American businesses are investing record amounts in solar, with the top corporate users adding 325 megawatts (MW) of installed capacity last year, according to the "Solar Means Business 2017" report from the Solar Energy Industries Association (SEIA). The impact of corporate solar is significant: the solar installations analyzed in the SEIA report produce enough electricity to power 402,000 U.S. homes and offset 2.4 million metric tons of carbon dioxide each year.



Here, CNBC's Sustainable Energy looks at the top 10 corporations in the U.S. by their installed capacity of solar power.

10. Amazon.com — 33.6 MW

Amazon corporate office building in Sunnyvale, California Lisa Werner | Moment Mobile | Getty Images

It's not only solar power that Amazon in embracing. Last year, the business announced that its largest wind farm to date, Amazon Wind Farm Texas, was up and running. The facility, located in Scurry County, has more than 100 turbines and will add one million megawatt hours of clean energy to the grid each year.

9. Macy's — 38.9 MW

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As well as having installed almost 40 MW of solar capacity, Macy's wants to increase the amount of its waste diverted from landfills to 70 percent by this year.

8. IKEA — 44.9 MW

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By 2020, the IKEA Group wants to produce as much renewable energy as it consumes in its operations. On its website, the business says it wants to source all its wood from more sustainable sources, also by 2020.

7. General Growth Properties — 50.2 MW

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Real estate business General Growth Properties describes sustainability as "an integral component of GGP's long-term success."

6. Costco Wholesale — 50.8 MW

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Costco is embracing solar in a big way. The businesses states that at the end of the fiscal year for 2017 it was using solar photovoltaic systems at 100 warehouses, from New York to Japan.

5. Kohl's — 51.5 MW

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Department store Kohl's is not only turning to solar power to reduce its environmental impact. On its website, the business states that it recycles around 150,000 tons of materials annually, which represents more than 80 percent of waste generated.

4. Apple — 79.4 MW

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Tech giant Apple places fourth in the SEIA's list. Earlier this year, Apple announced that its global facilities were powered by 100 percent clean energy. CEO Tim Cook described the development as a significant milestone for the business.

3. Prologis — 120.7 MW

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Third placed Prologis has a little under 121 MW of installed capacity, according to the SEIA's report. The business is targeting a 20 percent cut in corporate greenhouse gas emissions by 2020, from a 2011 baseline.

2. Walmart — 149.4 MW

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With just under 150 MW of solar capacity installed Walmart grabs second place in the SEIA's list. Looking at the bigger picture, the retail giant wants to slash emissions from its value chain by one billion metric tons by 2030.

1. Target — 203.5 MW

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