Planning for Sydney’s energy revolution
The Better Buildings Partnership, which presented at Total Facilities 2012 on the topic, provides advice on what to consider when contemplating connecting to Sydney’s new thermal reticulation network.
Almost 90 percent of electricity used in Sydney currently comes from remotely located coal-fired power stations. This means that major savings can be delivered by using a low carbon decentralised precinct-scale energy network comprising trigeneration and local renewable energy systems.
Recognising this, in April 2012, the City of Sydney entered into a formal agreement with Cogent Energy (a subsidiary of Origin Energy) to design, finance, build, operate and maintain a trigeneration energy network on its behalf. Under the development agreement, the City of Sydney will own the new thermal reticulation network (TRN) infrastructure. This network will generally consist of flow and return heating hot water (HHW). Where chilled water (CHW) pipework is reticulated, this will be based on the provision of local satellite thermal stations, delivering HHW or CHW to buildings for space and domestic hot water (DHW) heating and comfort cooling for tenants. Cogent Energy will be responsible for the energy centres and retailing the electricity and thermal energy produced. It will also be responsible for operating and maintaining the City-owned thermal networks.
The low carbon power and thermal energy that trigeneration provides will revolutionise Sydney, but individual owners will need to assess the commercial and infrastructural impacts on their assets to build an individual business case for connection.
TRN CONNECTION CONSIDERATIONS
The Better Buildings Partnership is currently developing case studies and business checklists to uncover issues that building owners need to consider when evaluating how and when to connect to low carbon energy sources.
Five buildings were selected as case studies to review the high-level technical opportunities and constraints associated with connecting to a TRN. The sites represent buildings of different uses, age, load profiles and connection challenges. As such, each building has unique opportunities in making up part of the larger overall network. The findings are intended as guidance only. Building owners interested in evaluating a business case for connection should contact the City of Sydney/Cogent Energy for a detailed proposal.
In conducting these studies, the Better Buildings Partnership has begun work identifying the requirements individual business owners need for a business case. Numerous considerations exist, including (but by no means limited to):
- avoidance of electricity network charges
- electricity network capacity charges
- NABERS (National Australian Built Environment Rating) Energy uplift
- hosting an energy centre or a local satellite thermal station
- CAPEX (capital expenditure) and the asset replacement cycle
- electricity and thermal energy supply agreements
- risk and reliability, and
- reduced exposure to the carbon price.
1. Avoidance of electricity network charges
Network charges, including Transmission Use of System (TUOS), Distribution Use of System (DUOS) and network capacity charges currently represent circa 50 percent of typical electricity bills and are expected to increase to 60 percent of electricity bills by 2014. Trigeneration can reduce network charges by avoiding TUOS and reducing electricity demand through thermally driven absorption cooling.
2. Electricity network capacity charges
Where a technology shift has occurred from electric to absorption chiller plant, network capacity charges can be avoided if the redundant electric chiller plant is disconnected and removed from the building. It should be noted that some existing low-load water-cooled electric chiller plant would typically be retained for redundancy, low-load and peak conditions to maximise utilisation of the absorption chiller plant. If buildings retain the redundant electric chiller plant, they will continue to pay the network capacity charges.
3. NABERS energy uplift
Uplift in NABERS Energy ratings is expected based on the thermal supply arrangement (i.e. HHW CHW reticulation connection), the proportion of the building’s space for DHW heating and comfort cooling demands met by thermal energy supply, and uptake of low carbon electricity. To deliver a Commercial Building Disclosure rating uplift from low carbon electricity, building owners should consider hosting an energy centre.
4. Hosting an energy centre or a local satellite thermal station
Owners may elect to host an energy centre, whereby electricity used by the building is produced on-site, avoiding virtually all network charges. Hosting an energy centre would require a low- or no-cost lease to the City of Sydney, which will sub-lease to Cogent Energy. Hosting a satellite thermal station could assist in reducing upfront capital costs.
5. CAPEX and the asset replacement cycle
Inherent asset replacement cycles may support capital upgrade works, including retrofit of building services and connection to a TRN and recycled water network. Customers may elect to replace plant early to deliver financial, tax and other benefits, such as the ability to shield against increasing electricity network charges, carbon price impacts and organisation carbon disclosure.
6. Electricity and thermal energy supply agreements
As outlined in the Decentralised Energy Master Plan – Trigeneration, replacing electric chiller plant with absorption chiller plant (HHW fired) in customer buildings will offer economic benefits to customers.
7. Risk and reliability
The TRN will be designed with multiple energy centres feeding into the network. If an energy centre were to fail, the TRN would still be supplied through other energy centres. The trigeneration network will also have back-up boiler plant and thermal storage at the energy centres or customer buildings, which will be used to supplement the daytime thermal load, should any generator downtime be experienced. This provides redundancy within the TRN and it is expected that connection to the network should provide the same, or better, security of supply than what is offered by the electricity and gas supply networks.
8. Reduced exposure to the carbon price
Based on an interrogation of the Energy Price Projection developed by the Institute for Sustainable Futures, University of Technology, Sydney for the New South Wales Office of Environment and Heritage (OEH) in December 2011, mitigating exposure to the carbon price through a TRN connection could support annual electricity cost savings in the order of 15 percent by 2020, depending on the volume of electricity displaced through a technology shift from electric chiller plant to absorption chiller plant.