Green Bridge

The Tennant Avenue Bridge is a typical overpass that one may see throughout the United States. Its construction wasn’t unique; that is, no changes were made to its construction schedule to compensate for the reduced carbon footprint. The carbon footprint was reduced 25% compared to traditional mixes and may well have been further reduced. The specifications by which the concrete mixes were allowed to be used represent a dramatic change that provides a glimpse into the future sustainable design and construction of the infrastructure

The Tennant Avenue Bridge

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Green Buildings Economy:

Prima facie, green buildings cost more. However between three to five years, unlike a normal construction, a green building actually starts giving you returns. Since a green building conserves energy and also makes the most of sunlight the energy costs are slashed by 40 to 50 per cent. A US study, for example, found that certified green buildings cost 1.8% more to design and construct, but yield 20% cost savings over the life of the building. However the obstacles to achieving these benefits in the fragmented property sector are also well documented. The sustainable building design, green materials and green technology are often more expensive than normal building blocks and are often not easily available but the upside monetary advantages more than compensate for that. These buildings are also eligible for carbon credits, since they save the environment from carbon-dioxide emissions. That opens up another revenue stream for the developer. It is therefore no surprise that the projected growth potential for green buildings in India is Rs 2,000 crores.

The financial barriers, including high initial cost barriers and an inadequacy of traditional financing instruments, are a key element preventing private actors from engaging further towards making the residential building sector more energy efficient, according to a study from the International Energy Agency (IEA). Despite the proven cost-effectiveness of energy-efficient technologies, their potential remains untapped in the building sector "due to numerous market barriers", states the IEA, based on the results of case studies of the residential sector in France, Germany, the UK, Japan and the US.

The green buildings are important for India. In spite of India's per capita consumption of energy being far lower than western economies, it's building sector has climbed to an usage of nearly 30 percent energy, up from a low 14 percent in the 1970s. India's energy conservation laws for buildings are voluntary but this is one area in which the country is already greener than in many parts of the developed world. According to the Indian Green Building Council (IGBC) set up in 2000, the country's modest 25,000 square feet of green buildings in 2003 have grown to a phenomenal 25 million sq.ft in just 4 years, projected to grow to one billion sq. ft per year by 2010. One of the reasons for this rapid growth is India's high economic growth and emerging status as the global business giant, resulting in imminent demand for commercial, infrastructural and residential construction. The country seconds China in its growth and demand of infrastructural development. The IGBC's standard of green buildings is based on the U.S.' Leadership in Energy and Environmental Design (LEED). The savings in cost of energy and water alone are attracting more commercial builders into the IGBC

Condition air with tinted windows:

A new product may soon emerge from the race to create better materials for green building. Sage Electrochromics, based in Faribault, Minnesota, recently raised $20 million from investors to continue its development of tinted windows, which automatically shift from light to dark as environmental conditions change.

The electrochromic windows and skylights sense the change in surrounding temperature and respond accordingly to save energy. If it is warm, the windows darken to keep the building cool. When it is cool, the windows appear clear again. The technology aims to reduce the need for air conditioning, which is notoriously energy-inefficient and increasingly costly.

The windows are undeniably cool. But, as this article notes, the high-tech electrochromic windows may find it difficult to compete with other lower-tech, less expensive solutions already on the market:

Other companies, such as Denmark's PhotoSolar, make windows that block solar heat with a simple passive film inserted between two sheets of glass. The windows have a permanent, gray tint to them, but you can still see out of them. More importantly, they don not require any electronics or controls.