OrionWorks wrote: > I sent the following message to the editors of Kiplinger: > > In you March 27, 2009, newsletter under the topic of ENERGY: > > **************************************************** > Is it an oak, maple or birch? No, it's a "power tower"...a generating > system designed to mimic a tree's form, using it to capture both solar > and wind energy. Wafer thing "leaves" absorb sunlight, converting it > to electricity to be stored or used.
This line: > Ditto, the energy released when > faux foliage rustles in the breeze. seems very implausible. I can't imagine a system you could build today that would be affordable, durable, and would be able to convert the fluttering motion of the leaves to electricity. Piezoelectric? It would be outrageously expensive to build an entire *tree* with a piezo converter on every leaf; it's inconceivable that the cost would be recouped by the energy harvested. Anything else I can think of which makes any kind of sense for a single leaf also fails to scale to the size of a tree. With that stake in the ground, we can go back and think about how easy it would be to make tens of thousands of small solar panels each as durable and light as a leaf -- and then let the "wafer thin" panels rustle around, bang into each other, each one just suspended from a wire. Does this seem reasonable with today's technology? Barely possible, maybe. Note that a full grown real tree has something like 50,000 leaves, or perhaps more. Does this make any sense as an approach to building a solar generating station? No. They overplayed their hand with the "wafer thin" leaves and the conversion of wind energy as a result of the leaves "rustling" in the breeze -- without that, we could imagine it would be like the fake-tree microwave towers, which look just enough like trees to make them blend in, "sort of". But the author went too far, and it reads like sci-fi, not like a sensible proposal. Note that real deciduous trees have lots of flimsy leaves, but they treat them as disposable. They're all replaced every year (twice a year if the gypsy moths get them). "Lots of flimsy" anythings isn't a good plan if you want your "anythings" to keep working long enough to recoup a large initial investment. > A single "tree" could power a > house year-round. A house *where*? And with what kind of heating system? A single tree has maybe the exposed sun-pointing surface area of a good size roof. (Remember, it's not the total area of the leaves that matters, it's the total area of the shadow cast by the 'tree' -- adding more leaves only helps if they can be added outside the umbra of the top layer of leaves.) > A grove of them...a fifth of a typical town's needs. > > The first towers will show up around 2011. In a decades...a bumper crop. > ****************************************************
