A lot of leading companies have committed to getting all of their energy from renewable sources. Google has dispensed with its aspirational phase and will actually achieve this milestone in 2017, the company revealed Tuesday.

"Over the calendar year globally, for every unit of energy we consume, we’re purchasing the equivalent amount or more of renewable energy" in 2017, said Neha Palmer, head of energy strategy at Google's global infrastructure division.

The search engine and web services provider has long been a leader in corporate renewables, using its clout and purchasing power to open up new avenues for procuring clean energy. The future of federal renewables policy remains hazy since the election of Donald Trump, meaning corporate leadership could play an even greater role in the adoption of wind and solar power in the next few years.

The announcement means that all of Google's data centers, offices and operations will be powered by clean energy. Not all of that clean electricity is available in the vicinity of the facilities, so in those cases, the company buys the equivalent power and retires the associated renewable energy credits.

It's hard to say this milestone has been reached ahead of schedule, because the goal was not pegged to a specific date. With that said, Google's announcement comes ahead of most of the 83 companies in the RE 100 group that have announced a 100 percent renewable goal.

Elsewhere in Silicon Valley, Apple got to 93 percent in 2015 but evidently hasn't closed the gap. Adobe is aiming for 2035. Facebook has targeted half of its data center energy use by 2018, with full company-wide renewables "eventually." Of the big tech players, Microsoft took the gold medal, meeting its carbon neutral commitment back in 2014.

The gap between the goal and the achievement does not close easily. Google first procured wind energy in 2010, and established the goal in 2012. The company reached 37 percent renewable in 2014 and 44 percent in 2015. A number of deals that closed about a year ago are now bearing fruit, Palmer said, leading to 900 megawatts coming on-line in the next four to six weeks. That will help close the distance to 100 percent.

Accomplishing the 100 percent goal followed not just renewables procurement, but extensive demand-side work to reduce the load Google has to serve. In doing so, the company followed the corporate sustainability steps laid out by Hervé Touati, the managing director of the Rocky Mountain Institute, in a recent episode of GTM's podcast the Interchange.

"It's clear for most, if not all, businesses that the first thing to do is energy efficiency, because that is the most cost-effective way of going toward executing on your targets," he said.

For Google, that meant serious work at the data centers to cut down on the electricity needed to run all those searches and YouTube clips. Those data centers now deliver 3.5 times as much computing power as they did five years ago, while using the same amount of electricity, the company said. 

Google's parent company Alphabet also leveraged in-house expertise from DeepMind, its machine-learning subsidiary, to reduce energy needs. By training the computers to optimize operational factors like fans and cooling systems, DeepMind was able to cut the energy use for cooling data centers by 40 percent, yielding a 15 percent drop in overall energy overhead.

Efficiency can only get you so far, Touati noted. The same applies to onsite generation -- the data centers need too much power.

"[If] you can cover the roof of a data center with solar PV panels, maybe you cover 5 percent of the electricity needs," Touati said. "If you want to reach your...100 percent renewable target, the only option you have today is to actually source electricity from offsite projects."

That's what Google did, to the tune of 2.6 gigawatts worldwide. In some locations where renewable purchase options didn't exist, the company worked with the local utilities to create them. That process helped produce Duke Energy's Green Source Rider, which enabled Google to purchase power for its North Carolina data center from a 61-megawatt solar project. Now other companies can buy through that program as well.

"We hope we can expand markets even more and work with market structures to enable customers to have choice in their energy supply," Palmer said. "The green rider was one way to do that."

Up next for Palmer's team: procuring new generation to keep pace with the company's growing energy needs, and focusing more on finding renewable energy sources in the regions where Google consumes energy.

"Trying to navigate all those individual markets can be a challenge sometimes," Palmer said. "You really have to tailor the approach to each individual market. It's our hope that it can become a lot easier."