Automation, the Industrial Internet of Things (IIoT) and renewable energy sources provide the capabilities required to build smart electricity grids that manage the increasing complexity of electricity demand, generation and distribution. Most businesses cannot afford constant new capital investments, and a study by The Manufacturer’s Organisation found that the UK’s gross fixed capital formation as a share of manufacturing value-added was only 15 per cent in 2015. This means smart grid infrastructure must be designed to remain functional for many decades which will require forecasting of changes in electricity demand, generation and distribution by analysing data from multiple stages across the grid.
Instead of investing in replacements for every part of the grid, more affordable new technology can be retrofitted to existing infrastructure to add smart functionality. For example, sensors can be retrofitted to transformers to allow voltage optimisation. These smart transformers provide the exact amount of power needed and respond instantly to fluctuations in the grid.
Engineers designing the smart grid must concentrate on the components of the existing grid that are at the greatest risk of becoming obsolete.
Britain’s grid was not designed to supply the huge amount of electricity that we now use. Because the UK does not have enough new power stations to meet demand, it still relies on older power stations to deliver the remaining power. The problem is that these old plants are highly inefficient and upgrades and maintenance are essential for improving their efficiency and functionality, to prevent them from becoming obsolete in the future.
Substations also have issues with obsolescence, mainly due to their age and the amount of operation they have had. Moving parts experience wear over time, causing parts such as insulation to degrade. Many substation assets have paper insulation, for which degradation is irreversible.
Future Intelligent Transmission Network Substation (FITNESS) is a project intended to upgrade substations in Britain by digitalising them, allowing greater protection, monitoring and control of transmission lines. The substations will employ standardisation and interoperability, meaning all appliances, technologies and connections will be compatible with the rest of the infrastructure — future proofing the grid.
In addition to deterioration over time, unavailability of spare parts contributes to the obsolescence of substations. For example, SF6 circuit breakers have become obsolete due to their complicated construction and the need for various auxiliary equipment such as compressors and control devices. Protective relays are another component of the grid at risk of obsolescence due to a shortage of spare parts. Many protective relays are nearing the end of their operational life and National Grid estimates that approximately ten per cent of electromechanical and solid-state protective relays will need to be replaced in the coming years.
Obsolescence is not an issue exclusively for old equipment. Since the Hinkley Point C nuclear plant was proposed in 2010, power from more environmentally friendly sources such as wind, solar and hydroelectric energy has become more affordable, efficient and popular. A 2016 analysis by University College London predicted that the nuclear plant, which is expected to begin operating in the 2020s, will be outpaced by environmentally friendly energy sources, rendering it obsolete by its tenth year of operation.
Power from renewable sources is likely to be an important part of the smart grid. To avoid obsolescence, designers of the smart grid must consider how renewable power will integrate into existing infrastructure.
Renewable energy is highly intermittent — solar power is only generated during sunlight hours and wind power is only generated on windy days. This variability means a complex, intelligent system will be required to ensure that total power generation sufficiently meets demand. For example, when wind levels drop, an alternative energy source must increase power production to make up for the reduction in wind power. Better integration of sensor technology, PLCs and actuators will also help to translate power needs at a regional level, into control actions at a local level that can be used to respond more quickly to power demand during the day.
Another trend that is becoming popular in the renewable sector is to go off-grid entirely, using localised microgeneration rather than centralised power stations. Here, smaller renewable sites can be used to generate enough power to supply local areas rather than centralised power stations that generate electricity for an entire region. In smart microgrids, centralised power plants may be repurposed to provide back-up supply, instead of becoming obsolete.
As well as integrating new physical assets into the existing infrastructure, a smart grid will require software that can monitor and control the entire grid.
Smart grids rely on vast amounts of real-time data to control power generation and distribution in accordance with demand. Software such as COPA-DATA’s zenon offers a way of gathering and analysing this data automatically. zenon is an industrial automation application that incorporates a Supervisory Control and Data Acquisition (SCADA) system and a human-machine interface (HMI). Such a system could automatically collect data from an entire smart grid, control grid operations and provide an interface for workers to interact with.
National Grid previously used two SCADA systems. However, by 2003, they were incapable of handling the increased demand for real-time data and control capacity. The company implemented a new energy management system (EMS) provided by GE Energy Management, to manage the entire grid. This system consists of hardware and software that can be upgraded as required, demonstrating that thought is already being given to obsolescence.
The demand for electricity and the way it is consumed is expected to continue changing. National Grid’s new EMS is well equipped for the increasing electricity demand because it can support over 150 dedicated user consoles and a database of 1.2 million points. Advancements in technology will give rise to decreased latency and increased bandwidth of communication. Therefore, the smart grid must be built to cope with lower latencies and higher bandwidths than are currently possible, to ensure that it does not become obsolete.
The electricity grid infrastructure that Britain built in the mid to late 1900s does not need to become obsolete. By keeping obsolescence in mind, we can make our energy grids smart without completely overhauling them.
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