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Why CCS?

If the rise in global temperatures is to be limited to 2 degrees Celsius in line with global emissions reduction targets, all nations including Australia must meet their emissions reduction targets. To avoid economic disruption, it is essential that this is done in a way that maintains reliability and affordability while reducing emissions.

Coal-fired power plants can supply reliable, low-cost energy, however their carbon dioxide (CO2) emissions need to be reduced.

Renewable energy sources such as wind and solar are clean sources of energy but can cause instability in the power grid due to the variability of the wind and sun. While natural gas has lower (but still significant) emissions than coal and can provide stable energy supply, its price continues to rise.

Australia’s COAL21 Fund is investing in minimising emissions from coal-fired power production and developing carbon capture and storage (CCS) to support cost-effective, reliable and cleaner energy.

THE NEED FOR STABILITY

Australia’s power supply includes a network or grid of power providers and consumers connected by transmission and distribution lines through the National Electricity Market (NEM).

This grid includes the east coast states, Tasmania and South Australia, comprising around 40,000 km of transmission lines and cables and supplying around nine million customers each year.

Grid stability occurs when there is a steady balance between supply and demand which must be maintained through supply responding to demand variations.

For example, Australia generally has higher demand in summer than in winter, daily variations (such as low demand overnight, moderate demand in the middle of the day and peaks in the morning and evening), minute-by-minute variations which occur when nine million customers turn electrical devices on and off, and split-second variations which arise due to faults or other disruptions on the grid.

Australia’s grid stability has traditionally been provided by large power plants (coal, gas and hydro) that can supply electricity in a way that ensures a stable grid. A number of these plants are scheduled for closure.

Renewables such as wind and solar are unable to provide a stable grid due to their highly variable nature. The addition of battery storage or pumped hydro storage to help stabilise their output greatly increases the cost.

As the proportion of total electricity supply from wind and solar increases, the grid becomes increasingly vulnerable to power supply disruptions. If grid stability is sufficiently compromised by having too much variable supply with inadequate back-up, widespread power outages will occur.

RESPONDING TO AUSTRALIAN CONDITIONS

The Australian NEM is not connected to any other region or country and consists of five interconnected state grids.

Each state has unique demand profiles, weather patterns, existing generation plants and natural resources. While the NEM is similar in technical respects to other grids worldwide, it is geographically very different, having relatively low total demand which is spread over a very large area from Cairns in the north, to Hobart in the south and beyond Adelaide to the west.

This results in a grid that carries electricity over large distances with few alternative pathways if a line failure should occur.

Rapid change is placing pressure on the reliability of Australia’s electricity system as it responds to the challenges of climate change through the deployment of highly variable, low- and zero-carbon emissions technologies.

THE ROLE OF CCS IN ACHIEVING A LOW-EMISSIONS FUTURE

While each electricity-generating technology brings its own advantages and disadvantages, diversity of supply using a range of low- and zero-emissions technologies is required to achieve energy security through reliable, affordable, and clean energy.

No single technology can meet this challenge. Coal with CCS offers several valuable attributes that other technologies cannot provide.

Coal plants with CCS can achieve very deep decarbonisation of the electricity grid, reducing emissions while maintaining grid stability.

Coal with CCS is a technology that can provide essential grid stability services over all time frames from the split-second to the seasonal in a predictable and controlled way, while reducing emissions to very low levels at a competitive cost.

TOWARDS A 90 PER CENT EMISSIONS REDUCTION

Research shows that replacing ageing coal-fired power stations with new high-efficiency, low emissions (HELE) plants integrated with carbon capture and storage could reduce emissions by around 90 per cent.

HELE plants have significantly higher efficiency than older coal-fired power stations due to the use of supercritical technology, which refers to the very high temperature and pressure of the steam generated in the power station boiler.

LOWER EMISSIONS, LOWER COSTS AND RELIABLE SUPPLY

HELE technology is integral to the further adoption of CCS because such plants reduce the volume of CO2 to be captured, transported and stored. This means that higher-efficiency plants require smaller capacity CCS units, resulting in reduced capital costs.

Such an approach – which could be combined with renewable energies like wind, solar and hydro power as part of a long-term plan – would deliver reliable electricity supplies at affordable prices while meeting Australia’s emissions reduction targets.

New plant is increasingly being built to be CCS ready. CCS is recognised by the United Nations, International Energy Agency (IEA) and many countries as a crucial technology for both energy security and emissions reduction over this century. Read the IEA’s Technology Roadmap: High-Efficiency, Low-Emissions Coal-Fired Power Generation’.

Comparison of Energy Sources: Long-Term Supply Planning

NOW

Reliability

  • Coal
  • Gas
  • Wind/Solar (No Back-up)

Emissions

  • Coal
  • Gas
  • Wind/Solar

Cost

  • Coal
  • Gas
  • Wind/Solar

Today we generate our most reliable energy supply using coal. Coal costs less than gas or renewables but generates the highest emissions.

2020 – 2030

Reliability

  • Coal
  • Gas
  • Wind/Solar (Battery Back-up)

Emissions

  • Coal
  • Gas
  • Wind/Solar

Cost

  • Coal
  • Gas
  • Wind/Solar

The use of high efficiency, low emission (HELE) coal-fired power plants would reduce emissions by up to 20%. While generating fewer emissions than coal, gas will continue to cost more due to the price of gas, and the cost of wind and solar will have to increase significantly to deliver reliable supply through battery storage.

2030 – 2050

Reliability

  • Coal
  • Gas
  • Wind/Solar (Pumped Hydro Back-up)

Emissions

  • Coal
  • Gas
  • Wind/Solar

Cost

  • Coal
  • Gas
  • Wind/Solar

The use of high efficiency, low emission (HELE) coal-fired power plants with CCS will provide low emissions at the least cost. It will cost more to integrate CCS with gas power plants, and while wind and solar using pumped hydro storage will cost less than battery storage, the cost will still be higher than HELE with CCS.

Note:

The scale from low to high is indicative and for comparison purposes only. Actual values can be found in the Prospects for a HELE USC Coal-fired Power Station Report.

While wind and solar do not produce emissions when generating electricity, the production of steel and concrete required for their construction, along with maintenance crews driving to and from site, create indirect emissions. All electricity generation technologies, including wind and solar, generate indirect emissions.

HELE WITH CCS EMISSIONS REDUCTION

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