A second day of production at Bensonwood.




All photographs courtesy of Naomi C. O. Beal Photography

MONTHLY kWh PROJECTED OUTPUT

BBB is projected to produce approximately this amount of power per month.

Month AC Energy (kWh)


Jan 587
Feb 687
Mar 796
Apr 734
May 762
Jun 712
Jul 770
Aug 761
Sep 706
Oct 631
Nov 455
Dec 463

Total 8062

BrightBuilt assembly at Benwonwood Day 1

This week the BrightBuilt Barn is in the shop at Bensonwood. Detailed dimensioned drawings of the floor, wall and roof panels have been sent from the Bensonwood CAD software to their CNC cutting machines on the shop floor, where the panels are cut and assembled.



All photos courtesy of Naomi C. O. Beal Photography.

Embodied Energy: Carbon Debts and Kilowatt Holes

As we try to decrease the carbon footprint of our buildings, we need to consider two distinct, but inter-related issues: reducing the carbon footprint of the building process itself, and reducing the carbon footprint of running and maintaining the structure once built.

Addressing the second issue led us to choose super-insulation (to minimize the energy required to heat the place) and sustainable energy sources such as solar thermal and photovoltaics.

Here I want to say just a few words about the other issue, minimizing the carbon emissions resulting from the building process itself.

First of all, this is to my mind a much harder problem to solve than that of reducing the carbon impact of ongoing energy use. Ongoing energy needs can be straightforwardly addressed by judicious design (to decrease consumption by eliminating waste) and switching to zero-emission sources of energy such as wind or solar. To solve the problem of reducing the impact of the building process itself, we need to consider the carbon load introduced by making, transporting, and assembling each and every component of the building. This calculation quickly becomes extremely complex, requiring detailed knowledge of materials, manufacturing processes, and modes of transport.

To take a simple example: the chemical process by which cement powder is turned into hardened concrete (just add water and stir!) releases CO2 - lots and lots of it, it turns out. So we have tried to use more wood and less concrete, even though concrete has many desirable properties as a building material (easy to shape, high thermal mass). But if the wood is harvested in Indonesia (as much wood is) and transported to us by boat, train, and truck, we have incurred the carbon load of all that transport. So we have tried to minimize transport by local sourcing of wood, to the extent feasible. And on and on.

The underlying concept here is generally called embodied energy: each structure embodies all of the energy (and associated carbon emissions) used to make its constituent parts, transport them to the site, and assemble them into the finished building. On the BrightBuilt team, we usually call it the carbon debt we have incurred by building a structure where there wasn't one, or the kilowatt hole we have to dig out of by generating zero-emission electricity that displaces high-carbon fossil fuel use.

It turns out that there is no central database containing data on the embodied energy of common building materials. Worse, there is no single, widely accepted method for calculating embodied energy.

We have consulted experts around the globe, from MIT to Australia, in an attempt to calculate the embodied energy of BrightBuilt Barn. While we believe that we have made a serious and intellectually honest attempt, we do not claim to have precise and unassailable results.

Brian, of Opus One Studio, has become our resident expert on the subject. In a future post, he will give some of his findings and methods.

For now, we will only say that the carbon debt incurred by even a small building such as BrightBuilt barn is surprisingly high, and will require years of excess clean energy production to pay back. We are helped here by 1) our commitment to durable materials, which greatly lengthen the usable life of the building, and so give us a longer time frame over which to amortize the carbon debt; and 2) our decision to maximize the excess energy we produce, by using superinsulation to reduce energy demand while covering the roof with solar energy systems despite the reduced need for ongoing energy.

Brian's Energy Meter will track the energy surplus, both minute-to-minute and cumulative, and we will put the results on the web at the BBB site, so anyone can track the progress we make in climbing out of our "kilowatt hole."

"Barn-Raising" Set for Week of July 7

We seem to have a firm date for the delivery of the offsite-fabricated structural panels from Bensonwood - they are due to arrive onsite July 7.

Assembly of the pre-constructed panels into the unfinished Barn will take approximately one week.

Those in the Rockport area are welcome to watch the "barn-raising" (accomplished with cranes - no bystanders will be pressed into service :-) ). [The picture above is of an old-fashioned Amish barn-raising, and has nothing to do with how BrightBuilt Barn will look or be constructed - apologies for my offbeat sense of humor.]

Those following progress from afar will be able to see pictures and video on the Barn website.

At long last, BrightBuilt Barn will fulfill our promise to make it a built structure, not just a design study.

Stay tuned for more developments.

James Hansen PhD - Climate Crusader

Yesterday, on the 20th anniversary of his ground-breaking first testimony to Congress on the perils of global warming, Dr. James Hansen, esteemed head of the NASA Goddard Institute for Space Studies and an adjunct professor at Columbia University, provided Congress an update.

The verdict: 20 years later, the evidence suggests that his warnings of 1988 were, if anything, understated, and that climate change may be fast approaching a "tipping point" where massive disruption becomes inevitable. In his view, only vigorous action to bring atmospheric CO2 levels below 350 parts per million (ppm) can stave off serious consequences (current levels are 385 ppm, and rising approximately 2 ppm per year.)

Dr. Hansen's 1988 Congressional testimony brought into the public discourse the subject of climate change due to greenhouse gases released in the burning of fossil fuels. Hansen has been a clear and steady voice publicizing the findings of climate scientists around the world, and a tireless advocate for a greener future. Vilified by climate-deniers, he was subjected to censorship by the Bush II administration, which required all of his public statements be run past the NASA public relations staff, who edited many of these statements to soft-pedal suggestions that climate change was man-made and potentially risky. Dr. Hansen refused to be muzzled, and his whistle-blowing on the Bush II administration's attempts to censor climate science led to a public outcry against political interference with science.

Yesterday's testimony before Congress was a typical blend of impeccable science, blunt warnings, and outspoken advocacy for change to save the planet for our children and grandchildren.

You can read his testimony here:

http://www.columbia.edu/~jeh1/2008/TwentyYearsLater_20080623.pdf

His associated slide presentation is here:

http://www.columbia.edu/~jeh1/2008/TippingPointsNear_20080623.ppt

Together, these serve as a handy summary of the science, the issues, and many of the major proposals for ameliorating global warming.

A quick summary of Dr. Hansen's life and career can be found here:

http://en.wikipedia.org/wiki/James_Hansen

Read, and be enlightened - and, hopefully, inspired to action.