load) - MD charge reduction: RM 14,200/month (MD registration reduced from 620 kW average to 380 kW average, a 240 kW reduction at RM 59.00/kW under the C2 MD tariff applicable to the R&R's substation connection)
Projected annual savings: RM 325,200. System installed cost: approximately RM 1.82 million. Simple payback: 5.6 years.
Grid upgrade cost avoided: The TNB grid upgrade study revision — following the revised 450 kVA connection request — confirmed no infrastructure upgrade was required beyond a standard tap change. The RM 800,000 grid upgrade cost is fully avoided.
Charging economics: With TNB MD charges no longer constraining the simultaneous charger operation, the operator has been able to set EV charging tariffs competitively at RM 0.65–0.80/kWh (DC fast) without margin erosion from demand penalty exposure. During the Hari Raya 2026 peak weekend (6–7 April), the site recorded 1,840 charging sessions over two days with zero charger-induced TNB MD spikes — the operational validation the concessionaire needed before committing to the Phase 2 rollout.
Note: Financial figures represent indicative modelling based on Trexon installation data, TNB C2 tariff schedules, and site charger utilisation data. Client details are anonymised per commercial confidentiality.
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