Low-tech Magazine

Bike powered electricity generators are not sustainable

Pedalling a modern stationary bicycle to produce electricity might be a great work-out, but in many cases, it is not sustainable. While humans are rather inefficient engines converting food into work, this is not the problem we want to address here; people have to move in order to stay healthy, so we might as well use that energy to operate machinery. The trouble is that the present approach to pedal power results in highly inefficient machines.

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?

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.

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.

Viva Las Vegas: LEDs and the energy efficiency paradox

The incandescent light bulb is abused by environmentalists – but the alternative will only raise energy consumption. More and more, compact fluorescent lamps are considered to be an interim technology, awaiting the arrival of Light Emitting Diodes (LEDs) and Organic Light Emitting Diodes (OLEDs).

At the moment, LED technology is no competition for the incandescent light bulb. However, it can be considered a worthy improvement of another technology: neon lights. Whether or not white LEDs will finally arrive, the success of coloured LEDs is a fact. Though some of them are definitely useful, they all introduce lighting in places and situations where there was no lighting before.

Urban windmills harm the environment

A small windmill on your roof or in the garden is an attractive idea. Unfortunately, micro wind turbines deliver hardly enough energy to power a light bulb. Their financial payback time is much longer than their life expectancy and in urban areas they will not even deliver as much energy as was needed to produce them. Sad, but true.

Carbon sequestration: bury the idea, not the CO2

Why introduce yet another expensive, energy-intensive and risky technology if there are so many other and better ways of fighting global warming? 

Capturing CO2 from the smokestacks of power stations with the intention of storing it in underground reservoirs, oceans, rocks, consumer products, chemicals or fuels has gained a lot of credibility recently. Many experts believe that we will burn the world's remaining fossil fuels anyway, and we should therefore try to lower the impact if we are to prevent a catastrophic climate change. Yet capturing, transporting and storing carbon dioxide raises energy consumption considerably and brings with it serious health and environmental problems. The benefits, on the other hand, are shadowed in doubt.

Is ecotech the new asbestos?

What will remain of greentech, cleantech and ecotech if nanotechnology turns out to be harmful for humans and the environment?

It’s hard to keep track of the soon-to-be-implemented technological solutions that will solve our energy and environmental woes by means of nanotechnology – the science of manipulating individual atoms. Solar panels and batteries might be far from optimal solutions now, but nanomaterials will boost their efficiency and dramatically lower their costs. Transporting electricity from solar plants in deserts may not be possible yet, but nanotechnology will bring us cheap superconducting cables and efficient hydrogen storage. Unfortunately, more and more research indicates that nanomaterials might become a severe health problem and an environmental nightmare.

Leave the algae alone

While the first generation of biofuels is wreaking havoc on the environment and the food markets, the second generation is set to make things even worse.

Since it has become clear that ethanol and biodiesel made from food crops are doing more harm than good, the hope for finding a substitute for oil has shifted to algae and cellulose. If we can believe the advocates of this ‘second generation’ of biofuels, these combustibles will deliver way more energy than it takes to make them, without threatening the world’s food and water supplies. Upon taking a closer look, however, this is very hard to believe. They might even cause bigger problems than biofuels made from food crops. Maybe this time around we could sort this out before the damage gets done?