One of the project requirements was the reduction in the consumption of energy in comparison with the consumption levels of the former Enniskillen Hospital, which had to be kept below 50 GJ/m3 per annum and with CO2 emissions of less than 120 kg/m² . To achieve this reduction in energy consumption, the hospital design envisaged a Combined Heat and Power unit (CHP), to take advantage of the waste heat energy produced to become water vapour used in the heating system, thereby saving on energy consumption, which was the target set in the project.

However, when an attempt was made to purchase the planned CHP it had been discontinued, so the construction team had to look at the construction stage for an alternative with equal or better benefits than that originally planned with the acquisition of the CHP unit.

Having studied a number of different alternatives, such as geothermal energy or the installation of a wind turbine, the solution finally adopted to replace the CHP unit was to use a Spilling Engine, which produces the same amount of power and heat as the discontinued unit.

For the installation of the Spillings engine one of the 8 bar biomass boilers was replaced with a new 30 bar boiler with similar specifications to the one it replaced but larger and with a greater heat capacity.

The Spilling engine generates electricity and produces steam at a pressure of 8 bars, after passing through a pressure reduction system, which is combined with the steam produced by the other boilers and channelled to the hospital to cater for its heating requirements.

Following the installation of the Spilling engine and the new system, it was observed that although more fuel pellets are consumed, the annual calorific energy output is higher than expected according to the original design, and so the overall cost of the installation is lower.

There has also been a considerable reduction in the maintenance work needed as the Spilling engine works according to the hos pitals demands for heat, in contrast to the on/off control system of the CHP unit envisaged in the original project design.

All of the above is evidence that the solution selected has enhanced the energy efficiency of the building in its post-commissioning phase. This and other actions taken helped the project win the Green Apple Award in the category "Improvement of the Environment and Architectural Heritage."