One of the ways we support the development of new technologies is by piloting them on our own turf—putting our campuses on the cutting edge of renewable energy use. We’ve tried new renewable energy options that help our operations run more efficiently while helping these technologies evolve and scale more rapidly.
In addition to our 1.9 MW solar array, we've incorporated other forms of renewable energy into our corporate campuses. This includes running a 970 kW cogeneration unit off our local landfill gas, which not only removes the methane, a particularly potent greenhouse gas, but converts it into electricity and heat that we use on campus. We've also installed an efficient ground source heat pump and deployed solar water heating on our office buildings in Mountain View, Hyderabad, and Tel Aviv.
In other words, we are confident that the technology will deliver a return on investment (ROI) in a reasonable period of time. For example, the 1.7 MW solar installation we implemented in 2007 produces over 3,000,000 kWh of clean energy per year, saving us a great deal in energy costs and reducing our carbon footprint.
We believe that by putting our dollars and resources behind a promising new technology—or allowing companies to use our campus as a testing ground—the technology will have a better chance of scaling. For example, in 2007, we hosted the first installation of a promising new fuel cell technology that has the potential to use biogas. The company, also based in the Bay Area, was able to more quickly evolve the technology by having a working real-world pilot nearby.
The lack of financing for renewable energy developers has been a significant roadblock to the expansion of renewable energy. We're working on changing that by buying electricity directly from our utility providers and wind farms near our data centers. We've now signed five contracts for over 570 MW of wind energy, which is enough to power approximately 170,000 U.S. households. This is an important step toward our long-term goal of powering our operations with 100% renewable energy.
We've completed several, large-scale Power Purchase Agreements or PPAs—long-term financial commitments to buy renewable energy from specific facilities. The first is for 114 MW of wind generation from NextEra’s Story County II facility in Iowa, and the second is for 100.8 MW of wind generation from their Minco II facility in Oklahoma. The third is for 72 MW of output from a wind farm under construction in Northern Sweden. The fourth is for 239.2 MW of wind generation from a wind farm in the Texas Panhandle. We've also signed a fifth agreement directly with an utility, as detailed in the section below.
The power we purchase from wind farms is incorporated into local power grids, increasing the percentage of renewable electricity on those grids and flowing to our data centers nearby. We also provide clean energy developers certainty on the payments for their power, which allows them to get additional financing to build new projects. These purchases are long-term, meaningful actions to reduce our carbon footprint in a financially sustainable way. They also help us secure clean energy in the future—for ourselves and the world.
We’ve made the details of our power procurement strategy publicly available to provide a useful blueprint for other companies to green their operations and the grid. Read on about our criteria for PPA projects and other details on how we purchase green power.
We’ve also been working closely with our utility partners to find ways to source renewables directly. In September 2012, we signed an agreement with the Grand River Dam Authority (GRDA) to supply Google’s Mayes County, Oklahoma data center with 48 MW of wind energy from the Canadian Hills Wind project in west central Oklahoma.
As its first-ever wind energy project, this agreement is a milestone for GRDA. It’s also a milestone for Google because it’s a little different from our other wind PPAs: instead of purchasing energy directly from the developer, we’ve contracted with a utility provider. We’re excited about this collaboration because it leverages our respective strengths: utilities like GRDA have the ability to integrate renewable energy into their generation mix and to deliver power, while we're a growing company that seeks to use clean energy for our operations in a scalable way.
In addition, we've been working with a number of utilities to develop a new class of services that would give Google and other large electricity consumers the option of purchasing renewable energy directly from our local utilities. For instance, Duke Energy is developing a new, voluntary program for large customers in the state that want to buy renewable energy. We've released a white paper explaining the benefits of the renewable energy tariff and offering guidelines on how utilities and large energy consumers can develop their own proposals.