As recent investments in obscure technologies like the human-powered monorail and robot-driven cars have some people questioning Google's (Nasdaq: GOOG) strategic and entrepreneurial intentions, the company's big announcement Tuesday that it would invest in a 350-mile offshore wind energy transmission "backbone" off the Mid-Atlantic coast serves as a reminder that the Mountainview, California-based tech giant is still quite serious about renewable energy, and in particular, is still bullish on wind power.

The Atlantic Wind Connection (AWC) backbone will stretch from New Jersey to Virginia and will be able to connect 6,000 megawatts of offshore wind turbines, enough to serve approximately 1.9 million households.

With the demand for energy (and especially renewable energy) in California, one might wonder why Google didn't invest in building out an offshore wind transmission grid in the Pacific. While Google likely considered several variables before dropping money on the AWC, the answer boils down to two:  demand and depth.

As Casey Johnston at ArsTechnica notes, "The power lines in this region struggle to keep up with demand, and the system can go from operational to nonfunctional in a few moments, as in the 2003 blackout that hit several Northeastern and Midwestern states." And at the Official Google Blog, Google Green Business Operations Director Rick Needham explains the decision this way:

"These shallow waters make it easier to install turbines 10-15 miles offshore, meaning wind projects can take advantage of stronger winds and are virtually out-of-sight from land. With few other renewable energy options ideally suited for the Atlantic coast, the AWC backbone helps states meet their renewable energy goals and standards by enabling a local offshore wind industry to deploy thousands of megawatts of clean, cost-effective wind energy."

And Google isn't the only one to see logic in developing Atlantic coast offshore wind energy first. The Department of Interior just granted its first-ever offshore wind energy lease to Cape Wind, off the coast of Massachusetts. And according to a Department of Interior study, the Atlantic coast holds 1,000 GW of offshore wind energy potential, roughly two-thirds of which is off the coast of the population-dense Mid-Atlantic states.

The AWC project is led by independent transmission company Trans-Elect and is financed by Google, Good Energies and Marubeni Corporation. Google is financing 37.5 percent of the critical initial development cost.

"We believe in investing in projects that make good business sense and further the development of renewable energy," writes Google's Needham. "We’re willing to take calculated risks on early stage ideas and projects that can have dramatic impacts while offering attractive returns."

Earlier this year, Google solidified its interest in land-based wind farms by investing $38 million in two North Dakota wind farms and agreeing to buy the output of a 114-megawatt Iowa wind farm.