Given the uncertainty surrounding the safety of certain technologies that can help significantly reduce carbon emissions and environmental degradation, it is important for regulatory frameworks and practices to reconcile these safety concerns with the need to harness innovation to address climate- and environment-related threats and risks of irreversible damage. Applying the precautionary principle (PP) is one way to do so. This report contributes to a better understanding of the conditions under which the precautionary principle can support effective decision-making, including the policy choices that are inherent to its use.

For example, as is the case for most nascent technology applications, the use of hydrogen still involves some imperfectly known safety risks. Hydrogen has been used industrially for several decades and much is already known about its behaviour in different scenarios. However, its application in residential use, such as for heating, requires more investigation into safety. Where technology applications involve several risk dimensions, as in the case with hydrogen, the PP should be applied in a way that factors in risk-risk trade-offs holistically. Addressing individual risks in isolation—for instance those relating to climate change, biodiversity loss, and pollution, or water needs in situations of water stress—can hamper useful technological innovation for the energy transition.

Despite its longstanding presence in regulatory discourse, the PP does not have a clear definition. Originally designed for environmental harm prevention, its application has extended to areas such as public and consumer safety. More recently, different regulatory responses to the COVID-19 pandemic showed that, despite similar levels of scientific knowledge and evidence across regulatory regimes, PP interpretation has been far from consistent. Enabling a constructive and appropriate application of the precautionary principle is critical to help bring about an energy transition in line with net-zero emissions policy goals. This report provides governments and regulators with a set of principles and practical guidance for that purpose. It does not imply that OECD members do or should subscribe to the PP. Rather, it provides analysis to rethink the PP in the context of the energy transition. Even for countries, which do not subscribe to the PP or incorporate “precaution” as a founding element of their policies, this report presents important elements regarding the management of conflicting risks and uncertainty in the context of the climate emergency and the energy transition, and as such contains findings and recommendations that are relevant in any case. Thus, while “precaution” and “PP” are kept because of their specific relevance in particular to EU countries, the report’s contents can be read and used independently of this specific wording, as pertaining to risk trade-offs and risk uncertainty.

This report is part of a project requested by the Netherlands on Precaution in the energy transition and improved knowledge for hydrogen risk regulation. The action was funded by the European Union via the Technical Support Instrument, and implemented by the OECD, in co-operation with the Directorate-General for Structural Reform Support of the European Commission. This document was produced with the financial assistance of the European Union. The views expressed herein can in no way be taken to reflect the official opinion of the European Union.

The report was approved by the Regulatory Policy Committee via written procedure on 17 May 2023 and prepared for publication by the Secretariat.

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