James Martin/CNET

It's not just Apple going green. Many of its suppliers also are making a vow to run on renewable energy.

Apple early Thursday morning said it has nearly doubled the number of suppliers -- now totaling 44 -- that have committed to running their Apple production on 100% clean energy. Because of that, Apple will also beat its aim of bringing 4 gigawatts of renewable power into its supply chain by 2020. It now expects to have 5 gigawatts in that time frame.

"We've made it a priority to hold our suppliers accountable to the same environmental standards we observe and hope that our collaboration will show others what is possible," Lisa Jackson, Apple's vice president of environment, policy and social initiatives, said in a statement. "We won't stop driving change within our industry to support the clean energy transition happening globally."

Video: AirPods 2 have a new rival... from Apple

Apple has been focused for years on making its products and its operations more environmentally friendly. CEO Tim Cook in 2014 famously said he doesn't "consider the bloody ROI" (return on investment) when it comes to issues like the environment, accessibility and worker safety. It has long been his and Apple's goal to run entirely all of the company's operations on renewable energy.

Last year, it finally accomplished that goal, when it said all of its facilities around the world run on 100% clean power. In 2018, the company and its suppliers generated enough clean energy that it could have powered over 600,000 homes in the US.

At the same time, Apple has been pushing to recycle parts from its devices and build new products using recycled products, with disassembly robots speeding up the process. In March, the company said that it hit a new environmental achievement. Last year, it announced the iPhone was manufactured with a zero waste certification, and this year it added the iPad, Mac, Apple Watch, AirPods and HomePod to that program.

While Apple has doubled the number of suppliers vowing to use renewable energy, it's unclear how many supplier in total the company works with.

Originally published April 11, 12:01 a.m. PT.

Correction, 8:04 a.m.: The initial version of this story incorrectly stated the number of Apple's suppliers. The company hasn't revealed that number.