Vestas has secured a 15-year service contract extension for a 570MW wind farm complex in California. The deal stretches across NRG’s Alta 2, 3, 4 and 5 projects in the Mojave Desert in the south of the Golden State. Hardware covered totals 190 of the Danish manufacturer’s V90-3MW turbines. Contract scope encompasses the Vestas Active Output Management 5000 service package. Alta 2 was completed in 2010 and features 50 turbines. The 150MW Alta 3, 102MW Alta 4 and 168MW Alta 5 followed in 2011.