Become a fan of Slashdot on Facebook


Forgot your password?

Comment Re:Well, Duh! (Score 1) 448

They are not cowards, they are smart.

The business to be made out of terrorism and terrorism-related wars is in trillions. The security theater with scanners, personnel and redesigning airports is just a small bit of it. If you use terrorism as an excuse for a war, that gives you sales of helicopters, missiles, bombs, consumables, after war rebuilding contracts, wheelchairs, meds and other stuff to fix soldiers with bits blown off. If you manage to get $2 out of every $10 spent in war, it sums up nicely. Added bonuses include ability to control oil and/or other commodity prices, with good multiples on futures and options. While the net effect on the economy is negative, the $8 comes from pockets of taxpayers, target country and generally someone else, so it is not a problem. Correctly timed war will also get you re-elected, so you can go on poaching for another term. After two terms you are maxed out, so you give the mess to someone else to clean up, blame him for the results, get elected again and repeat. Every cycle transfers a percentage of your country's net worth to you pocket, so the bigger the mess the better!

And these smart guys won't be suffering of the airport security, as they fly private jets anyway, but that is really the small bit of it.

Comment Re:Misleading CO2 (Score 1) 272

I would think that showing tailpipe emissions does make sense, as long as your electric bill also shows your emissions per kWh. You can generate electricity yourself, which is rarely possible or more difficult with liquid fuels. Ok, producing your own alcohol does have side benefits...

Generating 50 mile daily driving requires 20kWh (using your figure) requires approximately approximately 20m2 of solar panels (4kW). Cost is probably somewhere around 15k for that, assuming no subsidies. Seems actually less for current thin-film panels.

Combine higher energy efficiency of battery electrics and the investment buys itself back in reasonable amount of time, at current and likely increasing gas prices. That is, assuming you can find a reasonably priced plug-in or plug-in hybrid.

If your average driving is less than 50 miles per day, which is quite common, the numbers obviously come much more attractive and payback goes to few years. Being CO2 free becomes additional benefit.

In many European countries you can select the power source you can select from various power companies and often they also have packages with various power sources. You can pick wind-only capacity, CO2 free only, or nuclear only, whatever you wish. Transmission cost is separately priced, so your bill ends up with cost of transmission (approximately half) and cost of generated electricity. While the electrons are not tagged, it works, they build more wind turbines the more they sell wind-only power. Wind is obviously more expensive than nuclear, but CO2 free mix is quite reasonable.

European Emissions trading has also motivated many coal power sites to use wood instead or reduce power outside peaks, so the network is cleaning up even on the worst offenders.

Comment Where did they find so expensive turbines? (Score 2, Informative) 510

The cheapest turbine they have is 4300 euros. This is ridiculously high price. In Finland, you get a 2.1m diameter rotor for less than 1000 euros (controller, mast, turbine), and a full kits with batteries, inverter and solar panels for 1400-2500 euros. A 3.2m diameter turbine here costs around 4000 euros and 8m diameter turbine around 20k-30k depending on configuration. These are list consumer prices including taxes. The prices quoted in the Dutch "test" seem to around 4 times what you pay here!

The quoted average wind of 3.8m/s seems inland wind speed. It is quite obvious that there is no point in installing turbines in locations where the average wind speed is low, but they seem to get some power from the larger turbines, though the price level they have kills the payback times.

They correctly point out that taller mast makes a difference, but one point for large industrial turbines is ignored - industrial turbines do need a grid to deliver the energy. For small turbines, the idea is to use the energy where it is produced, avoiding cost of grid. Grid cost in Finland is around half of the the bill, and taxes around 30%. We have grid/transmission cost separately priced so you can select to buy renewable-only energy from grid).

They did figure out, which I assume most people in industry already know, that the diameter is the interesting factor. The power generated is in relative to diameter and square of wind speed and efficiency factor. There are lots of snake oil companies out there claiming bogus production numbers, which is unfortunate as it spoils the reputation of good idea. There can be easily spotted by calculating a wind area covered by the turbine and dividing that by price. As getting efficiency up by few percent tends to be very expensive, it is easier to just make simple blades few percent longer. The cheapest wind turbines sold here have continuous profile blades, and they still perform nicely, even though the center part of the turbine probably does not do much work.

We have 2.7m diameter unit (, 500W nominal) at our vacation home we use in summertime. This is very non-optimal location, only northern winds and too much shadow for solar, so we took more diameter and big battery pack to offset non-windy periods. We use the power for lights, computers, 3g WLAN access point for network. Total cost of all electrical installation including lights, wiring, 2kW inverter, 980Ah battery pack, was less than getting grid to the place. Not enough for heating, but we burn wood for that, the plot is large enough to provide us practically unlimited supply of firewood. The power has been plentiful for our use. Electric chainsaw works for chopping the firewood, though we need to avoid continuously sawing more than 1 hour to avoid emptying the battery pack more than third :)

If you do not have a grid connection, the install cost of it will offset quite a big turbine and solar installation, so small turbines are very popular in vacation homes. And for vacation home, the more remote the better. Which means very expensive or impossible grid connectivity. In Scandinavia, solar does not work early spring or late fall, so wind turbine here may be the only option if you need electricity off-summer times. Combining solar and small wind turbine makes a lot of sense as the electrical installation is similar.

The same thing applies to developing countries. It often makes more sense to go directly to renewables than build grid to every small village. In south solar power or hybrid solar-wind is probably more dominant.

They claim that turbine does not even make up the energy used in making it. This is true only if the turbine is located in a low-wind location, or it is faulty design (no diameter!). I agree fully that it does not make sense to install turbines in city areas where buildings mess up wind flows. The location has to be one with good wind conditions.

To our experience, if you already have grid connection, you do need more than just price of electricity as motivation for renewable energy installation, as the payback times are long (less than 10 years only in optimal locations). However, you get additional benefits, independence from grid, good feel factor of using renewables, not paying tax for electricity, etc. And the price of wind and sun is not going up.

Comment Robust solar charger (Score 1) 184

Suntrica makes a flexible charger with buffer battery, they presented it in Mobile World Congress, see It looked like very robust design, and they had charger tips for almost anything. It is not the top efficiency panel as it is flexible, but if the idea is to charge handheld gadgets it is likely to be plenty enough, and buffer battery allows you to have it in the sun all the time and charge the device when needed.

Slashdot Top Deals

If A = B and B = C, then A = C, except where void or prohibited by law. -- Roy Santoro