Australia is undergoing a significant revolution on the energy mix that powers our cities, towns and industries. The traditional energy supply mix of coal (black and brown) fired based load power stations augmented with liquid or gas fired power stations as well as hydro power stations, has given way to a much more diverse range of power sources. These sources include wind, rooftop solar, utility solar and battery powered to mention some of many (see Figure 1).
As renewable energy sources increase their presence in the National Energy Market, coal fired power stations will be required to burn less coal overall hence improving the carbon emissions profile of the national power system.
Figure 1: Energy Source Types in the Australian Market
These renewable sources have significantly different generation profiles over a 24 hour period and many have seasonal variations. Figure 2 shows the typical generation profiles for the various power sources.
Coal and gas power sources provide true 24 hours per day, 7 days per week base load capability whilst the renewable sources such as solar and wind demonstrate a dependence on their location, local time of day and weather conditions with respect to their output.
Figure 2: Energy Source Generation Fluctuations
The Role of Coal Fired Base Load Power
For modern coal fired power stations the penetration of renewable power sources into the energy mix has effectively meant that the demand profile has changed, with less demand during daylight hours when solar is predominant and more demand in the evenings to the early morning.
This demand loading cycle provided a number of challenges to coal fired power stations. These include issues with turbine and boiler thermal cycles as well as all the supporting ancillary systems which allow modern coal fired power stations to provide the reliable base load power expected by the community.
One of the major challenges resulting from the changing operating demand profile is the need to handle and burn less coal overall whilst improving the power grids carbon footprint. This also adds to other operational requirements to handle coal from the suppliers via all the available transportation systems including road, rail and overland conveyor.
The challenge stems from the changes these demands impose of systems that have been designed or evolved under the previous 24/7 base load paradigm. Many existing power station systems have been operated and maintained during daylight hours and moving these activities to the night time, to match the actual power station demand requirements, represents challenges and opportunities.
These opportunities include:
- Modification of boiler designs and operations to accommodate the changes in power usage profile.
- Alterations to the coal handling systems to allow better stockpile management options.
- Improvement of the overall power station operating efficiency to reflect the lower overall coal demand.
- Minimise combustion products waste streams and maximise recycling opportunities.
Flexibility through Automation Solutions
The changes in power demand on base load coal fired power stations resulting from the significant penetration of renewable energy (especially solar power), require improvements and the operating practices combined with innovation in the use of existing plant and equipment to adapt and thrive in the changing Australian energy market landscape.
Improvements in the automation and usage of existing plant and equipment can lead to significant upside movements in power station performance. This option should be considered as an alternative to the outlay of significant capital for new equipment. These improvements stemming from automation on existing equipment include:
- The ability to operate at high effectiveness at times of maximum demand. Hence improved automation allows optimal operations in a 24 hour cycle where night time operations will see the maximum plant demand. These operations can also be undertaken with minimal increases in operating costs.
- Increased safety through minimising human interaction during non-daylight hours.
- Reducing manning costs resulting from a shift to more intense non-daytime operations.
- The minimisation of capital outlay to achieve improved performance and productivity from existing equipment.
The Possible Future with Automation
Automation in the coal fired power industry can be achieved in a number of practical ways. The main focus of such improvements should be on upgrading existing equipment through the use of automation, as opposed to outlaying capital on new equipment where possible. Areas where this is possible include:
- Automation upgrades for coal handling equipment including bulldozers, stackers and reclaimers, haul trucks and rail haulage systems.
- The use of GPS and other software driven options to improve safety and plant operations reliability. Such system include geo-fencing and improved inventory control through real time stockpile analysis.
- The use of real time analysis and control of the milling, burner and waste combustion products management systems.
Such productivity improvement options need to be rigorously assessed for technical and commercial viability prior to any implementation commitment. Furthermore, this assessment must not only include financial and engineering feasibility dimensions, but must also include the management of change issues associated with the cultural and operational changes that are inherent in upgrading the levels of automation in mature operating sites.
Engenium’s team of specialists welcome the opportunity to discuss how we can add value to your existing assets, from initial concepts and ideas through to commissioning and ongoing support.
Project Manager, Newcastle NSW
Engenium Pty Ltd.