As a consequence of the broad spectrum of organisations engaged in inventory compilation there is a range of different approaches taken to emissions estimation by different regions and areas. This has resulted in several fundamental discrepancies within the inventories differences, examples of which include regions that have manipulated boundaries to exclude certain emission sources, and others taking differing views when assigning emissions from the generation of electricity, attributing them to either the location of the power station (source) or the area where the electricity is consumed (end user), among many others. Some approaches  utilise detailed data sets, whereas others employ a purely top down approach to inventory development -where national data is disaggregated to the regional scale by using a factor, such as population or GDP.

These basic inconsistencies are magnified by disparities in the availability of relevant data, the accessibility of data sources and the depth of understanding regarding GHG emissions and sources. The upshot of these differing approaches is a high level of mistrust in the resultant emission figures and inventories.

These disparate approaches make it difficult to make meaningful comparisons and evaluations across the regions, year-on-year or against a national inventory. In order to minimise mistrust, uncertainties and misunderstandings, GRIP is based on a consistent methodology over three data levels, with a reliable calculation of the associated uncertainty at each Level—represented in a colour coded format. The GRIP approach utilises a similar approach to that of the national inventory, while also taking cognisance of the IPCC guidelines governing inventory compilation on a national scale.

In addition, GRIP has also taken account of other methods explored within the UK and abroad at a sub-national level. The GRIP approach is based on five critical principles, making it: Timely in its approach; Adaptable to available data sets; Transparent in nature; Easily replicable; and Presented with a consistent reporting structure. GRIP delivers these guiding principles through a practicable inventory methodology that spans three levels of data intensity, each with its own prescribed level of uncertainty. The system is designed to negate double counting and intrinsically programmed to accommodate differing levels of base data accuracy by utilising its integral uncertainty functionality. This allows GRIP to function in environments of differing data availability.

The tool is available to use by public bodies, making it a cost effective alternative to other inventory packages. By implementing the GRIP approach, regions permit themselves to monitor  their emissions, gauge the effectiveness of mitigation policies and gain insight into emissions drivers. The GRIP approach also enables inter-regional and year-on year comparisons, all delivered in a cost-effective, user friendly manner.

The inventory tool can be found at www.carboncaptured.org.uk

The step by step guide can be found here