SAN FRANCISCO, US: Online software start-up Hara, which makes software to track energy usage and carbon footprints, has added grocery retailer Safeway Inc to its list of customers.

The multiyear contract with Safeway follows Hara's deals in recent months with media giant News Corp and tax software provider Intuit Inc.

Hara said on Wednesday it will provide the software to help the retailer measure, analyze and reduce the chain's energy usage in about 1,800 stores.

The Redwood City, California-based firm, initially funded in 2008 by Silicon Valley venture firm Kleiner Perkins Caufield & Byers, is catering to a growing market for carbon and energy accounting software, which has attracted the attention of some big players like SAP and Oracle Corp.

Hara Chief Executive and co-founder Amit Chatterjee said some estimates project the market for carbon tracking software and services could expand to $4 billion by 2015. The market was estimated at around $132 million in 2009.

"We are closing about a deal a week in terms of market momentum," he said.

Giving a boost to firms like Hara, and the market for carbon accounting software, is the new guideline from the Securities and Exchange Commission that urges public companies to disclose risks associated with climate change in their annual reports.

Chatterjee said business inquiries also jumped soon after the world's largest retailer Wal-Mart Stores Inc said it will start asking suppliers to start providing environmental impact data, such as tracking carbon emissions.

The nascent carbon tracking market is expected to receive a huge boost if the United States implements any kind of "cap-and-trade" legislation that will gradually reduce the amount of greenhouse gases emitted by industry, by requiring companies to have permits to spew their emissions.

Hara's software first collects information on a company's use of electricity, water, gas and chemicals and compares it with outputs of greenhouse gases, solid waste and waste water.

It then devises a strategy to manage and reduce energy costs and greenhouse gas emissions.

"Hara adds value by giving us not only reliable insight into the size and makeup of our energy usage and carbon footprint, but also a solid road map for achieving further cost reductions and better carbon management," said Joe Pettus, senior vice president of fuel and energy at Safeway.

Apart from the big software firms, Hara also competes with a few other smaller players such as Carbonetworks and Enervity.