Low-tech Magazine

The monster footprint of digital technology

The power consumption of our high-tech machines and devices is hugely underestimated.

When we talk about energy consumption, all attention goes to the electricity use of a device or a machine while in operation. A 30 watt laptop is considered more energy efficient than a 300 watt refrigerator. This may sound logical, but this kind of comparisons does not make much sense if you don't also consider the energy that was required to manufacture the devices you compare. This is especially true for high-tech products, which are produced by means of extremely material- and energy-intensive manufacturing processes. How much energy do our high-tech gadgets really consume?

Fighting marine debris: the dustcarts of the sea

Considering that the oceans hold more garbage than fish by now, this might be the right time to retrain our fishermen and let them hunt for litter. Several companies offer equipment to fish garbage out of rivers, lakes and harbours. They say they could build larger dustcarts for seas and oceans, too. Send the bill to the disposables industry - and let the cleanup begin.

Small windmills put to the test

A real-world test performed by the Dutch province of Zeeland (a very windy place) confirms our earlier analysis that small windmills are a fundamentally flawed technology (test results here, pdf in Dutch). Twelve of these much hyped machines were placed in a row on an open plain (picture above). Their energy yield was measured over a period of one year (April 1, 2008 - March 31, 2009), the average wind velocity during these 12 months was 3.8 meters per second (note: update on the wind speed). Three windmills broke. Find the disappointing results of the others below.

Sailing at the touch of a button

Lloyd Alter at Treehugger talks about our article on cargo ships and wonders if it is time for a new age of sail. One reader comments that sailing boats require a much larger crew than today's cargo vessels, which would make a comeback of wind power unrealistic. Maybe, but these days, sailing boats can also be controlled by computers instead of sailors.

Cargo ships, then and now

On an early afternoon last month, the Eugen Maersk (the world's longest ocean freighter at 1,300 feet) has left Rotterdam, the Netherlands, on the tail end of a journey from Shanghai. But the giant freighter is cruising at 10 knots, well shy of her 26-knot top speed. At about half speed, fuel consumption drops to 100-150 tons of fuel a day from 350 tons, saving as much as $5,000 an hour.

The German Preussen (picture above), the largest sailing ship ever built, was launched in 1902 and travelled mainly between Hamburg (Germany) and Iquique (Chile). It was rammed by a large steam vessel in 1910. A one way trip between Germany and Chile took the cargo vessel between 58 and 79 days. The best average speed over a one way trip was 13.7 knots.

One giant container ship can emit almost the same amount of cancer and asthma-causing chemicals as 50 million cars, study finds. 

Picture credit.

Read more: Sailing at the touch of a button: Wind-powered, computer-controlled.

No Tech Magazine

Mixed links and updates (previously published in the side column, filed under "found") are now posted on another page, called No Tech Magazine (subscribe). It can be reached via "mixed links" in the side column, above the fold. Low-tech Magazine keeps publishing in-depth original reporting, No Tech Magazine links to interesting material from others.

Who killed the electric grid? Fast-charging electric cars

Charging electric cars with off-peak power is a fantasy.

Fast recharging times generate lots of excitement, but what seems to be forgotten is that they can lead to a fabulous amount of peak demand.

If you charge an electric car with a battery capacity of 25 kWh during 8 hours, it needs a power output of 3,125 watts. If you charge the same car in just 10 minutes, it needs a power output of 155,000 watts.