In recent years, the term “carbon footprint” of the product has become more and more frequent: governments are developing relevant policies, the media are continuing to report, businesses are actively disclosing and scholars are studying it in depth. It appears to have moved from a professional term to a high-frequency term in the green low-carbon transition. For many, however, it is still difficult to clarify what the carbon footprint of the product is, why it is important and what it is used to do。
What's the product carbon footprint
Turning to carbon emissions in the past, more attention has been paid to how much carbon is released in a region, industry or enterprise. The carbon footprint of the product, on the other hand, is concerned with a specific product: the acquisition, manufacture, transport, sale and maintenance of the material until it is eventually disposed of, resulting in total carbon emissions。
For example, the carbon footprint of a battery, not only how much carbon is released from a battery plant, but also greenhouse gases generated during mining, material processing, parts manufacturing, electricity consumption, transport and even recycling. The carbon footprint of a garment is not only related to the emissions of the garment factory itself, but also to cotton cultivation, fibre-optic production, dye processing, packaging transport and washing and disposal。
Thus, the product's carbon footprint is not the moment the product is on the shelf, but the whole process behind it。
At the national level, product carbon footprint management systems are an important component of the construction of a “two-way carbon emission control” system during the “155” period. This means that the product carbon footprint is not only an accounting issue, but will gradually affect low-carbon product identification, green procurement, green finance, export trade and industrial policy implementation。
For enterprises, the product carbon footprint is also moving from environmental advocacy to market access, supply chain management and the core of international competition。
The most typical example is the eu battery and waste battery regulation. The regulation imposes requirements for the progressive implementation of carbon footprint declarations, performance levels and maximum thresholds for relevant batteries entering the eu market. For batteries exporting to europe, the product carbon footprint is moving from voluntary disclosure to compliance requirements。
More importantly, batteries are probably not the end point, but the starting point. Under the eu green policy system, other products may face similar carbon footprint requirements over time. In the future, the carbon footprint of products will be an important player in international green trade rules, and enterprises will increasingly have to prove that they are not only of good quality but also of good quality。
What about the carbon footprint
Its bottom method is usually derived from life cycle evaluation, the lca. Generally speaking, lca is a “life-cycle environmental book” for the product。
Ideally, each of the processes in the product life cycle should be retrospectively clear, with an understanding of what each process consumes, what is emitted, and then aggregated the ghg emissions from these processes。
Batteries continue to be used as examples: from mining, material processing, component production, battery assembly, transport use, to final recovery treatment, the carbon footprint of the cell can theoretically be aggregated if the amount of greenhouse gas emitted from each process is captured。
But in reality, that is hardly possible。
Modern industrial systems are too complex. A product appears to be simple, with hundreds and thousands of upstream processes behind it. Businesses usually have only their own direct production data, or data from some major suppliers, and it is difficult to trace all the upper layers of the process throughout the life cycle。
The actual data of the enterprise itself can be used for a process that is retrospectively clear, and for processes such as upstream materials, energy, transport and disposal, which are retrospectively unclear and cannot always be recalculated, they need to be replaced by averages or typical values of industry, geographical and time representation. These data are derived from the product carbon footprint factor database。
Here's the factor, which can be simply understood as the “unit carbon footprint” that was calculated earlier. For example, per ton of steel, per kilogram of plastic, and per kilo of electricity, the average carbon emissions from behind are generated under representative industry, region and process conditions。
It should be noted that the “factors” in the product footprint database are generally not the actual data of an enterprise, a production line, a batch, but can represent the average or typical values of an industry, an area, a typical process. It provides, like a public ruler, a unified, credible and traceable base of data for these unretroactive material, energy, transportation and processing processes。
That is why the product carbon footprint database is very difficult to build. In summary, there are four main difficulties: difficulty of coverage, difficulty of connectivity, difficulty of precision, difficulty of regulation。
First difficult: covering difficult
The most misleading point is that the product carbon footprint database can be done slowly in one industry. This year, for example, the battery industry will be refined, the steel industry next year and the chemical industry next year。
This approach may be established for the general industry database, but not for the product carbon footprint factor database。
Because the product's carbon footprint is the entire life cycle. While a product belongs to one industry, it will soon be extended upstream to other industries。
One ton of steel, for example, cannot be counted solely on iron and steel smelting per se, but also on iron ore mining, coke production, limestone supply, heat consumption of electricity, transport processes and by-product processing; on-call electricity, not just electricity generation, but on fuel extraction and transportation, material consumption in operation at power plants, and grid distribution processes. Even the most basic raw materials and energy products are connected to multiple industries and processes。
If the database covers only one industry, the carbon footprint of the product can be cut upstream even if it is done very carefully within the industry。
It's like building a house. A wall cannot be laid, painted and decorated before the foundations, beams, roofs, windows and utilities are considered. A more rational way would be to put together the main structure of the whole house. It may not be sophisticated at first, but at least it can be continued and progressively refined。
The same applies to the product carbon footprint database. The most important of the first phase is not to be extremely sophisticated in a particular industry, but rather to link a sufficient number of industries, products and processes to ensure adequate coverage and to form a basic system that can be calculated. Without adequate coverage, full life cycle calculations cannot be supported。
Second difficulty: difficult to connect
Many think that the product carbon footprint factor database is a table of how much carbon a ton of steel is, how much carbon a kilogram of plastic is, and how much carbon a once-time electricity is。
But the database that really supports the carbon footprint of the product is not a simple product-number correspondence, but an industrial chain network。
For example, the carbon footprint factor for “plastic particles” is not an isolated number. It is backed by crude oil or coal mining, refining or coal-chemicals, production of essential chemicals, polymerization response, electricity and heat consumption, packaging and transport; then it follows up, and inputs such as crude oil, coal, electricity, catalysts and assistants themselves have their own upstream processes. In other words, the underlying factor of a basic material is often linked to energy, chemical, mineral and transport industries。
It follows that the database is not about labelling each product with a carbon label, but rather about building up a set of relationships: “who consumes, who produces, who goes upstream”。
Common factor forms are the address book, just tell you which number a name corresponds to. The product carbon footprint database is more like a traffic map, with roads, directions and connections, not just a location。
If there is no road at the location alone, people cannot reach their destination. Similarly, the carbon footprint of products is incomplete if only product names and isolated factors are not connected upstream or downstream。
It's hard. It's hard
Even though the database covers many industries, upstream and downstream connections have been established, and another problem is encountered: under the same name, in reality, it may be entirely different products and processes。
Irons have long processes of “heavy-turner” as well as short processes of waste steel furnaces; hydrogens of coal, gas, electrolytic hydrogen; methanols of coal, gas, and biomass methanol; aluminium with high carbon footprints and much lower results if produced with hydropower; and plastics with oil routes, coal-chemical routes, recycled materials and bio-based routes。
Therefore, the database cannot simply describe “the steel factor” as “the battery factor” but must indicate which process it corresponds to. It is important not only to give a value but also to clarify what conditions this value applies to。
Iv: normative difficulties
The product carbon footprint factor database does not allow for the collection of numbers. The data are not as good as they are, and the key is to be used in the same set of rules。
Where data boundaries are inconsistent, unit incoherent, regional and temporal attributes are unclear, and quality levels are unclear, even if more numbers are collected, they cannot be calculated directly together。
For example, some factors are counted at the factory entrance only, some include transportation to customers; some by-product emissions are distributed by quality, some by economic value; some are available 10 years ago, some are now; others are available in china and others abroad; and others are measured by enterprises, some by literature or model estimates。
If these data are put together unprocessed, it is like collating statistical tables of different ages, different calibres and different units. On the face of it are numbers that are neither comparable nor aggregated。
More importantly, product carbon footprints are not developed once and for all. The power structure changes, industrial processes progress, raw materials sources change, modes of transport change, and recycling rates increase. The factors that apply today may no longer represent reality in a few years。
Thus, the product carbon footprint factor database is not a static form built on a one-time basis, but a system that requires continuous maintenance. It requires uniform rules, quality evaluation, version management and updating mechanisms。
How do we build it? First the skeleton, then the perfect
The product carbon footprint database is difficult to build, but not impossible. The key is not to interpret it as a one-time collection of data, nor to expect a perfect database from the outset. A more realistic path is to build a calculable foundation, followed by continuous replenishment, correction and optimization。
First, build the skeleton, then finish the details. Implementation of the road to construction begins with addressing the issue of coverage. The construction of a product carbon footprint database will first address the question of “calculability” rather than the pursuit of a few industries and a few products at the outset. The so-called “bone skeleton” is, first and foremost, a sufficiently large industry coverage. Additional details, refinements and reflections of business differences will follow only if a framework of calculation is developed that has a sufficiently large coverage and is largely compatible with upstream and downstream relationships。
Second, build the bottom seat before focusing. Building on the coverage of larger industries, priority is given to public background data that are recurrently found upstream of products such as energy, electricity, steel, colour, chemicals, building materials, agriculture, transport, waste disposal, etc. These are not industry-specific data, but are public floors where a large number of product accounting will be used. The more complete the public base, the more able to calculate. On this basis, priority products such as batteries, photovoltaics, aluminium, cement, plastics, textiles and electronics are being deepened around policy needs, industry needs and international regulatory pressures。
Third, build rules first, then recycle data. In the absence of uniform rules, the more data the greater the confusion. Product classification, system boundaries, functional units, regional attributes, time attributes, process routes, distribution methods, data quality levels, version management and updating mechanisms are clear first. The rule is the syntax of the product's carbon footprint factor database; without grammaticality, it is difficult to make up a reliable computational language。
Fourth, a clear division of labour before convergence. The product carbon footprint database is not a single sector, industry, enterprise alone. Government departments focus on setting rules, building mechanisms, safeguarding public trust; scientific institutions focus on providing methodological, modelling and data quality assessments; industry associations focus on representative data on typical processes in the organization; and enterprises focus on providing real production data and participating in data updating while preserving business secrets。
Fifth, it can be updated before it matures. The mature product carbon footprint database does not begin without a gap, but rather knows where it is and has mechanisms for continuous replenishment. The first edition of the widely used ecoinvent database was published in 2003 and continues to be updated more than two decades later; databases such as uslci and japan's idea are also the result of long-term construction and ongoing maintenance. Database construction is not short-term raids, but long-term iterative. Only through the participation of a wide range of actors can the database be kept close to the real industry。
Concluding remarks
The product carbon footprint factor database is difficult to build, not because of the lack of a few “emission factors”, but because it transforms large industrial systems into a calculable, traceable and up-to-date data infrastructure。
It needs to be broad enough to count; it needs to be connected in order to be complete; it needs to be fine enough to count; and it needs a calibration to be credible。
As a result, the construction of a product carbon footprint factor database cannot take the path “to perfect one industry before another”. A more rational approach would be to build the skeletons, then to complete the details, first to cover, then to refine, first to build rules, then to recycle data, first to clarify the division of labour, then to aggregate, first to be updated and then mature。
Only if we can figure it out first can we be more accurate. The carbon footprint accounting of products does not stop at local emissions only if a full life-cycle calculator is formed。
The creation of a product carbon footprint factor database is not just a matter of calculating how much carbon has been released from a product, but also of justifying low-carbon products, generating returns on emissions reductions from enterprises, mastery of government policies and a bottom line of international competition. It is a foundational project that cannot be seen but cannot be bypassed. The earlier the data base can be calculated, updated and trusted, the more it will support carbon double-control policies, low-carbon industrial development and international green competition in the 15th century。
