These methodological guidelines support compiling ERTR accounts in line with the SEEA, while ensuring consistency with data collected in the OECD Revenue Statistics and the OECD PINE database. The practical application of the OECD guidelines was successfully pilot-tested in 2018-2019. The results show that it is feasible to compile ERTR accounts in countries with varying degrees of experience, though their full completion may require additional work. They also show that the guidelines can facilitate the compilation of SEEA-consistent ERTR accounts across OECD countries and beyond.
The feasibility study and two rounds of data collection from OECD and selected non-OECD countries indicate that it is possible to integrate the reporting of ERTR accounts into the WPEI’s regular data collection. Countries that already report ERTR accounts to Eurostat are welcome to report, on a voluntary basis, on the split between revenue from energy and non-energy related GHG emissions taxes, as well as on the four additional memo items. This can help to further align the two approaches (OECD, Eurostat). In the meantime, the accounts compiled using the OECD approach can be made consistent with Eurostat data (though not vice-versa). These methodological differences will require further discussions with Eurostat and international partners with the aim to progressively achieve full harmonisation.
To refine the measurement of ERTR accounts even further, the following points could be explored as part of a research agenda:
Further aligning existing data: The compilation of ERTR accounts provides an opportunity to align data on revenue from environmentally related taxes (and environmentally related fees and charges) with the data collected in the OECD Revenue Statistics and the OECD PINE database, and to better understand the reasons for any differences across these data sources [ENV/EPOC/WPEI(2018)7].
From environmental relevance to environmental costs: The existing approach to identify environmentally related taxes is based on tax bases that are of environmental relevance (see Table 1). This approach has many practical benefits and ensures a sufficient level of “objectivity” necessary for accounting purposes. A related body of literature studies to what extent environmentally related tax rates internalise negative environmental externalities. A dedicated empirical study could explore how closely the ERTR accounts reflect internalisation of negative environmental externalities.
Future extensions of this work could go beyond taxes (the ERTR accounts) and compile information also on the revenue from environmentally related fees and charges. This is important because they are no different in terms of internalising negative environmental externalities; in fact, the environmental economics literature makes no difference between the two and treats fees and charges as equivalent to "taxes".
Another future work stream could focus on subsidies. While the OECD has worked extensively on both environmentally beneficial and environmentally harmful subsidies (OECD, 2005[17]), including the development of an OECD inventory of support measures for fossil fuels (OECD, 2018[18]), compiling accounts on environmentally related subsidies has not been done so far. However, information on environmentally beneficial subsidies is collected in the OECD PINE database and work on environmentally harmful subsidies is on-going at OECD (including support for fossil fuels, fisheries, agriculture and biodiversity-harmful subsidies). Future work could usefully build on these elements for compiling accounts on environmentally related subsidies, including experiences in countries (e.g., Sweden, Italy, New Zealand) and on work done by Eurostat.