SOLAR POWER A rooftop revolution

Kevin Joyce

Kevin has been a regular contributor to ACES’ Terrier, and here considers the integration of solar power in new build housing as well as options for re-roofs of listed buildings and properties in conservation areas 

Background 

In October 2024, at an International Investment Summit at the Guildhall in the City of London, global investors pledged to invest £63bn in eight growth areas of the UK economy: manufacturing, financial services, clean energy, life sciences, creative industries, digital and technology, defence capabilities, and professional services. At the Summit, the Chancellor announced that the UK Infrastructure Bank is to be transformed into a new National Wealth Fund with £27.8bn to be invested in green energy and other growth industries (1). 

This commitment aligns with government targets to, by 2030, double onshore wind and quadruple offshore wind energy generation, as well as triple solar power generation, as part of a concerted drive to combat climate change. 

A rocky shoreline

A rooftop revolution 

Solar power development will, in part, see a ‘rooftop revolution’ take place, encouraging builders and homeowners to harness solar energy through more thermal and photovoltaic rooftop installations (2). 

Solar PV panels have traditionally been fitted to mounted brackets which sit on top of roof tiles or slates, usually with a gap between the panels and roof, and are angled on the best side of a roof to ensure they receive maximum sunlight (3). Solar PV slates and tiles, also known as solar shingles, are like mini solar panels, and may be installed as part of a roof alongside slates and tiles, rather than sitting on top of the roof. Designed to blend in with a roof’s aesthetics, they can be installed in new roof construction or if a replacement roof is to be fitted (3). 

Traditional solar panels have attracted some criticism, for example, because of their bulky appearance, or with gaps between the panels and roofs becoming nesting areas for birds and small mammals (3). More integrated solar panel designs are emerging though, with continuous advancements in materials and manufacturing techniques creating lightweight, thin and flexible panels which sit much flusher to roofs. 

Solar PV slates and tiles can be made of a variety or materials, including monocrystalline solar cells which are the most efficient but cannot be moulded into elaborate shapes; thin-film solar cells made of copper, indium, gallium and selenite semiconductor material that are light and flexible; glass and steel that can work well for contemporary houses; or recycled plastic (4). Being a more recent product, there are only a limited number of manufacturers in the UK offering them at present. 

These are a good option in particular for listed buildings requiring replacement roofs, and for properties in conservation areas. I referred to St. Silas Church in Islington in north London in a previous article (2011 Autumn Terrier), a Grade Two listed building where the roof was replaced, in what was then a pioneering project involving a seamless integration of solar slates and natural Welsh slates on the south face of the roof (5). I revisited this recently and the roof still appears as aesthetically pleasing today as back then. 

St. Silas Church Roof in Islington

A leading manufacturer and installer, GB-Sol, has installed both integrated and edge-to-edge PV slate roofs nationally in both new construction and replacement roofs projects. Edge-to-edge roofs allow solar energy capture to be maximised more fully, and has been utilised on the slate roof on a chapel conversion in Spinkhill, near Sheffield. A pair of new build houses with a shared edge-to-edge PV Slate roof at Nansledan in Cornwall use a roof which complements a Cornish natural slate roof next door. 

Chapel conversion in Spinkhill

New build houses at Nansledan

Note: Photographs of Spinkhill and Nansleden reproduced with the kind permission of GB-Sol 

Battery storage 

Solar installations may include battery storage in their systems, enabling excess electricity generated to be stored for use when the panels/tiles are not producing enough electricity to meet occupiers’ needs. Many battery systems can be set up to benefit from cheaper night rate electricity that can then be used during the day. Roughly 15% of users choose to add more than one battery storage unit, to further increase stored energy capacity (6). 

Battery storage is benefitting from the development of more advanced battery technologies with, for example, the use of lithium-ion and flow batteries having improved energy density, lifespan, and charging and discharging capabilities, enabling better utilisation of the stored solar energy (7). 

References 

1. ‘Investors pledge £63 billion at summit after red carpet treatment’   Richard Vaughan and Chloe Chaplain   i newspaper   15 October 2024 

2. ‘Labour’s rooftop revolution to deliver solar power for millions’   Toby Helm and Robin McKie  The Observer  14 July 2024 

3. ‘Solar Roof Tiles v Solar Panels: Pros, Cons and Costs’   Solar Guide   www.solarguide.co.uk 

4. ‘Solar Roof Tiles in the UK: Costs and Benefits’   Joshua Pearce  www.greenmatch.co.uk  January 2025 

5. ‘How affordable are low and zero carbon (LZC) renewable technologies in new property development?’  Kevin Joyce   The Terrier   Autumn 2011 

6. ‘Guide to solar storage batteries’ (Updated for 2024)   Pure Volt Solar   www.purevolt.ie 

7. ‘Seven New Solar Panel Technology Trends Shaping the Future’ www.greenlancer.com  January 2023.