Project overview

Orion Building Engineering Services completed the Solar Photovoltaic (PV) system install projects at two residential buildings: Pond Close and Emma Rothschild Court. Both projects were carried out with the objective of pursuing energy efficiency and cutting carbon emissions: working closely in partnership with Dacorum Borough Council.
The services that Orion energy provide on this project and others, provide renewable and sustainable energy services to help reduce emissions, creating a more comfortable world for generations to come.

Pond Close

Emma Rothschild Court (Left) Pond Close (Right)

Solar Photovoltaics

Solar PV (Solar Photovoltaics) generates a source of electricity using energy/irradiance from the sun.

The light energy is transferred from the solar panels to the premises via an inverter and electrical infrastructure. This form of energy reduces the costs of running a building such as Emma Rothschild and Pond Close, as utilising solar energy can be seen as a means of ‘free’ electricity from the sun.

The installation of a Solar PV system further reduces the environmental impact that the business has, by reducing carbon emissions from standard business operations.

The Projects

1. Design Requirements and Consumption

The design and consumption phase are a critical stage in both projects to ensure the most efficient and suitable systems according to the building complexity and client’s goals are created.

This stage involved:

Consumption details : Analysing energy data to get an idea of the current energy usage data for both buildings.

On this project, ½ hrly consumption data was not available to analyse against the proposed PV Generation and therefore assumptions were made.

It was assumed for the purpose of this feasibility study that 50% of the total consumption was during the day. The financial modelling was based around 70% of the PV system generation being utilised by the building with 30% exported to grid.

Design requirements:

Pond Close Satelitte

Pond Close

Initially, we were asked to review using an optimised solution (Solar Edge / Tigo). However on desktop inspection via Google Earth, there seemed to be limited shading from buildings and objects (arguably some towards the Northwest of the PV System). We therefore provided the feasibility proposal utilising string inverter technology.


Emma Rothschild Satellite

Emma Rothschild Court

A single south facing roof was removed from the design process due to significant shading from a tree. Limited shading was apparent from other sources and therefore String inverter technology was recommended. Due to the decentralised location of the roofs (and the PV Panels), the system was designed with decentralised 3-phase inverters installed nearer their perspective PV arrays (5 inverters in total).

Financial modelling

We calculated 70% of the PV system would be consumed by the building with 30% being exported to Grid. Albeit there are higher rates for Export tariff’s available, we calculated the Export tariff at £0.04per kWh as a fair representation of today’s market rates.

In doing so, we were able to provide out client with ratios and savings expected for both projects, including:

  • Return of Investments (Yrs)
  • Projected Return (20 Years)
  • Solar PV Generation Per Annum
  • Annual CO2e

All design requirements described above were needed to produce the following outcomes:

Orion Energy Infographic

2. The Project Plan

Planning is crucial in ensuring all activities are carried out within the required time frames and as safely as possible. As well as ensuring a project is completed in the respective time-scale, planning allows us to monitor progress and keep the client informed throughout. We also believe it is of great importance to keep the residents of each building up to date with the progress.

Each of the two projects took a duration of up to approximately 12 weeks from project start to final completion/handover to the client.


Health and safety (H&S): H&S plans and RAMS site inductions were carried out in order to remain compliant with safety all precautions.

3. Works

First, scaffolding was erected at both buildings:


Works in progress:

Building Works   Orion Energy Banner

Final Result:

Solar Solar Orion Orion Solar

4. Project Outcomes

All requirements of these projects met both the clients and residents needs. Most notably, the main goal of reducing carbon emissions was achieved. To put the extent of the carbon saved into perspective, please see below:

Orion Energy Outcomes


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