Site location

Norfolk benefits from being close to one of the largest sources of offshore renewable generation, ranking it one of the parts of the UK electricity grid with the lowest emissions. The project will utilise technologically innovative advancements that contribute to establishing greener status as well as supporting greater stability of the local energy infrastructure and helping to avoid future network reinforcements.

The co-location of the EBI within already consented infrastructure will enable us to maximise performance by connecting directly to the electricity transmission system while minimising infrastructure and land needs.

Site selection

The site of the proposed EBI is located to the south of the Norwich Southern Bypass (A47) and east of Main Road (B1113). To the south and east of the site are Mangreen Quarry and Ipswich Road (A140). The proposed EBI development area is approximately 11 ha of relatively level ground. The site currently consists of agricultural fields and has access to the proposed EBI available off the B1113.

The EBI will be co-located within the same footprint as the Hornsea Three Onshore substation and will cross-utilise part of the existing planned infrastructure to maximise the use of this site, for example, the permanent site access, sustainable drainage systems, internal roads and vehicular parking. As a result, the Orsted EBI development is not proposed to occupy any additional space than previously consented within the Hornsea Three Offshore Wind Farm Order Limits. Similarly, we would plan to deliver the development within the same construction programme window (36 months maximum) with the aim of limiting disruption to the local community and road users.

Site layout

It is proposed that the EBI will have up to two areas of energy storage (depending on final design selection) of modular or containerised units to the north and south  of the site (as shown in the site plan above). The temporary laydown area is also anticipated to be contained within the site.

Many of the key site features, such as the construction and operating access, boundary fencing, operating electricity supply, offsite sewage connections, landscaping and planting, will service both developments simultaneously, although the EBI will require its own short internal-access road and internal-drainage design for each compound area within the site.

Ecology and biodiversity

An ecological assessment has been conducted to quantify the habitat features and ecological status of the site. This information will be used to inform the detailed design in terms of soft and hard landscaping and the use of boundary vegetation. We will look to mitigate any impacts and enhance biodiversity of the site through the use of native species and improving habitat at the site margins.

Culture and heritage

The wider area surrounding the site features designated heritage assets including listed buildings, scheduled monuments and Roman remains, but the consented development for the site has been shown to not affect them directly.

The potential loss of undesignated assets has previously been assessed through the Environmental Impact Assessment conducted for the Hornsea Three Offshore Wind Farm. As a result, and in mitigation, an overarching and agreed written scheme of investigation resulting from the Hornsea Project Three will already be undertaken in advance of work in consultation with Norfolk County Council’s archaeological planning team.

Flood risk and ground conditions

Orsted has commissioned flood risk, hydrological and geological surveys to assess any potential effects caused by the proposed development during the construction, operating and decommissioning phases.

The proposed EBI site is underlain by chalk bedrock, which is classified as a principal aquifer, so measures will be provided to protect groundwater during construction. However, it is not expected that the underlying geology will be adversely affected as a result of the construction of the project.

As the flood risk of the site is considered extremely low, no additional mitigation measures will be necessary.

Construction phase

If consented, the EBI construction phase will take place within the 36-month construction window anticipated for the site consent and, as a result, will be less disruptive to the local community and road users than if we were to develop two independent sites.

It will be constructed in an environmentally sensitive manner and will meet the requirements of all the relevant legislation, codes of practice and standards adopted at the time of construction. Our proposals will also identify and offer mitigation measures for access and HGV movements (deliveries), working hours, housekeeping, noise and dust management, etc., by addressing best practices.

For example, Ørsted recognises that deliveries and construction activity can have undesirable noise, dust and vibration impacts on stakeholders near the development site. Most of the work will be in rural areas where background noise levels are likely to be low, so the objective will be to control and limit levels as much as is reasonably practicable and to minimise disturbance to sensitive receptors.

To manage any noise from construction activities, construction work will be undertaken within the working hours agreed with the local authority and in accordance with the best practicable means. This may include using quieter alternative methods and plant and/or equipment; installing site hoardings, enclosures; and maintaining and operating all vehicles, plant and equipment in an appropriate manner to ensure that noise from mechanical vibration is kept to a minimum.

Mitigation plans will be developed during the detailed design stage of the EBI to achieve an agreed noise rating level acceptable at noise-sensitive residential receptors.

Construction site hours

The standard working hours proposed are 7am–5pm Monday to Friday and 8am–1pm on Saturdays. It may be beneficial to carry out some activities outside standard working hours, for example, abnormal load or construction plant delivery; work within the highway or footpaths; or work affecting operational railways. All activities outside the standard working hours will be agreed with the relevant local authority environmental health officer.

Site access

Access to the proposed EBI is available via the consented temporary and permanent access off the Main Road (B1113), which will deliver good visibility for access and egress.

Operational site activity

The proposed site whilst being in operation 24/7 will be unstaffed and monitored remotely from our control room. Routine maintenance and concurrent corrective visits will be serviced by a small technician’s van via the established permanent access. Occasional HGV access may be required over the lifetime of the EBI asset, for example, to replace degraded batteries, which will be moved off-site for recycling.
The operational EBI will be relatively inconspicuous. Operating noise from the cooling fans, etc., will be mitigated and lights will be directed into the site.


The consent application for the EBI will include provision for the decommissioning of the site at the end of its operational life. Should the utility-scale energy storage become partially or fully redundant, all the electrical infrastructure above ground will be removed and any waste arising disposed of in accordance with the relevant regulations. The decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vehicles and equipment.