Tech Talk, Round 2: Singapore's "Supertrees"

As you may have gathered from reading this blog, I am a fan of the multitude of steps that Singapore has undertaken to decrease its climate footprint in order to combat man-made climate change.  The country is among the world's leaders in creating policies that further the adoption of energy-efficient technologies and strategies to reduce its carbon emissions.  And the country has also been one of the most innovative in coming up with unique solutions to combat climate change.  One such undertaking really showcases a way where climate mitigation can be as beautiful as it is practical.

The finishing touches are being applied to Singapore's Gardens By the Bay exhibit, which is set to open by the end of the month.  Source:  CNN.com

Singapore's National Parks Board (NParks) is set to open a new exhibit this month, Gardens by the Bay, which will showcase flora and fauna from around the world and create an "urban oasis" within Singapore's city limits.  The main attraction consists of two conservatories, the Cloud Forest and Flower Dome, that will end up displaying over 200,000 plants from the rest of the world's ecosystems.  The designers, however, chose to integrate the biospheres' support systems into the attraction as well, by designing a grove of "trees" to act as collectors of energy.  The "trees" are designed to generate solar power by collecting energy through photovoltaic cells in their canopies, which will then be used to run the technology in the conservatories themselves.  The trees will collect rainwater, and also serve as vertical ventilation shafts for the conservatories.  According to CNN, "the large canopies also operate as temperature moderators, absorbing and dispersing heat, as well as providing shelter from the hot temperatures of Singapore's climate to visitors walking beneath."  NParks is also building skywalks to integrate the "trees" with the rest of the exhibit, and provide visitors with a bird's-eye view of the greenhouses.  

The Cloud Forest conservatory is one of two main display areas for the world's flora and fauna in Singapore.  Source:  CNN.com

This "urban oasis" will not only help reduce Singapore's urban heat-island effect by absorbing sunlight within its natural canopies, but will provide entertainment for its citizens too.  Already, NParks is working on building in bike paths and hiking trails so that visitors can explore the rest of the gardens in the area,  and the addition of marina boardwalks will help visitors to take advantage of the natural beauty of Dragonfly and Kingfisher Lakes, and relax by the water.  The park is a practical and gorgeous example of how climate mitigation strategies can be entertaining to the eye, and beneficial for the planet, too.

Bike trails and boardwalks invite visitors to explore the entirety of Singapore's Gardens by the Bay. Source:  CNN.com

Tech Talk: The Advent of the Wind Lens

One of the most exciting aspects of green energy production is that, because it is a nascent industry, technological advances can occur at a relatively rapid pace.  One such advance, made possible by scientists at the University of Kyushu, could end up helping wind power take flight.

Computer simulation of proposed wind farm off the coast of Kyushu, Japan.  Source: http://polizeros.com/2010/08/02/wind-lens-turbines-could-triple-energy-output/ 

The "wind lens" is actually a series of modifications to the traditional wind turbine that help to increase airflow through the blades of the turbine, and subsequently, increase total power output.  The design works by encasing the blades themselves in an outer shell.  The shell is designed to create small vortices on the leeward side of the lens.  These vortices then create an area of low pressure where the wind exits the turbine (Fig 1).  Because pressures are lower where the wind exits the turbine, more air must move in to fill that area and attempt to achieve equilibrium; this effect causes wind speeds to increase in front of the blades and force more wind through the turbine.

Fig 1: Diagram of wind lens creation of low pressure system.  Source:  Kyushu University RIAM Wind Engineering Section Homepage. http://www.riam.kyushu-u.ac.jp/windeng/en_aboutus_detail04_02.html

The effects of this phenomenon, the researchers found, was to increase wind power by up to a factor of three from the "traditional" turbine design.  Thus, by upgrading wind turbines to wind lenses, existing wind farms could produce up to three times as much power, and energy needs could be satisfied with 1/3 of the space (Fig 2).  Now, due to additional materials usage, and the additional personnel required to retrofit existing structures and construct new fields, the initial startup costs for wind lens technology will be higher than that of traditional designs, but the long-term power advantages will be huge.  With wind lenses deployed in enough locations, the United States could see nearly 90% of its current energy usage accounted for by these wind farms.  Additionally, the wind lens is reported to be quieter than current windmills, and can be created in differing sizes to take advantage of microclimatic conditions in cities or countrysides.  

Fig. 2:  Comparision of results for wind generation between "conventional" turbines and wind lens technology.  Source:  Kyushu University RIAM Wind Engineering Section Homepage.  http://cleantechnica.com/2011/09/02/wind-lens-triples-turbine-output/

It's heartening to know that advances in green tech are rapidly closing the "cost gap"  between nonrenewable sources of energy and renewable, clean alternatives.  As costs fall, companies will be more inclined to pursue these sources to power their operations, since the social benefits combined with lower costs will be a boon for them both on their balance sheets, and in their public images.  Hopefully, proper subsidies and grants will be forthcoming for this technology in the coming few years, so that construction will be initiated in a timely manner, and the transformation of the world to a clean energy society can continue.