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A big leap for microgrids

Technological advancements in renewable energy and battery storage are contributing to the microgrids success story

Microgrids are starting to usurp the role of bespoke networks in remote locations that are isolated from centralised and established grid and power systems. Such localised networks connect a number of energy resources and loads, and can be used in off-grid applications. They can also connect to, draw from and provide services to the grid, at times when the network is under strain.

While microgrids have existed for decades, interest in them is rising because users benefit from the falling cost of renewable and storage technologies. Other advantages are the growing ability to monitor and manage power flows across networks and avoid the network costs associated with centralised generation, while ensuring reliable and secure power.

Trading with the grid helps a microgrid operator reduce costs and increase the resilience of the grid itself. The ability to disconnect ensures greater energy security for those connected to the microgrid.

The energy resource of a microgrid typically consist of renewables, gas or diesel-fired generating units and storage. Examples can be found in off-grid and remote locations, but also within sites that share interests, such as university campuses, military compounds, industrial estates and, increasingly, residential areas.

In the oil and gas sector, microgrids complement and streamline operations. In Western Australia, Woodside plans to deploy a lithium ion battery on its offshore Goodwyn A platform to provide spinning reserve services. This battery will replace one of its gas turbines and reduce the need to use the emergency diesel generator. This, in turn, will enable Woodside to sell additional gas and reduce expenditure on diesel and maintenance, aside from reducing greenhouse gas emissions.

Further afield, a more complex example of microgrid use is the integration and co-ordination of 2.2 gigawatts of gas-fired generation at Saudi Aramco's Shaybah facility in the kingdom's remote Empty Quarter. The super-giant oilfield, Shaybah was brought online in 1998 and uses 18 combined-cycle gas turbines to power its one natural gas liquid plant and four gas-oil separation facilities.

The Shaybah power units are centrally controlled and can split into 10 viable islands. Such systems need to maintain frequency and voltage control in the same way as a utility-scale network. But significantly less high-order monitoring and control functions, such as fast load or generation shedding, need to be in place to ensure sufficient system stability.

Microgrids are also being deployed by island nations to help provide more reliable power needs and enable them to tap into emerging, clean-energy technologies. Australia-based Carnegie Clean Energy has been pioneering the installation of discrete energy systems made up of distributed energy sources. These can operate independently of the main power grid.

Carnegie's renewable microgrids combine multiple renewable-energy-generation sources, including solar and wave energy, with battery storage. This combination reduces the reliance on fossil fuels and traditional forms of energy to supply reliable 24/7 power. The company has rolled out such microgrids in the Mackerel Islands and Garden Island, offshore Western Australia.

In general, microgrids can enhance a user's power supply arrangements by pursuing more economically-viable solutions while maintaining high levels of reliability. Given the spread of electrification and electric vehicles, microgrids can help address simple-to-complex problems and be scaled up over time.

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