ines ▁are ▁supported ▁by ▁con ical ▁tub ular ▁steel ▁to wers . ▁These ▁to wers ▁represent ▁ 3 0 % ▁– ▁ 6 5 % ▁of ▁the ▁tur bine ▁weight ▁and ▁therefore ▁account ▁for ▁a ▁large ▁percentage ▁of ▁the ▁tur bine ▁transport ation ▁costs . ▁The ▁use ▁of ▁l ighter ▁materials ▁in ▁the ▁tower ▁could ▁greatly ▁reduce ▁the ▁overall ▁transport ▁and ▁construction ▁cost ▁of ▁wind ▁tur b ines , ▁however ▁the ▁stability ▁must ▁be ▁maintained . ▁High er ▁grade ▁S 5 0 0 ▁steel ▁costs ▁ 2 0 % - 2 5 % ▁more ▁than ▁S 3 3 5 ▁steel ▁( standard ▁struct ural ▁steel ), ▁but ▁it ▁requires ▁ 3 0 % ▁less ▁material ▁because ▁of ▁its ▁improved ▁strength . ▁Therefore , ▁replacing ▁wind ▁tur bine ▁to wers ▁with ▁S 5 0 0 ▁steel ▁would ▁result ▁in ▁net ▁sav ings ▁both ▁in ▁weight ▁and ▁cost . ▁ ▁Another ▁dis adv antage ▁of ▁con ical ▁steel ▁to wers ▁is ▁that ▁construct ing ▁to wers ▁that ▁meet ▁the ▁requirements ▁of ▁wind ▁tur b ines ▁t aller ▁than ▁ 9 0 ▁meters ▁proves ▁challeng ing . ▁High ▁performance ▁concrete ▁shows ▁potential ▁to ▁increase ▁tower ▁height ▁and ▁increase ▁the ▁lifetime ▁of ▁the ▁to wers . ▁A ▁hy brid ▁of ▁prest ress ed ▁concrete ▁and ▁steel ▁has ▁shown ▁improved ▁performance ▁over ▁standard ▁tub ular ▁steel ▁at ▁tower ▁height s ▁of ▁ 1 2 0 ▁meters . ▁Con crete ▁also ▁gives ▁the ▁benefit ▁of ▁allowing ▁for ▁small ▁pre cast ▁sections ▁to ▁be ▁assemble d ▁on ▁site , ▁avoid