Our top 10 project plans
From the convertible picnic table to the outdoor shower, over the past 23 years, we’ve published plans for countless handy cottage projects. For a limited time only, our top 10 project plans are available for free courtesy of your local TIM-BR MART. Happy building and enjoy!
How to build a gazebo
As soon as the hammering began, interest around the bay was piqued. First, a pedal boat cruised by; the pedallers had heard construction noise and wanted to see what was going on. Their compliments were enough to make this old builder’s heart swell structures are used for just about everything—eating, sleeping, working, lounging, and conversation. […]
How to build a convertible picnic table
Last summer, my wife, Lynn, and I dropped in on cousin Kathleen and her husband, Ross, at their Wahwashkesh Lake cottage. After the customary welcome refreshments and sharing of family news and gossip, Ross and I naturally started talking cottage stuff. I noted that he had recently replaced the deck on the side of the […]
Vertical-Axis Wind Turbines: The Future of Micro Wind? [w/video]
![Vertical-Axis Wind Turbines: The Future of Micro Wind? [w/video]](https://i0.wp.com/cleantechnica.com/files/2008/06/dscn0012-300x278.jpg?ssl=1 "Vertical-Axis Wind Turbines: The Future of Micro Wind? [w/video]")
![Vertical-Axis Wind Turbines: The Future of Micro Wind? [w/video]](http://cleantechnica.com/files/2008/06/dscn0012.jpg "Vertical-Axis Wind Turbines: The Future of Micro Wind? [w/video]")
Walking the floor of WINDPOWER 2008, the annual conference and trade show for the wind energy industry, one couldn’t help but be transfixed by all of the different types of turbines – at least I couldn’t. The wind turbine has become the iconic symbol of clean, renewable energy. But the classic three-bladed turbine horizontal axis wind turbine, with its gracefully swooping blades, has become the symbol of not only renewable energy, but also of environmental consciousness and ecological possibility.
Despite the ubiquity of the three-bladed turbine, the oft-overlooked vertical-axes turbines are making quite a splash in the world of wind energy, especially in small and micro-applications. So what’s all the fuss about? Vertical-axis turbines apparently do not suffer from some of the same problems that plague small wind applications in urban settings including, aesthetic concerns, space requirements and sound levels.
Other advantages of vertical-axis turbines:
- Can produce up to 50% more electricity per year than conventional turbines with the same swept area
- Generate electricity at much lower wind speeds, as low as 4 mph (1.5 m/s)
- Will continue to generate power in high wind speeds, up to 130 mph (60m/s) depending on the mode
- Direct-drive units have no gearbox. No gearbox means a more efficient transfer of energy and no leaking oil
- Will not harm wildlife, in terms of bird and bat strikes
Below, I’ll cover some more basic differences and show you a few photos and short videos of some of these turbines I saw down in Houston at WINDPOWER 2008.
The designers from Taiwanese start-up A.N.I.T.A. Energy (pictured above and in video below) showed me why their models have a low start-up wind speed, and that is because of the light metal bands you can see surrounding the turbine itself. Apparently this design allows users with a less substantial wind resource (particularly those in urban applications), squeeze some electricity from the local winds. The larger model pictured above is scalable and can be stacked as many as three-high and integrated with the rooftops of large buildings.
Another design I saw scattered throughout the show floor were those that integrated small solar and wind together on the same unit (top photo and photo below). The unit below integrates both solar and wind onto a single 400W streetlight platform.
The turbine itself is a “GUS” from a company called Tangarie which features a reflective coating that reduces glare and can even be slathered with an advertisement or a state flag of Texas, as is the one below. The complete solar/wind/streetlight/pole package (made by another company altogether) costs about $7,000, not including installation.
There will undoubtedly be substantial growth in the vertical-axis turbines, especially in urban settings. Personally, I think this technology could best be applied in poorer countries to help address the most basic of energy needs, like lighting and light-duty water pumping.
Other Posts on Small and Micro Wind Energy:
“Top Five Micro Wind Turbines”
“Liveblogging from WINDPOWER 2008: Photos of Small Wind Turbines”
“Small Wind Remains in Farm Bill”
*Thanks again to the American Wind Energy Association for providing travel and conference support to WINDPOWER 2008.
Evaluating the Cleanliness of Solar Photovoltaics Can Be Complicated
I am a frustrating individual who likes to delve deeply into decision making computations and hates easy answers that sound like sales pitches. One of the best compliments I ever received came from one of my division officers when I was serving as the Engineer Officer on a submarine – he told me “Eng, you ask hard questions.”
As vocal advocate for nuclear fission power I recognize that it has many associated questions, but I after 30 years of study, I have determined to my own satisfaction that most of the important questions have reasonably good answers. In contrast, I have not yet found reasonable answers for many of my questions related to other renewable energy sources. (Yes, I – perhaps controversially – classify fission as renewable, but that is a discussion for a different post.)
Solar photovoltaic (PV) cells are a popular and often discussed (see, for example Atlantic City Convention Center Plans Largest Solar Roof in U.S., 10% of U.S. Electricity From Solar by 2025, SF Passes Largest City Solar Program in U.S. (Finally), all of which were published within the past week) form of “renewable” or “green” energy, but a casual scratching of the surface knowledge that many people have about the technology reveals some troubling details.
Not only are the panels expensive sources of electricity, but they do not last as long as advertised, they do not provide as much energy as the nameplate capacity implies, they consume significant quantities of energy in their production, installation and transportation, and they often use some very nasty materials in their manufacturing process.
The longevity of a solar panel will vary greatly depending on where it is installed, but any customer should remember that they are buying a product that will inherently need to spend as much time as possible fully exposed to the sun and weather. Though there are no visibly moving parts in a solar PV panel, there are many parts of the system where continuous chemical and physical reactions take place that can eventually lead to system degradation and failure.
Take a good look at panels that have been installed for several years and you will notice discontinuities and shiny areas where the components have been damaged and where the power production is reduced. If you have any panels, might want keep a record of the current production so that you can see this effect – or perhaps you will not want to find out just how fast that long term investment is decaying.
The literature accompanying most solar panels provide customers with numbers related to their peak capacity – what I call “noon on a clear day at the Equator”. That quantity of power is only available when the sun is directly overhead, when the panel is perfectly clean and when there are no clouds shading the cells. The cleaning part is important, any panel owner that wants maximum performance needs to set up a routine for cleaning and clearing the panels of any debris.
Leaves and snow are particular nuisances for rooftop solar panels, but sand and bird droppings can be important in some areas as well. Not that the article was specifically discussing PV panels, but I recently read about the 4,000 gallon water tanker trucks that are part of the maintenance equipment at some desert solar power plants.
Some of the most energy efficient solar panels, in terms of both the energy required to produce the panel and the panel operating efficiency are made of a semiconductor material called CdTe (Cadmium Telluride). Companies that make CdTe cells like to brag about the quality of their products, but they have also recently had to warn their investors that they may not be able to sell their panels in the EU for much longer because of rules about using toxic heavy metals in electronics. What they have not made clear yet is what their long term liability is for the panels that they have already sold. What will happen in 5, 10 or 20 years when the panel output is no longer useful and the materials need disposal? Can they be recycled without releasing the heavy metals? Will their customers be able to return the panels to the original producer? Will they make the effort or simply take the systems to the dump like many consumers do with batteries made of similar materials? (Those are the kinds of questions that my former division officer was talking about.)
There are definitely answers to some of the questions that I have about solar PV, but that does not mean that the issues are fully solved. If you are in the market for solar PV systems, please ask the hard questions and realize that anyone who wants you to buy the systems without good answers is just a salesman who is not much different from any other salesman.
Photo credit – The Sun Works (photos to be shared)