Non stop renewable that would end the nuclear debate

The IPCC proved this week that mankind is changing earth’s climate at an alarming rate. Greenhouse gases are the culprit. We need to act really really fast if we want to have a chance of staying within 2 degrees temperature rise compared to pre-industrial times.

“Wind power and solar are going to save us” was my state of mind for years. Especially PV is becoming so cheep so fast that it is inevitable that it will become a serious source of electricity in our lifetime. Wind and sun have some very important drawbacks that make them unsuitable to run a whole modern society on:
– the energy is available intermittently : PV doesn’t work at night and in the winter, wind is predictable but not always there
– the solutions are very dispersed, you need vast amounts of area to gather significant amounts of energy
– suitable storage solutions (power2gas and flow batteries) are a long way down the road

So I have come to the conclusion that we need yet another source of electricity. Nuclear has crossed my mind I must admit because it solves a couple of important issues:
– very energy dense
– very high load factor (hours running/hours in 1 year)
I got enthusiastic about 4th generation reactors: Liquid Fluoride Thorium Reactor. Only problem, it’s fantasy technology, nobody had got it working and nobody has plans to go that way. Older reactors running on Uranium are not feasible because there is not enough Uranium ore available.

That was a long introduction to get to what I came across today: Plant-e (pronounce – plenty). A Dutch startup/spinoff from Wageningen University.
They discovered that soil microbes excrete electrons as part of their metabolism. The electrons are a real waste product for them. If you are able to collect these electrons, run ‘m through a bulb and return them to the soil you have a sustainable, unstopable, vast amount of “free” electricity. The microbes only stop when it freezes, but huge wetlands (rice fields) never freeze and could deliver enormous amounts of energy. The facts look something like this :
* 280 MWh/ hectare / year
* 3-5 years until hectare scale size
* original function of soil remains in tact : pasture land, wetland, rice fields
* electricity gathering with long pipes buried in the wet soil (no figures on density yet).
* The low energy density is not really an issue here because of this fact because the energy is removed as a bonus from the land use, it’s not the main “task” of the land

The main question is what the cost price per hectare will be. The electricity it gives of would be worth $15000 a year (@ 5ct/kWH). So if you require a 7 year payback time you have a $100.000 budget. I believe the electrodes will be placed in the form of pipes.

At this moment I am cautiously optimistic that this could actually work. It would deliver base load electricity in parts of the world where reliable energy is now not available and truly sustainable. Question: How are we going to help them get the first hectares up and running as they’re only testing small patches now? If this actually works it needs industrial style upscaling ASAP.



Leave a Reply