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What is a resource flow analysis?

A resource flow analysis aims to quantify the flow of resources, in terms of mass, within a defined geographical area or industry sector over a set period of time. The generic model shown in Figure 2 illustrates the main flows of resources through a defined boundary. A resource flow analysis can point to opportunities for understanding and managing materials consumption and minimisation (Griffiths & Lewis, 2004 & Linstead & Ekins, 2001).

Figure 2
The generic structure of a resource flow analysis

fig 2

PC = Total physical consumption, where certain materials and products are perishable within a year (such as food) and their byproducts are returned to the environment in the form of waste, while the remaining consumption concerns goods and materials likely to remain within the economy for longer periods (such as buildings).

Source: Rodrigues & Giljum, 2004

Resources can be defined as materials or products. Raw materials are extracted from nature and consumed as they are or combined with other materials to produce finished products ( Linstead & Ekins, 2001 and Linstead et al., 2003) . The consumption of materials and products creates waste and emissions as by-products. Resource flows also identify hidden flows, which are materials extracted from nature but not consumed or incorporated into final materials and products (Bringezu & Shutz, 2001; Rodrigues & Giljum, 2004). Therefore, to complete a resource flow analysis of a geographical area it is necessary to quantify:

  • Material imports, production and exports.
  • Product imports, production and exports.
  • Waste production.
  • Hidden flows.
  • Water consumption, and waste water production.
  • Emissions to air.

Resource flow analysis guidelines presented in the Mass Balance UK: Mapping UK resources and material flows (Linstead & Ekins, 2001) were adopted for this project, making the findings comparable to previous mass balance studies. These guidelines were supplemented by mass balance accounting principles agreed on during a Biffaward meeting in April 2003 (Biffaward, 2003).

Calculating stock: Resources remaining in the economy

Stock is materials and products which remain in a region's economy beyond the period of study. Analysis and identification of stock makes a resource flow analysis more complete. To calculate stock changes from one year to another, the volume of stock at the beginning of the study period needs to be known. Unfortunately there is no method of measuring initial stock for a geographical region, other than doing a full resource flow analysis. Therefore, this study did not measure initial stock, but did calculate the change in stock over the reporting period. Stock was calculated as the difference between the input and output of resource flows, and is reported as resources remaining in the economy.