Energy efficiency in motor vehicle assembly plant : a case study of a vehicle assembly plant in Kenya.

Abstract

Energy is defined as the capacity to do work and comes in various forms such as motion, heat, light, electrical, chemical, nuclear, and gravitational. There are two forms of energy: primary energy which is extracted or captured directly from the environment and secondary energy which is converted from primary energy in the form of electricity. Energy efficiency means a physical ratio of output and input of a system. Efficiency refers to valuable work obtained from a process or system when related to the total energy input; it is, therefore, an indication of the performance of a device in energy use terms. The industrial sector is the largest consumer of energy globally and this is the case too in Kenya. The major forms of energy used in Kenyan industries are electricity, diesel oil, compressed air, steam and solar energy. Energy in industries is used for various activities such as heating and cooling, lighting, processing, manufacturing, air conditioning and assembly; a lot of energy is lost during these operations due to poor maintenance of machines, poor management, misuse and mishandling of equipment, bad attitude and lack of knowledge among workers. In vehicle assembly plants energy is used in heating, welding, assembly, lighting, painting and office work. The major types of energy used in vehicle assembly plant are compressed air, electricity, industrial oil and diesel. These industry sectors face a lot of challenges because many cars used in Kenya are imported from Japan because the locally assembled cars are more expensive although they are durable. Among the factors which make them expensive includes raw material, payment of salaries and wages, process of assembly, and heavy payment of bills. The major bills in many industries after payment of salaries are energy bills for electricity, diesel and industrial oil. The cost of electricity and diesel in Kenya is escalating due to high demand and low supply, thus making locally made items more expensive than imported ones. Industries in Kenya are struggling to adopt new manufacturing processes and designs to cut down operating costs and improve the quality of products to meet the competitive demand. The same case applies to the automobile assembly industry; they are trying to come up with new designs and models to increase sales, but are forgetting to pay attention to methods of reducing energy costs. Energy efficiency in many industries remains silent and this is because the issue of balancing the operation costs and investing in energy efficiency is only remembered when the bills climb high. Many researches have concentrated on improving the design of assembly lines, changeover of machines and equipment to improve the system, but little has been researched regarding the energy used during the assembly of the vehicles. As manufacturers face an increasingly competitive environment, energy efficiency management can provide a means to create a good reputation for the company, hence increase its sales, but also a method for reducing energy costs. The aim of the present study is to contribute to improvement in energy efficiency in automotive industries by estimating the amount of energy used and lost by various equipment, identifying the barriers to energy efficiency and the driving forces inhibiting or preventing implementation of energy efficiency measures, and providing recommendations on useful energy efficiency opportunities and maintenance measures. The study was carried out in one of the four major automotive assembly plants in Kenya. Questionnaires, observation, measurements, oral interviews and audits were used to collect data. From the analysis, welding machines and fans are the major consumers of electrical energy with an approximate of 45 % and 17 % respectively. Burners and generators are the major consumers of oil with 73 % and 15 % respectively. From observation, the use of aged equipment, lack of training and ignorance among employees are the major causes of energy loss. Idling of machines, leaks, dust and faulty lamps are the major source of energy loss in the plant. It is recommended to clean, switch off, train workers and do proper maintenance. The research study was able to estimate the amount of energy used and lost in various machines and equipment and various recommendations were given. It was concluded that, to improve on energy management in this motor vehicle assembly plant, energy management should be treated equally in importance with production and sales.