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I'd recommend the book The Grid as a primer on how stuff like this can happen. Energy is strange, in the sense that everything produced needs to be used more or less immediately. Maintaining the energy grid is a careful balancing act between preventing surges and blackouts.

There are a lot of grid-related engineering problems that come from increasing decentralization (e.g. wind, solar, hydro) because it increases unpredictability in supply.


I wonder if we will ever get appliances that respond to the grid, a freezer that drops its temperature a couple of degrees because energy is cheap or a washing machine that waits an hour because it is expensive.

I suspect there is quite a bit of personal demand that could be shifted easily.

Yup, pretty sure we will. Actually, they've been around for a couple of years now [1, 2]. I think there are smart-grid-enabled electrical heating systems as well.

"Smartening" appliances can lead to surprising security issues [3] as well. If you have the time (and interest) for an entertaining primer into the subject, watch any of Mikko Hyppönnen's recent Talks explaining "Hyppönnen's Law".

[1] http://laundry.reviewed.com/features/whirlpools-new-connecte...

[2] https://aquanta.io/

[3] http://securityaffairs.co/wordpress/53247/cyber-crime/buildi...

When I lived in Zambia, Africa in 2005 there were refrigerators made by South African companies for countries without 24 hour power. Similar idea to this, really.

German aluminum smelters are already doing this.

My house has a smart power meter in it that reduces/shuts off AC during times of peak demand (as commanded by the power company, PEPCO). In return you get a certain amount off each bill.

Bought the book, but spoil a little for me if you would: I know that some utilities turn on pumped hydro storage to handle excess capacity, but what other ways are there to efficiently waste energy?

Rail storage uses a long incline track and an electric engine with large mass to store excess electrical energy as potential energy.


A long inclined track, and magnitudes of order more energy inputs in the form of steel and super heavy duty tracks and earth moving and maintenance than could ever be recovered.

Soneone here recently ran the numbers assuming you could move rocks unencumbered up and down earths gravity well and the mass required to generate enough electricity to power the world even for a brief movement. The numbers were sobering.

Yea rail storage is pretty niche and definitely can't power the whole world.

The only advantage is that there is a very low switching time on the load from charge to discharge compared to pumped hydro. This could be extra useful for load balancing a distributed grid.

I suspect flywheels would do the job without the added complexity of a train.

Flywheel storage for wind energy. It's mostly used for grid balancing.

Beacon Power has a complete solution but they went bankrupt in 2012, then got bought by Rockland Capital who intend to rehire the staff and build a 20 MW plant in Pensylvania.

Also, here's an article of such an energy storage project in Ireland by Schwungrad Energie Ltd.


Right now and for the foreseeable future, lithium ion batteries are a better alternative to flywheels, though they will see some use for applications that require high power but little total stores energy.

The power:energy ratio is high, but has few applications on the grid. Even lithium ion's typical 4:1 MW:MWh is a bit high.

The really unexplored territory is seasonal storage. Electricity to hydrogen, methanol, etc. have huge round trip efficiency hits, like 30%-50%, but may make a ton of sense.

It's telling that a company with a "complete solution" went bankrupt.

Compressed Air Energy Storage is pretty neat.


Several organizations are investigating batteries.


There are also more traditional 1-2MW batteries that fit in tractor-trailers, etc.

There are couple out there, summarized here [0]

- compressed air cavern

- molten salt

- regenerative crane

- pumped hydro

- inclined rail

[0] https://www.nytimes.com/2017/06/03/business/energy-environme...

Increasing consumption for certain industrial processes, like electrolysis used in metal extraction.

molten salt can be used for solar

The Grid is excellent. I learned about it from Bill Gates' reading list.

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