Apple has convinced its main manufacturing partners, Taiwan Semiconductor Manufacturing Company (TSMC) and Foxconn, to makes its parts and/or devices using green energy by 2020. This achievement is a big part of the OEM's current drive towards making its business as sustainable as possible.
https://www.notebookcheck.net/Apple-procures-pledges-from-Foxconn-TSMC-to-fulfil-its-orders-using-renewable-energy.416747.0.html