A Water Efficiency Breakthrough

Rain patterns are changing all over the planet. Being in a multi-year drought, Southern California is acutely aware of this indispensable resource and our lack of it. Santa Barbara has cut its non-agricultural water consumption by 35 percent. If we can cut usage even more, we can minimize additions to our water supply from the most costly, most energy intensive sources such as desalinization or the California State Water Project.

A promising development that can help cut water consumption even more is the atomizer mist technology. Nozzles harnessing this technology can be attached to most faucets or the concept can be incorporated into showerheads. The Swedish firm, Altered, has created a simple device that atomizes tap water into a fine mist. Although simple, it has been years in development. The result, per the company, “is a 98 percent reduction in water use, with no loss in functionality.” Although using only about 2 percent of the flow from a tap with no flow restrictor, the dispersion of millions of tiny droplets of water created by the high spread mist, makes it as effective in performing tasks like washing hands, cleaning a toothbrush or rinsing vegetables, or, for that matter, doing most other tap-related tasks.

At times, more water is needed more quickly than the atomizer can provide. Because it takes minutes to fill a glass or a pasta pot with water in the mist mode, the nozzle can easily be switched to a higher volume flow, called the Saver mode. This mode increases the flow to almost a gallon (0.8 gal) per minute. Since, on average, about 18 percent of household water consumption is through sink faucets, retrofitting with these small, attractive devices could reduce overall household water usage by 15 percent or more.

Another recently developed product using the same atomizing approach is the Nebia showerhead. Produced in the US, it similarly disperses water into millions of microscopic droplets to create 10 times more surface area than a regular shower’s water pattern, while saving 70 percent of water in the process. It has a built in multi-layer filter to catch sediment and other solid buildup. The Nebia comes with a wall mounted bracket that allows the showerhead to be adjusted vertically, or even detached completely to be used as a portable unit.

Both of these devices, new players in the strategic game to make more efficient use of our available water resources, show great potential as they move into the marketplace.

Carbon Storing Building Materials

Since my recent article on constructing carbon storing buildings, many have asked for specifics on carbon sequestering building materials. Here is a partial list:

·         Cross-laminated timber (CLT) panels of varying dimensions made up of alternating layers of perpendicular boards. Because small diameter trees, pest damaged trees and even trees killed by wildfires are used in fabricating these members, forest resources are more fully utilized. In addition to being strong, stiff, stable and relatively light weight, CLT panels are highly fire resistant and hinder fire spread. CLT can often be substituted for steel, even in high rise construction.

·         All bamboo building materials. Bamboo is a fast-growing wild grass that takes carbon out of the air faster than other plants. When laminated into posts, beams, glue-lams and trusses (trade name Lamboo), it rivals the strength ratio of steel yet is more fire resistant without the use of ecologically unfriendly fire retardants.

·         Cal Star bricks and pavers.  These are manufactured from fly ash, a waste product, using a small fraction of the energy needed to fabricate other masonry products. Another technology, on the cusp of commercialization, is growing bricks at ambient temperatures using bacteria and biomass. Absorbing pollution and carbon is part of the process.

·         Hemp lightweight composite (building) blocks (developed by JustBioFiber Structural Solutions). The blocks are highly resistant to fire, mold and insect damage. Hemp products are top performers in the negative carbon materials classification.

·         Calplant MDF rice straw panels. These panels utilize a carbon sequestering waste material that normally is disposed of by farmers flooding their fields using large amounts of valuable water.

·         Low-carbon insulating materials: cellulose, fiberboard (Gutex Multitherm), hemp board, recycled denim and mushroom insulation. Ecovation is the brand name for mushroom insulation. It can be sprayed into wall cavities or seeded, filling the cavity in 3 days.

·         Ecosmart drywall. This product uses less energy, resources and water to manufacture, is fire resistant and lighter in weight, thus requiring less energy to transport.

·         Green concrete. Cement accounts for around 6 percent of greenhouse gas emissions (GHG). Green concrete focuses on 3 strategies: cutting GHG emissions, reducing inputs of natural resources, mostly by substituting recycled materials, and lessening air, land and water pollution related to its production. Ceratech, a US company, has created a feed mixture for cement that is 95 percent recycled fly ash and 5 percent renewable liquid additives, yielding an almost zero carbon footprint. Its concrete mixes reduce virgin resource inputs by 95 percent and water by half. This hydrated cement has superior properties to Portland cement, the industry standard. Another innovation is a cement that cures by absorbing CO2.

Incorporating these and other low or negative carbon materials in new and remodeled construction can substitute for many traditional building materials. Traditional materials like steel, concrete, aluminum and glass account for 11 percent of global CO2 emissions, according to a report from the UN Environmental Program. All materials listed above, except the bacteria grown bricks, are currently available and fit standard construction practices.

Building with Wood

For several decades there has been a debate in the building industry as to whether wood frame or steel frame construction is more sustainable—wood being a renewable material, while steel has recycled content, often incorporating 70-80 percent old automobiles. Perhaps the debate is finally being decided due to a panel technology called cross-laminated timber, CLT for short. Developed in Europe in the 1990s, it is only recently gaining popularity here.

A CLT panel usually consists of 3, 5, 7 or 9 layers of kiln-dried boards stacked in alternating directions, bonded with structural adhesives and pressed to form a solid, straight, rectangular panel. Surprisingly CLT has good fire-resistant properties: it is hard to ignite and once lit resists fire spread. Because the layers are oriented perpendicular to each other, the CLT panels are exceptionally strong, stiff, stable, relatively light weight and able to handle load transfer on all sides. They can be used for walls, floors and roofs in a single building system, or used interchangeably with other wood products.

Most commonly CLT panels are 40-60 feet long but can be as much as 100 feet. They are up to 18 feet wide and any thickness up to 20 inches. These panels are widely used in Europe, Australia, Canada and Japan. The possibility of large panels is revolutionizing how 10, 20 and 30-story buildings are being built. Currently an 18-story, 400 student residence (174 feet high) at the University of British Columbia is the largest CLT structure, but a 24-story tower is under construction in Vienna and a 35-story building in Paris is in the works. The most ambitious proposal to date is London’s CLT framed, 80-story Oakwood Tower.

Not only are CLT panels frequently made using small-diameter trees, but also can use less desirable wood from pest damaged trees, or even trees killed by wildfires, without compromising the panel’s overall integrity. These small, less-than-perfect inputs to panel manufacturing are leading to better utilization of forest resources. Pulling out small and medium sized timber, as well as dead trees, contributes to healthier forests.

Processing these culled trees into CLT panels, which then get incorporated into buildings, sequesters carbon from the atmosphere. CLT not only emits less carbon dioxide during the manufacturing phase but the finished buildings then help sequester carbon for longer periods. Scientists estimate that buildings made with these materials result in a 25-30 percent reduction in global warming potential compared to those made with traditional materials—concrete, masonry and steel.

Because they lend themselves to design versatility, fast installation, reduced waste and good thermal and seismic performance, CLT can reduce construction costs by up to 50 percent. Perhaps the biggest advantage, however, is sequestering carbon while creating healthier and more resilient forests.

Nature Knows Best - Carbon Farming

For the past 20 years, since Ed Mazria calculated that buildings use almost 50% of energy consumed in this country, I have been on a quest to make buildings super energy efficient, while producing any additional energy needed from site-generated renewables. But now I am coming to believe that there is another option for reducing greenhouse gases that is equally, if not more, important.

A carbon experiment on a small number of ranches in Northern California is establishing a simple, benign way to remove carbon dioxide from the air. UC Berkeley scientists have measured the impact of a one-time spreading of compost ( ½ “ layer) on rangeland and found, to their surprise, that it boosted the soil’s carbon sequestration capacity on average one ton per hectare per year for each of the 8 years they have been testing. They forecast that this sequestration process will continue for at least two decades.

Grazing is the largest land use on the planet and most grazing lands are degraded. If this one-time thin application of compost were applied to a quarter of California’s rangeland, the soil would absorb ¾ of California’s greenhouse gas emissions for the year, and since the effect is cumulative, it would keep doing so for a number of years.

For centuries humans have been bleeding soil-stored carbon into the atmosphere through plowing, overgrazing and poor agricultural practices. These recent compost applications can reverse this and create what scientists call a positive feedback loop. Plants pull carbon dioxide from the air through photosynthesis and transfer a portion of the carbon to the soil through their roots and soil microorganisms, then turn that carbon into a form commonly known as humus. This process improves soil fertility, boosts plant growth and captures even more carbon, while enhancing the soil’s ability to absorb and retain water.

Where is all this compost going to come from and who is going to pay to have ranchers spread it on their land? The compost has to come primarily from cities. San Francisco composts 700 tons of residential and commercial organic waste everyday—the largest such operation in the world. This can become a great resource for ranches. As for compensation, key efforts are being made to incorporate soil carbon offsets in California’s cap-and-trade system as a way to make it profitable for ranchers to restore their land.

Although only recently recognized as a carbon sequestration strategy, “carbon farming” has already captured the attention of the White House and officials as far away as Brazil and China. This inexpensive, low-tech harnessing of natural systems holds the potential to turn the vast rangelands of California and the world into a weapon to reverse climate change.