Acceleration of clean energy innovation, supported by effective innovation policies, is critical for achieving net-zero emissions by 2050, and the technology development in the business sector will be to success. As their ambitions for technological change rise, governments are increasingly asking how they can measure the performance of their energy innovation systems, prioritise technologies and benchmark progress internationally. However, in most countries, information about private energy innovation is much less readily available and less reliable than that for the public sector. In addition, the available approaches to filling this gap have never before been compiled in a single place. By presenting a wide variety of different approaches to tracking clean energy innovation in the business sector, this Overview demonstrates that governments and other analysts already have a range of practical options open to them. For example, the wealth of existing experience with surveys of business sector innovation, including R&D, has been applied to questions of energy by several countries. The different approaches that have been followed provide invaluable insights into their advantages, as well as the main challenges of gathering reliable energy-related innovation data from the private sector. These challenges can include the need for upfront investment, institutional capacity building and consistent classification of technologies. However, the advantages in terms of policy-relevant insights can outweigh the drawbacks, especially when data is complemented by other sources of quantitative and qualitative information.