Leaf-Mimicking Design Boosts Output of Solar Panels

e360 digest

Leaf Mimicking Solar Panel

By adding microscopic folds onto the surface of photovoltaic materials, a design variation borrowed from a natural leaf, researchers say they have been able to boost the solar output of flexible plastic solar cells by 47 percent. According to the scientists, who published their findings in the journal Nature Photonics, the folds acted as a sort of “wave guide,” channeling light waves and increasing the material’s exposure to light. “I expected that it would increase the photocurrent because the folded surface is quite similar to the morphology of leaves, a natural system with high light harvesting efficiency,” said Jong Bok Kim, a researcher from Princeton University and lead author of the study. “However, when I actually constructed solar cells on top of the folded surface, its effect was better than my expectations.” And since the researchers used relatively inexpensive plastic materials — as opposed to the more expensive silicon commonly used in panels — they hope their findings will help lead to a cheaper and efficient source of solar power.

Yale School of Forestry
& Environmental Studies

Esther Dyson on Charter Cities

Charlotte van den Hout –

The Long Now Foundation:

In a recent article on Slate, Long Now Board member Esther Dyson takes up the concept of Charter Cities – Paul Romer’s model for the creation of prospering, sustainable zones of urban life, about which he spoke at a 02009 SALT lecture. Dyson suggests that Romer’s business-model approach to the construction and functioning of urban centers could work not only for new cities, but for old ones as well.

Cities already behave a bit like corporations, she writes. With greater flexibility and open borders, cities can compete for “customers” in a way that countries cannot, and are more directly involved in the daily lives of citizens. Dyson argues that a little more market-style competition can compel existing metropolises to improve their infrastructure and resources as a way to attract potential citizens. This investment will pay off in the form of flourishing residents, who in turn will bring in additional resources and allow the city to prosper. On a larger scale, a prospering city will then compel its neighboring towns to improve their own functioning as well, to become better competitors on the market of citizens and resources.

In the end, it’s all about the long view: it’s about encouraging civilization to prosper as a whole. Cities are an appropriate unit of civilization to work with, Dyson writes, because they have shown more long-term stability than countries or empires:

“Most cities have grown, through evolution, from unpremeditated beginnings. Moreover, they rarely die. Cities (and their imperfections) persist in a way that large political entities, even those of which they are a part, do not. Compare, say, Athens, Jerusalem, Vienna, Beijing, Moscow, or Istanbul, to the Roman Empire, Austria-Hungary, the Ottoman Empire, Imperial Russia, the Third Reich, or the Soviet Union. And, as we are seeing worldwide nowadays, national governments are difficult to overturn and also difficult to (re)build. Democracy does not always lead to liberty or good outcomes. So, perhaps cities are the right place and have the right scale for massive social change.”

Wastewater treatment…evolved

Living Machines –

The idea of using wetland ecologies to clean polluted water was first conceived by Dr. Käthe Seidel, a biologist at the Max Plank Institute, in the early 1950s. Though she was often opposed by colleagues (who sometimes disparaged her as “Bulrush Kate”), Dr. Seidel conducted experiments throughout the 1950s and 60s which showed that plants and microorganisms could clean water much more effectively than had previously been thought.

The idea was taken up by many ecological designers in the 1970s and 80s. One of these was Dr. John Todd, who designed what he called living machines which sought to marry technology with natural processes to create an environmentally responsible way to treat wastewater on site.

Early model Living Machine®, Findhorn Foundation, Moray, UK

The vegetation in Todd’s systems required greenhouses, and were planted on top of “activated sludge” containers. To produce usable water, they required a settling tank called a Secondary Clarifier, which separates a large amount of messy, smelly sludge from the water. The sludge produced by these systems must be disposed of frequently.

Todd’s versions of the Living Machine® were an innovative effort, but they didn’t get consistent treatment, and could not be made to be simple and cost effective. In 1999, Tom Worrell, an investor and partner of Dr. Todd’s, acquired the Living Machine concept, the company, and all of its intellectual property from Dr. Todd. He then put his engineers to work making the technology practical, reliable, and cost efficient.

One of Worrell’s first ground rules was “No Clarifiers.” He wanted a system that would not depend on activated sludge to do the core of the work. The result was the first Living Machines® that used a wetlands model to treat the water without generating troublesome biowaste that needs disposal.

Wetlands Living Machine® at El Monte Sagrado Resort, Taos, NM

The Next Generation Living Machines® developed by Worrell Water Technologies use beneficial microorganisms (incorporated via engineered biofilms), wetlands plantings, and sophisticated control systems to reliably and efficiently produce water treated to the highest standards. They are stable, healthy, living ecosystems which require less energy to operate, and less work to maintain, than competing treatment systems. They also have a much smaller footprint, and operate in a way that produces no excess waste to be carried away.

Next Generation Living Machines® can be designed for indoor or outdoor applications across a wide variety of climates. For a description of how they work, see our How it Works page.

To read about The Living Machine® in action, go to our Portfolio page.

For more technical information, see our Resources page.

The Sustainability Sweet Spot

Alison Singer – Worldwatch Institute –

What does a truly sustainable country look like?  How do you measure true sustainability in a country? One way has been to compare how well a country achieves human needs, and at what ecological cost. Continue reading “The Sustainability Sweet Spot”

Ancient Hawaiian Civilizations Reveal Ways to Manage Fisheries for Sustainability

Science Daily –

Ancient Hawaiian Fisheries a Model of Sustainability
Ancient Hawaiian Fisheries a Model of Sustainability

“Ancient Hawaiian society effectively practiced what we now call Ecosystem-Based (Fisheries) Management, which is something that modern society often struggles to achieve,” … “Incorporating some of these ancient techniques into today’s policy may be the key to sustaining our fisheries.”

Ancient Fisheries Management