Advantages of Ocean Infrastructure
Substrate matters. Many of the properties of our buildings are greatly influenced by the substrate that they are built upon. This article discusses four ways in which the ocean substrate reduces the cost and complexity of building infrastructure compared with the terrestrial substrate and one area where the land is better. I write this to challenge the common perception that building on the ocean is more difficult than building on the land. There are more advantages than people commonly think. We have had the technology to do this for over a century and it is lack of challenging conventional wisdom that is largely holding us back.
Physical infrastructure on land is susceptible to higher peak loads than on the ocean. You have to build to the worst case earthquake, cyclone, flood or bushfire but 99.999% of the time the building will not be subjected to those events. In the doldrums around the equator ocean structures are subject to none of these peak loads. The main source of peak loading is probably with rouge waves and storms. But the loading of both of these events for larger structures is likely much less in both magnitude and infrequency than land based equivalents.
Land is highly heterogeneous. Building foundations are highly dependent on soil types which change from lot to lot. Cities are constrained by natural geography such as lakes, rivers and mountain ranges. Highways benefit from being straight and cities benefit from having an orderly grid however the reason that no city or highway is built this way is largely due to the heterogeneity of the land it sits on. In contrast the ocean is highly homogeneous on its surface. One square kilometre of ocean is indistinguishable from its adjacent neighbour. This leads to orders of magnitude lower scaling costs and more efficient organisation.
The land protects settlements by dissipating the energy from the sun, wind and waves. This reduces the structural requirements for infrastructure. But in the era of harvesting these elements for energy is increasingly becoming a disadvantage.
Finally the land is incredibly rich ecologically. 80% of the world’s animal species are found in terrestrial ecosystems despite 71% of the world being covered by oceans. It’s gotten to the point where you basically can’t convert any natural space into infrastructure without putting some species significantly closer to extinction. The ocean also has incredible ecology but this is largely limited to the coral reefs which make up 0.1% of the ocean’s surface. The vast majority of the ocean is a watery desert. So shifting the burden of humanity’s infrastructure particularly agricultural infrastructure from the land to the ocean will go a long way to alleviate the pressure on so many irreplaceable ecosystems. In this transition it is important that ocean infrastructure limit the negative externalities in their environment. I’ll note here that ocean infrastructure can do more than just reduce the harm on terrestrial ecosystems it can also turn ocean deserts into artificial coral reefs. This represents a shift from conservation to ecological creation. We could increase the size of reefs by orders of magnitude.
The ocean is a much more corrosive environment than the land. Advances in material sciences has eroded much of this land based advantage. Modular structures are crucial to enable cheap and quick repair of damaged sections. Cathodic protection shifts the bulk of the corrosion burden from material replacement to electricity generation which is almost certainly going to be cheaper on the ocean.
