Land Securities' PV Installation at Gunwharf Quays


At Gunwharf Quays in Portsmouth, Land Securities has installed the largest array of photovoltaic roof panels on any UK shopping centre. This is set to produce 280,000 kWh of clean power in the first year, with payback within 10 years. It will cut CO2 emissions by 3,750 tonnes and will save around £1.5 million on electricity costs over the next 25 years.

£563,000 capital investment

£1.5m total income over 25 years*

3,750 tonnes of co2 saved over 25 years


As the UK’s largest commercial property company, Land Securities recognises the need to reduce the impacts of its property portfolio. The company aims to reduce CO2 emissions rom its like-for-like properties by 15% by 2019/20, compared to 2010/11. As well as being good for the environment, this will help mitigate long-term energy price risks.

Gunwharf Quays in the historic Portsmouth Harbour is one of the UK’s largest shopping destinations. It offers 95 designer outlets, 30 bars and restaurants, a 14-screen cinema, a 165-bed hotel and a 24-hour casino on site. It also has the largest underground car park in the UK which, for health and safety reasons, is lit 24/7.

Gunwharf Quays consumes some four million kWh of energy in common parts each year, with the underground car park accounting for almost 60% of consumption. A site-specific environmental management plan drives efficiency measures as part of business of usual.

In late 2011, Land Securities invited renewable energy consultancy Syzygy Renewables to identify the optimum renewable energy solution for Gunwharf Quays among other sites across the UK.


Analysis supported the installation of photovoltaic panels at Gunwharf Quays:

  • Portsmouth has one of the highest levels of solarisation (sunshine hours) in the UK
  • Gunwharf Quays offers a large roof area suitable for panels
  • Photovoltaic panels are a well-established technology with low maintenance requirements
  • Panels can be fully insured for design and installation, with a 25-year performance warranty
  • 10-year payback period, with strong financial benefits over the 35-year life expectancy, wit the Government’s Feed-in Tariff offering 55% of the overall savings.

Syzygy specified and developed an outline design for a 300kW roof-mounted photovoltaic solution across two sites, on a series of flat and pitched metal sheet roofs. In total, 1,070 panels were installed, covering 34,500 sq ft.

The design incorporates aerodynamic, low ballast K2 panels on the flat roofs. An innovative Schletter pitched roof mounting system increases the tilt on the panel to enhance output and improve the self-cleaning performance of the panels.

The system was installed by EvoEnergy, one of the UK’s largest photovoltaic installation contractors. The entire installation took four months and was completed at the end of July 2012.


The photovoltaic panels are expected to generate 280,000 kWh in the first year, fulfilling 7% of the Centre’s energy demand in common parts. This is enough to power 70 homes and will save 3,750 tonnes of CO2 over 25 years.

As well as supporting the CO2 reduction target Land Securities has set, this will:

  • Mitigate long-term energy price risks
  • Decarbonise the service charge for occupiers
  • Deliver a lower carbon retail destination for shoppers.



  • Capital investment: £563,000
  • Year one electricity cost savings: £28,000
  • Year one Feed-in Tariff revenue: £36,000
  • Payback period: Within 8.7 years.

Over 25 years:

  • Total income*: £1.5 million
  • Total operating and management costs: £250,000.

*Based on occupiers using 100% of energy produced and paying the market price through the service charge.

Challenges & Achievements




How to introduce photovoltaic panels given that Gunwharf Quays incorporates listed buildings from the 19th Century naval dockyard?


Land Securities and Syzygy worked closely with Portsmouth City Council to design a system that was sympathetic to the surroundings, taking the nearby listed buildings into consideration.


Syzygy produced an outline system with photovoltaic modules positioned across a series of roofs with detailed string layouts. The positioning of the panels also minimised potential shading from the nearby Spinnaker Tower and ‘Lipstick’ residential tower, maximising potential output at all times of the day.




How to efficiently monitor the output, usage and efficiency of the system?


Mobile-enabled smart meters were installed to record generation and any export to the National Grid.


To monitor the day-to-day performance of the hardware, Land Securities also installed a remote monitoring system. This allows detailed analysis of the system down to a string level of around 20 panels, as well as measuring solarisation and panel temperatures to monitor system conversion efficiency.


Land Securities will report the performance of the system annually through the company’s annual Corporate Responsibility Report.

Find out more

Neil Pennell

Head of Engineering and Design

Land Securities

“This project demonstrates Land Securities’ commitment to reducing CO2 emissions by installing the appropriate technology for our buildings. As the largest property company in the UK, we should lead by example, encouraging other landlords to follow.”

Paul Boreham, Group Energy Manager at Land Securities