Challenge
Our client went out to tender on the Pro6 framework to look for a company that could help the college meet their primary objectives of lowering their carbon footprint, greatly reduce the site’s energy bills and receive a good return on their investment.
Despite not offering the cheapest price against six other companies, we won the contract by demonstrating excellent installation capability over the rest of the competition, in addition to offering quality products that matched the existing system with warranties that gave the client peace of mind. Remote monitoring of the PV system (via eMig) and a live visual display in the college reception were also factors that offered added value.
However, when the project was submitted to the DNO for grid connection permission, it declined the connection due to the lack of capacity on the grid in Cambridgeshire to accept any more locally generated electricity (via export). This response required us to call on our ability to overcome grid constraints, as we’ve done for previous successful projects.
Our Solution
Our design and technical team jumped into action to present a new solution that would satisfy the grid export limitation. Due to the manner in which electricity was distributed on the site, a single export limitation device – originally pioneered by ourselves – was not a possible solution.
So, we evaluated each college block to determine the location of maximum power consumption onsite and proposed reducing the number of blocks that were to be installed upon to three key energy consuming blocks. Three separate export limitation devices were then installed to make sure the college exported no electricity as per the limitation imposed by the DNO. This change in design also meant that two of the original buildings selected for the PV installation were changed; A, F and J were selected, where originally E, F, G and J had been chosen.
Cambridge Regional College already had several PV systems installed on-site. So, the solution we proposed utilised the same inverter equipment (ABB) as the existing system to make life easier for the client in terms of familiarity, compatibility and to offer the same point of contact in case of any issues.
Following a detailed onsite survey, we also identified that splitting the system over four specific rooftops would maximise the generation potential. Trina 275W panels were also specified to offer the highest efficiency and best value.
The Result
The project was delivered and fitted over a period of four weeks with the installation team utilising rope access techniques on two of the rooftops to eliminate the need for scaffolding in order to minimise disruption to staff and students. The PV system was also installed battling adverse weather conditions in November and December to make sure the client received the higher feed-in tariff rates ahead of the deep cuts.
The installation of a display in the college’s reception gave students, staff and visitors a live reading of the electricity generated by the PV system; this was perfect synergy in particular for the students that were enrolled on the practical solar installation course that is tutored at the college. The system now helps the college to save 96,344kg per year, whilst showcasing their commitment to limiting their impact on the environment.