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.
One of the constraints of solar power is that it is not always available: it is dependent on daylight hours and clear skies. In order to fill these gaps, a storage solution or a backup infrastructure of fossil fuel power plants is required -- a factor that is often ignored when scientists investigate the sustainability of PV systems.
Whether or not to include storage is no longer just an academic question. Driven by better battery technology and the disincentivization of grid-connected solar panels, off-grid solar is about to make a comeback. How sustainable is a solar PV system if energy storage is taken into account?
It's generally assumed that it only takes a few years before solar panels have generated as much energy as it took to make them, resulting in very low greenhouse gas emissions compared to conventional grid electricity.
However, a more critical analysis shows that the cumulative energy and CO2 balance of the industry is negative, meaning that solar PV has actually increased energy use and greenhouse gas emissions instead of lowering them.
The problem is that we use and produce solar panels in the wrong places. By carefully selecting the location of both manufacturing and installation, the potential of solar power could be huge.
Combining the old local heating practices with modern radiant and conductive heating systems could lower energy consumption, improve health, and increase thermal comfort. This is especially true for uninsulated buildings, where air heating is particularly disadvantageous. Local heating sources can be applied on their own, but can also be used in combination with air heating. This may mean, however, that thermal comfort standards need to be redefined.
However, restoring the old way of warming would not make sense without new technology. Most heating systems from the old days were inefficient, polluting, dangerous and impractical. Today, we have better options available, which can be combined in interesting ways.
These days, we provide thermal comfort in winter by heating the entire volume of air in a room or building. In earlier times, our forebear's concept of heating was more localized: heating people, not places.
They used radiant heat sources that warmed only certain parts of a room, creating micro-climates of comfort. These people countered the large temperature differences with insulating furniture, such as hooded chairs and folding screens, and they made use of additional, personal heating sources that warmed specific body parts.
It would make a lot of sense to restore this old way of warming, especially since modern technology has made it so much more practical, safe and efficient.
The steadfast rotating fan has been employed to keep people cool since the eighteenth century, and it remains highly effective, requiring much less energy and providing more comfort than air-conditioning. Cooling people by increasing local airflow is at least ten times more energy efficient than refrigerating the air in a given space, and it also adds the benefit of a personally controlled thermal environment.
If used in combination with air-conditioning, fans could lower energy use by 30-70%, even in incredibly hot climates or during heat waves. Circulating fans, which have become very energy efficient in their design, can be readily and cheaply applied in both new and existing buildings. Recent changes in international comfort standards have paved the way for their comeback.
While modern cooking stoves are convenient, when it comes to energy use they leave a lot to be desired. As we have seen in the previous article, the thermal efficiency of an electric hob does not exceed that of a conventional open fire. In both cases almost 90% of the primary energy is lost during the cooking process.
Cooking food could be achieved in a far more energy efficient way, especially if the cooking pot itself is insulated. This is the principle behind the fireless cooker, a well-insulated box that keeps food simmering with only the heat of the cooking pot itself. A fireless cooker doubles the efficiency of any type of cooking device because it shortens the time on the fire and limits heat transfer losses.
In the early twentieth century, fireless cookers were common additions to western kitchens, similar to the refrigerator or cooking stove. Some models even integrated fireless cookers with gas or electric hobs. These functioned by lowering an insulated hood over the cooking pot once the heat had been switched off.
Despite technological advancements since the Industrial Revolution, cooking remains a spectacularly inefficient process. This holds true for poor and rich countries alike. While modern gas and electric cooking stoves might be more practical and produce less indoor pollution than the open fires and crude stoves used in developing countries, they are equally energy inefficient.
In fact, an electric cooking stove is only half as efficient as a well-tended open fire, while a gas hob is only half as effective as a biomass rocket stove. And even though indoor air pollution is less of an issue with modern cooking stoves, research indicates that pollution levels in western kitchens can be surprisingly high.
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.