**2. Lean and green manufacturing: environmental impacts**

#### **2.1 Lean manufacturing concept and practices**

Lean manufacturing techniques and methods, which provides higher efficiency than that its successor mass production processes, is based in Toyota Production System [2, 11] and the term 'Lean Production' was first coined by John F. Krafnick [12, 13]. To accomplish the aims like productivity, efficiency, profitability, product diversity, improved product quality, and customer satisfaction at higher levels [2, 14], the most vital practices of lean approach according to several scholars in the literature [5, 15–19], the tools they employ and their main contributions to production are presented in **Table 1**.

These practices, namely just-in-time (JIT), total productive maintenance (TPM), autonomation, value stream mapping (VSM) and kaizen or continuous improvement (CI), have been implemented by manufacturing businesses across the globe to realize the above-mentioned purposes of lean systems.

The five principles of Lean Production concept [1], displayed in **Figure 1**, are established to manage and minimize waste, which in turn protect the environment. Within the context of lean, waste which is considered any activity that does not add value to a product comes in seven main types and eighth types is included by Jeffery K. Liker [24]. These are in the form of overproduction, waiting, unnecessary transport, over processing, excess inventory, unnecessary movement, defects, and unused employee creativity as they are shown in **Table 2** along with their effects on environment.


#### **Table 1.**

*Most Essential Practices of Lean Manufacturing, adapted from [15, 16, 20–23].*

#### **2.2 Green lean concept and principles**

Recently, carbon footprint and the environmental efficiency of the manufacturing companies has been an important topic [25] and green manufacturing concept whose goal is to continually incorporate better environmental conditions of manufacturing operations with the aims of mitigating air, water and land pollution that may pose threats to humans and other species and lessening the use of raw materials and energy, has emerged [26, 27]. It is defined as a series of activities that focuses identifying, measuring, evaluating, and managing the environmental waste created in various areas of production such as designing, manufacturing and planning [28].

Green manufacturing has both product and process perspectives. Concerning the product perspective, green manufacturing intends to produce eco-friendly products, keep the use of resources at a minimum level, and use materials that does not damage the nature. As for process perspective, it aims for minimum consumption of raw materials and energy, minimum dispersion of hazardous substances and minimum generation of waste [29].

#### **Figure 1.**

*Five Principles of Lean Manufacturing, adapted from [1].*


#### **Table 2.**

*Seven Types of Waste and Their Effects, adapted from [14].*

Considering this definition of green manufacturing, lean and green production have common features as both endeavors to diminish waste and to boost the efficiency of production operations [30–34]. Green manufacturing is seen as the positive side-effect [34], a natural extension of lean manufacturing [25] in academic literature.

#### **2.3 Lean manufacturing and its impact on environmental performance**

Since its introduction, lean manufacturing has become a significant model in manufacturing industry as a successful process in contributing to competition capacity of organizations [35]. Nevertheless, the growth in ecological concerns due to climate change, environmental degradation and exhaustion of natural resources has compelled the manufacturing establishments to take steps beyond organizational quality by adopting more environmentally sustainable activities and strategies. Therefore, the study of lean and green production has grown into a crucial component of the environment protection agenda [2, 36, 37] and the relationship between these two concepts along with their impacts on environmental performance captured the attention of scholars.

Most studies refer that lean manufacturing supports environmental performance of organizations. Evidence shows that adoption of lean systems minimizes waste and pollution [32, 34, 38]. With its fundamental principle being zero waste [39], lean manufacturing reduces emissions of contaminants by decreasing

#### *Lean Manufacturing Practices and Environmental Performance DOI: http://dx.doi.org/10.5772/intechopen.96973*

many types of operational waste such as disposed materials and unnecessary use of energy or water [40]. Furthermore, waste reduction aims of lean are inherently ecological such as unnecessary transportation of products or raw materials [27, 31, 37], whose elimination reduces the unnecessary use of resources along with operational costs [31], and overuse of inventory whose reduction has both financial and environmental benefits [25].

In addition, organizations engaged in lean systems tend to embrace environmental innovations [41]. Lean practices result in less pollution through lower marginal cost of activities that aim for pollution reduction or through lower cost of finding new ways of pollution prevention. Research indicates that capacity of improving operations is enhanced by adoption of lean practices [42], and that higher search costs may prevent managers from discovering new opportunities for environmental protection and investing in them [43].

Being a multifaceted concept, lean approach corporate several practices that intends to achieve the objective of efficiency. Among them JIT practices are used the most and considered one of the most beneficial lean practice with its tools serving to show environmental wastes in production [44, 45]. Also, studies show that VSM generates less emissions to air, less energy use, and more savings [46, 47] and positively affects the amount of solid waste, hazardous substances, water consumption and water pollution [48, 49]. As for kaizen, also known as continuous improvement, it detects and removes hidden wastes and ameliorates the amounts of hazardous chemicals use, water use, savings, water pollution, solid waste [48], material use and emissions to air [48, 50]. TPM affects positively the use of materials as it optimizes the condition of production equipment which in turn supports more efficient use of raw materials with less waste [20, 51] whereas JIT reduces the consumption of material through increasing quality by reducing inventory [15, 21, 52]. In addition, Vais et al. [53] confirmed that adoption of lean practices and tools such as 5S, kaizen and autonomous maintenance optimizes the number of resources used and products manufactured which improve the environmental performance of organizations.

In contrast to positive effects of implementing lean practices on environmental performance, some studies show that lean manufacturing adoption may cause negative effects [25, 32, 54, 55]. For instance, a study demonstrated that firms may incorporate lean systems but air emissions of volatile organic compounds during the production is not reduced [56]. Furthermore, it is presented that quality may be improved by way of consuming more hazardous substances to secure rust-proofing [57] and that more frequent trips for delivery of supplies generates more greenhouse gas emissions [58].

However, overall there is a strong evidence that there is a positive opinion on the effects of lean manufacturing on improved ecological performance particularly in the context of continuous improvement and waste reduction. Most scientific work on the subject shows that lean production reduces overuse of material and energy by continuously advancing operational productivity.
