Electrical
Utilities and renewables design
Incoming supply applications, substation and metering requirements, and PV, battery storage and EV charging design and connection.
- Discipline
- Electrical
- Typical timescale
- Applications submitted at Stage 2; DNO response times are outside the design programme
WHAT IT IS
Utilities work is the interface between the building and the networks that feed it: the electrical supply capacity application to the distribution network operator, the gas and water connections, the substation or switch room the DNO requires, and the metering arrangement.
Renewables sit on the same interface, because generation on site is a connection question as much as a design one. Photovoltaic arrays, battery storage and EV charging all change the site's import and export profile, and anything beyond the smallest installation needs the network operator's agreement before it can be energised.
WHEN YOU NEED IT
As early as Stage 1 or 2. Utility connection lead times are measured in months, and a diversionary quotation or a new substation can determine both the programme and a significant part of the budget — so a load estimate that supports an application is one of the first useful things a services engineer produces.
For renewables, at the point the energy strategy is being written, because whether generation is credited in the Part L or Section 6 calculation depends on it being designed rather than aspirational.
OUR PROCESS
Estimated maximum demand first, with diversity, then the application. Where the design is still moving, an application is made on a defensible estimate with a stated contingency rather than delayed until the load is certain — the lead time is the constraint, not the accuracy.
Generation is sized against the site's own consumption profile rather than against roof area, because export is worth less than displacement and a system designed to fill the roof often spills. Battery storage is sized on the same profile.
Connection applications — G98 for the smallest installations, G99 above it — are prepared and tracked with the DNO, and the metering arrangement is confirmed before commissioning is programmed.
DELIVERABLES
What you receive
- Estimated maximum demand and diversity calculation
- DNO application and connection offer review
- Substation, switch room and metering requirements
- PV array sizing, layout and yield estimate
- Battery storage and EV charging capacity assessment
- G98 or G99 connection application support
STANDARDS
Standards applied
The editions in force at the time of design. Where a standard is amended mid-project we confirm which edition the appointment is based on.
- ENA EREC G98Connection of micro-generation to public low voltage distribution networksEnergy Networks Association
- ENA EREC G99Connection of generation to public distribution networks above micro-generationEnergy Networks Association
- BS 7671:2018+A4:2026Requirements for Electrical Installations, including Section 712 solar photovoltaic supply systemsIET
- BS EN IEC 62305Protection against lightningBSI
- Approved Document SInfrastructure for charging electric vehicles (England)GOV.UK
- Technical Handbook Section 6Energy (Scotland)Scottish Government
- MCS 012 and MCS 3002Microgeneration Certification Scheme — roof mounted photovoltaic installationsMCS
QUESTIONS
Common questions
How long does a new electricity connection take?
The distribution network operator has regulated timescales for issuing a quotation — typically a matter of weeks for a small service and longer for a connection requiring reinforcement — but the works themselves are commonly several months and can exceed a year where a new substation or network reinforcement is needed. The application is made as early as a defensible load estimate allows.
What is the difference between a G98 and a G99 connection?
ENA Engineering Recommendation G98 covers fully type-tested micro-generation up to 16 A per phase, which can be connected and then notified to the network operator. G99 covers everything above that and requires the network operator to agree the connection before the installation is energised. Which one applies is determined by the inverter capacity, not the panel area.
How is a photovoltaic array sized?
Against the building's own half-hourly consumption profile rather than the available roof area. Generation used on site displaces imported electricity at the full tariff; exported generation earns considerably less, so an array sized past the site's daytime baseload has a much longer payback. Roof structure, shading and access for maintenance then constrain the result.