Buyers flex purchasing power for the environment. Suppliers save billions.

Companies are looking to their supply chains as they expand efforts to promote energy efficiency and other environmentally friendly business practices.

A new report from CDP (formerly the Carbon Disclosure Project) reveals that some of the world’s largest companies are asking their networks of suppliers to disclose energy use and carbon-emission data.

The U.S. information technology company Hewlett Packard Enterprise, for example, helped its suppliers save more than $65 million by developing energy-saving action plans.

Wal-Mart, General Motors Company and Microsoft Corporation are among the 89 organizations that provided data for the report. The results show that suppliers who acted to reduce carbon emissions saved $12.4 billion in 2016.

Much of the savings in the top 100 projects came from energy efficiency.

“Lower emissions in the supply chain isn’t just about helping the environment; it’s a business imperative which boosts our competitive advantage and builds our resilience for a low-carbon future,” said Nicola Kimm, head of sustainability at Philips Lighting.

For more details, including the “A-list” of companies demanding greener supply chains, see the CDP’s 2017 Global Supply Chain report.