“Once all these projects come online, our carbon-free energy portfolio will produce more electricity than places like Washington D.C. or entire countries like Lithuania or Uruguay,” Pichai says.

Google is already the world’s largest buyer of renewable energy. The company’s latest round of power purchase agreements boosts the Silicon Valley behemoth’s portfolio of renewable energy projects to a total of 52, increasing the amount of power the company generates from wind and solar by 40%.

The company’s announcement comes just days ahead of Climate Week—an annual series of environmentally minded events concurrent to the United Nations General Assembly in New York. This year’s Climate Week is especially high profile as it coincides with the U.N. Climate Action Summit, which is held only once every five years. In the lead up to the event, major corporations have been eager to flex their green credentials.

On the same day that Google announced its new purchasing plan, Amazon pledged to obtain net-zero carbon emissions by 2040—at long last putting a timeline on the company’s previously open-ended pledge to go carbon neutral.

Amazon, once the world’s largest purchaser of renewable energy, lost that mantle to Google long ago. For the past two years, Google has purchased enough renewable energy to power the entirety of its operations, covering both its offices and massive, electricity-guzzling data centers.

However, since the sites that generate renewable energy are often connected to grids far from where Google houses its servers, a lot of Google’s operations aren’t actually powered by the renewable energy it buys. For example, according to Greenpeace, just 4% of the power supplied to Google’s data centers in Virginia comes from renewable sources.

“We say that we ‘matched’ our energy usage because it’s not yet possible to ‘power’ a company of our scale by 100 percent renewable energy,” Google’s senior vice president of technical infrastructure, Urs Hölzle, explained in a blog last year.

“It’s true that for every kilowatt-hour of energy we consume, we add a matching kilowatt-hour of renewable energy to a power grid somewhere. But that renewable energy may be produced in a different place, or at a different time, from where we’re running our data centers and offices,” Hölzle says.

The 18 projects Google announced yesterday will lead to $2 billion worth of construction on new renewable energy infrastructure, adding to the $5 billion of construction spurred by Google’s previous power purchases. However, according to the company’s latest Environmental Report, the company has only invested $2.5 billion of its own money into renewable energy projects since 2010.

Even if the renewable energy doesn’t flow directly to Google itself, the company’s commitment to green energy purchases ensure that more green electricity is entering the grid somewhere, sometime—and that boosts the overall sustainability of the supply chain.

Following yesterday’s announcement, a Google spokesperson told Fortune, “It is our hope that, as a result of our efforts and those of other organizations making similar purchases, that renewable energy will someday be plentiful enough to enable Google to power our operations 24 hours a day with clean, carbon-free energy.”

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