This case study explores the principal ethical issues that occur in the use of Smart Information Systems (SIS) in smart grids and offers suggestions as to how they might be addressed. Key issues highlighted in the literature are reviewed. The empirical case study describesone of the largest distribution system operators (DSOs) in the Netherlands . The aim of this case study is to identify which ethical issues arise from the use of SIS in smart grids, the current efforts ofthe organisation to address them, and whether practitioners are facing additional issues not addressed in current literature. The literature review highlights mainly ethical issues around health and safety, privacy and informed consent, cyber-risks and energy security, affordability and equity, sustainability. The key topics raised by interviewees revolved around privacy and to some extent cybersecurity. This may be due to the prevalence of the issue within the sector and the company in particular or due to the positions held by interviewees in the organisation. Issues of sectorial dynamics and public trust, codes of conduct and regulation were raised in the interviewswhich are not discussed in the literature. The paper hence highlights the ability of case studies to identify ethical issues not covered (or covered to an inadequate degree) in the academic literature which are facing practitioners in the energy sector.