Nitrogen as an Energy Store ...

Just spotted this on the News: **LINK**

https://inews.co.uk/inews-lifestyle/people/green-electricity-peter-dearman-liquid-air-energy-invention-822608

The embedded link to the development in Manchester is perhaps more convincing that that happy little snippet.

MichaelG.

________
.

... Better to discuss this ^^^ than start a civil war about lathe registers ?

Ref. **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=170237&p=2

.

Edited By Michael Gilligan on 11/01/2021 11:35:43

The Carnot Cycle efficiency of such a system is appaling.

.... But if you are using cheap surplus electricity, surely it’s only an alternative to the ‘Electric Mountain’ approach [without the inconvenience of searching for a suitable mountain with upper and lower lakes]

MichaelG.

.

Edit: 259 views, and that’s the only discussion 

Edited By Michael Gilligan on 11/01/2021 21:06:34

I suggest that the most efficient engines use fuel that will run out, or minerals ditto, and while they remain in use they are damaging our ecosystem, might be a good reason not to shy away from alternatives which are less efficient but more sustainable.

And particularly if they are excellent for driving fridges which it happens are needed, right now, to get us through a disaster.

Cheers, Tim

Compressed gas energy storage scores very low both in terms of energy density and efficiency. It's mentioned in Prof. Mackay's book on sustainable energy. In fact It comes bottom on his list of efficiencies.

Yes but it doesn't matter because green is so cheap. Conversion efficiency only matters when the input is expensive. Coal and oil have to be extracted, processed and transported, which costs a bomb, whereas the sun just shines.

A sunny day with a half decent breeze delivers far more energy than we need and the input costs nothing. But ways of storing it are needed because green energy comes and goes at the whim of mother nature. The through life cost of storage matters, but not efficiency because green energy is wasted unless some of it is stored.

Dave

A key factor in this application is that the 'coldness' is part of the value to run a fridge and the power to weight ratio for a mobile use. Plain ice is not solution as it needs to be below zero not at zero. However dry ice is also a possible contender.

Where does that info come from? As far as I can see, installed wind capacity is 24GW and installed solar is 13.4GW. That is installed capacity, not actual output. Max Demand earlier this evening was 42GW. This website shows interesting info on the actual generation mix. If you look, a high proportion of electricity is from gas - doesn’t go below about 25% at any time.

**LINK**

I read a while back that excess energy from solar power in a plant in Germany is used to split water into Hydrogen and Oxygen which is stored and then burnt again to run a generator when more energy is needed.

Another option I read about planned to use heavy weights in a hole in the ground. When you need energy the slowly falling weight drives a generator. When you have excess wind or solar the weight is driven back up by the combined generator/motor.

We've been down this road before, briefly

1. you can't compress nitrogen to a gas, you have to cool it. Anybody who says you can has lost my attention from then on
2. storing energy as compressed gas is wildly inefficient (as others have said). It was used in mining locomotives, but not widely
3. the amount of energy that can be stored by raising weights up mine-shafts is trivial compared with the likes of Llanberis Magic Mountain
4. green energy s only cheap if you can build the windmills and solar panels for nothing, you can't which is why we've had a green levy (ie more expensive power) to kick start it. Even after you've paid off the capital you still have to maintain it, which is neither easy nor cheap when it's offshore

If there is lots of 'free' liquid nitrogen left over from making liquid oxygen, why not just build a dewar flask into the lorry and use the evaporating gas to keep the lorry cool

Don't get me wrong, I'm all for renewables, but let's not waste money on technologies which are unlikely to be much use.

Edited By duncan webster on 12/01/2021 00:43:35

There is a paper written by for the US Marine Corps by MIT which looks at mobile power generation for expeditionary USMC operations. The list of parameter requirements goes through usual military concerns, for example low infra red emissions, low noise, lightweight and portable, efficiency and multi fuel capability.

The paper examines conventional ICE both gasoline and diesel fuelled, gas turbines, Wankel rotaries, compounds, etc, The most interesting was a engine described as a 'chemical engine' and this was fuelled by HTP (High Test Peroxide) and any available hydrocarbon could also be introduced as a power booster.

Basically Hydrogen Peroxide is introduced to Potassium Permangate which acts as a 'disassociation' catalyst splitting the Hydrogen Peroxide into steam and oxygen.

Martin

Hardly an original or unique idea. I'm sure we had a forum thread recently that included a drawing of a proposed nitrogen power station, full sized gigawatt type thing. Based on sub-cooling nitrogen via refrigeration with cheap green power when it was available on sunny windy days etc then releasing the liquified nitrogen to drive turbines and the like when extra power was needed on cold windless nights etc. Perhaps someone with better search skills than mine can find it. Seemed like it was getting ready to start construction?

This latest story seems a typical example of a technologically illiterate journalist waxing lyrical over some old git in his workshop with a dream project that the rest of the world has discovered and discarded for various reasons, including probably the practicalities of producing, storing, shipping and dispensing liquid nitrogen.

Our local paper used to run a story every year or two about the locally made Lutec 1000 generator that was claimed to produce more power than it took to run it and included all the usual perpetual motion speak of motors driving pivoting magnets and then the increased power driving generators etc. LUTEC FREE ENERGY

500 per cent efficiency, the Cairns Post journalist reports. 500 per cent compared with a car's 40 per cent!!! Scientifically radical, to say the least, but it never stopped the journalists -- who majored in English not Science -- from spruiking it year after year in breathless terms about saving the world etc. You could plug it into a wall outlet in your house and produce enough power to run the whole suburb etc etc. Saaaay whaaat?

I don't know if their investors, impressed by such reports no doubt, ever got their money back let alone a dividend.There were, apparently, millions to be made but it seems to have dropped from sight.

Not that old mate in his shed with his nitrogen engine is perhaps the same thing but the willingness of journalists to take the word of a lone old git in his shed against the scientific and industrial establishment's is the same.

Edited By Hopper on 12/01/2021 03:39:56

Edited By Hopper on 12/01/2021 03:41:31

Turns out the first nitrogen powered car was made in 1902 in the USA and ran at 12mph. Flying for its day!

So Dearman's idea is not a new invention. But I think what is innovative is its combination with refrigeration to make use of the latent heat absorbed in converting the liquid nitrogen into a gas. Which the journalist does not really make clear.

But what happens if the fridge compartment is already cold enough? Run atmospheric air through it? Any humidity condenses and forms frost on the exchanger? According to wired.com they were getting ready in 2016 for a trial with some supermarket trucks. But no further word...

Don't confuse capacity with potential! Before canals and railways the energy obtained from coal was tiny despite a good part of the UK being sat on a giant coal-field. To benefit from coal it was necessary to build a lot of expensive infrastructure and to develop new technologies like electricity.

Green energy is the same. There is a development phase. New technology is expensive and unreliable at first, then it becomes cheap and reliable.

Rather than digging up and burning fossil fuels laid down hundreds of millions ago, green exploits solar energy directly. And the amount of energy delivered by the sun to the earth's surface is enormous - about 1.3kW per square metre. In total the Green energy potential is between 4 and 16 million Terawatt/hours per year. Forever.

Everything has pros and cons. On coal's plus side storage is trivial - it can be stacked in a heap - and power output can be controlled by throwing more or less fuel on a fire. Straightforward to manage with primitive methods. Coal also has many disadvantages; it has to be mined, cleaned, graded and transported. It's dirty to handle, tricky to burn efficiently. and the combustion products are polluting. Boilers are expensive to build and high-maintenance. As it took 200 years for the industrial revolution to put coal powered electricity into all UK homes, I think Green has made excellent progress. Although heavily subsidised at first, green today is the cheapest form of energy available in the UK. The 24GW wind and 14GW of capacity installed so far barely tap into what's available.

Cheap and plentiful but imperfect. (All technologies are imperfect.) The big problem with green is how to manage a source that comes and goes with the weather. At present green feeds into the grid and it's been possible to shut down coal generation almost entirely. This is good because the coal is imported from Brazil, Australia and the USA. But it can't replace everything. Green is flawed because it fades in and out at inconvenient moments. So the UK system relies on Nuclear, imported electricity, and Gas to cover the gaps. Effective electrical storage systems would eliminate gas as well, but there is no simple answer. Many options but they are all more-or-less high tech.

Mark's reference to Carnot suggested efficiency mattered, and I'm saying it doesn't in this case because the input energy is free and clean. Provided the infrastructure is affordable and stores a reasonable amount of power, running inefficiently on solar energy can be extremely wasteful without concern. Although the same system is completely uneconomic, wasteful and polluting when powered with fossil fuels, it makes sense when powered by Green energy. The rules change when one form of energy is substituted for another.

Dave

Edited By SillyOldDuffer on 12/01/2021 10:09:34

A little more information, to fuel the discussion:

**LINK**

https://www.rechargenews.com/transition/work-starts-to-build-worlds-first-commercial-liquid-air-energy-storage-plant/2-1-908259

MichaelG.

.

Duncan

Can I assume that you meant ‘to a liquid’ ?

MichaelG.

That's the plant I was thinking of. Same principle as the gent's engine in the OP but not on a transportable scale.

I read somewhere that to super cool nitrogen they use either cryogenics or a reverse cycle Stirling engine. Not sure how that would work?

.

... and mentioned in my opening post

MichaelG.

Edited By Michael Gilligan on 12/01/2021 10:42:35

Some might wonder how denizens of a thin habitable layer, sandwiched between boiling magma and a zero degree Kelvin void could want for energy.

Others might wonder how you get to be an environmental reporter when you obviously have less scientific understanding that my cat Mopsy.

A relative that lives in Switzerland clubbed together with three other neighbours to have a deep bore hole drilled adjacent to their properties. The cost of drilling this hole was not insignificant at the time but now it’s done all four houses benefit from very cheap heating.