The Covid-19 pandemic and the subsequent lockdown have led to a significant reduction in energy demand, besides changes in the sales mix and the load curve. In the power generation segment, this has resulted in lower utilisation of power plants, reduced maintenance activities, increased flexing requirements and postponement of capacity additions. In view of this, digital solutions are being deployed to support the efforts of the coal-based power generation industry to transition to new models of efficient and sustainable supply. Developers are making digitalisation the core of their operation models.
Another growth driver for the digitalisation of power plants is the increasing commercial viability of digital technology and the emergence of software distribution models, such as software-as-a-service, which is making digital solutions affordable for developers. Apart from this, the use of digital solutions in coal-based power plants can reduce emissions by enabling fuel analysis and better combustion performance, and improve flexibility to effectively manage the impact of cycling and increase the share of renewables. Digital solutions help developers respond to regulatory and market changes promptly, and enable data-driven decision-making.
A suite of digital technologies such as industrial internet of things (IIoT), big data, analytics and artificial intelligence (AI), digital twins, cloud and mobility have been developed and are being applied to power plants. IIoT provides the building blocks of a digital power plant, allowing the collection, transmission, analysis and management of data related to operations, processes and assets. Software, such as artificial neural networks (ANNs) and simulation models, provides tools to identify or predict any issues, and determines the appropriate actions with real-time responses to prevent and resolve the problems. It also maximises potential performance and profitability of assets, power plants and fleets to achieve the best possible outcomes. By using software that understands a machine’s physical capabilities relative to its theoretical potential, deviations from set points can be detected and operating parameters can be adjusted in real time to optimise the operational and environmental performance and minimise production costs.
Digital applications are being used to achieve maximum steam temperature in boilers without violating material limits. Temperature optimisers are robust and easy to parameterise, and are equipped with adaptive state space controllers. They can be used during start-up/shutdown over the entire load range. They can also work as a solution to control the reheat steam temperature. In addition, digital solutions can help in merit order despatch. In a multi-unit plant, it is possible to meet the demand for power and steam in more combinations and attain the optimum capacity utilisation factor by loading more high efficiency machines more and less low efficiency machines.
The concept of a digital twin has gained traction in the power sector. Digital twins provide a platform to simulate and visualise individual equipment, processes and plant operations, and help keep track of the performance and operations and maintenance (O&M) requirements. The cloud provides power producers with computing service over the internet with faster innovation, flexible resources and economies of scale. Data is the main driver in the digitalisation of power plants. AI and machine learning (ML), combined with big data, enable power plants to shift from the existing preventive maintenance systems to predictive and condition-based maintenance. Digital tools can detect anomalies and operational issues, assess the likelihood of asset failures, identify their respective root causes, and recommend quick actions for their resolution. Consequently, forced outages are minimised, uptime is increased, and the lifetime of assets and power plants is extended, leading to reduced O&M costs and improved economic value of the plants. Big data, advanced analytics and AI can provide power producers with insights into the state and performance of assets, processes and operations within a plant as well as system-wide, and help them to make better, faster decisions and maximise the plant’s operational efficiency while responding optimally to the changing grid and power market conditions.
The country’s largest power generator, NTPC is leveraging digital technologies to develop a sustained competitive advantage for the organisation. The utility is taking several digitalisation measures at its 2,000 MW Simhadri super thermal power plant (STPP) in Andhra Pradesh. As a pilot project, new initiatives are under implementation at the Simhadri STPP on a proof-of-concept basis. These include advanced process control, monitoring of stockyard and asset management.
Another digitalisation system under implementation is the advanced management of stockyard (AMS). AMS supports unmanned automatic operation of stacker reclaimers. It provides 3D profiling of the coal stockyard for volumetric analysis. The plant operator can visualise the replica of the coal heap, cross-sectional volume and other details of a particular heap of coal. AMS also enables hotspot detection, automatic sprinkler operation and identification of temperature zones in the stockyard.
NTPC is also implementing advanced asset management, which comprises asset information management, asset performance management, IIoT application in generating units, and the digital worker 3D model, at the Simhadri STPP. NTPC has also introduced the concept of digital worker at the Simhadri STPP, under which smart devices are deployed for field operation rounds, digital helmets are provided for remote assistance and monitoring, and real-time tracking facility is made available. In addition, a three-dimensional digital twin is being used for training and maintenance planning.
Private major Sembcorp Energy India Limited (SEIL) has taken a host of digital initiatives at its TPPs in Andhra Pradesh with an aggregate capacity of 2,640 MW. One of the key measures adopted by the utility is the use of drones for coal inventory management. Digital intervention has reduced the inspection time, outage time and the O&M cost to a greater extent as compared to traditional methods. Connected field force is another digital measure adopted by SEIL, which automates field data. It provides integrated data access for field operators while monitoring the machine health, location route map, communication with the control room as well as computer-aided programmes to monitor abnormalities such as oil leakages, dust accumulation and flames. Another significant digital solution deployed by the utility is the lone worker manager platform, which connects lone, remote and vulnerable workers to an alarm receiving centre via dedicated devices, mobile phones and computer applications.
At Adani Power Limited, all generation assets (including about 12.5 GW of thermal assets) are connected to a cloud platform. The data is collected on a centralised platform and diagnostics are performed from a central location. It is remotely monitoring the performance of all generating assets. Some of the planned initiatives by the genco are advanced analytics (monitor and predict failure of transformers, performance degradation analysis of solar modules, etc.), and VR-based safety training.
In 2017, Nabha Power implemented enterprise resource planning (ERP) and carried out certain non-ERP enhancements (dashboards for O&M, commercial, fuel sourcing, materials management and procurement, finance, and human resource functions). In the following year, the automation of manual processes and business functions was undertaken. Further, in 2019, it implemented analytics-based solutions. In 2020, it plans to use cognitive technologies such as AI, ML, IoT and robotic automation in plant processes. The utility has automated business processes through the use of e-surveillance systems at strategic locations, wagon tippler systems, management information systems, and energy management systems, among other things.
Digitalisation for flexibilisation
Digital solutions can help monitor and enhance the flexibility of a TPP. Common software systems for automatic mill operation (mill scheduler), main steam temperature control, reheat steam temperature control, automated start of fans and pumps, integrated start-up automation, flame detection system, flue gas temperature control, and online coal flow measurement can be deployed by TPPs to aid flexible operations of a power plant.
The installation of condition monitoring systems is also critical for plants undergoing flexible operations as cyclic operations often lead to fatigue and creep in mechanical components, stresses on turbine shells due to changing pressure and temperature, failure of boiler tubes, overheating of reheater and superheater, and cracking in dissimilar metal welds. Condition monitoring can aid the plant operator to constantly monitor these systems and schedule preventive maintenance whenever necessary.
Digital data and analytics can reduce power system costs in at least four ways – by reducing O&M costs; improving power plant and network efficiency; reducing unplanned outages and downtime; and extending the operational lifetime of assets. As digitalisation advances, power plant operations become increasingly dependent on information and communication technologies, which increases the risk of cyberattacks. That said, hardware and software have been developed and implemented to protect energy infrastructure from such attacks. Further, digital solutions based on AI, ML and blockchain for enhanced cybersecurity are under development.
In sum, digitalising coal power plants with innovative technologies will increase their efficiency, affordability, reliability and sustainability.