How to Construct a PV-Storage-Charging Integrated Station: A Detailed Construction Guide
Constructing a solar photovoltaic storage charging integrated station is possibly one of the most challenging EV infrastructure projects you could embark upon. Yet, when done properly, it brings savings of 30-50% on operational costs in comparison with grid-based charging stations, provides additional income through the peak-valley power difference, and makes a site into a true source of zero-emission energy generation rather than just a parking lot.
However, this is not an exercise in winging it. Over the past few years, we have successfully completed multiple PV storage charging facilities for highway rest areas, industrial zones, logistic complexes, ports, and even off-grid remote locations around China and overseas. Here, we provide a practical guide on how we build it — step-by-step, with five major phases, and the stumbling blocks which can surprise a novice developer.
Definition of PV-Storage-Charging Integrated Station
Firstly, to better understand our construction process, it is necessary to make some clarifications regarding our target object. It is called a PV storage charging integrated station and includes three elements built together:
- PV array: Solar panels installed on the roof or a carport that produce electricity under sunlight conditions.
- Battery Energy Storage System (BESS): Allows storing additional solar energy and buying inexpensive energy from the grid at night when prices are the cheapest, and discharging during daytime peak periods.
- Electric Vehicle Charging Equipment: It can include slow or ultra-fast chargers using electricity from both BESS and the grid.
It is controlled by an EMS (Energy Management System), and the decision of which source should be used—photovoltaics, batteries, or the grid—is made according to price minimization or renewable energy maximization purposes. They should be considered together from the first moment.
Stage 1: Site Feasibility and Project Planning
All begins with load assessment and the realistic evaluation of the capacity of the site. Overlooking this aspect—or treating it as a formality to go through—constitutes the most frequent reason for project budget overruns for PV-storage-charging facilities.
Connection to the grid will be the first limiting factor. Commercial sites typically operate under an existing power transformer capable of supporting the present load. With the addition of high-wattage DC fast chargers (above 120 kW), the load will easily exceed the capacity. The initial stage will require obtaining written proof from the local utility regarding the capacity availability and cost of necessary upgrades to the grid. Sometimes, proper design of a storage unit can render upgrades to the transformer unnecessary because the peak demand will remain within its limit.
Solar energy resources will require assessing the average level of irradiation over 20 years at the site along with the roof canopy size. An approximate 1,000 m² area will suffice to install 150-200 kW worth of panels, producing around 180,000 – 240,000 kWh per year under 1,200 peak sunlight hours.
Load forecasting has to be done to forecast the anticipated daily energy demand profile. This decides the total storage capacity needed. If a highway service area experiences higher energy demand during mid-day and in the evening, it needs a far larger BESS compared to a nighttime charging logistic depot.
Output from this step includes: verified grid connection information, estimation of PV energy generation, sizing of BESS, charging capacity plan, estimated investment, and payback period projection.
Stage 2: System Design & Engineering Approvals
Now that feasibility has been established, it is time to design the whole system. At this point, the integration challenges will become apparent.
- Electrical System Topology: The decision to have a DC-bus or AC-bus system impacts compatibility, efficiency, and cost throughout the entire process chain. A DC-bus directly connects PV, storage, and charging components, eliminating conversion processes and improving efficiency. Note: Hongjiali’s 215 kWh and 261 kWh storage-charging stations feature a proprietary DC-bus topology system, reducing energy losses by roughly 5% to 8%.
- Grid-Tie vs. Off-Grid: All commercial facilities are normally set up as grid-tie by default, with islanding capabilities. This involves transfer switches capable of handling the entire connected load and maintaining independent frequency and voltage regulation.
- Structural Engineering: Solar canopies and carports must bear the weight of solar panels, plus wind and snow loads based on local codes. The structural design must be approved by an engineering stamp prior to construction.
- Equipment Specifications: Model numbers, electrical specs, and communication protocols must comply with OCPP 1.6J or 2.0.1 standards.
Stage 3: Procurement of Equipment and Construction Works
After all necessary approvals have been obtained, procurement and construction paths begin. Lead time for high-power DC charger installation and BESS systems is typically 6-12 weeks.
Civil works include: earthwork and drainage, trench digging, transformer pad construction, battery container pad preparation, EV charging bay surface treatment, and anchoring points for solar canopies. An example 10-stall fast-charging station with 500 kWp of solar and 300 kWh of BESS could require 8-12 weeks of civil construction.
Cable Selection: Cables carrying direct current from batteries to charging stations have heavy loads. The team at Hongjiali performs calculations using actual load curves rather than nameplate maximums, reducing cable costs by 15-25% while ensuring safety for the system’s 15-year lifespan.
Battery Installation: Must adhere strictly to manufacturer instructions, especially for LFP installations where cell balancing is crucial. Ventilation, fire extinguishing systems (e.g., FM-200), and temperature controls are critical design issues that cannot be easily implemented later.
Stage 4: System Integration, Testing, and Grid Connection
This is where PV generation, energy storage, and charging systems integrate into one. Skipping thorough testing here results in poor performance months down the road.
- Equipment Verification: Verify all wiring on paper before connecting the electrical circuit. Terminations and protective devices must match the technical documents.
- EMS Commissioning: Configure the Energy Management System for site-specific tariffs and operation priorities (e.g., prioritizing solar during peak day hours vs. off-peak grid at night).
- Protection Coordination Test: Ensures relays, breakers, and isolators function in synchronization during fault conditions (typically takes 2-3 days).
- Grid Connection Commissioning: Carrying out tests for anti-islanding protection and metering systems in the presence of the utility representative to receive the grid connection certificate.
Stage 5: Grid Connection Acceptance, Operation and Maintenance
Operation commences following grid connection acceptance. Profitability depends on managing the station over its 15+ year lifespan.
BESS Performance Monitoring: Evaluate actual discharging capacity relative to nominal capacity monthly. Monitoring helps identify degraded modules early for replacement without a full system overhaul.
Performance Ratio (PR): Monitor the PV system’s PR monthly. A ratio over 80% is excellent. Decreases usually call for immediate inspection regarding soiling or shading obstacles.
Maintenance Schedule: Includes monthly visual inspections, quarterly panel cleaning, semiannual electrical inspections, and annual protection system tests. Hongjiali offers full maintenance protocols and remote diagnostics to ensure long-term ROI.
Takeaways for Developers and Site Owners
- Early Grid Interconnection Application: Submitting the application before completing the design work provides a crucial scheduling buffer.
- EMS as a Key Deliverable: The control logic determines whether the site actually reduces energy costs or just charges vehicles.
- Integrated Solutions: Choosing equipment that is known to be compatible minimizes integration risk. One of the reasons Hongjiali integrates all three systems is to eliminate such technical risks.
Regarding Hongjiali’s PV-Storage-Charging Systems
Hongjiali New Energy (HG Power) is a leading manufacturer of EV charging products, battery storage systems, and PV storage charging packages. Our key products hold CE, TUV, CB, SAA, and ISO certifications.
Our PV-ESS-DC fast charging stations (215kWh and 261kWh) are currently powering highway service stations, industrial zones, and ports in over 30 countries. Ready to start your integrated EV infrastructure project? Contact our engineering team today for project inquiries and expert technical advice.