The information society promises to dematerialise society and make it more sustainable, but modern office and knowledge work has itself become a large and rapidly growing consumer of energy and other resources.
The typical solar PV power installation requires access to a private roof and a big budget. However, wouldn't it be possible to get around these obstacles by installing small solar panels on window sills and balconies, connected to a low-voltage direct current (DC) distribution network? To put this theory to the test, I decided to power Low-tech Magazine's home office in Spain with solar energy, and write my articles off the grid.
In today's solar photovoltaic systems, direct current power coming from solar panels is converted to alternating current power, making it compatible with a building's electrical distribution.
Because many modern devices operate internally on direct current (DC), alternating current (AC) electricity is then converted back to DC electricity by the adapter of each device.
This double energy conversion, which generates up to 30% of energy losses, can be eliminated if the building's electrical distribution is converted to DC. Directly coupling DC power sources with DC loads can result in a significantly cheaper and more sustainable solar system. However, some important conditions need to be met in order to achieve this goal.
During the second half of the nineteenth century, water motors were widely used in Europe and America. These small water turbines were connected to the tap and could power any machine that is now driven by electricity.
As we have seen in a previous article, operating motors with tap water was not very sustainable. Because of the low and irregular water pressure of the town mains, these motors used unacceptably high amounts of drinking water.
While the use of water motors in the US came to an end early in the twentieth century, the Europeans found a solution for the high water use of water motors and took hydraulic power transmission one step further.
They set up special "power water" networks, which distributed water under pressure for motive power purposes only, and switched to a much higher and more regular water pressure, made possible by the invention of the hydraulic accumulator.
Almost all these power water networks remained in service until the 1960s and 1970s. Hydraulic power transmission is very efficient compared to electricity when it is used to operate powerful but infrequently used machines, which can be distributed over a geographical area the size of a city.
We are being told to eat local and seasonal food, either because other crops have been tranported over long distances, or because they are grown in energy-intensive greenhouses. But it wasn't always like that. From the sixteenth to the twentieth century, urban farmers grew Mediterranean fruits and vegetables as far north as England and the Netherlands, using only renewable energy.
These crops were grown surrounded by massive "fruit walls", which stored the heat from the sun and released it at night, creating a microclimate that could increase the temperature by more than 10°C (18°F). Later, greenhouses built against the fruit walls further improved yields from solar energy alone.
It was only at the very end of the nineteenth century that the greenhouse turned into a fully glazed and artificially heated building where heat is lost almost instantaneously -- the complete opposite of the technology it evolved from.
The modern glass greenhouse requires massive inputs of energy to grow crops out of season. That's because each square metre of glass, even if it's triple glazed, loses ten times as much heat as a wall.
However, growing fruits and vegetables out of season can also happen in a sustainable way, using the energy from the sun. Contrary to its fully glazed counterpart, a passive solar greenhouse is designed to retain as much warmth as possible.
Research shows that it's possible to grow warmth-loving crops all year round with solar energy alone, even if it's freezing outside. The solar greenhouse is especially successful in China, where many thousands of these structures have been built during the last decades.
Wireless internet access is on the rise in both modern consumer societies and in the developing world.
In rich countries, however, the focus is on always-on connectivity and ever higher access speeds. In poor countries, on the other hand, connectivity is achieved through much more low-tech, often asynchronous networks.
While the high-tech approach pushes the costs and energy use of the internet higher and higher, the low-tech alternatives result in much cheaper and very energy efficient networks that combine well with renewable power production and are resistant to disruptions.
If we want the internet to keep working in circumstances where access to energy is more limited, we can learn important lessons from alternative network technologies. Best of all, there's no need to wait for governments or companies to facilitate: we can build our own resilient communication infrastructure if we cooperate with one another. This is demonstrated by several community networks in Europe, of which the largest has more than 35,000 users already.
In terms of energy conservation, the leaps made in energy efficiency by the infrastructure and devices we use to access the internet have allowed many online activities to be viewed as more sustainable than offline.
On the internet, however, advances in energy efficiency have a reverse effect: as the network becomes more energy efficient, its total energy use increases. This trend can only be stopped when we limit the demand for digital communication.
Although it's a strategy that we apply elsewhere, for instance, by encouraging people to eat less meat, or to lower the thermostat of the heating system, limiting demand is controversial when applied to the internet, in part because few people make the connection between data and energy.
How to downsize a transport network: the Chinese wheelbarrow For being such a seemingly ordinary vehicle, the wheelbarrow has a surprisingly exciting history. This is especially true in the East, where it became a universal means of transportation for both passengers and goods, even over long distances.
Firewood in the Fuel Tank: Wood Gas Vehicles Wood gas cars are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars.
How to make everything ourselves: open modular hardware Consumer products based on an open modular system can foster rapid innovation, without the drawback of wasting energy and materials. The parts of an obsolete generation of products can be used to design the next generation, or something completely different.
Power from the Tap
Power from the Tap: Water Motors Just before the arrival of electricity at the end of the 19th century, miniature water turbines were connected to the tap and could power any machine that is now driven by electricity.