Plug Power has signed another potential $600 million deal for its fuel cell systems with another large retailer, this time Walmart.

The deal follows in the footsteps of Plug Power's $600 million deal with Amazon three months ago. Amazon was given stock warrants tied to cash payments in that agreement, giving Amazon a potentially large stake in the Latham fuel cell maker.

The Walmart deal is nearly identical, except that the initial warrants provided were given a higher exercise price of $2.12 per share compared to the $1.18 per share exercise price given to Amazon. The difference is due to the fact that Plug Power's shares have risen about $1 per share since April when the Amazon deal was signed.

Under the deal, Plug Power should add 10 new Walmart distribution sites to its GenDrive fuel cell fleet, which will equate to $80 million in added revenue. Plug Power's total revenue for 2016 was $85.9 million. The net loss for the year was $57 million.

Plug Power makes hydrogen-power fuel cells that are used in forklifts. The fuel cells replace or augment batteries that are traditionally used in indoor warehouses for retailers like Walmart and others.

Plug Power also sells fuel and onsite fueling stations that keep its fuel cells running.

Although Plug Power has not yet become profitable, the Amazon and Walmart deals are expected to drive revenue and cash flow for years while giving the company two large and respected shareholders with a long-term interest in the company's success.

Plug Power says that as in the Amazon deal, it plans to collaborate with Walmart on technology development, although Plug Power CEO Andy Marsh has repeatedly declined to explain the exact nature of that collaboration, citing confidentiality agreements.

However, Marsh did say in a conference call with stock analysts that Plug Power can learn a lot from Walmart, like Amazon a pioneer in retailing innovation.

"When I look out my window in my office, I see a FedEx van, delivery van driving around the parking lot. And that's very similar to products we'll offer to Walmart as well as to others. And you know, we believe that the best learning comes from working with real customers delivering real products, as we've done with Walmart in the past," Marsh said.