PV Retrofits: More than just Space and a Business Case


After months of planning, preparing and installing, Hammerson’s 130kW solar photovoltaic (PV) array on the WestQuay Shopping Centre started generating zero carbon renewable electricity last month. It will be the first PV retrofit on a Hammerson asset and as project lead, it is an exciting moment for me and for the business.

The carbon and financial savings of PV are well known. In the case of WestQuay, this equates to a 4% reduction in landlord’s CO2 emissions and a 3% reduction in grid electricity demand annually, which is enough to provide 40 homes with power.  

Financially the returns meet our internal investment threshold even though the benefit of the Feed In Tariff is now relatively small. This was achieved in two ways: firstly, by using the generated power to displace grid electricity in common parts to maximise its value rather than exporting to the grid and secondly, by recognising the electricity savings and FIT payments as an income stream and capitalising to increase the asset value. Natural capital savings haven’t been measured in this instance but from a recent analysis of PV at the adjacent Watermark development there was an improvement in payback from 11 to 9 years when the financial implications of reduced CO2 on society are factored in.

Other co-benefits such as demonstrating Hammerson’s commitment to its Positive Places sustainability agenda, positive PR and of course, the feel good factor, are also important at both business and personal levels.

The project did come with challenges, many of which are less well documented, but none were insurmountable and solving them has certainly been a valuable exercise. In addition, delivering a project that provides a demonstrable environmental benefit has been rewarding and brought home the scale of the challenge to meet global climate change and national carbon reduction targets.

A key challenge was knowledge. For example, questions regarding weight, wind loadings, roof penetrations, coastal environments (including seagull attacks!) and service charge ‘recharge’ mechanisms all required careful consideration, much discussion and some head-scratching. For most of us involved, installing a solar PV array on an existing asset with more than one owner was a new experience. There wasn’t any reluctance to do it, just concern to get it right and wariness of the implications of getting it wrong. Persistence, dialogue and diligence to navigate through these issues played a major role in delivering this project successfully.

Significantly, the business case did demonstrate that there is still enough value in the Feed In Tariff to turn a marginal project into a viable one. Of course, this was helped by the steady yet significant drop in PV panel prices over the last few years and was sufficient to alleviate fears that renewable energy is an expensive option.

The biggest physical barrier encountered was the limited space on the roof to install the panels. Whilst our roofs can be large, space is taken up by kit, man-safe areas and so on. In the UK, roof space is significantly under-utilised and the generation potential is large if more is used for solar PV. The time and effort required to install a rooftop array isn’t necessarily proportional to system size so this can often be a significant factor in the decision to proceed with marginally attractive projects. The same feasibility studies, approvals, discussions and negotiations are required whatever the system size so where roofs are cluttered or overshadowed a project may simply be too small to justify. Over time, better knowledge, learning and experience in client organisations will help as PV becomes a routine retrofit project but the industry isn’t quite there yet; the renewable energy generation potential or roof-space across the UK will take a little while longer to really utilise.  

What next? For Hammerson, we are looking at the potential to install PV across many of our existing roofs and car parks as well as on our new developments. A clear business case is perhaps still the main hurdle to overcome although addressing some of the more pertinent technical and logistical points at an early stage does ensure smoother delivery and this all helps in the promotion of schemes both internally and with our partners. Although project time and effort isn’t proportional to project size, it will decrease as we progress more projects and this is where real efficiencies and ultimately positive environmental outcomes can be made.

This article was originally posted by Richard Quartermaine on Linkedin, here