Month: October 2016

Renewable liquid fuels – No silver bullet, but perhaps important.

Over the last few days I’ve seen a number of tweets appear like this

and like this

The story is one about a paper in Science which goes way over my head, but which appears to talk about a new catalysed method of sucking CO2 out of the air and using it to produce ethanol. A number of people have reacted as though this will solve all our problems. They are wrong. This is not a clean fuel source that will solve all our energy problems, because the process will require an energy input greater than that which is released by burning the ethanol. I’m no organic chemist, but if that wasn’t the case it would be bucking some of the most fundamental principles of physics. This isn’t free energy, and it isn’t going to make climate change go away.

However, it may still be important. If the round-trip efficiency is good enough, it may provide a useful means of long-term storage of energy. Even if the efficiency is relatively poor, it may still be important as a sustainable way of producing an energy-dense liquid fuel for those transport applications, such as aircraft, ships, or heavy trucks, that don’t show any prospect of being electrified any time soon. In this way the new technology is in competition with other ideas for producing methanol, ammonia, or (beloved of many) hydrogen. If the new catalyst makes this more efficient, all the better.

Posted by simon in The wider world

Timber structures and notions of permanence

There was a sign that amused me, on the summit of a sacred mountain, which read,

“The Konpon Daitō is the tallest building in Kōyasan… In later centuries the Konpon Daitō was destroyed in fires caused by lightning striking five times, and rebuilt each time. After the great fire of 1843, only the foundation stones remained. The existing building was rebuilt in 1937.”

Some people just don’t seem to get the message!

But it illustrates a wider observation, which is that in Japan an ancient wooden temple or other structure can still be ancient even if it has been rebuilt many times, the latest sometimes being quite recent. Indeed, it is tradition that some of the most important temples are deliberately torn down and rebuilt every few decades. Other places are “renovated” every 50 years in a way that pretty much entails dismantling them and putting them back together again, replacing timber wherever it is no longer sound. These processes don’t cause anybody to think of them as modern structures.

A white, traditional castle. Although it's hard to tell, it's constructed from concrete.

Kokura-jō: Four hundred years old, or sixty?

A similar concept applies to castles. Castles in Japan were made of wood, and thus prone to being burnt down – sometimes by accident, sometimes by the enemies of the occupants, and sometimes by the occupants themselves on the occasion of their departure. When one visits a castle one tends to find a litany of all the times they were destroyed and rebuilt. It’s not unusual for the last rebuilding to have been in the 1950s or 60s, out of reinforced concrete, but they’re not really thought of as replicas.

There’s a strong element of My Grandfather’s Axe here. It’s echoed to some degree in descriptions of British churches (and occasionally pubs), which tend to go “There has been a church here since 1273…”, but the British think in terms of the site: there was a church here, but it was not this church. The Japanese view of it, at least as I perceived it through the flaws of translations, is that it’s the same building. It’s as though it’s the notion of the building that’s important, rather than its physical or material structure.

A new-looking timber building behind a fence in woodland, built in the style of a pre-buddhist Shinto shrine

Ise Grand Shrine: Two thousand years old, but rebuilt every twenty. Photo: Flickr user Kzaral, licensed CC-BY 2.0

Posted by simon in Working in Japan