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Storing the power produced by intermittent generation

(10 Posts)
Elegran Mon 31-Aug-20 09:33:06

One of the limitations on relying on power produced by wind/wave/sun systems is the storage of the power produced in good conditions for use at other times. This project uses weights suspended in mine-shafts etc. The 250-kilowatt demonstrator project being built at the Port of Leith will enable the technology to be trialled on a smaller scale initially, using an above-ground structure. Should be interesting.

Our patented technology is based on a simple principle: raising and lowering a heavy weight to store and release energy. The Gravitricity system suspends weights of 500 - 5000 tonnes in a deep shaft by a number of cables, each of which is engaged with a winch capable of lifting its share of the weight. Electrical power is then absorbed or generated by raising or lowering the weight. The weight is guided by a system of tensioned guide wires (patents applied for) to prevent it from swinging and damaging the shaft. The winch system can be accurately controlled through the electrical drives to keep the weight stable in the hole.

Gravitricity™ technology has a unique combination of characteristics:

50-year design life – with no cycle limit or degradation
Response time – zero to full power in less than one second
Efficiency – between 80 and 90 percent
Versatile – can run slowly at low power or fast at high power
Simple – easy to construct near networks
Cost effective – levelised costs well below lithium batteries
Each unit can be configured to produce between 1 and 20MW peak power, with output duration from 15 minutes to 8 hours.

Oopsadaisy4 Mon 31-Aug-20 10:00:45

I dread to think that they will be sending huge shafts down in to the earth, especially if they will need several for each town /village, but an above ground one sounds like a good idea.

Elegran Mon 31-Aug-20 10:09:29

I think they plan to use existing shafts at former coalmines and so on. There are plenty of those in some areas.

Oopsadaisy4 Mon 31-Aug-20 10:12:24

Really? That sounds ok if the shafts are in good repair, but I wouldn’t think it likely. Interesting though.

Elegran Mon 31-Aug-20 10:13:26

If they build above-ground shafts with the lifting mechanisms at the top, as high as mine-shafts are deep, there could be objections.

Oopsadaisy4 Mon 31-Aug-20 10:23:11

I think that there will objections whichever route they go!
Shafts opening up all over the place can be a nightmare 50 years down the line and the costs involved will be very high either way .
Think of all the old shafts opening up over the country.

Elegran Mon 31-Aug-20 10:34:58

The trial run in Leith will show up whether it seems viable. The ideal would be a reduction in the use of power, but that is increasing as the demand for more gadgets and equipment seems apparently insatiable.

Nuclear power and coal-fired power have drawbacks and dangers. Alternative sources are cleaner, but not as continuous and dependable. If this system stores power and brings it back into availability faster, cheaper and more efficiently than anything currently known, it will be worthwhile for energy firms to get old shafts back into use and safe.

keyline Sun 17-Oct-21 19:28:38

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Katie59 Sun 17-Oct-21 21:59:03

This is the same energy storage system used in grandfather clocks or with a spring in any clockwork mechanism, you can store compressed air, or pump water uphill then release it to generate power, they have all been used at some point

Their efficiency is poor, using a battery to store electricity from solar or wind generators is around 90% efficient. Tesla Powerwall is one system, another connects the battery in your electric car to store, then release power to your home. Currently too expensive for most of us, maybe widespread in 10yrs.

M0nica Sun 17-Oct-21 22:33:23

We visited the Dinorwic pumped storage sytem in Wales a few years ago. We were told that more electricity was used pumping the water uphill to the storage area than was generated when it was released through the tubines.

Think about that.

It worked because the water was pumped up when demand for electicity was low (late at night/early morning) and released to generate power when power demand was at its highest.

From Katie59's post I deduce that something similar happens when you compress air, more power is needed for compression than is generated when it is released.

The biggest danger from big batteries, however efficient they are, is the danger of explosions- and a big battery exploding would do a lot of damage over a large area.

You may remember a few years ago Samsung developed a small high capacity battery for one of its mobile phones, but it had to be withdrawn after a few months because of its tendency to explode, especially on planes.

At the end of the day there is no easy way out of the current system of hydrocarbon generated electricity. No matter how many wind turbines we build offshore all round the British Isles, The British Isles are often covered by large weather systems that mean the wind conditions are the same, whether on the furthest northern top of the Shetlands to the southern most tip of the Scilly Islands and in all our coastal waters.

I regularly check a site called GridWatch which gives the source of all the electricity the country is consuming at any given time. Over the last fortnight, on different days, it has been as much as 40% + of all our power and as little as 3%. It means that we will always need to have nearly as much back up capacity as there is wind capacity installed to provide support for when the wind doesn't blow.

Like it or not, until the Holy Grail of Fusion is sorted, the only way we can meet the exponentially growing demand for electricity, as everything now powered by hydrocarbons moves to electricity, is nuclear power.

Not the huge behemoths costing billions of £s and requiring Chinese technology, but the much smaller modular systems championed by Rolls Royce with the nuclear reactor based on their expertise in designing the engines for our nuclear submarines which have been in use for decades.