Ground-scanning Beamway for Energy Crops

by Olav Naess

Harvesting Solar Energy

Solar cells are fine for collecting solar energy, but become expensive and obtrusive for large scale energy harvesting.

Harvesting the energy through plants, from which liquid fuel is produced, is likely to be preferrable for large scale operation. Covering large areas with solar cells will block and disturb human and animal activities, unless the solar cell array can be placed in a desert, whereas an energy crop area can be quite usable for people and animals if it is designed following the guidelines outlined below. The natural energy carrier from energy crops will be liquid fuel, which is the most convenient energy carrier for vehicles.

Hydrogen is commonly regarded as the energy source of the future: clean and CO₂-neutral. But hydrogen (for chemical combustion) is not an energy source, just an energy carrier – like a copper cable is. And it is difficult to store and transport, requiring either high pressure, supercooling, or chemical binding which yields an awkward to handle solid, or at best a liquid 3-4 times less energy efficient than gasoline or diesel. Descriptions of chemical hydrogen binders generally disregard the most efficient binder: carbon – evidently because the carbon-hydrogen combinations are simply the old familiar fuels: gasoline, diesel and (with a little oxygen added) alcohol. But when the carbon is borrowed from the air, energy crop products like biodiesel become CO₂-neutral, consequently becoming valid and efficient hydrogen economy products. A purism denouncing these fuels will be just a stunt environmentalism.

It is now (in 2008) common to reject fuel crop growing (like the bio-ethanol production in Brazil, or the corn-based fuel production in the US) due to present production methods consuming significant amounts of farmland, farmer workpower, fertilizers and even production machinery fuel.

The purpose of this article is to outline a production method which:

• uses less energy – because rail transport is far more energy efficient

• needs no farm land – because quite awkward terrain can be used

• requires very little farmer workpower – because computer controlled machinery will do most of the work

• can do without fertilizers – because all harvested crops (minus the energy and what the atmosphere later re-supplies) are brought back to the fields

The energy crop plants needn't be limited to the few species which presently seem to have been chosen by farmer habits. Harvesting several meters above the ground could for instance mean that the plants can be combination plants: A bush or tree on the ground (the host plant) can have an undisturbed root and leaf canopy, and other plants grafted on top of it should just shoot energy rich stems upwards. The upper plant could repeatedly be harvested by being cut a little above the grafting point. It might be genetically modified to yield maximum energy content, and might be unable to grow a root and procreate. Vegetable oils are fuels which are simple to extract and use. The plants yielding most of these oils are listed here. Genes from one of the best of these plants might be transferred to graftable plants in which the young stem could be oil-producing. Gene manipulation is controversial when done in food, but shouldn't be so problematic for energy crops, particularly if the artificial plants lack a root.

If mangroves could be used as host plants, biofuel could be produced in wetlands.

The object of the following technique is: To enable energy-efficient and computer-controlled access for machinery and crop containers to all parts of the field to be cultivated, even if the terrain is quite uneven.

Ground-scanning with Beamway

Working the earth by means of machines essentially implies XY-scanning the two-dimensional surface like a computer printer/plotter does with a sheet of paper. This work is traditionally done by moving the machinery across an earth surface which, for the sake of work efficiency, is quite flat, although the plants don't need this flatness. In the contrary: A slope facing the sun would receive more energy.

Transporting passengers and goods is much more energy efficient on rail than on roads, and the worst road is less energy wasting than the most level soil. So why not do agriculture by means of an XY-scanning railway which is elevated over that messy earth surface? The beamway, as described in other articles on this website, is quite suitable for this purpose.

This energy crop field on a sunny slope is harvested automatically by XY-scanning railways. The two towers rolling upon the lower rails hold the upper rail, a beamway as described in the beamway introduction article. The machinery for harvesting (and otherwise working) the fields are moving around computer-controlled like beamway trains, along with connected crop container wagons. This machinery should to some extent be able to move vertically, so that it can deal with uneven terrain, and may then be compared with an XYZ plotter.

The movable beam to the right has connected its left end to a switch (which serves also the other adjacent rectangle), so that the container on that beam can enter the external beamway running along the lower part of the picture.

The lower rails can have unlimited lengths, or they can, like in this picture, go up a hillside, so that the movable upper rails, along which there is more movement, can be more level. The lower rails are held up by concrete pillars, 2-3 meters above the ground, so that people and animals can pass freely across the fields.

In wetlands, the lower rails may be omitted, and the upper rail can be carried by floaters guided by cables running where the lower rail would have been.

The lower rails may seem to be monorails, but it would be more correct to regard a pair of them as constituting a very wide-gauged standard track, as the two bogies are connected (by a crossing, upper rail) to act like one. When this wide bogie connects with the external beamway, it should be skewed, so that only one end of the moving beam contacts with the external beam. If there is little traffic on the external beam, so that switching speeds are unimportant, a simplified switching mechanism may be used: The end of the moving beam can push aside the adjacent end of the external beamway beam in order to take its line connection. The skewed position of the moving beam may be permanent.

An alternative method for connecting to the external beamway is: All the movable beams are lined up with each other and with the end of the external beamway.

The harvester is ready, but the tall energy plants are not sown yet.

Working from a beamway across the fields has several advantages:

• The field may be sloped, uneven, marshy, or simply a water surface.
  Energy crops growing in water (e.g. like rice on terraces) need not close their respiration pores to conserve water, so they can avoid wasting their energy on breathing (destroying their carbohydrate fuel) during nights.

• Energy plants need not be cut at the ground (coppicing), but can be cut well above the ground (pollarding).
  This means various animals can live rather undisturbed on the ground, and/or people can use the area as a park, walking on paths which don't reduce the harvesting area. The leaves in a permanent canopy enable the plants to rapidly grow the leafless new stems which are ideal for energy harvesting.

• Traffic on elevated rails is simple to automatize, and doesn't conflict so much with animal life.
  If the machines work at night, it is easier for their IR-detectors to detect the presence of body heat. (And people using the area as a park are not much disturbed.)

If there is a need for working the earth (plowing, tilling, root removal, etc.) the beamway can't exert so much force as a tractor on the ground, but it can use weaker tools and compensate by working rapidly day and night. Also harvesting should be done steadily at a low noise level, thus requiring small and simple machinery.

Crop containers on the beamway can easily be sent to an industrial area (with e.g. a power plant), moved by motorized bogies. They may spend some time in front of parabolic mirrors – for sun energy treatment like removing excess moisture.

The masses remaining when the energy/fuel has been extracted, are likely to be exactly what the plants need as fertilizer, so they are sent back and spread on the field. A conventional ground-based harvesting method is unlikely to do this properly and economically.

Energy crops are likely to be in danger of crop field fires, but the ground-scanning beamway system has unique potentials for firefighting because its vehicles are always ready to go anywhere unmanned. One of the extreme positions for the movable beam should be over a safe area devoid of inflammable materials. This could be a road or a river, and if there is a connection to an external beamway line, it should be in this safe area. It should be possible for machines to suck up water there and store it in standard crop containers. Then the beamway vehicle could go for the flames like an over-sized ink-jet printer, guided by IR-detectors in the top of one of its towers.

The external beamway line is hopefully a useful line for other goods and passenger transport purposes, so a large biomass processing system, with extensive crop fields served by a large processing factory (or power plant), should be quite economical.

3D Landscape Printing

This XYZ mechanism can also be used for shaping the landscape – just like those 3D printers presently used for creating small objects. But this beamway-based mechanism can be used on a much larger scale – for building groups of houses. With "ink jets" for concrete, sand, isolating foam and plastic materials, it can build platforms, plumbing and walls, and then transport in beams and floor plates to place upon the walls. The vegetation layout is of course created by the same mechanism, also in gardens, verandas and on roofs.

Copyleft   Olav Næss 2006, 2008