Metro is taking on a plan to cut its energy use and carbon footprint — an endeavor so wide-ranging that it could be the equivalent of taking 35,000 cars off the road per year.

"Everybody is affected by climate change, and so this is something that we have put a focus on," said Sherri Ly, WMATA spokesperson.

Metro revealed its first-ever energy action plan on Monday, coinciding with Earth Day. The goal is to reduce the transit agency's energy use, contain operating costs and guide sustainable growth.

"Every day, Metro reduces the carbon footprint of the National Capital Region by providing public transit to nearly one million riders," the report states.

But it takes a lot of energy to power all those trains and buses. The report is a serious internal checkup to see how Metro can cut its energy consumption, which in turn would reduce greenhouse gas emissions.

Energy costs are Metro's largest expense outside of personnel, the report says. Increasing sustainability won't only help Metro reach environmental goals; it's also necessary to help with long-term cost reductions, the report said.

Some of the efforts sound small, but they could still have a big impact.

"Well, it's as simple as changing lightbulbs," said Rachel Healy, sustainability director at WMATA. "We are changing every single lightbulb in the system" to LED bulbs, which require less energy.

Other strategies include capturing and storing the energy given off when trains brake, using more solar panels, buying electric buses, and even looking at more efficient bus boarding and payment systems to cut down on idling.

"I think the agency as a whole is looking at sustainability as something that is important not only to Metro, but to the entire region," Ly said.

So what actions can you take on your own?

Leave the keys at home, for starters. The travel choices we make every day have a direct impact on the planet. Cars and trucks account for nearly one-fifth of all U.S. emissions, according to Climate Central. Your vehicle likely spews out about 20 pounds of unwanted carbon dioxide for every gallon of gas burned. That's about a pound of carbon dioxide for every mile you drive, and it's all going straight into the atmosphere.

"Every Metrorail trip uses 40 percent less greenhouse gases, than if you were to drive in a car all by yourself," Ly said.

If you want to pitch in and make an immediate impact, try parking your car one or two days a week to start, and walk, bike, carpool or take public transport.