Home Depot cut 4,800 cars worth of emissions with this green energy tech

Home Depot (NYSE: HD) is slashing the carbon footprint of its big box stores by using green energy tech that fits in a little box.

The home improvement retailer has joined the growing ranks of companies turning to fuel cell technology maker Bloom Energy to generate electricity on site. Home Depot now powers 140 stores and charges forklifts at two distribution centers with Bloom Energy Servers.

The parking space–sized containers house fuel cells that turn fuel such as natural gas into electricity through an electro-chemical process rather than combustion, delivering low-emission off-grid energy. The servers also power eBay (NASDAQ: EBAY)'s data center in South Jordan, Utah and Morgan Stanley (NYSE: MS)'s New York City headquarters.

By adopting the technology, Home Depot has driven down its electricity costs by 15 to 20 percent in the locations where it runs the servers, said the retailer's Chief Financial Officer Carol Tome. It has also cut carbon dioxide emissions by 50 million pounds since 2014, she added.

"That's the equivalent of 4,800 cars removed off the roads, so we're thrilled," Tome told CNBC's "Squawk Box" on Tuesday.

While the Bloom servers emit fewer emissions than the electric grid, an NBC Bay Area investigation found their efficiency dropped over time, somewhat narrowing the gap with the grid. Bloom revised the data it promotes following the investigation.

Home Depot will be one of the first customers to participate in a strategic alliance announced Tuesday between Bloom Energy and Atlanta-based utility Southern Company (NYSE: SO) to integrate Bloom's servers with Southern subsidiary PowerSecure's power storage devices.

That will allow Home Depot to bank energy during non-peak times, such as overnight when stores are closed. That stored energy can then be drawn on during the day.

"It's rocket science in the box, but what it is for the customer is very simple," Bloom Energy founder and CEO K.R. Sridhar told "Squawk Box" on Tuesday.

"For the first time, we are bringing customization tailored for the specific need of a particular business … for electricity."

Bloom, one of CNBC's 2016 Disruptors , has raised more than $1 billion in investment and recently filed confidentially for an IPO.

Companies buy a set amount of electricity-generating capacity from Bloom, which is provided through a collection of its servers. That allows them to reap lower costs and predict their prices for a number of years, Sridhar said.

The fuel cell business has seen something of a renaissance in recent years after an initial period of early hype that was followed by a prolonged period when pioneers saw their stock prices collapse as the technology failed to catch on.

Revenue from fuel cells and other distributed generation exploded from $755 million in 2011 to an estimated $7.5 billion last year, according to Navigant Research. The firm expects revenue from fuel cell systems to reach $57.8 billion in 2023.

Tax credits and state rebates have helped lower the cost of purchasing fuel cell technology. But the turnaround is also due to advances by companies like Bloom, which uses cheap, abundant ceramics rather than the rare earths utilized in earlier technology.

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