Powered by the Sun: Solar Buildings and Wind Towers

Magnificent CME Erupts on the Sun - August 31In our ongoing drive to find ways to meet energy demands in a clean and sustainable way, solar power is the clearly the top contender. While inroads have certainly been made in terms of fusion technology, the clean, abundant, and renewable power that can be derived from our sun seems to hold the most promise. In addition to the ever-decreasing costs associated with the manufacture and installation of solar cells, new applications that are appearing all the time that allow for greater usage and efficiency.

Consider the following example that comes from Seoul, Korea, where Hanwa – the largest solar company in the world – has chosen to retrofit its aging headquarters with a solar facade that will provide both for the buildings needs and cut down on energy costs. Having been built in the 1980’s, the Hanwa building is part of a global problem. High-rise buildings suck up around 16% of the world’s energy, and most were built to specifications that do not include sustainability or self-sufficiency.

solar_skyscraper3Even though the most recently-built skyscrapers are helping change things by employing renewable energy and sustainable methods – like the Pertamina Energy Tower in Jakarta –  that still leaves tens of thousands of inefficient giant buildings on the ground. And rather than tear them down and erect new buildings in their place, which would be very wasteful and inefficient, it is possible to convert these buildings into something cleaner and less reliant on other external sources of electricity.

Basically, the plan calls for plastering the 29-story building with three-hundred new solar panels. These will be placed on the sunniest spots to harvest energy, and other strategically placed panels will automatically adjust to help keep the interior cool but bright with natural light. New high-performance windows will save more energy. In total, though the final details are still in progress, the retrofit may save well over a million kilowatt-hours of electricity each year.

solar_skyscraper2In theory, say designers from Amsterdam-based UNStudio, this type of facade could be added onto any skyscraper. As the researcher explains:

It would be the principles that could be applied of course and not the design, as every building has its own context, program, size, view corridors, orientation etc. which would affect the design parameters differently. Each building would be unique and would require a tailored approach.

Retrofitting old skyscrapers is an important way for cities to fight climate change, say engineers from ARUP, which worked with UNStudio on optimizing the design. And it’s usually a better solution than building something brand new. Accroding to Vincent Cheng, who led the project from ARUP’s Hong Kong studio, retrofitting is a better option for old skycrapers, both in “terms of reducing embodied carbon emission and waste elimination.”

solar_downdraft_towerAt the other end of things, there are the ongoing efforts to expand solar power production to the point that it will supersede coal, hydro, and nuclear in terms of electrical generation. And that’s the idea behind the Solar Downdraft Tower, a proposed installation some 686 meters (2,250 feet) in height with 120 huge turbines and enough pumping capacity to keep more than 2.5 billion gallons of water circulating. In terms of output, it would generate the equivalent of wind turbines spread over 100,000 acres, or as big as the Hoover Dam.

The process is quite simple: water is sprayed at the top, causing hot air to become heavy and fall through the tower. By the time it reaches the bottom, it’s reaching speeds of up to 80 km (50 miles) per hour, which is ideal for running the turbines. The immediate advantage over standard solar and wind energy is the plant runs continuously, day and night. This addresses the issue of intermittency, which remains a problem with solar and wind generation.

solar_downdraft_tower2Basically, solar and wind farms cannot provide if the weather is not cooperating, or if the solar cells become covered in dust or sand. But as long as the local environment remains warm enough – a near certainty in the deserts of Arizona – the tower will continue to produce power. Best of all, the plant itself runs under its own generated energy – with approx. 11% of the output being used to power the pumps – and aboutt three-quarters of the water is collected at the bottom.

According to Ron Pickett, CEO of Solar Wind Energy Tower (the Maryland company behind the design):

This is totally clean energy that actually makes money. It makes energy at a cost comparable to if you were using natural gas to power a plant.

The simplicity of the technology is also a major selling point. For more than a century, people have been working on variants of solar wind towers. In the 1980s, engineers in Spain built a 195 meter (640-foot) test tower that pushed air upwards through turbines and generated power for seven years until it fell over in a storm. The tougher issue is the enormous expense, which is an inevitable result of building something so big. According to Picket, the Arizona project is likely to cost as much as $1.5 billion to build.

solar_downdraft_tower1However, Solar Wind Energy recently jumped two hurdles to getting the tower realized. First, it won a development rights agreement from San Luis, a city on the Mexico border, that included a deal with the local utility to purchase power, and the rights to the 2.5 billion gallons of water necessary to the project. It also reached an agreeing with National Standard Finance, an infrastructure fund, for preliminary funding that will begin to pay for generating equipment and related costs.

Solar Wind Energy also has plans to see similar towers build in Chile, India, and the Middle East, places that are also well suited to turn warm air temperatures into electrical power. And they are hardly alone in looking for ways to turn solar power into abundant electricity in ways that are technically very simple. As the 2010s roll on, we can expect to see more and more examples of this as renewables make their way into the mainstream.

In the meantime, check out this video from Solar Wind Energy that details how their Tower concept works:

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