2 February 2022

Historic buildings could be protected from rising energy bills by solar panels

Solar panels could be used to help protect key historic buildings from the rising cost of energy bills whilst also reducing their carbon footprint, according to a new study by researchers at the University of Sheffield.

The outside of Bath Abbey on a warm summer's day
  • New research shows how solar panels could be used to help protect key historic buildings, such as Bath Abbey, from rising energy bills 
  • Findings also reveal how using solar panels can help reduce the carbon footprint of listed buildings
  • Research finds installing solar panels on Bath Abbey could produce around 45 megawatt hours per year, which accounts for roughly 35 per cent of the Abbey’s annual usage
  • Study calculates solar panels could save Bath Abbey 10 tonnes of carbon dioxide per year - equivalent to an average car driving almost twice the circumference of the Earth - pay for itself in 13 years and provide a profit of £139,000 over a lifespan of 25 years

Solar panels could be used to help protect key historic buildings from the rising cost of energy bills whilst also reducing their carbon footprint, according to a new study by researchers at the University of Sheffield.

The study, which included Adam Urwick, a Doctoral Research Student in the University’s Department of Chemical and Biological Engineering, has calculated that solar panels could save Bath Abbey 10 tonnes of carbon dioxide per year – equivalent to an average car driving almost twice the circumference of the Earth. 

Published in the journal Energy Science & Engineering, the study in collaboration with the Universities of Bath and Liverpool, looked at the dimensions, tilt and orientation of the Abbey roof, along with historic weather data and shading of the roof from spires, to model the best configuration for 164 photovoltaic (PV) panels and estimated the amount of electricity that could be generated in a normal year.

The team found that the set up could produce around 45 megawatt hours per year, which accounts for roughly 35 per cent of the Abbey’s annual usage. The equivalent amount of carbon dioxide saved, versus buying the electricity from the National Grid, would be around 9.6 tonnes per year, significantly reducing the carbon footprint of the building.

A cost-benefit analysis showed that the system could pay for itself in 13 years and provide a profit of £139,000 over a lifespan of 25 years. It would also future-proof the Abbey from the rising costs of energy bills. 

The findings show that despite a large initial outlay, the system would be financially feasible for the historic grade I listed building.

Adam Urwick, who performed the abbey modelling, module design and shadings analysis from the University of Sheffield, said: “Bath Abbey has been pursuing methods to reduce its carbon footprint; first with LED lighting and then with underfloor heating powered by renewable energy from Bath's hot springs. Now, with the insights of this paper, a solar array could be installed that could save the Abbey up to £150,000 over it's 25 year lifetime, with a payback period of 14 years. Not only does it make financial sense, but the installation of solar panels on Bath Abbey could inspire reinvigoration of solar PV deployment in the UK which has stagnated over the past 5 years.”

In the model, the panels were sited such that they couldn’t be seen from the street, only from a distance from the Bath Skyline, so would have minimal visual impact on the historic building.

Matthew Smiles, PhD researcher at the University of Liverpool, who is first author on the study, said: “It’s very difficult to insulate historic Grade I listed buildings like Bath Abbey, so installing solar panels is a good way to reduce the carbon footprint of these buildings.

“The problem with putting solar panels on homes is that the electricity demand is higher in the evening when it’s dark, meaning electricity generated must be stored in batteries. In contrast, most of the Abbey’s electricity is used during the day, when the panels would be generating energy from sunlight. With increasing energy prices, installing solar panels could result in large cost savings.”

Professor Alison Walker, Director of the Centre for Doctoral Training in New and Sustainable Photovoltaics at the University of Bath’s Department of Physics, has collaborated with Bath Abbey for several years on the project. She said: “This paper is an amazing collaboration between the PhD students and the Bath Abbey Footprint Project who first invited us to look into solar for the Abbey and arranged for the students to visit the Abbey roof to see how solar could work. It’s great for the students, whose research projects are all on solar power, to see a practical application of the training they have done in universities across the UK.”

The research was performed as part of a feasibility study for the Abbey’s Footprint programme, as part of the Church of England’s campaign, Shrinking the Footprint, which aims to reduce the carbon footprint of its historic buildings. 

The Bath Abbey Footprint programme has already reduced its carbon footprint by using the geothermal hot springs of the local area to provide underfloor heating and installing LED light bulbs to illuminate the interior.

Although environmental and planning rules must also be considered carefully, installing solar panels is another potential way the Abbey could reduce its footprint further.

Nathan Ward, Footprint Project Director at Bath Abbey, said: “It’s been fantastic working with the University of Bath and the other universities on this project. The students and staff have shown a high level of commitment, knowledge and enthusiasm and have provided us with well-considered and invaluable research that we would like to use practically in the future. 

“The research will help us greatly in exploring the use of solar panels on the Bath Abbey roof. The Abbey is highly committed in the outstanding care of both our built and natural environment and to reduce our carbon footprint. 

“This has been achieved in part thanks to our Footprint project which saw the installation of new LED lighting and eco-friendly underfloor heating that uses energy from Bath’s natural hot water, but the use of solar panels would enable us to reduce our carbon footprint further.”

The Centre for Doctoral Training in New and Sustainable Photovoltaics is a consortium of seven universities and 12 industrial partners led by the University of Bath and funded by the Engineering and Physical Sciences Research Council (EPSRC). The universities include: The Universities of Bath, Cambridge, Liverpool, Loughborough, Oxford, Sheffield and Southampton.

The study, Next steps in the footprint project: A feasibility study of installing solar panels on Bath Abbey, is published in Energy Science & Engineering. To access the paper in full, visit: https://doi.org/10.1002/ese3.1069 

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