Old trends often come back in a different form. A current trend is a feeling that we are running out of resources in the way the Club of Rome predicted in its famous ‘Limits to Growth’ report from 1972, the year I was born. That this particular theme has been resurrected from its shallow grave is no surprise. It is a fact that despite a sluggish economic growth in most of the Western world, the demand for oil keeps on growing while production is on a plateau, optimistic stories about non-conventional oil and gas notwithstanding. Likewise worldwide fisheries are in a slow collapse after decades of overfishing. And as the number of times copper thieves manage to disrupt railway traffic proves, metal prices are at an all time high while proven reserves aren’t growing much either. So it’s no wonder people are looking into the tea leaves at the bottom of their cups and try to guess what changes peak resource will bring.
Let’s look at some of the typical predictions, the first being that global supply chains will be a thing of the past. Except that they won’t.The assumption is that having widgets produced in China out of raw materials shipped to China by combining Chinese labour with energy from fossil fuels (again shipped to China) is a too energy-intensive habit to continue. That may be true for the embedded energy in those widgets, especially if they’re made from steel or aluminium. But not necessarily so for the logistics side of it all. Because by and large the longest legs of the travels a rubber duckie you get from China are not that energy intensive at all. The rubber duck is most likely to be transported by container. So let us focus on container shipping.
To give an example, the world’s biggest class of commercial vessels in operation right now are the Maersk E-class container ships. True behemoths with a length of 397 meters, a width of 56 meters and a 15.5 meter draft. Powered by a 80 MW two-stroke diesel engines each (plus auxiliary engines for harbour maneuvering), they are currently the most fuel efficient way of hauling goods around the globe. Because of fuel prices, their even larger successors, the Triple-E class, will be powered by two 32 MW two-stroke diesel engines each and have a carrying capacity of 18,000 TEU. Because of the fuel economy, these titanic ships will be ”slow steaming” at a mere 19 knots, a speed not unlike the average speed the windjammers of the early twentieth century were operating at. At that speed it will be consuming about 36 MW of power. This is still quite a bit of energy being consumed, but already within the realm of being done purely renewable.
One has to bear in mind that for example wind power, which right now is a curiosity in maritime shipping, is not necessarily constrained to the nineteenth century masts-and-sails. Although even with automation these can also be made useful nowadays. The current development that is the most promising is the use of advanced kites to reduce fuel consumption[The largest-scale application right now is the use of a 320 square meter kite on a 170 meters long bulk cargo, vessel, the Aghia Marina. Source]. A 320 square meter kite is the propulsion equivalent of a 2 megawatt engine. If we apply this to Maersk Triple-E container ships, this would require the equivalent of 10,240 square meters of kite, assuming that this scales geometrically. Which places it an order of magnitude over the size of the largest kites ever build and deployed, which are about a 1,000 square meters big. It is not far-fetched to assume the feasibility of deploying a) multiple kites and b) the development of kites of at least 4,000 square meters each, or c) over 10,000 square meter sized kites. Although being quite an engineering challenge, such kites would make it feasible to propel the biggest container ships ever, the Maersk Triple-E container class, on wind power alone. In addition to propulstion power, that massive surface area can be used for an additional source of energy: flexible, polymer-based, solar photovoltaics. Although flexible photovoltaics typically have a lower efficiency than traditional silicon, deployment at these staggering scales still can provide significant amounts of electricity. To build further on the example of the Triple-E class: even with a mere 100 watt per square meter (at higher latitudes) such a kite with a flexible photovoltaic polymer applied on its surface should be able to produce 10 megawatt of electricity. And this is fairly conservative estimate, since the main shipping routes between Asia and Europe are typically in the tropics, the energy output could easily triple. All this means that the end of cheap liquid fuels does not necessarily means the end of the backbones of our current long supply changes. The availability of long supply chains also provides enhances our global resilience to shocks in agricultural production: food, especially grains, can be shipped over long distances.
It does however change regional and local supply chains dramatically, especially over land. But that is subject matter for another post.