Oct 16 (Reuters) - Spanish oil company Cepsa aims to develop up to 15 biomethane plants in Spain by 2030, it said on Monday, as the country's energy firms flock to the renewable gases market amid a push towards decarbonisation.

Naturgy and Repsol have also recently announced projects in this area, and have called on the government to step up its biogas ambitions.

Cepsa is teaming up with renewable energy asset promotion and management firm Kira Ventures to develop the plants, which are part of its goal to have a 4 terawatt hour a year portfolio by the end of the decade.

The plants will use agricultural and livestock waste to produce biomethane aimed at replacing natural gas in Cepsa's industrial activity, it said.

This will allow the reuse of 10 million tons of waste and avoid the emission of 728,000 tons of CO2 every year, it said.

The first five plants are expected to start operations between 2025 and 2026. Cepsa wants to reach net zero emissions by 2050. (Reporting by Pietro Lombardi; Editing by Jan Harvey)