Efforts to boost electricity generation in LDCs thus need to be complemented with upgrading of the T&D network. Moreover, the importance of the latter will be further amplified by progress towards universal access and structural transformation, and as increasing penetration of variable renewables increases the need for system balancing and flexibility of the supporting transmission infrastructure. This gives rise to a risk that the poor quality of existing grids might constrain the viability of some technologies, interfering with the choice of the most appropriate power generation mix. As discussed in chapter 1, 82 per cent of people without access to electricity in LDCs live in rural areas, where electrification rates are particularly low; and this rural predominance is likely to persist (figure 3.9).