Tech companies are getting more eco-friendly. Several of the biggest names on the web and in social media have been carrying out similar plans on a very large scale, Google and Facebook being the latest examples.

The search giant is hedging $1 billion in green investments now that it has injected $94 million into the Sacramento-based Recurrent Energy. The solar power firm will use the new capital to carry out four different photovoltaic projects in the city, which will use to power local households via via a two decade agreement with the Sacramento Municipal Utility District.

“This investment represents our first investment in the U.S. in larger scale solar PV power plants that generate energy for the grid — instead of on individual rooftops,” Axel Martinez, assistant treasurer at Google Treasury, wrote on the Google Green blog. “These projects have a total capacity of 88 MW, equivalent to the electricity consumed by more than 13,000 homes.”

Facebook has evidently taken a cue from its rival. It hired Bill Weihl, Google’s former green energy czar to “advance sustainability” at the company. His employment will begin in January 2012.

The appointed follows not too long after Greenpeace published a report criticizing Facebook for its dependency on coal-fired energy to power its datacenters. According to the figures the green activist group released, Facebook is only second to Apple in terms of coal dependency, at over 53.2 percent. This is in comparison only 34.7 percent of the power Google is consuming is produced from coal, so it seems Weihl is now in charge of changing Facebook’s positioning on the list.

This is the second push by Facebook to fend off the bad PR it’s getting from Greenpeace. Four days ago we covered a rather extensive joint initiative between the two involving internal policy changes and other commitments.