▁has ▁either ▁purchased ▁a ▁plant ▁or ▁passed ▁on ▁their ▁opportunity ▁to ▁bid ▁on ▁a ▁plant . ▁Most ▁power ▁plants ▁require ▁one ▁or ▁a ▁combination ▁of ▁resources : ▁coal , ▁oil , ▁garbage ▁( see ▁waste ▁to ▁energy ), ▁and ▁u ran ium , ▁in ▁order ▁to ▁supply ▁electric ity . ▁Wind ▁tur b ines ▁and ▁hyd ra ul ic ▁plants ▁do ▁not ▁require ▁resources . ▁ ▁Ph ase ▁ 3 — ▁Bu ying ▁Resources ▁In ▁reverse ▁turn ▁order , ▁players ▁can ▁buy ▁resources ▁for ▁their ▁plants . ▁Play ers ▁may ▁only ▁purch ases ▁resources ▁they ▁can ▁use , ▁and ▁each ▁plant ▁may ▁only ▁hold ▁twice ▁the ▁number ▁of ▁resources ▁it ▁needs ▁to ▁run . ▁Thus ▁a ▁plant ▁that ▁uses ▁two ▁oil ▁may ▁hold ▁up ▁to ▁four ▁oil . ▁As ▁resources ▁are ▁purchased , ▁they ▁become ▁more ▁expensive , ▁thus ▁the ▁person ▁who ▁is ▁last ▁in ▁turn ▁order ▁can ▁buy ▁resources ▁at ▁the ▁che apest ▁prices ▁for ▁that ▁round . ▁ ▁Ph ase ▁ 4 — ▁Building ▁In ▁reverse ▁turn ▁order , ▁players ▁may ▁build ▁into ▁cities . ▁In ▁the ▁first ▁round , ▁a ▁player ▁may ▁choose ▁to ▁build ▁into ▁any ▁city ▁that ▁is ▁not ▁already ▁occupied . ▁A ▁player ▁may ▁continue ▁to ▁expand ▁by ▁pay ing ▁the ▁cost ▁to ▁build ▁into ▁the ▁desired ▁city ▁slot ▁plus ▁the ▁value ▁of ▁all ▁connections ▁to ▁that ▁city ▁from ▁an ▁already ▁occupied ▁city . ▁No ▁player ▁may ▁build ▁into ▁more ▁than ▁one ▁slot ▁in ▁a ▁city . ▁S lot ▁one ▁costs ▁ 1 0 ▁' E le