Enhancing Efficiency: Gencos explore T&M solutions to improve performance

Testing and measurement (T&M) sol­utions are needed to operate po­wer generation plants safely, produ­cti­vely, and in an environmentally fri­en­dly manner. They play a vital role in extending the asset life and in the early detection of failures, thereby minimising eq­uip­ment outage. The implementation of these solutions involves the de­ployment of sensors, transmitters and related eq­uipment for tracking the desir­ed plant parameters such as water quality, pressure, temperature, flow, emissions, and combustion efficiency. This requires several critical measurements, from combustion performance and water chemis­try to stack emissions, to enhance the op­erational efficiency of power plants, lower emission levels, and optimise operations and maintenance. In renewable energy plants, T&M is helpful in mo­nitoring condition, structural health system architecture, etc. For hydropower projects, especially pumped storage pla­nts, testing is becoming a key focus area for gencos to determine the hydrau­lic/electrical efficiency of the units, fulfil contract guarantees and reduce contractual disputes.

Power Line takes a look at some of the T&M solutions being deployed by gencos…

Thermal power plants

  • Emission and effluent monitoring: For online monitoring of emissions and ef­f­luents, continuous emission mo­nitoring system (CEMS), predictive emissi­on monitoring system (PEMS), conti­nu­ous effluent quality monitoring syst­em (CEQMS) and continuous ambient air quality monitoring system (CAAQMS) technologies are being de­p­loyed by gencos. CEMS/PEMS and CEQMS are real-time air and water pollution monitoring systems respectively. CEMS technology involves the use of SO2, NOx and particulate matter analysers for stack emission while in CEQMS technology pH, TSS and temperature analysers are deployed for effluent mo­ni­toring in all the operating stati­o­ns/units. The Central Pollu­tion Control Board has mandated the installation of CEMS for real-time pollution monitoring of stack emissions and CEQMS for effluent quality monitoring in 17 categories of highly polluting industries, in­cl­uding power plants. Meanwhile, CAAQMS is used for monitoring the ambient air quality in real time. Besides these, mercury analysers are deployed for emission monitoring wherever stipulated.
  • CEMS: It deploys complex extractive analysers, which remove flue gas sa­mples from the duct and use a series of individual gas sensor modules or more advanced spectroscopic techniques to determine the composition. It is preferable to analyse flue gas as close to the combustion pro­cess as possible. Such in-situ analysis can take the form of sensors placed directly in the flue gas, or line-of-sight optical absorption me­a­sure­ments, for which a transmitter and a receiver are placed on either side of the duct or furnace. CEMS technology provides continuous measurement of data on a real-time basis at the mo­ni­t­oring site of interest, and enables immediate corrective/preventive mea­su­res in case of any disturbance. Hen­ce, it can help gather real-time data, and allow plant operators to remotely access plant performance as well as conduct continuous performance checks on air pollution control devices.

In the adoption of CEMS, utilities face challenges in terms of choosing between different monitoring systems and instruments, different su­ppliers and multiple data formats, multiple platforms and communication protocols, and different data collected from heterogeneous systems. To overcome this issue, there is a need to have coherence between central and state regulatory systems, clarity in the CEMS audit protocol and a compliance mechanism.

PEMS: PEMS is the next level of emi­ssion monitoring and does not use hardware-based sensors to measure emissions. It uses unique algorit­h­ms to predict the emissions of a pla­nt, based on the input parameters. While there are standalone versions of PEMS available, these syste­ms are widely used as part of an integrated environmental mo­nitoring approa­ch, capable of ad­d­ressing mul­tiple sources in a plant. Wh­en co­m­bined with data acquisition and handling systems, and integrated in plant-wide IT and communications networks, PEMS can be a viable diagno­stic tool for lowering emissions and improving combustion efficiency.

  • Combustion efficiency: Efficient fuel combustion is essential for cutting op­erating costs and reducing emissions from power plants. For efficient combustion, the ratio of air to fuel is a critical factor. Insufficient air leads to in­co­m­plete combustion, resulting in emission of soot, smoke and carbon mono­xide, while excessive air reduces the overall boiler efficiency. The solution is to measure flue gas oxygen. The level of oxygen present in the combustion of waste gas is a key indicator of the am­ount of air supplied to the process. It can be monitored by using combustion gas oxygen analysers, which accurately measure the oxygen content in the combustion gas. Furthermore, these analysers can be used in conjunction with flow meters to regulate the amo­unt of air supplied to the burner.
  • Boiler efficiency: To achieve the optimum performance of a coal-fired po­wer pla­nt, careful monitoring of the quality of water and steam in the feedwater is essential. Several chemicals ne­ed to be monitored and controlled for optimum steam raising efficiency. Dissolved oxygen in the feedwater can cause pitting in the boiler and reduce its operating life. Dosing the feedwater with hydra­z­ine can reduce oxygen to form nitrogen and water. At high temperatures and pressures, ammonia is formed, which raises the feedwater pH level, increasing the risk of corrosion. Further, silica can hamper heat transfer efficiency and increase the risk of turbine malfu­nction by its precipitation on the bla­des. The solution includes pH ana­lysers for monitoring feedwater acidity or alkalinity. By indicating the le­vel of contamination, the type and du­ration of treatment can be determined.

Renewable energy plants

With the growth of renewable energy ca­pacity, there will be an increase in dema­nd for the T&M of renewable energy eq­uipment including solar cells, solar photovoltaic (PV) modules, and wind tu­rbine generators, besides hydropower plants.

  • Solar: Monitoring of solar PV plants can be done in both ways, that is, by us­ing human workforce or by using re­mote monitoring systems. The monitoring methods to be adopted could va­ry depending upon the size of the power plant and the site at which the plant is located. However, remote monitoring is preferred as it leads to reliable operation, better operations and maintenance, and improved output performance of the PV plant. For this, senso­rs, signal processing units, data tra­ns­mission, data storage and logging facilities, and cloud-integrated data analytics are deployed. These help in condition as well as structural monitoring of solar plants and facilitate plan­ned ma­intenance with deep insight in­to the component failures before they affect energy production.
  • Wind: In case of wind generators, condition monitoring of structural components, such as foundations, blades and towers, is critical, as failure of str­uctural components can affect the operati­onal costs. Offshore wind turbines are particularly exposed to the harsh environments and are at a higher risk. There­fore, it is essential to mo­nitor the structural components to re­duce maintenance costs and avoid catastrophic fa­ilures. Besides this, co­ndition monitoring of wind turbines is important to detect changes in the turbine be­haviour and predict faults so as to mi­nimise performance degradation and cost. The most commonly used se­n­­­sors for wind turbine condition mo­nit­oring include accelerometers, temperature sensors, pressure se­nsors, rotational speed sensors, and cu­rrent clamps.
  • Hydro: In June 2023, the Central Ele­ctricity Authority notified the guideli­nes for field efficiency test in hydro­power plants including pumped storage projects. The guidelines will be ap­plicable to any size/type of unit, comprising a generator–motor, an impul­se/reaction turbine and a pump-turbi­ne with a unit size greater than 5 MW. These gui­delines specify a genera­tor/mo­tor fie­ld efficiency measurement test to verify the efficiency of synchronous generators/induction ma­ch­i­­nes at site; and a turbine/pump efficiency measurement test. For these, instruments inclu­ding flowmeters (to check the flow rate of fluids), thermal detectors (to determine the temperature rise of the liquid coolant) and coolers (calo­rimeters needed for the bearing oil, and for the cooling water of air- or gas-coolers) will be utilised. Further, for measuring electrical quantities, ins­truments such as micro-ohm meters for resistance measurement, digital po­wer analysers, three–phase digital wa­tt­me­ters, and digital multi–function meters shall be utilised.

Remote monitoring systems

Drones are being increasingly deployed to remotely monitor power plants as they can track changes in performance over time. The use of drones for inspection of­f­­ers several advantages such as evaluation of the power plant condition, monitoring of inaccessible areas, reduced plant downtime and maintenance costs, and safety of power plant personnel. Drones are also relevant for monitoring of power stations with flue gas desulph­u­risation equipment. Further, lining failure due to inadequate material quality or faulty workmanship, or even localised da­mage, can lead to immediate corrosion and, possibly, structural damage. During a unit outage, drones can be operated in­side the chimney to provide a comprehensive, high resolution image of the in­ternal lining system.

Gencos are also keenly opting for control solutions that enable them to monitor and control equipment parameters th­rou­gh automation. For example, ML-algorithms have gained traction for intelligent fault detection, predictive maintenance capabilities as well as monitoring of the whole compressor system from the same human-machine interface us­ed for conventional process control. The T&M sector will witness many developments in the coming years due to the path-breaking innovations in recognition technology, artificial intelligence and machi­ne learning. Further, internet of things enabled T&M instruments will gain traction going ahead.


T&M solutions for power plants are necessary to identify and address challenges related to performance in real time. They help in maintaining the operational efficiency of a power plant as well as lowering emission levels. Further, they are useful in enhancing the life of power plant equipment, and in avoiding lapses in preventive and predictive maintenance that can lead to unsafe conditions, system br­eakdown, and revenue loss. However, the right combination of T&M equipment plays a vital role in checking the health of the critical power plant equipment. Go­ing forward, the adoption of comprehensive T&M solutions for power plants will help utilities repair or replace faulty units in real time.