The College has taken another important step towards a more sustainable future. Over the past year, the College has completed the installation of photovoltaic (PV) panels on both the Anniversary Building and the Principal’s Lodgings, generating clean electricity on site and reducing our carbon footprint.
Solar Energy for the Anniversary Building
When the Anniversary Building was first conceived, it included plans for rooftop solar panels as part of its sustainable design. Although these were not installed during construction, the original mounts were retained, and now, five years later, that vision has been realised.
Installed in autumn 2025 by Darke & Taylor, the new rooftop array consists of 33 Solarwatt Vision M 5.0 glass-glass panels linked to a high-efficiency SolarEdge inverter and 17 optimisers. Together, these provide an installed capacity of 14.85 kWp and a projected annual energy generation of 13.66 MWh, covering around 9 percent of the building’s annual electricity use.
Already, the system is delivering strong results. In its first month of operation, the Anniversary array has generated 579 kWh of energy. All electricity produced is consumed directly within the building, so no battery storage is required.
According to system modelling, this installation will save around 2.6 tonnes of CO₂ each year, equivalent to planting 121 trees annually. The array’s performance ratio of 81 percent reflects the high efficiency of modern solar technology, ensuring consistent output across Oxford’s seasonal conditions.
From a financial perspective, the project is performing well too. The system is expected to achieve a payback period of approximately eight years. With a 30-year design lifespan, it represents a long-term investment in both sustainability and cost efficiency.
Stats
Anniversary Building Solar Array
Installed capacity: 14.85 kWp
Annual generation: 13.66 MWh (about 9 percent of building energy use)
CO₂ saved each year: 2.64 tonnes
Equivalent to 121 trees planted annually
First-month generation: 579 kWh
Payback period: around 8 years
Lifetime savings: £83,000 (NPV)
Principal’s Lodgings Solar System
Installed: August 2024
Energy generated so far: 4.47 MWh (4,470 kWh)
Includes battery storage for night-time and low-light use
Uses SunPower Maxeon monocrystalline panels with a 40-year warranty
Solar Power at the Principal’s Lodgings
Our PV journey began earlier with a successful solar installation at the Principal’s Lodgings, where the south- and west-facing roofs provided an ideal site to test renewable energy generation on a smaller scale. This system, also installed by Darke & Taylor, incorporates battery storage to capture energy generated during daylight hours for use in the evenings and on cloudy days.
Since its installation in August 2024, the Lodgings system has generated an impressive 4.47 MWh (4,470 kWh) of renewable electricity. The batteries ensure that excess energy generated during sunny periods is stored for later use, maximising efficiency and minimising grid demand.
The Lodgings array uses SunPower Maxeon monocrystalline panels, among the most efficient in the world, with a 40-year performance warranty and minimal annual degradation. This installation has served as a valuable testbed for the College’s wider solar strategy, informing the rollout to larger buildings such as the Anniversary Building.
Building a Sustainable Future
These solar initiatives are part of St Hilda’s ongoing commitment to environmental stewardship and innovation. By combining practical investments in renewable energy with long-term planning for energy efficiency, the College is steadily reducing its carbon footprint and supporting the University’s Net Zero Carbon ambitions and our own sustainability strategy.
“Our aim is to ensure that the College continues to lead by example, demonstrating how heritage, modern design, and sustainability can work hand in hand.” Head of Estates Alex Horsfall-Turner