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The cement that eats carbon dioxide
Alok Jha, Guardian
Cement, a vast source of planet-warming carbon dioxide, could be transformed into a means of stripping the greenhouse gas from the atmosphere, thanks to an innovation from British engineers.
The new environmentally formulation means the cement industry could change from being a “significant emitter to a significant absorber of CO2,” says Nikolaos Vlasopoulos, chief scientist at London-based Novacem, whose invention has garnered support and funding from industry and environmentalists.
… Making traditional cement results in greenhouse gas emissions from two sources: it requires intense heat, and so a lot of energy to heat up the ovens that cook the raw material, such as limestone. That then releases further CO2 as it burns. But, until now, noone has found a large-scale way to tackle this fundamental problem.
Novacem’s cement, based on magnesium silicates, not only requires much less heating, it also absorbs large amounts of CO2 as it hardens, making it carbon negative.
… A spokesperson for the British Cement Association expressed a sceptical note, saying that though there was much ongoing laboratory work on new types of cement, there were also problems. “The reality is that the geological availability, and global distribution, of suitable natural resources, coupled with the extensive validation needed to confirm fitness-for-purpose, make it highly unlikely that these cements will a be realistic alternative for volume building.”
Vlasopoulos responded that magnesium silicates are abundant worldwide, with 10,000 billion tonnes available, according to some estimates.
(31 December 2008)
The Cost of Polishing a Turd
Nic Darling, 100K House Blog
… Most of the builders and developers reporting high premiums for pursuing LEED are still trying to build the exact same home they have always built. They are simply adding features to make that same house energy efficient, healthy and sustainable. This addition gets expensive.
Builders, successful ones anyway, often have a basic home that they build over and over. They know how it goes together. They can build it quickly and inexpensively, and most importantly, they know it will sell. When they are suddenly faced with the need to “go green,” they are understandably reluctant to make significant changes to the design of their proven house. Location, interior fixtures, numbers of bedrooms and bathrooms, square footage and window placement are all tested and successful specs. The familiar methods of construction they use are easy for them to estimate and well known to every sub-contractor and laborer on the site. There is, in their minds, less management and less risk.
So, they polish the turd. Rather than redesign the house that has been successful for them in the past, they add solar panels, geothermal systems, high end interior fixtures, extra insulation and other green features. The house gets greener. It gets certified, but it also increases significantly in cost. Since the features are add-ons and extras, the price rises as each one is tacked on.
To avoid these extra costs, one must start the home design process with affordability and sustainability factored into every decision.
(16 December 2008)
Wanted: Natural residents to share up-and-coming urban quarter in Sweden
Carolyn Fry, Guardian
It’s not only trendy urban types who are making themselves at home in Sweden’s Western Harbour housing project: innovative steps by the planners to promote biodiversity are proving successful as bats, birds and insects move into the Malmö development.
(2 January 2009)
