DUBAI, May 11 (Reuters) - Aluminium Bahrain (Alba) has put plans to boost its production capacity to 1.2 million tonnes per year on hold due to a shortage of gas needed for power generation, a company executive said on Monday. The company is currently operating at full capacity of 860,000 tonnes per year, said Musaad Abdullah al-Eid, general manager of marketing at Alba. "There is a shortage of gas, if we go ahead with the expansion plan," al-Eid told Reuters on the sidelines of an industry conference. "Revenues have gone down and this is another factor that is making us think twice about expanding."