10:00, 14th December 2016
Case study: Vital Energi's CHP at the University of Edinburgh
A combined heat and power (CHP)-based energy installation at Scotland's University of Edinburgh threw up more challenges than most for installer Vital Energi, with archaeology and conservation issues and restricted access. But with those challenges overcome, the project is now saving the university money on its energy bills while lowering its CO₂ emissions.
Key benefits include:
· A flexible solution that adapted to the client’s requirements and kept the project schedule on track;
· Careful preparation ensuring that multiple hurdles were successfully managed;
· A low carbon energy supply saving 1016 tonnes of CO₂ per year;
· A private wire network supplying campus buildings and cutting electricity costs.
‘The system being installed is one of the best low carbon solutions we’ve found over the years and we can make significant savings, in terms of thousands of tonnes of carbon per year, and that is a major contribution to our overall targets,’ says David Barratt, Operations Manager at the University of Edinburgh. ‘Vital have shown themselves to be flexible during the course of this project. There were several instances, such as during the exam period and the Edinburgh Fringe, when some areas of work had to stop and Vital have had to work around it. Through good planning and management they continued to meet the tight deadlines while causing as little disruption as possible to the University of Edinburgh and its stakeholders.’
In 2015, Scotland’s energy bill for its universities and colleges reached £25 million ($32 million) and these institutions have been officially tasked with reducing their energy bills and CO₂ emissions.
The University of Edinburgh is a perfect example of the challenges facing modern educational institutions. In the last 25 years its student population has almost trebled to well over 30,000 and it saw the number of computers connected to the university network grow from 1000 in 1999 to more than 16,000 in 2009.
This huge growth has seen a dramatic rise in the amount of energy consumed, but through continuous investment in its energy infrastructure and campus, the university has significantly reduced its CO₂ output despite its expansion. The most recent step to lower energy consumption and emissions saw a new £8 million low carbon community heating system and private electricity network installed by Vital Energi for the University of Edinburgh Utilities Supply Company.
The University of Edinburgh has a track record of investing a percentage of their annual utilities spend on energy efficiency improvements, a practice which has seen newspaper The Guardian describe their work as the country’s ‘quietest green revolution’.
The challenge and the solution
The University of Edinburgh proved to be one of the most challenging projects Vital Energi had undertaken. The 431-year-old University brought with it a mix of conservation and heritage issues, extremely limited access and a hugely challenging timescale for completion of the project. This timescale was made even more difficult due to scheduled periods where work ceased in order to accommodate the Edinburgh Fringe comedy festival and student exams.
Working within the historic part of Edinburgh brought its own challenges. The team had to lay district heating pipe beneath Flodden Wall, which is a historic monument, meticulously removing and replacing cobbled streets and accompanied by an archaeologist who was plotting the boundaries of the old city wall. The work also led to the discovery of a knight’s skeleton during excavation in High School Yards, which created a temporary delay.
Forethought and careful planning enabled Vital Energi to overcome some significant obstacles in order to successfully complete the design and build of a new combined heat and power (CHP) energy centre located within the staff car park area of The Centre for Sport and Exercise (CSE) to provide heating, hot water and electricity to the University campus via underground pipework and cabling. In its determination to meet the timescale, Vital Energi undertook a large amount of prefabrication work to ensure ease and speed of installation on-site. This included having all the energy centre mechanical pipe work prefabricated off-site to ensure quality of product, reduce on-site welding and save install time on-site.
The energy centre houses one CHP 1.4 MWe engine, a 100,000 litre thermal storage, two 9 MW backup/peak load gas boilers, High Voltage/Low Voltage switchrooms and associated plant. The CHP engine will provide heat and hot water via a district heating network which involved approximately 4 km of pipe connecting 13 sites and generating electricity for 14 buildings.
The new North and South Holyrood postgraduate accommodation blocks are included within the scheme and Vital Energi pulled out all the stops to include two additional buildings – Thomson’s Land and Paterson’s Land – which were originally scheduled for connection at a later date.
The energy centre site was only accessible through a narrow low tunnel measuring 3.5-3.7 metres in height. Vital Energi, therefore, had to design the equipment to fit through this access while still delivering optimum performance. This challenge was a first for the firm, but careful preparation meant that the team managed to bring all equipment and plant through the tunnel except the gas-fired boilers and the thermal store. Special permission from highways was obtained to shut Viewcraig Gardens, the street running alongside the CSE, while the remaining plant was craned on to site after Vital Energi had managed to build up good working relationships with the two highways departments impacted by the project.
At Thomson’s Land the team had to install the pipes up the side of the building and clad them in sandstone to match the existing building facade. At St Leonard’s there were two plant rooms originally, one serving the pool and the other providing space heating. The team combined the two plant rooms together to improve efficiency.
The entire scheme has been future-proofed by sizing the district heating to accommodate later extension to serve the OId College Area and link to George Square.
The University of Edinburgh has a long history of improving its environmental performance, was already utilizing CHP technology and had a clear idea of the areas where it could make improvements.
Vital Energi’s in-house expertise allowed them to be flexible with regards to planning and installation. They were on-site just two weeks after signing the contract and completed basic building work on the energy centre within three months.
The new community energy scheme was installed and finished in time and on budget and now saves the University approximately £170,000 a year in energy costs (gas and electricity) and reduces its annual carbon emissions by an estimated 1016 tonnes.