EV & Solar Service
Battery Storage
Commercial battery energy storage system (BESS) installation — DC-coupled and AC-coupled configurations, BMS integration, grid protection, DNO application and full BS 7671 commissioning for commercial and industrial premises.
What a commercial battery storage project actually has to solve
01
Peak demand charges that outweigh energy cost
Demand charges can represent a significant proportion of commercial electricity costs where peak consumption triggers higher tariff bands or network capacity charges. Battery storage systems can shift demand away from peak tariff periods — we model the demand profile against the available storage capacity to verify the financial case before specifying any equipment.
02
Solar generation that isn't being used on site
Solar PV systems without storage export excess generation at lower export tariff rates. DC-coupled battery storage captures this generation and makes it available for on-site consumption at peak demand times — we design the combined solar and storage system as a single coordinated package.
03
Grid protection requirements for larger storage systems
Battery storage systems above certain capacity thresholds require G99 grid protection and DNO approval. We manage the application and protection relay commissioning as part of the project scope — so this doesn't become a programme-blocking afterthought.
04
BMS integration with existing energy management systems
Larger commercial sites operate energy management and building management systems that need to coordinate with the battery storage controller. We design and commission the communications interface as part of the electrical scope — so the storage system integrates with your existing monitoring and control infrastructure.
Technical detail
Standards & compliance
- BS 7671 — DC and AC circuit requirements for BESS
- Engineering Recommendation G99 / G98 — grid connection
- IET Code of Practice for Energy Storage Systems
- BS EN 62619 — safety requirements for BESS
- DNO technical requirement compliance
System configurations
- DC-coupled storage (integrated with solar inverter)
- AC-coupled storage (standalone inverter/charger)
- Front-of-meter and behind-the-meter configurations
- Three-phase balancing and neutral management
- Islanding and backup power capability
Electrical installation
- DC isolation, fusing and protection
- AC connection and protection relay installation
- Grid protection relay settings and commissioning
- BMS communications wiring and interface
- Cable management for DC and AC circuits
Documentation
- DNO G99/G98 application and approval management
- As-installed single-line diagram
- BS 7671 test certificates
- Protection relay settings record
- O&M documentation and handover pack
The Numbers
G99
G99 application, protection relay commissioning and DNO approval managed as part of the project scope — not a post-installation afterthought.
DC+AC
We design and install both DC-coupled (solar-integrated) and AC-coupled (standalone) battery storage configurations to suit the specific site and load profile.
100%
BMS and energy management system integration commissioned at handover — with a generation and consumption baseline from day one.
Why specify Con-Tec
Storage Projects That Deliver on the Business Case
Our Battery Storage Approach
01
Demand Survey & Modelling
Demand profile review, peak consumption analysis and storage capacity modelling before any equipment is specified.
02
Design & DNO Application
System design, protection relay specification and G99/G98 application submitted to the DNO at the start of the design stage.
03
Installation
BESS enclosure, DC isolation, AC connection, protection relay and BMS communications installed to BS 7671 by NICEIC-approved engineers.
04
Commission & Handover
Protection relay commissioning, BMS integration verification, full BS 7671 testing and documentation package at handover.
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What our clients say
“Con-Tec consistently meets the rigour our estates teams expect. Their compliance documentation, site discipline and turnaround on remedial works are exactly what large-scale healthcare contracts require.”
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We respond to every commercial and industrial enquiry within one working day. Share your scope and programme and we'll come back with lead engineers, approach and a clear cost envelope.