The city plans to replace the street lamps on its major roads with energy-efficient, low-maintenance lights as a way to reduce its energy costs. The $530,000 project involves the installation of 1,130 light-emitting diode lights (LED) on 37 streets, the city’s heaviest traveled roadways, according to Mayor Scott D. Galvin. Galvin said the new lights are estimated to save Woburn $60,000 per year in electricity and maintenance costs, allowing the investment to pay for itself in just under five years. LED lights typically last for 23 years. The project is being funded through a $230,000 state grant the city received last fall and $300,000 recently appropriated by the City Council. Woburn qualified for the state grant through the “green community” designation it earned from the state Department of Energy Resources.