Apple is the greenest tech company in the world, according to Greenpeace (AAPL)

For the third year in a row, Apple has been deemed the most environmentally friendly of the world’s major tech companies, according to a new report from environmental organization Greenpeace.

Apple, along with Google and Facebook — the other highest scorers in the report — made a pledge in 2012 to to transition to 100% renewable energy. Its new headquarters, which are currently under construction, will run completely on renewable energy, with an estimated 700,000 square feet of solar panels.

According to the report, Apple has “played a catalytic role within its IT supply chain, pushing other IT data center and cloud operators who help deliver pieces of Apple’s corner of the internet to follow their lead in powering their operations with renewable energy.”

Greenpeace has been measuring the energy performance of the information technology sector since 2009, and its newest report states that the organization has seen a significant increase in the degree to which the largest internet companies prioritize renewables.

According to the report, the energy footprint of the IT sector is currently estimated to account for 7% of global electricity. But since global internet traffic is expected to rise threefold by 2020 — and with it the sector’s energy footprint — company commitments to and plans for sustainability will become even more important.

Greenpeace’s report notes that Apple and Google continue to lead the sector in matching their growth with an equivalent or larger supply of renewable energy. The report assigned Apple the overall grade of A – in the subcategories, the company got As in energy transparency, renewable energy commitment, energy efficiency and mitigation, and renewable procurement, wit its only B in the advocacy category. It’s clean energy index, calculated based on estimates of facilities’ power demand, was an impressive 83%. Google got As in all subcategories except for energy transparency (where it got a B), though its clean energy index was lower at 56%.

A newcomer to Greenpeace’s list of top scorers was Nevada-based telecommunications company Switch, which develops data centers. The company was the clear leader in the report’s ranking of colocation and content delivery network companies, with all A’s and a whopping 100% clean energy index.

Netflix, on the other hand, stood out with notably unimpressive scores. The report estimates that Netflix’s video streaming accounts for a third of internet traffic on North American networks, but the company received an overall grade of D, with Fs in three of five subcategories.

The report points out that Netflix has not given any public commitment to renewable energy, and that “unlike other major video streaming platforms such as Apple, Facebook, or Google, Netflix does not regularly provide energy consumption data, greenhouse gas emissions, or the actual energy mix of its global operations.”

The streaming company will have to make some changes if it wants a better grade next year.