Ultratech has earmarked a capex of Rs 1,424 crore to be spent over the next three years in order to improve productivity and tackle rising energy costs."Of this, Rs 844 crore is towards installation of captive power plants at production units in Gujarat and Chhattisgarh. The company will also invest in de-bottlenecking and cost efficiency," Kumarmangalam Birla chairman of Ultratech said at the company's AGM here today.