CLS Holdings plc Nearly Doubles its PV Output


A new 96.4kWp photovoltaic (PV) array at Reflex in Bracknell has almost doubled the PV output of CLS Holdings plc in 2018. One of the UK’s largest solar PV office installations, the project supplies occupiers with zero carbon electricity and enhances energy supply security. It has also provided a test bed for cost-effective arrays on complex pitched roofs, opening up opportunities for additional installations in the UK, France and Germany. 

£1,140 cost per kWp

£220,000 return over the 20-year lifespan

82% of electricity used by the Reflex gym and café provided by the PV

15 tonnes CO2 saved per year


CLS Holdings plc is a commercial European property investment company. Through its responsible business strategy, the company has been installing PV arrays and low carbon energy sources at its properties since 2000.

The Group’s drivers for PV arrays include:

  • To generate 5% of the Group’s managed like-for-like electricity from renewable and low carbon sources by 2020, and 15% by 2025.
  • To minimise the Group’s impact on the environment by reducing operational CO2 emissions and water consumption by a further 5% compared to the previous year.
  • To deliver financial returns in line with business expectations on renewable technology.

In 2017, CLS Holdings investigated the feasibility of installing its largest and most complex PV array to date on a pitched and flat roof area at Reflex in Bracknell. This is a multi-occupied office building with a gym and café.


CLS Holdings invited three PV providers to tender for the PV opportunity at Reflex. The focus was on identifying:

  • A financially viable solution, with reductions in Feed-In Tariffs and with total CAPEX costs below £1,200 per kWp.
  • A scheme that worked for pitched roofs, to open up opportunities for additional CLS Holdings assets.

Longevity Partners was able to satisfy the criteria and won the tender. At Reflex, they explored the potential for a 320kWp array across all pitched and flat roof space and settled on a 96kWp array across selected flat roof space. The 96kWp array offered the highest returns, as it excluded areas that were semi-shaded or highly pitched.

Over a six-week period, Longevity Partners planned and managed the installation of 357 panels across 571m2 of roof space. They worked closely with the building team to manage the project and minimise disruption for occupiers. The array was connected to the electricity supply in June 2018, with all electricity feeding into the common area of the building. There was the potential for connection to the Grid but this would have offered lower returns and was eliminated.


  • £110,000 capital investment by CLS Holdings, at a cost of £1,140 per kWp.
  • £220,000 return over the 20-year lifespan, with a yield of 12%.
  • £11,000 annual income for Reflex, including Feed-In Tariffs and mitigated saving for electricity costs.
  • £2,000 annual service charge savings for occupiers.


  • 36,240kWh renewable energy generated per year, by a 96.4 kWp array.
  • 82% of electricity used by the gym and café provided by the PV.
  • 15 tonnes CO2 saved per year.
  • Supporting CLS Holdings’ responsible business strategy and contributing to achievement of its renewables target.
  • Supplying occupiers with nearly zero carbon electricity.
  • Enhancing energy supply security at Reflex, Bracknell.
  • Proving the business case, which has opened up opportunities for additional PV installations across the Group in the UK, France and Germany.

Challenges & Achievements


How to overcome technical challenges?

No two PV systems are identical; they all present slightly different challenges. It is always important for an engineer to carry out structural checks prior to PV installations. At Reflex, CLS Holdings plc had not developed the scheme and did not hold all of the original building plans. Longevity Partners brought in a specialist electrical engineer to identify the best place to connect the PV array into the electrical system on the property owner’s supply. In addition, the original architects were contacted for diagrams to understand the structural design and ensure that the panels did not cross structural seams. Investigation was also made into the constituents of the roofing, to ensure that materials were compatible. As a result, a non-perforating frame was used to avoid risk of leaks.


How to bring occupiers on board?

The Facilities Management (FM) team liaised closely with occupiers at Reflex, who reacted positively to the idea of a PV installation to supply zero carbon energy to their gym and café. The discount versus Grid rates was also welcomed. Longevity Partners provided a single page information sheet on the environmental benefits, which the Facilities Manager shared with occupiers and displayed in the café. The installation team worked carefully to minimise disruption to occupiers, lifting panels onto the roof by crane over the weekend and connecting the panels into the building’s electrical system out-of-hours. The FM team is now looking at introducing a screen in reception, displaying information about how much power the panels are generating, along with information on weather and travel.


How will this PV installation inform future projects?

The success of this project has provided a test bed for cost-effective arrays on complex pitched and flat roofs, a robust business case for PV installation on long-term holdings. Many properties owned by CLS Holdings plc have similar specifications to Reflex, so proving that PV can work there opens up exciting opportunities for additional installations. Longevity Partners have already carried out a desktop analysis of additional properties in the UK, France and Germany for roof-mounted PV installations and delivered two more installations in France. This includes identifying available roof space, shading, schematic layout of panels and initial financial modelling. CLS Holdings plc is currently reviewing opportunities to install a further 1.5 GW across assets in France, Germany and the UK.

Find out more


Rowan Packer

Group Sustainability Manager


T: 020 7840 7779

“This project further illustrates our commitment to support our ambition in becoming a leading sustainable and responsible business in the real estate industry. We are equally proud to share this achievement with all our stakeholders at Reflex either through financial benefits or carbon emission reduction.”

Simon Wigzell, Head of Group Property at CLS Holdings plc