In its Environmental Responsibility Report, Apple said that as of 2014 all of its U.S. data centers, corporate offices and more than 450 Apple Retail Stores around the world are running on renewables.
"But our goal is to power all of them with 100% renewable energy. So we're tapping into energy from solar, wind, micro-hydro, biogas fuel cells, and geothermal sources," the company said. "We're designing new buildings and updating existing ones to use as little electricity as possible."
Apple has also been heavily investing in onsite energy production and partnering with third-party utilities that supply power from renewable sources.
"Even though we're manufacturing and shipping more products than ever, our carbon emissions per product have been dropping since 2011," the report said.
Apple's corporate offices, data centers and retail stores represent only 1% of the company's carbon footprint, while manufacturing in the U.S. and abroad makes up the lion's share.
From 2013 to 2014, Apple saw a 5% increase in manufacturing emissions attributed to the production needs of increased memory and storage capacity of its iOS devices and laptops.
But, the company said, its green corporate centers and retail stores "reflect our values, and we want them to act as models for others to follow. This is why we are constantly making our facilities more energy efficient and aggressively investing in renewable energy."
Over the past three years, Apple has reduced its facility emissions and those created by purchased electricity by 48%, "even while our overall energy consumption greatly increased."
Apple has been busily constructing new solar power plants around the country. Apple over the next year or so is expected to surpass Walmart as the largest corporate user of solar power.
Apple already has three solar power plants in North Carolina that generate more then 20MW (megawatts, or million watts) of power.
Earlier this year, the company announced it would invest $850 million in a solar power plant through a partnership with First Solar, one of the nation's largest photovoltaic (PV) manufacturers and provider of utility-scale PV plants. Through a 25-year purchasing agreement, Apple will get 130MW from the new California Flats Solar Project.
The new solar project is notable for a number of reasons, not just its size, which generates 280 megawatt (MW) of alternating current and is located on about 2,900 acres.
Apple is also investing in a $2 billion solar command center in Arizona, and claims its new California spaceship-like campus, now under construction, will be the greenest building on the planet.
Apple's solar plant in Yerington, Nevada, generates up to 20 MW of renewable energy for its Reno data center.
Apple has also developed a renewable micro hydro project to power its data center in Prineville, Oregon, and it's building a solar farm in China to offset energy used in offices and retail stores there.