Producing low-carbon energy for electricity, heating and cooling through a tri-generation plant at 8 Chifley Square, Sydney

Tuesday, September 1, 2015

Purpose of the project

This project is rooted in Keppel REIT’s triple bottom line focus on economic viability (save money), environmental protection (save energy) and social responsibility (save the environment).

In Sydney, buildings contribute over 50% of the city’s greenhouse emissions. Traditional buildings are powered by coal-fired power stations that produce around 80% of Sydney’s electricity.

A tri-generation plant generates electricity onsite using a gas engine, which is twice as efficient as coal-fired power stations and reduces approximately 40% of emissions. The generation efficiency is further enhanced with utilisation of waste heat for heating and chilled water generation via an absorption chiller.

 Approach

A highly efficient energy technology, the tri-generation system is one of the largest decentralised energy networks in the world. Located onsite, electricity is produced near where it is used, avoiding the need to bring electricity over long distances. It replaces coal-fired electricity and reduces overall emissions from buildings.

The tri-generation plant at 8 Chifley Square comprises of a 400 kW MWM TCG 2016 V8 natural gas engine connected in parallel to the grid. The engine is coupled to a 255 kW broad exhaust fired absorption chiller that is fully integrated into the building’s air conditioning, chilled and condenser water systems. Additionally, the tri-generation plant can produce 212 kW of heating for use by the building’s HVAC systems.

The tri-generation plant operates only during periods of high demand. During off-peak periods when the building requires lesser energy, electricity can still be purchased from the grid so as to ensure the building obtains the best environmental and financial efficiency.

An innovative aspect of this plant at 8 Chifley Square is its ability to export “excess” generation to another property, the first of its kind in Sydney. This allows the plant to operate at a higher capacity over longer periods, thereby improving efficiency, minimising material use and redundancy, as well as providing low carbon electricity to other buildings.

Results

The primary gains from the tri-generation plant at 8 Chifley Square are environmental and financial benefits.

The cost of electricity is reflected in the Energy Supply Agreement between the building owners of
8 Chifley Square and the owner and operator of the tri-generation plant. The agreement specifies the wholesale price for the electricity generated and supplied by the tri-generation plant. In doing so, the building owners are not subjected to higher retail electrical charges payable to the regular grid supplier.

On average, the tri-generation plant at 8 Chifley Square produces 22,599 kWh of electricity every week, or approximately 1.18 million kWh per annum. This is enough to power about 7,320 homes in Australia each year. The use of onsite generation rather than grid-based electricity has also resulted in a reduction of 1,234 tonnes (or 1,233,892 kg) of CO2, which is equivalent to over 6.2 million km of car emission.

The building’s ability to export “excess” electricity generated from the tri-generation plant to another property also results in a greater reduction in overall carbon emissions.

In addition, the tri-generation technology is recognised under Australia’s Green Star Design as a carbon and demand reduction initiative. This has gained 8 Chifley Square additional credits towards its 6-Star design and as built ratings, as well as supports its goal of a 5-Star NABERS energy rating.

 

"At Keppel REIT, we believe that resource efficiency is not only our responsibility, but also makes good business sense. In line with our commitment to embrace sustainability, 8 Chifley Square in Sydney is testament to how we can leverage innovative technology to achieve real cost savings while making a significant positive impact on our environment."