Sustainable product innovation and its communication with consumers are essential for the realisation of sustainability through sustainable consumption. Consumers are the receivers of the products developed and the services offered, and they make decisions on the consumption of the products and acceptance of the services. Therefore, it is important to communicate the sustainability information of the products and services to the consumers, to achieve the sustainability goal.
The concept of “sustainable development” emerged from the Brundtland Report 
, which defined the term as “development that meets the needs of present generations without compromising the ability of future generations to meet their own needs”. In 2015, the United Nations published 17 Sustainable Development Goals (SDGs), including targets that address environmental and climate change impacts, socio-economic issues, sustainable innovation, and consumption, which provide support to governments to align their national development plans and policies with the SDGs 
. Driven by sustainability, triple bottom line (TBL), a framework for sustainability that encompasses three dimensions of performance, namely social, environmental, and financial, was brought out as the expansion of the environmental agenda in a way that integrates the economic and social lines 
. In this definition of TBL, profit, people, and the planet are used as the three lines to measure sustainability performance.
Sustainability can be achieved by developing products that are more sustainable than the existing state 
. On one hand, from the perspective of life-cycle management (LCM), the product development phase determines the materials, suppliers, manufacturing methods and costs, as well as the value chain actors during the service phase, which is the most controllable and effective phase to avoid potential sustainability risks and reduce costs 
. For sustainable product and service innovation, the measurement of the environmental and socio-economic performance are significant indications for decision-making, ecolabelling scheme, marketing, etc. Life-cycle assessment (LCA) methodology, including environmental life-cycle assessment (E-LCA) and social life-cycle assessment (S-LCA), is constantly used to assess sustainability performance and determine how well the chosen sustainability requirements have been met 
On the other hand, in the context of TBL sustainability, the other objective of sustainable development is to create value to best meet consumer needs while balancing environmental, social and economic perspectives. However, there are difficulties to achieve sustainability of TBL by simply conducting sustainable product design 
. Sustainable purchase is a bridge between sustainable production and the realisation of sustainability. Therefore, studies to enhance sustainable purchasing are surging, such as creating product–service systems (PSS) that combine a marketable product and service to meet specific consumer needs and create profit for stakeholders, and better communication with consumers with ecolabelling or declaration with sustainable information to support sustainable purchasing. However, further efforts are still required to effectively integrate those methods into sustainable innovation and communicate sustainability to consumers.
2. Sustainable Product Design and Manufacture
Product design and manufacture are the key stages of product development as defined in 
. The literature on sustainable design is reviewed first, followed by the research of the literature on sustainable manufacturing.
Research studies addressing the environmental aspect of product design emerged in the 1990s. Studies in methods and approaches such as “green design” (Dowie, 1994) or “eco-design” investigated the theoretical basis for sustainable design 
. At the same time, life-cycle assessment (LCA), a method originally from the field of environmental engineering, was introduced into the product design discipline by the Society of Environmental Toxicology and Chemistry (SETAC) and the International Standards Organisation (ISO) to measure the environmental profile of products or services throughout their life cycle 
. Environmental impact assessment software tools based on the LCA method have been developed, such as Simapro 
, Gabi 
, openLCA 
, and more reviewed by Su, Ren, and Wu 
, making the implementation of LCA increasingly accessible and feasible. Subsequently, LCA has been considered an evidence-based reference in decision-making during sustainable product development, such as the selection of materials and design concepts, as well as environmental labelling schemes and environmental declarations 
In recent years, numerous studies have been conducted on sustainable product development methods and tools for sustainable design. They focus on a wide range of topics including the selection and evaluation of environment-friendly materials 
, innovation studies on product development with integrated eco-design tools 
, and decision-making support tools and evaluation criteria for sustainable design 
. These studies provide case-specific approaches that aim to reduce the negative environmental impacts of particular products. However, as the dimension of sustainability evolves, the interpretation of a sustainable product goes beyond a product with “recyclable material” or a “green exterior”. Rather, it is an interdisciplinary approach to the creation of new products or services to produce products/services that best meet the needs of consumers while considering environmental, social, and economic perspectives with the best possible coverage. Therefore, a comprehensive sustainable solution within the product life-cycle and supply chain is necessary. Social and economic aspects are also essential aspects to be considered in sustainable design 
. Nevertheless, few studies address the three pillars of sustainability during the product innovation process.
Sustainable manufacturing (SM) is of importance and inevitability amongst industries 
. SM can be described as the implementation of sustainable design. The definition of SM varies amongst researchers. Most definitions emphasise environmental sustainability in the context of the manufacturing process and trade-offs between environmental and economic factors 
. For example, according to the U.S. Department of Commerce, MS is “the production of products using processes that minimise negative environmental impacts, conserve energy and natural resources, are safe for employees, communities, and consumers, and are economically sound” 
. Malek and Desai described SM as the integration of environmental considerations into economic aspects of business that aims to reduce negative impacts during manufacturing processes 
Most of the studies deal with qualitative aspects and focus on a particular aspect or issue and industry. The literature from the automotive industry is the most extensive, followed by the electronics industry 
, which could be due to the high energy consumption of these industries and their products. There are a number of studies on the topic of SM, such as 
. Energy efficiency is the most studied topic by SM, followed by sustainable accounting and auditing. Topics on product design for remanufacturing and recycling and eco-design are also identified in SM studies 
Ahmad et al. reviewed various sustainability indicators for the manufacturing sector and the constant use of these indicators 
. Gbededo et al. conducted a systematic research of the contribution of sustainable manufacturing approaches that sought to address social aspects of SM 
. The study focused on life-cycle sustainability assessment and proposed a roadmap framework for the sustainability assessment of discrete-event simulation. The researchers argued that the production process should be evaluated and optimised based on holistic sustainability goals. However, the choice of assessment indicators is not in line with UNEP guidelines for social life-cycle assessment. Furthermore, the framework requires an established product and site-based manufacturing process to obtain the data for the assessment. Therefore, the design and manufacturing process cannot be easily adapted or optimised to the assessment outcome, not to mention the cost of change.
3. Product–Service System
In the context of TBL sustainability 
, one of the main objectives of sustainable design is to create value and innovation to best meet consumer needs while balancing environmental, social and economic perspectives.
However, barriers have been found and it is difficult to achieve sustainability of TBL by implementing sustainable product design alone 
. The traditional business model of selling products prevents consideration of the potential impacts of the other activities in the life cycle of the product after the sale, as the suppliers profit from selling the products and have no interest in extending the life of the product or reusing/repairing it, thus increasing consumption and disposal more than necessary. A more significant scope for action to promote radical change for sustainable consumption seems to lie in extending the opportunities for innovation beyond the product to a PSS 
A PSS is defined as a system that combines a marketable product and service to meet specific consumer needs 
. A PSS integrates aspects of the physical product side (goods) with an intangible service offering, such as after-sales service including maintenance, repair, and end-of-life service or similar. There are various PSS classifications, see e.g., 
, but three main types of PSS have become established, namely product-oriented PSS, result-oriented PSS and use-oriented PSS 
. Studies show that a PSS has great potential for environmental sustainability, sustainable production, sustainable consumption, and customer satisfaction 
. Therefore, comprehensive sustainable solutions within the product life-cycle and supply chain should cover sustainable development and sustainable service to achieve the TBL of sustainability.
The most recognised benefit of PSS is the reduction of environmental impact, which was agreed on by 62% of research on PSS 
. This effect is also one of the main reasons for developing and implementing a PSS. The PSS concept has been proposed as a way to address and contribute to system-level improvements 
. PSS is designed to extend the life and usefulness of products to enable better utilisation of resources and reduced waste production. From the customer’s perspective, the extended life of products promotes energy efficiency during the consumption phase and also reduces the costs associated with consumption.
From a sustainable development perspective, designers/engineers should consider the environmental impact of a product and service primarily at the design stage, while particular attention needs to be paid to the potential opportunities for reducing environmental impact at the use stage by providing alternative system solutions rather than owning products 
There are policy-driven reasons for business providers and industries to undertake sustainable consumption innovations 
, such as the profit in a sustainable business model for shared value creation. A PSS reduces mass production, which leads to a reduction in manufacturing costs. With the added value to the product, PSS providers can be more competent than traditional product providers in many ways, such as increasing sales, consumer retention and loyalty, and entering new markets. These benefits are based on consumer satisfaction, which promotes socio-economic sustainability.
4. Social Impact
Social sustainability is less developed in TBL and has not received the attention it deserves 
. According to the Western Australia Council of Social Services, “Social sustainability occurs when the formal and informal processes; systems; structures and relationships actively support the capacity of current and future generations to create healthy and liveable communities. Socially sustainable communities are equitable, diverse, connected and democratic, and provide a good quality of life
In recent years, the dimensions of social sustainability are addressed in the decision-making processes 
. However, the development of social sustainability has been less considered in the literature 
. A recent study shows that only 16% (46 out of 279) of sustainability-related indicators consider social performance, while 61% (170 out of 279) measure environmental performance 
. Moreover, few studies capture social performance for product development intentions that can inform the development of new sustainable products or product–service systems 
. A number of studies, such as those in 
, revealed that the same problem exists in SM, the social dimension of sustainability is underrepresented compared to the environmental and economic dimensions of sustainability. The economic dimension is still the topic with the highest percentage in the SM literature. As part of the sustainable product development framework, this is further evidence of the need for a holistic approach to sustainable product development (design and manufacture) that considers the triple bottom line of sustainability.
On the one hand, this may be due to the “intangible” and “complex” nature of social aspects and their interrelationships 
. On the other hand, product developers are still in the dark in terms of the triple bottom line of sustainability 
, especially in how to integrate social aspects and how to incorporate the results of social assessment into product/service design remains a challenge. Consequently, there is a need to explore issues and opportunities from both social and environmental perspectives to design products and services so that potential risks can be mitigated from a more holistic perspective for different stakeholders.
5. Environmental and Social Life-Cycle Assessment in Sustainable Product Development
E-LCA addresses the environmental aspects and potential environmental impacts (e.g., use of resources and environmental consequences of releases) throughout the life cycle of a product, from raw material extraction through production, use, end-of-life treatment, recycling, and final disposal 
. The procedure for conducting an E-LCA consists of four steps: goals and scope definition, in which system boundaries and unit of analysis are set; life-cycle inventory—the collection of all elementary input and output flow from and into the system in terms of resource use and emissions; life-cycle impact assessment (LCIA)—the assessment of impacts associated with the flows in the inventory, covering a wide range of environmental impact categories (such as climate change, acidification, ecotoxicity, etc.); interpretation.
S-LCA is a method for assessing the social impacts of products and services throughout their life cycle, coving supply chain, including use phase and waste treatment. S-LCA has the same assessment procedure as E-LCA, the stakeholder categories, i.e., workers, local communities, society, consumers, and value chain actors, form the basis of an S-LCA assessment as they are the items for which a justification for inclusion or exclusion in the scope must be provided. Associated with the stakeholder categories are the subcategories of impacts that encompass socially significant themes or attributes 
There are a large number of E-LCA studies on sustainable product development and a growing number of S-LCA studies 
. However, E-LCA and S-LCA should be conducted together to understand the rationale for promoting sustainability and to identify opportunities for improvement.
Franze and Ciroth have identified both environmental and social hotspots in the life cycle of a notebook and raised production 
. These are pioneering studies that show early efforts in combining E-LCA and S-LCA. Foolmaun and Ramjeeawon conducted a comparative E-LCA and S-LCA of used polyethene terephthalate (PET) bottles in Mauritius to identify a suitable method of disposal of used PET bottles 
. A software tool was used for E-LCA while three categories of stakeholders and eight subcategories of indicators were examined in the S-LCA study. Agyekum et al. created a simplified S-LCA approach combining a comparative LCA of bicycle frames with a simplified S-LCA due to data limitations 
. Chongyang et al. conducted a comparative environmental and social LCA of manual and mechanical harvesting of sugarcane in Brazil, reporting that mechanical harvesting has better environmental and social performance 
. In a more recent case study, Khorassani et al. developed an S-LCA operational model based on the UNEP/SETAC guideline and a standard E-LCA to identify the environmental and social hotspots in cultural heritage restoration 
. These studies show that the results of E-LCA and S-LCA can be interrelated or completely different, so both dimensions need to be assessed to understand sustainability holistically.
Moreover, E-LCA and/or S-LCA are usually conducted in the last stages of the design process where detailed information to calculate the performance of a product/service can be obtained. However, it is not as flexible and effective as the early design phase (conceptual design phase) in capturing the holistic sustainability of a product. Therefore, it is important to identify risks as early as possible in the design process to address and mitigate them at a lower cost 
. However, when it comes to sustainable design, it is difficult to convert the “uncertain” variables into design requirements 
. The conceptual design phase starts with “product design specifications” (PDS).
6. Sustainable Product Development and Service Approach
From the above research, a systematic approach that covers the whole life-cycle stages and addresses TBL during sustainable product innovation is needed. To overcome the gaps and challenges identified in the previous sections, the researchers proposed the sustainable product development and service (SPDS) approach, to support sustainable products and services with systemic innovation underpinned by interdisciplinary methods and tools 
illustrates the overview of the SPDS approach. This approach is within the framework of life-cycle thinking and life-cycle management (LCM) and is supported by sustainable product development and the PSS methodology 
. Life-cycle thinking considers the product or service’s life cycle as a whole so that any action could have an effect on the entire system of the product or service itself 
. LCM can be described as the application of life-cycle thinking in practice under the life-cycle approach 
. It has been mainly considered as a business management concept aiming to enhance the overall sustainability performance of the business and its value chains in general.
Figure 1. Overview of the SPDS approach.
However, the existing frameworks and concepts exhibit certain shortcomings during the implementation of sustainable innovation. For instance, as a business management concept, LCM focuses on implementing supply chain information and activities. However, it lacks specific methods in terms of sustainable product development. The SPDS approach is supported by various techniques and tools, such as LCA, to provide feedback on sustainability issues. This aids in identifying the opportunities for a specific enterprise to improve the sustainability performance of the new product and service, and to reveal the sustainable performance of the proposed product and service, which is advanced compared to LCM and PSS. Furthermore, the PSS adds a service component to a physical product in business models 
, such as an after-sale service of the existing product, which merely ensures incremental innovation in products and not a complete transformation in the procedure of system development 
. Therefore, to achieve systematic sustainable innovation, both product development and service must be considered simultaneously. For these reasons, the SPDS approach aims to improve sustainability by enabling the development of a sustainable product and service as a bundle to create a systematic sustainable innovation.
The key features of the proposed SPDS approach can be summarised as follows:
As a life-cycle approach developed based on the existing frameworks and approaches, the SPDS is more advanced than the existing LCM and PSS applications.
It considers all stages of the product life-cycle, from product design, manufacture, distribution, retail, use, maintenance, and repair, to EoL.
The TBL of sustainability is addressed in both products and services.
The interaction between product development and service phases enhances sustainability performance.
The SPDS approach covers the entire life cycle of the product, addresses three aspects of the TBL (environmental, social, and economic) and can be adapted according to the individual needs of the business/practitioner. It covers all stages of the product life cycle: design, manufacture, distribution, retail, use, maintenance and repair, and end of life. The first two stages, design and manufacturing, are covered by the sustainable product development phase, while the remaining stages are covered by the sustainable product–service phase.
6.2. Implementing the Approach
Figure 2 illustrates the SPDS implementation process. The approach starts with the definition of sustainable goals. Then, a sustainable product and service conceptual construction is conducted, consisting of data collection, sustainability assessment of in-service products (existing products), and implication of product and service design.
Figure 2. Flowchart implementing the SPDS procedure.
LCA methods, including E-LCA and S-LCA, are both applied. The results obtained from the assessments are analysed and the interlink between the results of E-LCA and S-LCA is identified to determine the evidence-based objectives and opportunities for the assessed case 
. The overlapping results of E-LCA and S-LCA identify the main opportunities for improving overall sustainability. They can therefore be directly applied to the design of sustainable products and services.
The LCA results of the existing product, together with recommendations received from other sources to improve the products, are integrated into the product design specification (PDS). Following the PDS, product design is carried out with an iteration process supported by the design for service (DfS) and service for design (SfD) methods. The DfS considers the service factors (such as facilitating the products repair, recycling and reuse) in the design phase to ensure sustainable features in the service phase of the product. The SfD addresses the issues related to product performance that arise during the product–service phase and provides useful feedback to improve the product. The sustainable characteristics of the product are then determined, followed by the manufacturing process where the appropriate sustainable manufacturing methods are applied.
Since the development of sustainable products and services requires interdisciplinary knowledge, co-creation is carried out based on the knowledge of life-cycle thinking and LCM. Designers and value chain actors will be involved in the co-creation to develop circular economy business models. The aim is to develop a product and service that meets consumer needs and creates value for providers with reduced environmental and social impacts. An application example of a sustainable lighting product and service can be found in studies