What do Australia, the United Kingdom and the United States have in common? They are among the few countries that are linking their national greenhouse gas (GHG) emissions data with GHG data from individual industrial facilities.
What does this mean? It means that these countries are taking advantage of a way to improve their GHG estimates and their GHG reduction strategies. Other countries should follow suit. Here’s why:
There are several types of GHG inventories. Potential linkages exist  between them, but most of those connections are not being tapped. First, some definitions:
A GHG emissions inventory contains a detailed record of GHG emissions, which have been calculated and reported using defined methodologies. Countries, cities, companies, and individual facilities can all perform their own inventories.
A national inventory gives emissions data for an entire country, organized by sectors such as energy and agriculture. Countries have agreed to conduct inventories as part of their participation in the UNFCCC.
A facility inventory is a report of emissions for an individual installation, such as a power plant or a cement factory. Facilities may develop inventories on their own, or to comply with mandatory or voluntary GHG reporting schemes.
Inventories provide a detailed understanding of GHG emissions sources and trends over time, which is necessary to formulate effective strategies to combat climate change. For example, they can help identify GHG “hot spots” for prioritizing mitigation activities that will result in the largest GHG emissions reductions.
Right now, national and facility inventory systems tend to exist independently of each other and involve separate data collection and management processes. National inventories are generally developed using a ‘top-down’ approach in which national data (e.g., on fuel use) are used to derive a country’s emissions footprint. Facility inventories are compiled using a ‘bottom-up’ approach. A facility gathers site-specific data on individual emission sources (e.g., fuel burnt in a kiln in a cement plant) within its boundary to calculate associated emissions.
How can we further improve the national and facility inventory systems? The two systems can, in many cases, be linked to derive mutual benefits. In our recent working paper , we discuss these linkages in more depth.
Two important areas for linkages include:
Utilizing emissions data from facilities in national inventories: For example, the UK national inventory agency has used facility data collected through the EU Emissions Trading Scheme to refine its emissions calculation methods. Information from facilities can improve the overall quality and accuracy of national inventories by providing a means to validate national inventory estimates. In the United States, the Environmental Protection Agency (EPA) has used emissions data from its facility reporting program to improve its national estimates from the natural gas sector.
Sharing institutional resources and technical expertise across the two inventory systems. This can save time and resources. For example, the US EPA tapped the in-house expertise in the national inventory team when developing a program to collect facility emissions data. The agency now houses teams that compile the national inventory and administer the facility reporting system respectively. A similar institutional linkage exists in Australia, where the Department of Climate Change and Energy Efficiency prepares the Australian national GHG inventory and also collects facility data.
Only a few countries are fully capitalizing on these linkages, as a few conditions should be met before facility data can be integrated in national inventories. For example, facility emissions data from a sector can help validate national inventories only when data are available from all the facilities comprising the sector. Moreover, the sectors should be defined in the same way in both the systems. Also, most developing countries do not yet have a system to gather emissions data from facilities. As countries put in place new facility inventory systems, they can explore potential linkages from the beginning.
Inventories are a fundamental tool for countries and facilities to measure and manage their GHG emissions. Establishing these linkages and sharing data between different inventory systems will continue to be critical in improving the quality of inventories, increasing their usefulness, reducing emissions at both the national and facility level, and enhancing their value for decision makers.