Installation of New CHP system at the Old Aberdeen Campus

Background The Central Heating Station at the Old Aberdeen Campus was 30 years old and the boilers were due for replacement. The existing steam mains were increasingly leaking. The electricity supply to the site was through 3 separate supplies, 2 at HV, 1 at LV.

Selection of New Plant An Option Appraisal was carried out considering a number of replacement alternatives. The decision was taken to replace the old Central Heating station with a new Combined Heat and Power station. This would supply the Old Aberdeen Campus with both heating and electricity.

Scope of Works A brand new heating station, to be built at Bedford Road. New CHP engine, boilers and ancilliary equipment to be installed. The existing steam pipe work to be removed and new LTHW pipe work to be installed forming a ring main. Reinforcement of the 11kV equipment, and installation of an 11kV ring main.

Cost Cost of the new installation: £10 Million pounds (Of which £1.75 Million was a Community Energy Programme Grant from the Energy Savings Trust)

CHP engine details The CHP engine installed is a Jenbacher 612, 12 cylinder engine that is fired on natural gas. This engine is capable of producing 1,630 kW of electricity and 1,700 kW of heat. The engine is set up to supply the University only and there is no export of electricity to the grid. The electrical output is sized to be able to meet the electrical baseload for the Old Aberdeen Campus which will give the maximum number of hours operation in this mode of operation. This load corresponds to approximately half of the Old Aberdeen Campus peak electrical demand of 3,300 kW. Over a year the engine is projected to produce over 60% of the Campus site electricity requirements

CHP engine details By making use of the heat the overall efficiency of the engine is 83% which compares very favourably with power stations. The result of this overall improvement of power generation efficiency is a substantial reduction in emissions, at the Old Aberdeen Campus, arising from use of electricity. Carbon dioxide emissions are reduced, and additionally oxide of nitrogen levels are reduced by 45%.

Carbon Dioxide Emissions The CHP unit has been running since May 2007 and has already reduced carbon dioxide emissions by over 1,200 tonnes from the University of Aberdeen.

Cost Saving The projected cost saving for the year 2007/2008 is: £500,000