Optimal Design: Measures to increase energy efficiency in industries

Measures to increase energy efficiency in industries

In India, industrial use accounts for the majority of energy consumption at present. There is a lot of scope for reduction in industrial energy consumption while increasing operational efficiency. Implementing best energy practices across industries will save substantial costs, improve operational efficiency and enhance the safety of the establishment. Energy optimisation in industries provides benefits such as reduced energy usage, decreased fuel consumption, increased revenue, improved safety and enhanced sustainability.

The potential measures to increase energy efficiency in industries can broadly be classified as replacement of energy-inefficient equipment, improvement in manufacturing-related planning, integration of efficient captive energy systems (waste heat recovery, cogeneration, etc.) and deployment of energy efficient systems.

Energy efficient equipment

According to several industry experts, equipment related to compressed air, heat and steam, and electromechanical systems such as motors and drives have a huge potential for improved energy efficiency. Since equipment entails a huge upfront capital expenditure, industries often purchase low efficiency energy equipment to reduce the cost of equipment. However, this less efficient equipment costs more over its lifetime owing to increased operational and maintenance costs, making it more commercially viable to procure energy efficient equipment.

Motors and drives are responsible for approximately 28 per cent of the total electricity consumption and 70 per cent of the industrial electricity consumption. Apart from this, 38-40 per cent of commercial consumption is attributable to motors and drives. Despite all these factors, 98 per cent of Indian motors are of sub-IE2 grade (very inefficient) leading to higher energy costs over their lifetime. According to some studies, the energy cost of running an electric motor over 10 years is at least 30 times the original purchase cost of the motor.

Today, there is industry-specific efficiency enhancing equipment available in the market. This equipment can significantly reduce energy costs. For example, multiport dryers, in place of conventional dryers, in paper machines can reduce steam consumption in paper manufacturing plants to a substantial degree. These multiport dryers will increase the rate of pulp drying via uniform temperature distribution along the cylinder walls. Similarly, closed condensate recovery pumps in textile plants help in mechanically recovering the condensate discharged by the plant and resupplying it to the boiler feedwater tank, thereby recovering 15-20 per cent of the steam/heat that would otherwise be redundant.

Energy efficient systems using IoT, ML and AI

In recent years, several components in electrical systems have been embedded with internet of things (IoT) to relay information in real time so as to modulate the equipment as well as aid rapid detection of issues in components. According to some sources, an IoT-enabled energy management system will help save 20-30 per cent of electricity costs in industrial units. Additionally, IoT systems are supported by artificial intelligence (AI) and machine learning (ML), which supply analytical insights to improve performance. Furthermore, they help managers simulate operations and make better decisions.

Integrating IoT-based machines supplemented by ML/AI algorithms will also help industrial units in forecasting and optimising energy consumption. The AI/ML algorithm will gather and analyse historical day-to-day data of various parameters such as temperature and lighting within an industrial unit to create a predictive model forecasting optimal energy in the future.

Captive energy systems

There are many industrial units that discharge and emit enormous volumes of unexploited steam and unused heat. The heat/steam released without any treatment is environmentally pernicious and energy inefficient. Hence, there are many industries such as paper, steel and cement that are developing captive cogeneration capacity using the heat discharged by the plant to generate electricity. For instance, there is a cement plant in Nalgonda, Andhra Pradesh, that used to purchase 15 MW of electricity annually to operate. However, following the installation of a waste heat recovery system in the plant, it began independently generating 12.28 MW of electricity using preheater and cooler vent gases. Captive energy systems are also a possible way of increasing the efficiency of industrial units as they increase the energy available at a unit’s disposal while other suggested methods help in optimising electricity consumption.

Improvement in manufacturing-related planning

There are several manufacturing plants and industrial units that are designed suboptimally with inefficient alignment of processes or parts contributing to higher energy consumption.  In recent years, several companies have developed integrated simulation tools analysing the level of automation and the environmental impact and ergonomics of manufacturing systems. These systems help manufacturing system design engineers in determining the correct system of alignment. Often, many industrial units overlook their energy consumption peaks while designing their processes, manufacturing systems and operations, leading to energy consumption peaks and consequently peak surcharges. Furthermore, such peaks lead to higher operating costs and inefficient energy consumption.

Each of the components within the system contributes to the smooth functioning of the system. Energy consumption is reduced when overdesign is avoided and valuable resources can be saved. Simulation coupled with modelling enables a quick comparison of various layouts possible, and this helps the manufacturers find the most suitable configuration.

Government regulations and PAT programme

The Energy Conservation (EC) Act, 2001, makes energy audits mandatory for industries notified as designated consumers of energy. This has helped identify various energy-saving opportunities in energy-intensive industries and other establishments. Many state governments provide financial support on the cost of audit for both water and energy conservation projects. In addition, a policy initiative to rate MSMEs on quality control and provide certification for energy efficiency, called the ZED (Zero Effect Zero Defect) Maturity Assessment Model, has enhanced resource efficiency. The Bureau of Energy Efficiency (BEE) assists MSMEs in improving their efficiency, which is a major factor constraining their profitability and growth in comparison to their large-scale counterparts.

The Perform, Achieve and Trade (PAT) scheme aims to reduce specific energy consumption in energy-intensive industries in a specified time frame. It includes a market-based mechanism that enables companies to trade excess energy savings via energy saving certificates. The mandated decrease in specific energy consumption under the PAT programme has led to a substantial decline in energy consumption in several industries.

The PAT scheme is a key programme for large industries and establishments. The scheme aims to enhance the cost-effectiveness of energy savings by upgrading technologies or by taking in-house actions to minimise energy consumption. It provides mandatory targets for identified large units and the excess energy saved by them is issued as energy saving certificates, which are tradable instruments. The different industries and establishments are assigned energy efficiency targets based on their levels of energy consumption and potential for energy savings.

Overall, the biggest achievement under PAT has been the change in industry perspective on energy efficiency. Cumulatively, the first two PAT cycles have saved about 97 million tonnes (mt) of CO2 emissions as against the objective to save 550 mt of CO2 by 2030 under all the schemes so that the country can achieve its targets under the Paris Agreement.

The way forward

Manufacturing units in India that account for vast volumes of energy consumption, can improve their energy efficiency and reduce their energy costs as well as emissions by deploying energy optimal designs, processes and machines. These units can be positively complemented by embedding IoT-based technologies supported by AI/ML in the components of the manufacturing units, which will enhance their effectiveness. In addition, the energy efficiency programmes pioneered by BEE with its superior incentive structures will accelerate the adoption and installation of energy efficient equipment. n