Supporting Coal’s Evolving Role in the Energy Transformation
By Michael Ruszkowski and Stephen Storm, Electric Power Research Institute
The power industry is in the midst of a full-scale energy transformation. Electric utilities are looking at future needs and assets that will provide efficient and safe power production worldwide while maintaining long-standing power-producing assets so they can continue to operate and be maintained during this transformation.
In this transition, coal-fired power plants are being challenged as never before. The traditional providers of baseload power have moved to flexible operations in response to market forces and the need to balance the variable output of solar and wind resources to meet modern society’s need for a reliable supply of economical electricity. Power plants originally designed for baseload operation with maximized efficiency were not designed to operate flexibly, and the change introduces significant challenges in plant management and maintenance.
This article discusses the market forces driving flexible operation of coal assets and how digital and data-driven technologies can improve processes, safety and make people more efficient and effective in addressing challenges such as maintenance and cyber security. A key message is the opportunity for the industry to take an active role in collaborative efforts to apply digital technologies, tools and know-how to support coal’s evolving role in this global energy transformation.
Drivers and Challenges
Flexible operation refers to the ability of a plant to operate at part load, load following and cycling (on and off) modes in response to economic conditions and increased utilization of non-dispatchable generation such as wind and solar assets. Operating conditions under flexible operation can reduce plant efficiency and increase component degradation and maintenance cost and frequency for critical components due to constant swings in operating temperature and pressure. The risks from flexible operation must be properly identified and managed so they can be weighed against the benefits to the plant.
In competitive electricity markets, as a fossil-fired plant ages, it is displaced in the merit order by newer, higher performance capacity generation. As the load factors for thermal plants fall, more cyclic operation increases and greater dependence emerges on successfully securing ancillary services or balancing income to mitigate falls in wholesale market revenues. Therefore, later in a plant’s life cycle, the focus will move increasingly towards maintaining or enhancing asset flexibility. Recent domestic and international market developments and increasing political action to reduce greenhouse gas emissions, including the introduction of carbon pricing in many markets and the rapid growth in intermittent renewable capacity, have accelerated this trend.
Compounding the challenge, utility operations and maintenance (O&M) budgets continue to shrink and utility workforces are in transition. Experienced workers have retired, taking their knowledge with them, and new personnel have to learn to perform multidisciplinary roles at ever higher levels of efficiency and effectiveness.
Against these challenges, digital and data-driven technologies hold the potential for significant benefit when applied to industrial and energy systems. For power generating assets, the integration of digital technologies into technical and business operations can yield significant improvements in efficiency, reliability, performance and cost management, while maintaining a high level of safety.
Digital technologies, such as advanced sensors, offer expanded and accelerated data collection and analysis that can yield a wealth of actionable information to make O&M more efficient and cost effective. This data can support the move to condition-based maintenance to reduce the frequency of equipment downtime and enable technicians to focus on the most important tasks.
Improved control logic and the implementation of automation to processes helps to achieve higher reliability and potentially allow for better response to power demands (e.g., improve ramp rate of units).
Sensors are a key enabling technology and the primary sources of data used to operate generating facilities. Applications for sensor data include monitoring and diagnostics (for example, smart alarming and condition monitoring), process control, data analytics and visualization, performance and optimization and digital worker technologies.
Technologies such as smartphones and augmented reality allow personnel to gather more information and perform their task more efficiently. These technologies are the new tools in a digital worker’s toolboxes. Current and future power industry employees have grown up with technology at their fingertips. These skills can be leveraged to develop more efficient and productive workforces while reducing safety concerns.
With the digital transformation come new hazards regarding cyber security. Industrial control systems are prime targets for cyber attacks that can be planned years in advance and lie dormant within equipment and systems until activated.
Now that data and equipment are routinely accessed remotely, a focused and effective cyber security program is as essential as a focused and effective maintenance program. Communication channels among companies (coal mine, coal transportation, coal power plant) and among employees, OEMs and vendors, must be secured. Moreover, workforces require training on cyber hazard prevention, detection, mitigation and recovery.
For maximum effectiveness, cyber security must transition into an essential embedded design of utility operations and become intrinsic. Plant design changes or system upgrades need to have the cyber-security team engaged as part of the engineering design team. Cyber protection is easier, cheaper and quicker in the initial design plan than trying to backfit it.
Collaborative R&D Yields Valuable Knowledge and Tools
Enabling digital integration requires a comprehensive fundamental understanding of the diverse capabilities of digital technologies, their limitations (with respect to service conditions, environmental factors, physical access, etc.), and the challenges associated with application to generation resources operating in multiple configurations. Similarly, efforts to improve plant flexibility and efficiency require a broad understanding of power plant design, operation, maintenance, ambient conditions, thermal-hydraulics, combustion, plant processes, measurement techniques, controls, materials and fuel types. For both digital integration and operational improvements to be successful, holistic approaches are required to drive the results of any action towards cost-effective, known and acceptable effects on the overall plant.
The Electric Power Research Institute (EPRI) has collaborated with the industry on fossil generation R&D projects since the Institute’s founding 50 years ago. The knowledge, experience and tools developed over the past half century enable EPRI experts to take holistic approaches to optimize plant flexibility and efficiency without causing adverse effects on plant equipment and operation.
EPRI has developed, demonstrated and advanced flexibility improvements via new technologies, hardware, software and cost-effective operating and programmatic practices for enhancing efficiency, flexibility and maximum reliability in fossil power plants. In addition, EPRI has identified and quantified effective solutions for operation along with performance issues associated with adverse effects of these improvements on baseload and flexible operations, heat rate and fuel quality.
EPRI’s collaborative approach to R&D yields valuable knowledge and tools that would be prohibitively costly or impossible to obtain by a single utility or organization.
The following is a partial listing of EPRI R&D results that can be brought to bear on coal asset flexibility challenges.
- Supply Resilience: Generation Hardening, Fuel Supply Assurance, and Generation Adaptation (3002020341)
- Descriptions of Past Research: Enabling Flexible Operation and Impacts of Cycling on Existing and Future Non-Nuclear Generation (3002020394)
- Advanced Thermal Performance Monitoring Methods (3002020702)
- Improving Dispatch Accuracy: Identifying Error Sources in Dispatch Heat Rates (3002020703)
- Evaluating Heat Rate Improvements for Low Load Operation: Combined Cycle and Coal-Fired Power Plants (3002020704)
- Flexible Operations Cost Management Tool: Conventional and Combined Cycle Units (3002020714)
- Methods to Understand the Effect of Heat Rate and Flexibility in Real Time: Conventional and Combined-Cycle Units (3002020715)
- Boiler Flexibility: Boiler Reliability Considerations for Pulverized Coal Fired Steam Generators Operating Under Flexible Operations (3002021205)
- Interrelationships of Heat Rate and Flexibility: NERC GADS–Assessment of 40 Years (3002023069)
In addition, EPRI in 2022 will produce more results including an incremental variable operations and maintenance (VOM) development procedure, flexibility program guidelines, flexibility failure mitigation strategies and a database for economic justification of heat rate and flexibility projects and strategies.
EPRI experts work closely with utility staff to apply these research results in power plants. EPRI also offers knowledge-transfer workshops and training to align people, processes and technologies.
Coal-fired power plants will continue to be required to provide continuity of supply and backup to variable renewable electricity sources. Applying advanced digital technologies and tools can help the industry ensure these traditional plants will be available to respond rapidly and operate reliably and efficiently when called upon to meet society’s need for power in a transforming energy landscape.
Michael Ruszkowski is senior manager for operations & execution and Stephen Storm is a principal technical leader at the Electric Power Research Institute.