Olympic stadium, with a roof made of 2,500 tons of steel tubing from recycled gas pipelines, is one example of sustainable design that is part of London's 500-acre Olympic Park. | Photo courtesy of iStock user <a href="http://www.istockphoto.com/user_view.php?id=2255267">Johnny Greig</a>.

Tomorrow the 2012 London Olympics will be officially underway, and the 500-acre Olympic Park constructed for the world competition is home to nine brand new sports facilities. With the enormous task of keeping tens of thousands of spectators cool, making sure the lights are on, and ensuring that hundreds of bathrooms are in good working order for the next several weeks, the London 2012 Organizing Committee and the Olympic Delivery Authority set out to build new facilities with energy efficient, sustainable, and recyclable designs. Here’s a rundown on how the London 2012 Olympics is cutting down the watts and water to keep the games clean, green, and energy efficient.

The Velodrome -- one of the most iconic and sustainable buildings ever built for an Olympic Games -- contains the indoor cycling track. It was built to hold 6,000 people and keep them cool this summer with a completely natural ventilation system using outside air. That’s right; no air conditioning required. In addition, the Velodrome uses natural lighting during the day to supplement fluorescent lighting, saving a lot of energy. Did we mention it collects rainwater for its main water usage with its sloped roof? Savvy indeed.

Then there is the Water Polo Arena, the first-ever dedicated water polo venue to be built for the games. The 5,000-person capacity arena sports a 37-meter pool and a uniquely sloped roof (from 25 meters down to 6 meters). But more interestingly, the arena was built sustainably in that it can (and will) be torn down immediately after the games, and the materials reused for construction. The building is made with polyvinyl chloride material, or PVC, which is easily recyclable.

Right next to the Water Polo Arena is the brand new Aquatics Center. The wave-inspired interior ceiling of the venue is spectacular to look at. Two temporary wings -- with the capacity to hold 17,500 spectators -- were built sustainably for the arena. Once the games are completed, the wings can be removed, enabling the London community to use the facility.

One of the largest sports facilities ever built for temporary use, the Olympic Park’s new Basketball Arena is perhaps one of the most interestingly designed facilities. In terms of design, it’s more of a tent or scaffold that’s entirely sustainable like the Water Polo Arena. Its steel frame, constructed in only three months, is covered in 20,000 square meters of white, recyclable PVC fabric. All of these materials can be taken down and reused after the Olympic Games.

The Copper Box is likely one of the most efficient buildings in the Olympic Park. It will be used for various exciting court-worthy events (handball or badminton, anyone?). Why is it named the Copper Box? The boxy building has 3,000 square meters of copper (mostly recycled) on its exterior faces, giving it a nice bronze sheen. In terms of sustainability and energy efficient design, the Copper Box has 88 pipes that bring in natural daylight, saving an annual 40 percent on lighting costs. Also, much like the Velodrome, the roof collects rainwater for the use of waste management (toilets), which will cut water costs by 40 percent per year.

The London games will leave a legacy as the most energy efficient Olympics to date. With these energy efficient, sustainable, and recyclable facilities, London is surely going for the green.