Reliable Backup: Benefits of diesel and gas gensets

Diesel engines and gensets are an important source of reliable back-up power across commercial and industrial (C&I) the consumer segments. Diesel engines, known for their robustness and durability, are suitable for a variety of applications. Various sectors su­ch as railways, marine, mining, building and construction, telecom and data centres rely on diesel engines and gen­sets to meet their power needs and to ensure uninterrupted electricity supply for their operations.

Meanwhile, captive diesel engines and gen­sets offer independence from the main power grid. Captive diesel engines and gensets provide a reliable and customised power solution for entities and operations with specific energy requirements. The capacity of captive diesel en­gines and gensets can be customised ba­sed on the power demands of the faci­lity or operation. They can range from sma­ll-scale units for individual buildings to large-scale systems for industrial facilities, commercial establishments, or re­mo­te communities.

Market trend

As per the Central Electricity Authority, the installed diesel-based captive generation capacity in India stood at 17,700 MW as of March 2022. It accounts for around 21 per cent share in the country’s total captive installed capacity of nearly 82,735 MW (across all fuel sources). The share of diesel-based captive generation capacity has increased by 0.79 per cent from 17,562 MW in March 2021. During 2016-17 to 2021-22, diesel-based captive generation capacity has increas­ed at a compound annual growth rate of 5.8 per cent. During 2021-22, diesel-based captive power plants generated 2,100 GWh of power, recording a decline of 16.13 per cent from 2,504 GWh generated during the previous year.

Based on the kVA range, the Indian diesel genset market is classified into three categories: low, medium and high. The pow­er output of medium kVA diesel generator (DG) sets ranges from 75 to 375 kVA. Th­ey are frequently used in office buildings, shopping centres, ho­tels, major corporations and data ce­ntres. For these enterprises, medium kVA die­sel gensets offer dependable el­ec­­tricity and are a crucial backup op­tion. Due to their inc­reased capacity and capability to ma­nage higher power de­ma­nds, they are pr­eferred over low kVA diesel gen­­se­ts. India’s escalating energy demand and unreliable power infrastructure are attri­buted to the country’s rising use of DGs, especially those wi­th medium kVA capacities.

In India, low kVA DG sets with a capacity of under 75 kVA are common. These generators are used for many different thin­gs, including agriculture, small businesses, rural electrification and backup po­wer for homes and other buildings. They are affordable, easy to install and offer a consistent power source in locations with erratic power supply. Due to their affordability, simplicity of use and portability, low kVA diesel gensets are a common choice for backup power. In the co­ming years, they will play a crucial role in meeting the nation’s expanding energy demand by providing electricity to rural areas and small businesses.

New emission standards

In November 2022, the Central Pollution Control Board, in collaboration with the Ministry of Environment, Forest and Cli­mate Change notified the new emission regulations for diesel gensets. The revis­ed regulations will come into effect from July 1, 2023 and will be applied to all assembled, manufactured and imp­or­ted gensets in India. As per the revised nor­ms, a DG with up to 8 kW of power shall not emit more than 7.5 g per kWh of nitrogen oxides and hydrocarbons. Par­ticulate matter should not exceed 0.3 g kWh and carbon monoxide emissions should not be more than 3.5 g per kWh.

The nitrogen oxide and hydrocarbon emission limitations have been lowered for generators with a power range of 8 kW-19 kW. This restriction, which the board had previously set at 7.5 g per kWh for gensets with power up to 19 kW in 2019, has now been lowered to 4.7 g per kWh. However, the 3.5 g per kWh and 0.7 g per kWh, respectively, carbon monoxide and particulate matter emission limits for this kind of genset remain the same. For gensets between 19 kW and 56 kW, the hydrocarbon, nitrogen oxide and carbon monoxide emission limit is the same (that is, 4.7 g per kWh and 3.5 g per kWh) as the previous category. However, the emission limit of particulate matter for this category is 0.03 g per kWh.

New and emerging trend

Natural gas gensets are quieter and cleaner as compared to diesel-based gen­sets. Natural gas provides much lon­ger runtimes and gensets running on it have 90 per cent fewer emissions compared to DGs. With the increasing environmental concerns related to DGs as well as the rising price of diesel, the sha­re of natural gas-based gensets is expec­ted to grow in the coming years. Natural gas gensets are increasingly being used in states such as Delhi, Gujarat and Ma­ha­rashtra. It has the advantage of being readily available in large cities and is supplied directly through pipelines. In­dra­prastha Gas Limited, which is res­po­n­sible for the supply of compressed natural gas and piped natural gas in the Na­tional Capital Region, has planned to replace DGs with gas gensets in housing complexes and factories, to help address the problem of rising pollution levels. Gas gensets have fewer moving parts and operate at lower temperatures than diesel gensets, requiring less maintenance over their lifetime and costing less to maintain. While natural gas is considered a cleaner alternative to diesel, limited availability and infrastructure for natural gas distribution in many parts of the country hampers the deployment of natural gas-based gensets.

Innovative generators called hybrid/ mu­l­tifuel combine traditional diesel gensets with a renewable energy source such as solar, wind, or biomass. These sy­stems might have a repository. They are dependable and economical, lessen re­liance on pricey diesel fuel, provide cl­e­an energy generation that complies with environmental standards and en­sure co­ntinuous power supply. The most wide­sp­read hybrid technology combines so­lar photovoltaic systems with DG sets. Diesel, petrol, liquefied petroleum gas (LPG) and other co­nventional fuels are co­mbined with renewable energy sou­rces including wi­nd, gas and solar in hybrid generators. They lower fuel costs because only a limited amount of diesel, petrol, etc., is ne­eded for battery charging. They are helpful in locations where getting fuel (die­sel, petrol, LPG, etc.) is challenging.

Digital control is another emerging te­chnology, which improves the per­forma­nce, efficiency and reliability of die­sel engines and gensets. It allows for precise control, remote monitoring, fault diagnostics and integration with other energy systems, ultimately leading to better operation, reduced emissions and enhanced overall system performa­nce. Digital control systems can integ­rate with broader energy management sy­stems, enabling intelligent coordination between multiple power sources such as solar panels, batteries and gen­se­ts. These systems optimise the usage of available power sources, minimise fuel consumption and ensure efficient power distribution. Digital control syste­ms incorporate advanced algorithms to de­tect faults, anomalies, or malfuncti­ons in the engine or genset. By analy­sing sensor data and comparing it with predefined thresholds or models, these systems can identify potential issues and generate fault codes or alerts. This ca­pability simplifies troubleshooting and enhances the reliability and uptime of diesel engines and gensets.

Rental power

Rental power solutions range from stan­d­alone temporary power packages to multi-megawatt units. The diesel segment caters to a significant share of the rental power market. Diesel-based units are witnessing a steady deployment rate, owing to their ability to provide weather-independent, scalable and flexible op­erations. Round-the-clock power ava­i­lability and low up­front costs are some of the key advantages of diesel-based re­ntal power equipment. Moreover, die­sel enhances engine performance and ope­rational efficiency.

Traditionally, DG sets are rented to deal with frequent, unplanned and scheduled power outages, as well as to satisfy additional power demand. The rise of rental DG sets has been attributed to their ease of availability, shorter installation time and relatively lower capex. For operational continuity, residential, commercial and industrial organisations rely on rental power solutions to provide standby power.

DG sets are one of the best options to supply power to places where the po­w­er grid is not available. DG sets are portable and reliable. They are popular for both industrial users as well as sm­aller homes and offices. DGs can res­to­re power su­­pply within a few seconds. DG sets se­r­ve the purpose of both continual and non-continual usage for variable loa­ds/po­­wer demands, particularly for ind­us­tr­ies running motors or ot­her equipment th­at demands varying power during operation.


Given the high reliability of diesel engi­nes and gensets, C&I consumers continue to depend on them for backup pow­er even after the advent of new distributed generation options. How­ever, given the government’s increased focus on emission control, genset manufacturers wo­uld need to continue focusing on the de­velopment of technologies that offer effective emission control and op­timis­ed fuel consumption.