Aztec Solar Energy has recently completed the design, installation and commissioning of phase 1 for a major solar PV installation at the University of Warwick. In this article Nick Jones, project manager at Aztec Solar Energy, outlines the lessons we can learn from a collaborative working relationship to work towards a net zero carbon footprint within the educational sector.

In common with many educational establishments, the University of Warwick is committed to reducing its carbon as parts of its net zero pledge. To help it meet this need, Aztec Solar designed and installed solar PV systems on the rooves of six of its buildings.

The commitment makes sense not only as part of the university’s efforts to achieve net zero, but at a time of rising energy costs it will help reduce its future expenditure.

Installing six large PV systems is a big commitment and at a busy university with 29,000 students plus staff and members of the public potentially on site, both health and safety and minimising disruption were vital factors, particularly during cranage and scaffolding work to get the PV panels and supporting structures onto the rooves.

Most of these lifts, scaffold erections and electrical shutdowns to connect the PV system to the supply were done at night. For one building, contractors were on site at 4.00am and because the project included six buildings all completed in just nine months, there was also a separate secure onsite compound for storage.

The design and specification for the installation was also complex. Aztec Solar had to consider the different roof types and their load bearing capacity and key safety issues for the installation and the future operations and maintenance of the systems.

Says Nick Jones, project manager for Aztec Solar: “Solar PV systems will last for 25 years and longer so when designing and installing a system you must look beyond the initial installation and consider the total lifecycle of the system. This is to ensure both ongoing efficient production and the safety of both maintenance personnel and emergency services such as firefighters who may need access to the roof.

“Solar panels will carry on generating electricity even in cloudy weather and typically have an output voltage of 30-60V. Connecting these together in a string creates a high voltage of up to 1000Vdc on a big installation which can be dangerous. Traditional string inverters cannot reduce this DC voltage even if they are turned off.

“Fortunately, modern inverter technology, like the SolarEdge system used at Warwick University, has power optimisers, inverters and individual monitoring on each PV module. This allows for the automatic shutdown of PV arrays and lowers and maintains the voltage in all DC conductors below 50V and to 1V per module for either maintenance or in an emergency. The lesson is to make sure that you know what your installer is fitting.”

The installation at the University of Warwick also provides fire-fighter breaks between panels for access in the event of an emergency and for future maintenance, whether that’s for cleaning, repair or even replacement.

With an eye to the future, the university can monitor the system for faults. If maintenance personnel identify a fault then thanks to careful planning, they can locate the exact panel or other equipment on the roof to save time.

To date Aztec Solar has installed 2009 panels. These will generate an estimated 795MWh per year, which is the equivalent of 7058 trees. Phase 2 of the project will start in 2024 when up to 14 more buildings will have PV systems installed on their rooves.