<prompt> Translate the following text to EnglishNjia nyingine ingehusisha upgrading ya zaidi ya kitengo kimoja kwa wakati mmoja wakati wa vipindi vya mahitaji ya chini na kuepuka kukatika yoyote wakati wa vipindi vya mahitaji ya juu.  <response>: Another alternative approach would involve retrofit of more than one unit at a time during low-demand periods and avoiding any outage during high demand periods. 