Small is beautiful and economic

tractorFarm tractors have been growing bigger and bigger, though perhaps not everywhere – the photograph was taken in Donegal, Ireland earlier this year.  The size of tractors is driven by the economics of needing a driver in the cab. The labour costs are high in many places, so that the productivity per tractor driver has to be high too.  Hence, the tractors have to move fast and process a large amount of the field on each pass.  This leads to enormous tractors that weigh a lot and exert a large pressure on the soil, which in turn results in between 1 and 3% of the farm land becoming unproductive because crops won’t grow in the severely compressed soil. But what happens if we eliminate the need for the driver by using autonomous vehicles? Then, we can have smaller vehicles working 24/7 that do less damage and are cheaper, which means that a single machine breakdown doesn’t bring work to halt. We can also contemplate tailoring the farming of each field to the local environmental and soil conditions instead a mono-crop one-size fits all approach. These are not my ideas but were espoused by Peter Cooke of the Queensland University of Technology at a recent meeting at the Royal Society on ‘Robotics and Autonomous Systems’.

It is a similar argument for modular nuclear power stations. Most of the world is intent on building enormous reactors capable of generating several GigaWatts of power (that’s typically 3 with nine zeros after it) at a cost of around £8 billion (that’s 8 with nine zeros) so about 50 pence per Watt. Such a massive amount of power requires a massive infrastructure to deliver the power to where it is need and a shutdown for maintenance or a breakdown potentially cuts power to about a million people. The alternative is small modular reactors built, and later dismantled, in a factory that leave an uncontaminated site at a lower capital cost and which provide a more flexible power feed into the national grid. Some commentators (see for example Editor’s comment in Professsional Engineer, November 2015)believe that a factory could be established and rolling modular reactors off its production line on the same timescale as building a GigaWatt station.

Regular readers will recognise a familiar theme found in Small is beautiful and affordable in nuclear powerstations on January 14th, 2015, Enabling or disruptive technology for nuclear engineering on January 28th, 2015 and Small is beautiful on October 10th, 2012; as well as the agricultural theme in Knowledge-economy on January 1st, 2014.

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2 comments

  1. The phrase “Small is Beautiful” was popularised by E F Schumacher as the title of his book published in 1972. I was lucky enough to hear Schumacher speak in 1973 and it remains one of the only two lectures (of the thousand or more I have listened to) I can clearly remember!

    Two comments on the tractor issue: In the UK the practicable size of any farm vehicle is limited by the size of farm gates and (more significantly) narrow roads. Lighter vehicles would be useful, as would remotely linked sets of smaller vehicles. Furthermore, advances in image recognition and spray nozzle design (apparently very different areas of engineering) will increasingly permit lighter loads and smaller doses of herbicide, insecticide or water to be applied to crops. This is really a win/win enabled by advances in engineering.

  2. I remember Interstellar had those tractors. Yes, it is a movie, but one of the things I like about science fiction movies (and novellas) is how they satire modern failings and encourage a brighter future.

    Although, whether things such as erasing the Moon Landings from canonical history are likely to happen in the future or not is another story… at that point I can hopefully say that it was just a movie and we can take inspiration from it and also laugh a bit at how slow progress is now, whilst also working to increase what matters.

    Perhaps in this vein, redesigning vehicles to be made mostly of light-weight plastics might be a way forwards. The advantages of metal are over-rated in many areas, especially considering how many different types of plastics can now be made, and how long plastic lasts, and how well it could be recycled (if designed for that).

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