International Energy Advisory Council

City Of Sydney Decentralized Energy Master Plan

Wednesday 23 August 2017

Sustainable Sydney 2030 is the vision and strategic plan for the City of Sydney to make Sydney a green, global and connected city by 2030 and was adopted by the Council in 2008.

Allan Jones MBE
21 July 2017

Sustainable Sydney 2030

Sustainable Sydney 2030 is the vision and strategic plan for the City of Sydney to make Sydney a green, global and connected city by 2030 and was adopted by the Council in 2008.

- The City will reduce greenhouse gas emissions by 70% below 2006 levels by 2030
- The City will meet 100% of electricity demand by local generation by 2030
Source: City of Sydney (2008)

As 80% of Sydney’s greenhouse gas emissions come from coal fired power plants the 70% reduction in greenhouse gas emissions could not be delivered without replacing coal fired centralized energy generation with low or zero carbon decentralized energy generation. Therefore, the 100% local electricity demand would need to be met principally by decentralized energy - 70% from trigeneration and 30% from renewable electricity generation by 2030.

Green Infrastructure Plan

A key objective in Sustainable Sydney 2030 was to prepare a Green Infrastructure Plan. Central to achieving this was the objective to develop a Green Infrastructure Plan comprising five Master Plans as

In addition, a Climate Change Adaptation Strategy would support and take into account the Green Infrastructure Plan as climate change mitigation and adaptation should be integrated holistically since the green infrastructure that a city needs to function must also be resilient and adaptable to climate change.

Trigeneration Master Plan

Based on the energy efficiency target in Sustainable Sydney 2030 the Trigeneration Master Plan was the first decentralised energy master plan to be developed and adopted by the City in 2013. The reason for this is that city energy demands are very high in relation to their geographical area and for a city like Sydney those energy demands have very high air conditioning or cooling demands, particularly in summer. The Trigeneration Master Plan forecast what the energy demands would be by 2030 on a ‘business as usual’ basis to ensure that the Master Plan adopted catered for the 2030 energy demand.

The Trigeneration Master Plan broke the city down into energy demand layers and geographical areas to determine the heating and hot water demands and how much of the electric cooling demands could be converted to heat fired absorption cooling demand. This would have the double benefit of significantly reducing electricity consumption and peak power by switching from electric cooling to thermal cooling. This in turn enabled more local electricity generation from the need for additional waste heat to supply both heating and cooling demands. The Master Plan was then developed into Low Carbon Zones for energy intense inner-city areas, energy intense hot spots outside the inner-city areas (eg, university campuses, etc) and the remainder of the city which would be mainly low rise suburban areas where domestic decentralized energy systems would be more appropriate.

The Trigeneration Master Plan showed that 70% of the City’s electricity demands and 100% of the City’s heating and cooling demands could be met by trigeneration and reduce the City’s greenhouse gas emissions emissions by 31.9%.

Although the initial fuel for the trigeneration network would be natural gas to enable the economic development of the heating and cooling network infrastructure the City resolved in 2012 that by 2030 renewable gases from waste and other renewable energy resources would replace fossil fuel natural gas in the trigeneration systems enabling them to provide carbon free electricity as well as carbon free heating and cooling. The renewable gas resources necessary to deliver this outcome would be included in the Renewable Energy Master Plan.

Renewable Energy Master Plan

The Renewable Energy Master Plan was the second decentralized energy master plan to be developed and adopted by the City in 2013. The Renewable Energy Master Plan established that no more than 18.2% of the city’s electricity demand could be met by renewable electricity generation, primarily solar PV. The reason for this is that cities have very high energy demands and tall buildings whose roofs are small in comparison to the number of energy consuming floors, small geographical area in relation to the city’s energy demands and over-shadowing and pollution haze is more of an issue in cities.

Therefore, the City needed to make up the balance of the 30% renewable electricity generation required from outside the city. However, the City did not want to include renewable electricity generation from Queensland or Victoria or even outback New South Wales whose electricity could never reach Sydney so the City developed a proximity principle that would only include renewable electricity generation within 250km of the city. In practice, enough renewable electricity generation could be sourced within 100-150km of the city to more than make up the 30% renewable electricity generation target. This would also avoid or minimize the very high cost of grid upgrades or reinforcements.

The second stage of the Renewable Energy Master Plan was to identify renewable gas resources derived from waste both inside and within 250km of Sydney. The renewable gas resources identified comprised virtually all forms of waste that are not otherwise recycled, such as from residential and commercial waste, sewage and landfill. Beyond the city, renewable gases can also be sourced from livestock manure, agricultural stubble and husks from crops or non-native forestry off-cut waste. Energy crops and native woodlands were specifically excluded from the Master Plan to avoid any potential land use conflicts with food crops, water and destruction of native woodlands.

The only exceptions to this were oil Mallee crops which play an important role in long-term sustainable farming in low rainfall areas to decrease the salinity levels of the land and bushland fire hazard reduction materials to reduce the current fire hazard reduction burn-offs, with consequential air pollution and adverse health impacts, and the risk of accidental bushfires.

Producing renewable gas from bioenergy, either by anaerobic digestion or gasification, converting into a substitute natural gas for injection into the gas grid for pipelining into the city enables typically 80% of the primary renewable energy resource to be recovered compared with typically only 20% for electricity only generation connected into the electricity grid. The renewable gas resources identified in the Master Plan are all within economic proximity to the gas grid.

The Renewable Energy Master Plan the City of Sydney identified that the total residual municipal solid waste (MSW) and commercial and industrial (C&I) waste resource available in New South Wales within 250 km of the City’s local government area (LGA) but excluding the City’s LGA was around 3.7 million tonnes a year, forecast to grow to 4.6 million tonnes a year by 2030. This was more than enough renewable gas resource required by the City for both trigeneration and other gas uses. Advantages for other local authorities in utilising local advanced waste treatment and renewable gas grid injection plants to meet the City of Sydney’s renewable gas demand would be the virtual elimination of non-recyclable waste going to landfill and the avoidance of the landfill levy which would save local authorities $177 million ($US135 million) a year and businesses $252 million ($US190 million) a year.

Advanced Waste Treatment Master Plan

The Advanced Waste Treatment (AWT) Master Plan was the third decentralized energy master plan to be developed and adopted by the City in 2014. The AWT Master Plan was a subset of the Renewable Energy Master Plan for the renewable gas resources available from the MSW collected by the City and from the C&I waste collected by city business waste contractors. The AWT Master Plan also provided the environmental and financial data to build an advanced waste treatment facility for the City’s own MSW and C&I waste.

The AWT Master Plan demonstrated that the diversion of MSW from landfill would increase from 61% in 2012 to 92% by 2030 and the diversion of C&I waste to landfill would increase from 49% in 2012 to 94% by 2030. Total recycling of MSW and C&I waste would therefore, increase from 52% in 2012 to 94% by 2030. This would reduce greenhouse gas emissions across the City’s LGA by 7% below 2006 levels by 2030. The City and the City’s LGA businesses would also save in the region of $3.9 million ($US3 million) and $18.7 million ($US14.25 million) a year, respectively, in the landfill levy. In addition, using advanced gasification as part of the advanced waste treatment would produce more than enough renewable gas to supply the City of Sydney’s own trigeneration and other gas uses.

Key Energy and Climate Change Targets in Sustainable Sydney 2030 - Source: City of Sydney

Taken together, the Trigeneration, Renewable Energy and Advanced Waste Treatment Master Plans would enable 100% of the City’s electricity, heating and cooling demands to be met by 100% renewable energy resources and reduce 2006 greenhouse gas (GHG) emissions by 74.6% by 2030.

Allan Jones MBE
21 July 2017