Monday, May 16, 2016

Freighter Grid

One way to move data from one computer to another is through an electronic network. Another way is for the source computer to write the data to some physical medium, e.g. a USB flash drive, then for someone to carry that flash drive over to the destination computer, which can then read the data from the device. That's "sneaker net" - you can move the data faster if you are wearing running shoes!

One of the challenges with energy in general is that places rich in energy are often far from the consumers of that energy. Of course, over time the consumers tend to relocate closer to the sources of energy, e.g. towns spring up where river flow can be dammed or where coal is nearby. Canals and rail lines can be built to carry coal, and pipelines can be built to carry petroleum and natural gas.

Electric transmission lines are another way to move energy. Rather than moving coal by rail, coal burning power plants are sometimes built near coal mines and the generated power moved across those long wires.

Moving energy is particularly difficult when the sources are widely distributed or rapidly changing. For example, natural gas fields are located in remote regions of Siberia. It is not cost-effective to build the very long pipelines that would be necessary to move this gas to existing customers. Gas-burning power plants could be built, but then very long electric transmission lines would be necessary, and those would also be too expensive. Natural gas is also a feed-stock for various plastics and nitrogen fertilizer, so another way to exploit the gas resource is to put a chemical factory at the gas field and then transport the materials produced, which embody the energy of the gas in a much more compact form. Aluminum ore is widely distributed, but aluminum production requires a lot of electricity. If aluminum ore is located near the gas field, then an aluminum plant can be built near the gas field. A paper mill is a similar way to use remote energy resources, allowing energy to be moved in a more compact product form.

At some point though customers want electricity itself rather than paper or aluminum. There are surely many windy places located on remote coastlines. One way to exploit this resource would be by transporting batteries back and forth between producers and consumers. Large ships could carry these batteries, loading up charged batteries from remote coastal areas, carrying them to ports near urban areas where they could be discharged into the power distribution grid, then carrying the depleted batteries back to the remote coastal areas to be recharged.

Today, battery power is generally too expensive to be used for bulk power. In most places batteries make better sense for providing ancillary services such as spinning reserves or power smoothing, though in remote areas battery power is already less expensive than alternatives. But as fossil fuel use becomes more limited and as battery technology improves, transmitting power by transporting batteries - "freighter grid" - seems to be a very practical way to keep the electricity flowing!