The Mass Balance Approach

Eine Fläche von rund 64.000 Quadratmetern - das entspricht 13 Fußballfeldern - umfasst der Steamcracker II, die größte einzelne Anlage am Standort Ludwigs­hafen der BASF. Der Cracker ist auch das "Herzstück" der Verbundproduktion. Seit 1981 ist dieser Gigant in Betrieb und spaltet unter Zusatz von Wasserdampf bei etwa 850 Grad Celsius Rohbenzin auf. Dabei entstehen im wesentlichen Ethylen und Propylen, beides unverzichtbare Grundstoffe für die Herstellung vieler Produkte in Ludwigshafen. Abdruck honorarfrei. Copyright by BASF.

Steam cracker II, the largest individual plant at BASF's Ludwigshafen site, covers a surface area of about 64,000 square meters, which is about the size of 13 soccer fields. The steam cracker is also the heart of BASF's Verbund production strategy. This giant plant has been operating since 1981 and uses steam to crack naphtha at about 850°C [1,562°F]. This process leads primarily to ethylene and propylene, both indispensable feedstocks for manufacturing numerous products in Ludwigshafen.Print free of charge. Copyright by BASF.

The chemical industry uses a small number of raw materials to create tens of thousands of different products. The lion’s share of chemical production starts in the steam cracker, where steam is used to split or “crack” naphtha, a long-chain hydrocarbon, into smaller molecules. These molecules then serve as the building blocks for downstream production. They include, for example, hydrogen, methane, ethylene and propylene, which are mainly processed into plastics, coatings, solvents and crop protection products.

Video: BASF's mass balance approach

The principle is therefore similar to when consumers buy “green” or “clean” electricity. Although the consumers cannot be certain that the electricity they use in their homes has come directly from renewable sources, the overall share of green energy in the grid rises in step with demand. In the chemical industry, renewable or recycled feedstock is added at the beginning of the production process and allocated to the end product. This calculation-based principle offers multiple advantages: It reduces greenhouse gas emissions and fossil feedstock inputs, while the quality and properties of a product remain the same. As a result, the products can be processed exactly like conventionally produced materials. There is therefore no need to adapt formulations, plants or processes. And customers who buy mass-balanced products can use them as they would traditional products, while benefiting from the same level of quality.

Independent bodies audit the allocation (i.e., how the volumes of the sustainable raw material are mathematically assigned to the final product). However, at the moment, experts are still using different methods – also known as standards – for auditing and certification.

We engage in collaborating in different stakeholder platforms:

  • Associations, e.g. Joint Task Force on mass balance at European Chemical Industry Council (CEFIC) and PlasticsEurope
  • Certification schemes: Active participant/member in leading scheme givers like ISCC (International Sustainability & Carbon Certification), REDcert, and RSB (Roundtable on Sustainable Biomaterials)
  • Member of different public private partnership initiatives, e.g. Circular Plastics Alliance initiated by the EU Commission, Green Deal initiated by the Dutch government
  • Norming: Member of different working groups like ISO PC 308 (chain of custody), ISO TC 323 (circular economy), ISO TC 207 (environmental management), ISO TC 61 (plastics)

Mass Balance workshop at BASF in Ludwigshafen

More than 90 international experts on recycling and standardization representing industry, nongovernmental organizations, certification bodies and government came together at BASF in Ludwigshafen on September 23, 2019, for a workshop on the mass balance approach. 

Here's the common sense emerging in the discussion: 

• A mass balance approach is needed to ensure a higher use of renewable and recycled feedstocks in the chemical industry

• There is a strong wish of harmonizing voluntary standards

• The brands and industry desired a stable multi-stakeholder standard with a clear label and claim (e.g. ISO/CEN)

• The participants clearly expressed their support for active cooperation in order to achieve the goal of a single standard


Impressions from the workshop on September 23, 2019


Download the Factsheet "Mass Balance Approach - Driving Circularity in Chemical Production" here. 


Download the Whitepaper "Enabling a circular economy for chemicals with the mass balance approach" by the members of the Ellen MacArthur Foundation network

Position of PlasticsEurope on the 2nd Reading of

Download the PlasticsEurope position paper on "Mass balance approach to accelerate the use of renewable feedstocks in chemical processes" here