This report focuses on the role of access to modern energy in economic structural transformation - a critical issue both for the least developed countries (LDCs) and for the 2030 Agenda for Sustainable Development. The report focuses on the particular circumstances, challenges and experiences of the LDCs. Second, the report focuses on transformative energy access - an approach to universal access that goes beyond basic household needs to provide the means for structural transformation of LDCs' economies through the development of more productive modern activities and sectors. Third, it shows the role of structural transformation in increasing energy access, by generating sufficient additional demand for electricity for productive uses. Finally, it presents new estimates of the investment costs of universal access to electricity and transformative energy access in LDCs.