With 1.4 bil­lion peo­ple lack­ing elec­tric­i­ty to light their homes and pro­vide oth­er basic ser­vices, or to con­duct busi­ness, and all of human­i­ty (and par­tic­u­lar­ly the poor) are in need of a decar­bonized ener­gy sys­tem can close the ener­gy access gap and pro­tect the glob­al cli­mate sys­tem. With par­tic­u­lar focus on address­ing the ener­gy needs of the under­served, we present an ana­lyt­i­cal frame­work informed by his­tor­i­cal trends and con­tem­po­rary tech­no­log­i­cal, social, and insti­tu­tion­al con­di­tions that clar­i­fies the het­ero­ge­neous con­tin­u­um of cen­tral­ized on-grid elec­tric­i­ty, autonomous mini- or com­mu­ni­ty grids, and dis­trib­uted, indi­vid­ual ener­gy ser­vices. We find that the cur­rent day is a unique moment of inno­va­tion in decen­tral­ized ener­gy net­works based on super-effi­cient end-use tech­nol­o­gy and low-cost pho­to­voltaics, sup­port­ed by rapid­ly spread­ing infor­ma­tion tech­nol­o­gy, par­tic­u­lar­ly mobile phones. Col­lec­tive­ly these dis­rup­tive tech­nol­o­gy sys­tems could rapid­ly increase ener­gy access, con­tribut­ing to meet­ing the Mil­len­ni­um Devel­op­ment Goals for qual­i­ty of life, while simul­ta­ne­ous­ly dri­ving action towards low-car­bon, Earth-sus­tain­ing, ener­gy systems.