“Concrete” energy storage: one more utopia

The views expressed in opinion pieces are strictly those of the author and do not necessarily reflect those of the editorial staff.Published August 11, 2018-A+

By Michael Gay.

An “incredible” invention has been looping since 2015 on social networks (nearly 900,000 views to date on Facebook). It was even cited by the National Center for Scientific Research (CNRS) during the visit to the THEMIS solar power plant in the Pyrenees on July 28, 2018!

Large groups would prevent it from emerging because this revolution would harm oil consumption. Its promoter would even be threatened so much his invention disturbs.

What is it about ?

It is simply a storage of electricity in a concrete flywheel combined with photovoltaic panels to, according to its inventor, make controllable and economically viable their expensive intermittent electricity production.

The presentation is suave and attractive, but poor

This clever presentation of concrete storage is clear, short, and convincing to most non-specialist listeners, but it is poor in significant figures: there are three.

To store approximately 300 million kWh (300 GWh) in order to autonomously cover only 15% of France's winter consumption (taking into account yields and losses), it would therefore be necessary:

The cost is glossed over

Only the operating cost is provided: 2 c€/kWh

Without further explanation, it is probably the cost of the concrete steering wheel, and not that of the complete investment (material and labor included). The latter should be at least 1500 € per system.

Supplying only 15% of France's winter consumption with this concrete inertial storage system would cost more than… €200 billion!

At this price, and assuming 1000 full daily restitutions (without additional costs or maintenance), each kWh returned would cost 20 c€, to which must be added the production costs of the photovoltaic panels and the losses.

Reminder: this kWh currently produced by nuclear energy costs less than 4 c€/kWh on the market.

For good measure, we should also add the cost of additional gas or coal-fired power plants needed to compensate for seasonal fluctuations…

Jacques Dutronc sang: "He's nice and attractive but, but, but, beware, it's...".

Storage by inertia for “safety niches”

Energy storage devices by inertia (without concrete) already exist in the world. They are mainly used to maintain the stability of electricity networks through rapid reactions, ranging from microseconds to minutes.

They also make it possible to wait for the start-up of other more substantial means (such as a diesel generator) to take over.

In these cases, the quantities of inertial energy stored are often small and costly, but the added safety value is significant because avoiding a cut avoids catastrophic damage (operating room in hospitals, IT, etc.). ).

It therefore seems that the seductive presentation of this engineer is nonsense, even a utopia for gogos, and that in terms of massive energy storage, the future of concrete will still reside for a long time in hydraulic dams.