In NUS, energy consumption makes up about 67% of the carbon emissions inventory. Therefore, the key to creating a more sustainable campus is to reduce its energy consumption. This is a daunting challenge given the ever-increasing energy demand to serve a growing research institute like NUS, coupled with our heavy reliance on air conditioning to cool the buildings in the hot and humid climatic conditions of Singapore.
Since 2008, although electricity consumption rose steadily with campus expansion and increased student population, electricity consumption remained flat over the preceding year in 2013. In fact, the campus Energy Usage Intensity (EUI) per unit area has actually been decreasing since 2010.
NUS will continue to reduce its campus EUI and aims to, by 2020, reduce its carbon emissions by 23% below Business-As-Usual levels (compared to 2008). To do that, we will deploy strategies ranging from implementing stringent energy-performance standards for new buildings and retrofitting existing buildings to programmes encouraging our staff and students to practise sustainable habits that reduce energy consumption.
The Energy Task Force has initiated and implemented various projects to reduce energy usage intensity on campus. Described below are some of the highlights:
Air conditioning accounts for about 60% of overall energy consumption in NUS. Since 22 October 2007, the air-conditioning default temperature set point has been adjusted to 25oC and NUS staff and students have been encouraged to adjust the fan speed and/or turn on the swing mode to improve ventilation to meet their required comfort level. In addition, to prevent excessive use, air conditioning in the rooms of student residences at University Town is operated on a pay-per-use basis.
Apart from these measures being taken, the engineering works of consolidating chilled-water plants (for building air conditioning) into a more energy efficient chilled-water plant will also play a significant role in reducing electricity consumption.
Presently, the planning of two such projects are underway in the Faculty of Arts and Social Sciences and in the Faculty of Engineering. Upon completion towards the end of 2016, the two plants will be serving about 12 buildings and new buildings built within the vicinity. Both plants are expected to perform at an efficiency better than 0.6kW/RT. This translates to an average energy reduction of over 30%, or 4 million kWh/year for Faculty of Arts and Social Sciences and 9 million kWh/year for Faculty of Engineering, based on the respective projected load for each plant.
A significant investment was made to evaluate existing metering and install meters in all buildings on campus in a multi-year project. The meters measure real-time electricity, water and chilled-water usage. Since completion, building owners and managers have been able to access online data to monitor energy consumption and detect unusual trends that can indicate possible problems with the energy systems in their buildings. This allows them to identify in particular, high energy consumption areas and prioritize energy conservation projects to reduce their operational costs. The project was completed and fully commissioned in mid-2014.
Corridor lighting, especially when there is nobody walking along the corridors, has been identified as a significant source of energy wastage. NUS aims to introduce LED lamps and motion sensors for corridor lighting in all buildings. Also, light bulbs in alternate lights were removed such that lighting intensity can be decreased without compromising on visibility in the corridors. Currently, these measures have been carried out in pilot projects in the MD6, Temasek Laboratories and E3 buildings. The next phase will include all other buildings.
Coupled with shutting down lifts during non-operational hours for all buildings, it is estimated that the corridor lighting adjustment measures will save 1.2 million kWh or $200,000 annually.