Does sugar yield drive lignocellulosic sugar cost? Case study for enzymatic hydrolysis of softwood with added polyethylene glycol

•PEG enhances softwood hydrolysis reducing sugar production cost at low enzyme doses.•Higher hydrolysis yields are beneficial, but lowest cost not at highest sugar yields.•Lowest production cost balances sugar yield with enzyme cost and hydrolysis time.•Technical conditions for lowest-cost sugars resilient to economic assumptions.