Inside a capacitor there are 2 conductive metal plates with only a very thin insulating material between them, insulating them from each other. Electricity is stored in an electrical field between one side (positive) of the metal plates and the insulating material.

While the capacitor is connected to a power supply, one side becomes positively charged and the other is comparably negatively charged. There is a potential difference between the two sides of the capacitor. With no electrical circuit connected, the capacitor will remain in that charged state for a long time. Then when a circuit is connected to the capacitor, the charge will flow from the positive side through the circuit to the negative side of the capacitor.

Real world explanation example:- Above, by "circuit is connected", I mean, hitting a switch. The actual circuit being perhaps the charging system for an Electrical Vehicle (EV). Switch on the supply from the capacitor and the EV will get charge.

How they made a capacitor in concrete

As concrete hardens, the water forms thin pathways inside the structure. By adding a processed form of charcoal to the wet concrete, before mixing and pouring, researchers at Massachusetts Institute of Technology (MIT) USA found that the charcoal particles also aligned inside these water pathways. When the concrete had largely cured the charcoal had formed long connected electrically conductive strands. With millions of strands running close to each other with non conducting cement between them, an electric field can form, with the potential to store electrons.

This is like an array of capacitance areas within the concrete. Many areas with positive charged electrons which want to flow to areas with negative charge. Connected to a circuit, the electrons on the positive side will get their chance to flow towards the negative side. That flow giving the circuit power to do work. Power that can be used to charge an EV battery for example.

A house with solar panels and / or a wind turbine, could store excess power in the foundations of their house. Research on how or if this stored power will affect people living in the house has not been conducted. There is some evidence that living close to high voltage overhead lines cause ill effects in people.

Other than in a domestic house, concrete is everywhere. In roads, bridges, office and industrial buildings to name but a few common examples. Having a road constructed with charcoal laced concrete could have the ability to charge EVs as they travel. The charge held in the concrete could supply a magnetic resonance circuit which can be picked up by a receiver on the underside of the car. No touching parts or electrical connections, similar to how an electric toothbrush charges. Constant power boosting the battery as you travel. Perhaps this could be installed on main roads, giving unlimited travel. The EV battery only draining when you come off the main road on to minor roads.

Adding more charcoal increases the capacitance value and therefore the amount of electrical charge that can be stored. However, too much can weaken the concrete, so a careful balance is required.

Real world tests have not yet been carried out, so it is unlikely that this technology will be available any time soon. It can not be installed in existing concrete, only new builds.

About The Author
Markus Woznica
Chewells Contributor

Markus is a renewable energy expert. The technology in this sector is changing fast. There is a... »

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Replies

• Roxy (Sept 2, 2024)
  This sounds like a potential fire risk to me.

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