June 28 (Reuters) - Spain’s Acciona plans a listing of its renewable energy unit valuing the business at up to 9 billion euros ($10.73 billion) as the engineering group on Monday set pricing at the lower end of its target price range. Acciona Energia’s IPO, aimed at 26.73 to 27.50 euros per share, is set to be one of the biggest listings in a record year so far in Europe. The shares are due to start trading on the Madrid stock market on July 1. Pricing the deal at the upper end of the range fixed on Monday would give Acciona Energia a market value of around 9.05 billion euros ($10.8 billion), Reuters calculations show. Acciona, whose family owners will remain the biggest shareholders, had aimed to raise as much as 9.8 billion euros from listing the unit, which generates most of its earnings. It originally approached investors with a range of 26.73-29.76 euros per share, but said it had decided to aim for the lower end ahead of closing the order books on June 29. It has attracted enough demand to cover the offer, which will all be existing stock, representing 15% of the business, plus a greenshoe over-allotment option representing a further 15% of the amount offered, the company said. Acciona will raise around 1.32 billion euros from the 15% sale. Taking into account the greenshoe option, that could rise to 1.52 billion euros. The company had given itself the option to list up to 25%. ($1 = 0.8381 euros) ($1 = 0.8385 euros) (Reporting by Aida Pelaez-Fernandez, Jesus Aguado and Isla Binnie; editing by Jason Neely) Our Standards: The Thomson Reuters Trust Principles.