s the end of the period is due, according to the authors of the sectoral chapter, to a steep drop in technology and equipment costs and in new-build investment, as saturation in user populations is reached and the vast bulk of spending concentrates on renewals and support maintenance. Indeed, maintenance and renewal spend is assumed to represent by far the largest share (about 80% in 2010 and over 90% in 2020) of annual infrastructure expenditures. The major part of future infrastructure will be in the form of fibre optics and, even more importantly, radio access networks. The largest proportion of infrastructure investment will be devoted to multiple forms of mobile packet radio. Fixed line will act as complementary long distance and feeder access network. Future infrastructure demand is likely to be determined by the increasing economic power of the developing world and by its populations' needs for accessibility - 3.5 billion potential users beyond the 2 billion or SO current users of telecommunications in all forms. Although over the 25-year period OECD countries are likely to account cumulatively for more than half of all global telecom infrastructure investment, spending on infrastructure investment in non-OECD countries is likely to overtake that in OECD countries sometime towards 2020. In consequence, the developing countries and their requirements will begin increasingly to shape future telecommunications infrastructures, and future infrastructure technology could well leapfrog current OECD progress. The architecture of telecommunications infrastructure will move to simpler, less smart networks, with intelligence based at the edges in servers and new devices. Electricity generation and networks Large amounts of investment will be needed in the coming decades to meet the increase in demand for both the quantity and quality of electricity services, as well as to maintain and replace existing infrastructures that will be retired. In a reference scenario, in which no new government policies are assumed, tota