This guide sets out what a battery storage EPC scope should cover, so owners and lenders can check that bids are complete and that responsibilities are clear between the EPC contractor, the battery supplier and the grid operator.
Start with the use case
The scope begins with what the battery is for. Energy shifting needs capacity measured in hours; frequency response needs fast power but shorter duration; backup for critical loads needs reliability and islanding capability. Many projects combine uses, which affects sizing and controls.
The EPC contract should state the use cases and the performance required for each, so that design and testing can be measured against them.
Sizing power and energy
Battery systems are described by power, in megawatts, and energy, in megawatt-hours. Sizing must consider the use case, round-trip efficiency, depth of discharge limits, degradation over time and any grid export limits.
Agree whether sizing is based on beginning-of-life or end-of-life capacity, and whether the EPC contractor or the owner is responsible for future augmentation to maintain capacity.
Battery containers and power conversion
The main equipment includes battery containers or enclosures with racks, thermal management and fire protection, plus power conversion systems that convert DC to AC. Step-up transformers connect the system to the medium-voltage collector network.
The EPC scope should define who supplies each item, who handles transport and installation, and how warranties pass to the owner.
Medium-voltage integration
Batteries connect to the plant collector system or directly to the substation. Integration includes cabling, switchgear, protection and metering. Where batteries share a connection with solar or wind, the design must manage combined output within export limits.
Our article on substation and transmission scope explains how the grid connection interfaces are defined.
Energy management and plant controller
An energy management system decides when the battery charges and discharges, based on prices, forecasts, grid instructions and site needs. A plant controller coordinates batteries with solar or wind and the grid connection.
Software, communications and cybersecurity are part of the scope. Define who configures the system, who owns the software licences and how updates will be managed after handover.
Fire safety and spacing
Lithium-ion batteries carry fire and explosion risks. The design must follow applicable codes and the supplier’s requirements for spacing between containers, fire detection, suppression, explosion venting and emergency response access.
Engage local fire authorities early. Their requirements can affect layout, water supply and access roads.
Grid studies and compliance
Grid operators require studies showing how the battery will behave during faults, frequency events and voltage disturbances. The battery may need to meet grid code requirements for fault ride-through, reactive power and frequency response.
The EPC scope should state who performs the studies, who submits them and who bears the risk if the grid operator requests changes.
Civil and structural works
Foundations, cable trenches, drainage, fencing and access roads form part of the scope. Battery containers are heavy and need stable foundations. Drainage must prevent water from reaching equipment.
Site investigations, as discussed in our general guide to EPC for renewable projects, should include the battery area.
Testing and commissioning
Testing should cover factory acceptance of key equipment, installation checks, functional tests of each subsystem, integrated testing with the plant controller and grid compliance tests. Capacity and efficiency tests confirm performance against the contract.
Define the test procedures and acceptance criteria in the contract, and link them to payment milestones.
Warranties and augmentation
Battery warranties usually cover capacity retention over a defined period, subject to operating within agreed limits. The EPC contract should align its warranties with the supplier’s and make clear who is responsible for capacity shortfalls.
Augmentation, adding more battery capacity over time, may be planned from the start. Space, electrical capacity and controls should allow for it.
Interfaces with the solar or wind contractor
When batteries are added to a plant built by a different contractor, or added later as a separate package, the interfaces multiply. Who owns the plant controller? Who adjusts protection settings in the existing substation? Who carries the risk if the combined plant fails a grid compliance test? Each of these questions needs a written answer in both contracts.
Where possible, give one party overall responsibility for integration and performance testing of the combined plant. Split responsibility is the most common source of disputes and delays in hybrid projects, especially at the final grid compliance stage.
Transport, storage and installation risks
Battery containers are classed as dangerous goods for transport, and modules may need to be kept within temperature and state-of-charge limits from factory to site. The EPC scope should cover shipping compliance, storage on site, handling procedures and the condition checks needed before energisation. Damage or deep discharge during storage can void warranties, so records of temperature and charge level from delivery to commissioning are worth keeping.
Lender and insurer requirements
Lenders and insurers often set their own conditions for battery storage: proven supplier track records, independent engineer reviews, specific fire safety measures and minimum warranty terms. Build these into the EPC scope early so they do not surface as late changes before financial close.
O&M handover
At handover, the owner or O&M contractor needs documentation, spare parts, training and access to monitoring systems. Battery systems need regular inspection, thermal management maintenance and software monitoring.
Payment milestones tied to completion of handover items, described in our article on EPC payment milestones, help ensure nothing is left out.
About this guide
Our renewable and hybrid EPC engineers prepared this page from scoping and delivering solar, battery and hybrid plants. USP&E builds and operates those plants as the EPC and O&M contractor, never as a broker, with 24+ years of delivery, 150+ power projects in 45+ countries and 25,000 MW contracted since 2002. Our hybrid work is described on the hybrid power page.
Offices: Colorado Springs (1755 Telstar Dr, Suite 300), Knoxville (800 S Gay St, Suite 700), London (162-168 Regent Street), Johannesburg (22 Kildoon Rd, Bryanston), Cape Town (31 Brickfield Road, Woodstock) and China (No. 1 Ningzhou Road, Wuxi). Regions: USA | AFRICA | UK | UAE | CHINA. ISO 9001 and ISO 45001 certified.
Battery storage EPC questions
What does a battery storage EPC scope include?
Design, equipment supply or integration, installation, medium-voltage connection, controls, fire safety, grid studies, testing and handover.
Who is responsible for battery capacity over time?
The contract must say. Warranties usually cover capacity retention within limits, and augmentation responsibility should be agreed upfront.
Why involve fire authorities early?
Their requirements can affect spacing, water supply, access roads and layout, which are hard to change late in design.
Do batteries need grid studies?
Yes. Grid operators usually require studies of fault, frequency and voltage behaviour before connection.
Scope your battery storage project
Send your plant details, use cases and grid requirements, and our engineers will help define a complete battery storage EPC scope.
Phone +27 10 822 2324 during office hours, or write to info@uspeglobal.com at any time; the renewable EPC enquiry form also routes straight to our project engineers. Generation equipment for hybrid plants is listed in our inventory.