Trees as Indicators of Prevailing Wind Direction

trees as indicators of wind direction“In mountainous areas, winds are often complex and the available wind data are limited and provide little information on wind direction. One technique for determining the mean wind direction is tree flagging. Trees have been used for hundreds of years as an ecological indicator of wind direction, wind exposure and as a measure of the severity of wind and ice damage. This handbook will describe techniques for ‘reading’ the information written on the trees by wind.”

“Flagged trees only reflect the prevailing wind direction of the strongest winds, which may occur during only part of the year. Seasonal variations in the wind have a pronounced effect on the type of wind deformation and these effects are characterized in this handbook. Techniques for estimating the mean annual wind speed have been developed using indices of wind effects on trees. These indices have been calibrated on two widely distributed species of conifers. The main conclusions are that trees provide a simple, inexpensive and quick method for identifying promising locations where more detailed measurements can verify the wind potential.”

Trees as an indicator of wind power potential (.pdf), John E. Wade & E. Wendell Hewson, 1979.
Vegetation as an indicator of high wind velocity (.pdf), DOE report, John E. Wade & R.W. Baker, 1977

More low-tech wind power.

The Junk Blue Book: Indigenous Fishing and Cargo Craft

Vietnamese junk qtbc 1 “The Junk Blue Book of 1962 is a detailed catalog of the indigenous boats of what was then South Vietnam, during a period when most such vessels were still powered by sail. It was a manual put together by the US Dept. of Defense early in the involvement in the war in Vietnam. It was used as a guide to identify coastwise marine traffic involved in smuggling supplies and personnel south into the Republic of Vietnam from then North Vietnam. Although its production was driven by perceived military necessity it is a unique chronicle of the indigenous fishing and cargo craft of the mid and southern Vietnamese coasts.”

The book is in the public domain and can be found on scribd. A pdf-version is available on a dedicated site. Via Indigenous boats. See also: the wooden work boats of Indochina.

Wind Farms Can Be Made 10 Times Smaller

Size of wind farms “Modern wind farms comprised of horizontal-axis wind turbines (HAWTs) require significant land resources to separate each wind turbine from the adjacent turbine wakes. This aerodynamic constraint limits the amount of power that can be extracted from a given wind farm footprint. The resulting inefficiency of HAWT farms is currently compensated by using taller wind turbines to access greater wind resources at high altitudes, but this solution comes at the expense of higher engineering costs and greater visual, acoustic, radar and environmental impacts.”

“We investigated the use of counter-rotating vertical-axis wind turbines (VAWTs) in order to achieve higher power output per unit land area than existing wind farms consisting of HAWTs. Full-scale field tests of 10-m tall VAWTs in various counter-rotating configurations were conducted under natural wind conditions during summer 2010. Whereas modern wind farms consisting of HAWTs produce 2 to 3 watts of power per square meter of land area, these field tests indicate that power densities an order of magnitude greater [21 to 47 watts] can potentially be achieved by arranging VAWTs in layouts that enable them to extract energy from adjacent wakes and from above the wind farm.”

Small wind farm “The results suggest an alternative approach to wind farming that has the potential to concurrently reduce the cost, size, and environmental impacts of wind farms.”

Read more: ‘Potential order-of-magnitude enhancement of wind farm power density via counterrotating vertical-axis wind turbine arrays’, John O. Dabiri. Introduction. Research paper (pdf). Via Ecogeek

The Homemade Windmills of Nebraska

home made windmills of nebraska

“The merit of homemade mills has enjoyed such prompt recognition that they are going up daily. Not to the detriment, we are happy to say, of those important adjuncts to the farm, the shopmade mills, but in addition to them.

In a given community, the man who puts up the first mill generally furnishes the model for the rest of the community. Hence it seems the more desirable that good models should be at hand, the better models are often of quite as easy constructed and no more expensive than the poorer, and their efficiency considerably greater.

It is advantageous to have good models to copy, and the next best thing to the actual model is a good simple drawing. This is the first object of this paper on our homemade windmills; it aims to supply cuts illustrating all sorts of windmills, as found in this State.”

The homemade windmills of Nebraska” (pdf), Erwin Hinckley Barbour, 1899. Illustration: a wind powered sawing machine.

Related: Windmills and wind motors – how to build and run them (1910), Building plans of Dutch Industrial windmills (1850).

Can Renewables Power Consumer Societies? The Negative Case

“Virtually all current discussion of climate change and energy problems proceeds on the assumption that technical solutions are possible within basically affluent-consumer societies. There is however a substantial case that this assumption is mistaken. This case derives from a consideration of the scale of the tasks and of the limits of non-carbon energy sources, focusing especially on the need for redundant capacity in winter. The first line of argument is to do with the extremely high capital cost of the supply system that would be required, and the second is to do with the problems set by the intermittency of renewable sources. It is concluded that the general climate change and energy problem cannot be solved without large scale reductions in rates of economic production and consumption, and therefore without transition to fundamentally different social structures and systems.”

Read more: “Can renewables solve the greenhouse problem? The negative case” (pdf), Ted Trainer, Energy Policy, March 2010. Also check out the author’s website, where you can find similar papers, like this one.

How to Rig a Windmill Sail

how to rig a windmill sail

Source: “Travailler au moulin / Werken met molens”, Jean Bruggeman, 1996.