Mobile Electrical Energy Storage and the Challenge for Chemistry

Harry Valentine | Mar 30, 2011

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As the market price of liquid fuels for the transportation sector increases, so does interest in alternative forms of propulsive energy. While various governments may provide research funding to such ends, there are numerous private groups that also seek to develop alternative and potentially viable forms of propulsive energy. Higher world oil prices have allowed the Government of Brazil to end subsidies to the sugar-cane fuel ethanol industry. However, opposition to bio-fuels increases as populations face higher food prices as the land can often be used directly or indirectly to cultivate food crops.

As debates about alternative methods of propulsion on land continue, the commercial marine sector has gained access to a modernized form of old alternative propulsive energy. A company from Germany and another in the SW USA offer kite-sails that use the kinetic energy of high-altitude winds to provide a portion of the propulsive power required by boats and ships. In times past, many of the old clipper ships sailed parallel to the trade winds that carried them to trading ports around the world. The modern day kite-sail technology achieves the same end with larger boats and taps into winds that blow at higher velocity and higher frequency that winds that blow at lower elevations.

There has been ongoing interest in competitively priced, plug-in electric vehicles for the consumer market. Private companies have answered the call by offering plug-in electrically assisted bicycles that can travel for up to 40-miles at up to 25-miles per hour. Thousands of such units that are powered by a motor of 500-watts (0.67-Hp) output have been sold across North America and the world. Political unrest in oil producing nations usually results in higher oil prices. Citizens in many nations now have an alternative mode of transportation that uses a different fuel.

The proliferation of electrically assisted bicycles has resulted in an epidemic of expired lead-acid batteries in several Asian nations. In North America, these units carry the more expensive lithium batteries that can endure some 5000-deep-cycle discharges and recharges, 10-times the number of the lead-acid counterparts. The rate of expiry of the batteries prompts discussion as to whether new-generation super capacitors could become a viable alternative form of electrical energy storage. Such devices are being used to store electrical energy that is used to start commercial-duty diesel engines on large trucks and railway locomotives.

Government funded researchers in the USA have indicated the possibility of developing a super capacitor technology that could propel an automobile for up to 500-miles at freeway speeds. However, the appearance of a cost-competitive carbon nano-tube super capacitor may be many years into the future. There is a need for a cost-competitive super capacitor technology that can be a viable alternative form of energy storage, independently of government subsidy or special tax incentives. One option would be for entrepreneurs to seek to construct super capacitors using readily available energy storage materials.

That option may result in the appearance of super capacitors that may be suitable for forms of transportation other than the private automobile. BASF developed the barium titanate [BaTiO3] storage compound that can store up to 280 Watt-hours per kilogram in super capacitors. Their research suggests that bi-metallic oxides with semi-conductor properties may offer potential as energy storage material in competing super capacitors. Such devices may actually find market application despite offering lower energy storage is the same size of package.

Micro-Power Vehicles:

A large super capacitor may use a commercially available material such as barium chromate [BaCrO4] to store energy, with market application in numerous sectors. The device may be built to a much larger scale than the batteries that power electrically assisted bicycles, offering operating range of 3-miles on an electrically assisted delivery vehicle. If most of the deliveries are within 1-mile of the point of origin and it takes 3-minutes to recharge the vehicle between each delivery, there may actually be commercial market application for such an energy storage system.

The low amount of power needed to recharge allows such vehicles to recharge from conventional power outlets. Entrepreneurs may develop coin operated recharging stations to recharge such vehicles from standard electrical outlets. Businesses that operate micro-power vehicles for delivery service, may install such units outside their premises to sell electric power to other users of micro-power vehicles. As the number of recharging stations increases in an urban area, so would the usage of super capacitor powered 2-wheeled micro-power vehicles.

Heavy Weight Vehicles:

A naturally occurring bi-metallic oxide ore or mineral called ilmenite [FeTiO3] is mined in remote locations such as Madagascar. Its chemical structure is very similar to that of barium titanate. Each molecule of ilmenite will store less energy than barium titanate. The low cost of the compound provides possible market application in some large-scale heavy weight, short-distance transportation applications such as railway operations and short-haul marine ferries.

A 4-axle locomotive that weighs some 240,000-lb may store electrical energy in multiple banks of super capacitors that contain some 45,000-lb (20,000 kg) of ilmenite. If the ilmenite can hold 50 watt-hours of energy per kilogram (very conservative estimate), the super capacitors could store 1000kW-hr (1340-Hp-hr) of energy. The locomotive could deliver some 3000-Hp for periods of up to 20-minutes, perhaps serving as an assistant to a diesel-powered locomotive on a multi-stop train, reducing diesel consumption in such operations.

It could also be coupled to an electric locomotive that would otherwise cause a major power swing on the distribution grid as is powers up to move a heavy train. The presence of the rechargeable locomotive on the train would reduce a sudden demand for electric power from the grid. It may be possible for a large rechargeable locomotive to operate commuter services, shunting and pull lightweight freight trains between inter-modal terminals.

The Search for a Polymer:

There are naturally occurring bi-metallic oxide molecules such as ilmenite [FeTiO3] and lithium aluminate [LiAlO2] with semi-conductive properties that allow them to store electrostatic energy in super capacitors. While barium titanate [BaTiO3] offers much greater energy storage density, there is potential market for a material that can greatly exceed its energy storage capacity. Much government-funded research has focused on developing carbon microstructures that are theoretically capable of storing immense amounts of electrostatic charge.

Such theoretical giant molecules or polymers of carbon may be several years to decades into the future. There may be the option of low-cost, privately funded research coming up with an intermediate form of polymer that may find market application until suitable carbon polymers appear in the distant future. The pharmaceutical industry has created many useful giant molecules using private funding and the list includes nylon, Teflon, polyester, nomex, kelvar and carbon fibers used to make various structures.

While it has been possible for many years to develop many bi-metallic oxides, the market application for such molecules was limited. Pure aluminum can chemically react with any of several metallic hydroxides and displace the hydrogen atoms. The list includes hydroxides of lithium, potassium, sodium [Na3AlO3], calcium [Ca3(AlO3)2], magnesium, nickel, iron (ferric and ferrous hydroxide) chrome [CrAlO3], manganese, barium and several other metals to produce a semi-conductive, bi-metallic oxide.

The challenge for chemists would involve modifying the reaction in a ways that produce a bi-metallic polymer of several hundred atoms. When incorporated into a super capacitor, the long chain of the polymer would be set at right angles (90-degrees) to the capacitor conductive plates. Such a layout may increase the spatial volume where the electrostatic charge is stored. However, the research challenge of producing a large bi-metallic oxide polymer may be daunting.

Organic-Metallic Oxide Polymers:

Private companies have long undertaken research into developing products based on long chains of carbon atoms. Variations include carbon fiber material and hydroxide molecules (-OH) being bonded to carbon atoms in glucose and carbohydrate molecules. There may be scope for chemical researchers to develop synthetic, extreme long chain carbohydrate molecules.

Aluminum can displace the hydrogen from metallic hydroxides and bond directly to the oxygen atoms. Researchers face the challenge of reacting aluminum with the hydroxide molecules in long-chain carbon polymers, to replace the hydrogen atoms with aluminum. Aluminum atoms may bond to pairs of adjacent oxygen atoms in some carbon chains and to alternate oxygen atoms in other chain, offering the possibly of linking 3 x parallel long carbon chains.

An alternate option would be to seek to replace pairs of hydrogen atoms with single barium atoms. The long chain of bonded carbon atoms would form the backbone of a polymer that would include a long string of barium atoms. The development of carbon fiber material may provide the precedent to develop parallel chains of carbon atoms, analogous to microscopic railway tracks with hydroxide molecules on both sides.

Researchers would need to develop a chemical reaction to replace the hydrogen atoms with a metal such as barium, to form metal-oxygen-carbon-carbon-oxygen-metal bonds perpendicular to the parallel carbon long chains. The result would be the carbon backbone carrying 2 x parallel long rows of barium atoms that may touch each other. The objective of such research would to develop semi-conductive polymers capable of storing substantial electrostatic charge in large-scale super capacitors.

Conclusions:

Considerable progress has already occurred in the research to develop super capacitors that offer high-density energy storage. However, such devices presently have limited market application in the transportation sector, starting diesel engines. Private cars would constitute the major market for super capacitors capable of propelling such vehicles over extended distances (100-miles). A competitive energy storage compound for such application may be many years in the future. Chemical researchers face the challenge of developing a polymer capable of storing extreme electrostatic energy densities in lightweight and compact packages.

Commercially available materials such as barium chromate may be appropriate as super capacitor energy storage material for micro-power 2-wheel vehicles that would offer limited operating range. A proliferation of recharging stations appropriate to such technology in urban areas could help develop a market for super capacitor powered micro-power vehicles. Naturally occurring materials such as ilmenite would have application as super capacitor energy storage material in the commercial transportation sector (railway and marine).

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Comments

Interesting paper Harry. Once the problem of storage of electrical energy on a medium to large scale is resolved there will be many changes that result from that technology. Load flattening of the grid being one major nut to crack.

Not so sure about the sailing ships concept though. The weight of a sailing clipper was about 300 to 500 tons. The weight of a typical container ship is about 150,000 tons and bulk carriers can weigh up to 400,000 tons. I doubt if it would make much of a dent in the fuel consumption of one of these vessels.

Has this idea been tried? Are there any numbers available to determine its true viability? Of course the other issue is that these big ships are staffed by only a few dozen sailors and unless the sail deployment was fully automatic the extra staff required would more than offset any savings in fuel costs. Most of the sailors on the clipper ships of olden days were required to deploy the sails and reef them in. No doubt it can be automated but sounds like lots of equipment that can go wrong for very marginal cost savings.

Malcolm

Answers to:

QUESTION 1: Does Heat Rate apply to solar PV generation of electricity?

QUESTION 2: Does Heat Rate apply to solar trough generation of electricity?

QUESTION 3: Does more than 3412.14163 BTU have to go IN for each 1 kWh of electricity OUT?

QUESTION 4: Is the second law of thermodynamics repealed for solar and wind generation of electricity?

QUESTION 5: Would it be better for New Mexico ranchers to install wind turbines to convert to electricity to power electric water pumps?

Or mechanically pump water from wind, as they have done in the past?
______
Sent: Friday, March 25, 2011 9:36:19 AM Subject: RE: Solar generation of electricity heat rate questions
I'm not one hundred percent clear that I understand the question you're asking, but I'll give an answer a shot:

I can start by pretty confidently saying that none of the laws of thermodynamics (or conservation of energy) can be violated by us...no matter what marketing language we choose to employ. So it is indeed a good exercise to compare output claims to available input to test whether some person's claims hold water or not. I used to do this as a hobby in the small wind area when people would periodically come out with claims that their particular vertical-axis wind machine somehow got around the issues of other machines and produced amazing amounts of power.

To attempt to address your heat rate questions, the term "heat rate" from an energy production perspective refers to the amount of energy a plant produces for every unit of fuel that gets put in. Specifically, it's the number of BTU's needed to produce one kilowatt-hour of energy. So strictly speaking, I would say that heat rate has no real meaning for solar PV or wind, since nothing's being burned. The efficiency of these technologies matters, of course, in that one wants to get as much energy output per unit input as possible. It's most important implication is how quickly we burn non-renewable resources to generate electricty. So heat rate is really an expression of (thermal) generator efficiency that doesn't have an immediate analog in renewable techonologies since we don't consume non-renewable resources in the latter.

So strictly speaking, the amount of energy required to be input into any device that gets its energy from the Sun or the Wind is not directly relevant; again, because we're not actually consuming anything. What does matter, though, is how much land (read "real estate") is required to harvest energy, and how much it costs to do it.

On the Texas/gas issue, my understanding is that cold weather led to natural gas problems, which caused at least a couple of power plants to fail, which then caused electricity supply issues that led to further natural gas delivery problems... I believe the heart of the matter was an old and weak natural gas delivery system, not fundamentally an electricity generation or delivery problem.

As for your Wall Street banker - I'm not sure what to say. Is utility scale solar thermal a fraud? No. It's simply a matter of whether it's cost effective in the face of other options. Some of my clients sure think it is.

Finally, "is it better for NM ranchers to install wind turbines to convert to electricity to power electric water pumps, or use mechanical means?" (paraphrased) Probably mechanical. It's mechanical pumping you want in this case. You introduce a lot of (mostly) unnecessary losses by converting from mechincal to electrical to mechanical energy. That's why you see wind pumps scattered across the NM landscape. The advantage of electrical pumping is that it can be turned on NOW and turned off NOW. And since electricity is cheap and we're addicted to convenience, people do indeed use electric pumps in many cases.
Hope that helps.


Frank Currie, PE
Project Engineer
Commonwealth Associates, Inc.
1599 S. St. Francis Dr.
Suite C
Santa Fe, NM 87505
505-982-4012
www.cai-engr.com

No comments yet?

Focus on on 'goesintos' and 'comesoutofs' not on what is happening on the inside. In this case we are looking at the 'comestoutof', then applying the second law of thermodynamics to calculate the minimun 'goesinto' which must be 3412.14163 BTU = 1 kWh.

Otherwise we have the electric equivalent of perpetual motion.

AND


Heat Rate
Source BTU/kWh

Geothermal heat rate 29,500
Nuclear 10,510
Nuclear (PV lease acquisitions) 10,420

http://www.prosefights.org/eprishumard/currie/currie.htm

Puzzled somewhat by Frank Curries response to Bill Payne's very valid questions. Frank - I agree that relatively speaking electricity is cheap (and I would like to keep it that way) and it is very convenient but the tone of your note seems to imply that is a bad thing. Surely being able to pump water at the flick of a switch inexpensively is a GOOD thing isn't it or are you implying that such convenience is bad. Perhaps you would feel better if we were hauling water out of wells with buckets and carrying it miles to our homes - as many African people do right now today.

I really do hope I am misreading your words.I really like the idea of being able to see at night at the flick of a switch and being able to pump water without having to wait for the wind to blow. I also like not having to pay a fortune for it.

Our electricity system developed over the last hundred or so years is a major plank in the well being of western nations and one of the reasons why so many people from poorer parts of the world flock to get a chance at our lifestyle.

Don't knock the convenience - it's one of the reasons we don't die at 40 any more.

Malcolm

Bill, In defense of solar (yes this is a first for me) I don't think the concept of heat rate does apply. Since the actual energy (solar radiation) is essentially free it does not really matter much. However what is important if the energy per unit area of collector. To make any meaningful contribution to electricity production the land areas required are very large which makes this technology impractical. To compound the problems these collectors will require cleaning to maintain their efficiencies. I cannot envisage vast armies of people with squeegee mops cleaning square miles of solar panels.

In cold climates where winter ice and snow are issues these units would be out of useful production for most of the winter.

So I do not see a rosy future for PV cells simply because too much area is required for the energy that is produced.

Malcolm

1859: A brilliant Frenchman named Gaston Plante’ invented the lead –acid battery.

1910: Several auto manufacturers were offering practical lead-acid electric automobiles. The main problem was that they could only go up to 75 miles at 25 mph on a charge. So began serious research into better rechargeable batteries.

1948: An engineering professor of mine mentioned en passant that “Nothing has been so resistant to improvement as the lead-acid battery, or the development of a better storage batter.”

2011: The world over, whether automobile, truck, bus, boat, etc. if it moves it has a lead acid battery. And so will nearly every one of millions of vehicles built this year, and next year, and…

We do have a handful of electric cars with batteries better than the venerable lead –acid battery, but with performance not even an order of magnatude better than a hundred years ago and at far greater expense. (We have become accustomed to both “better and cheaper.”) A very simple expression sets for all time the amount of energy we can get out of an internal combustion engine per unit of fuel. While I don’t know of any battery performance limit imposed by nature there are only so many kinds of atoms in the Periodic Chart and a myriad of the most likely combinations have long since been tried.

We await the first great leap forward in the 152 year history of the storage battery.

"To make any meaningful contribution to electricity production the land areas required are very large which makes this technology impractical." -- a true statement in some sense, though all is relative to one's interpretation of "very large". e.g. the entire energy usage of Europe can be supplied by a patch of solar collectors which would cover about the size of a postage stamp on a page-sized map of the Sahara Desert. Sure its a large area. Impractical? Not at all, HVDC transmission through Gibralter and Sicily, solar thermal generation at $0.035 / kwh achievable with minor and certainly do-able improvements to todays technology plus volume manufacturing, water provided by seawater de-salination...

Don: sooner or later, if we can keep it together for a few more years, volume manufacturing by direct manipulation of individual atoms will resolve the electricity storage problem, at least for transportation.

Len, I don't doubt that is true. If it is that easy one wonders why we have not already done it. Methinks there are some "very large" obstacles in the way. Presumably, like everywhere else on Earth the Sun's radiation cannot be captured very effectively when the solar collector is on the other side of the Earth from the Sun. This is called night time. I am not sure the German's and the French would appreciate the lights going out at night whether their electricity is generated by solar electric or solar thermal makes no difference.

Although I am not a weather forecaster, I am aware that the Sahara suffers from large sandstorms that last for days at a time. It is an inhospitable place to say the least and when the Sun is obliterated by blowing sand my guess is the solar output drops significantly. Someone of course will then have to clear all of the solar collectors of sand. A couple of thousand square miles of solar collectors will be quite a clean up job - that's if they still work after being sand blasted.

Also on the Sahara Desert weather front although the place is hot during the day it is very cold during the night so you would need to figure out some means of preventing freezing.

And lastly - desalination of seawater is an energy intensive and expensive process. I do not know of any country that has done it on a large scale and surely if it was that simple the countires of the Middle East would be doing it already to provide that most basic of necessities - drinking water.

I contend that this is a great deal more difficult than you imagine.

Finally I really cannot envisage any political leader in Europe putting their energy eggs in the basket of the Sahara that is governed by somewhat unstable rulers one of which is our dear Colonel G.

One tank shell into the HVDC cable and out go the lights.That would make oil dependency seem like child's play.

Good idea Len....but.

Malcolm

Oh dear Don, you really have to get your brain off the tram lines.You are assuming that batteries made of some physical combination of elements in the periodic table is all there is. There is a great deal of work going on in the area of microbial fuel cells which use bacteria to convert waste into electricity. A young man by the name of Kyle Schoel of Alberta Canada recently won the 2010 Manning Award for innovation by building a microbial fuel cell that uses bacteria to convert used rubber tires into electricity and water. How would you like to run your next car on an MFC

No doubt the bacteria are combinations of the elements of the periodic table but I don't think you had that in mind.

Malcolm

My comment was about electricity storage and very much in line with the article title. Quite a different subject than you dealt with in your comment questioning my brain while at the same time promoting the generation of electricity with microbes. So, recognizing this, let me know if you have found any fault with my comment.

Malcolm:

1) Sandstorms in the Sahara or not, insolation maps still show it as hosting the world's largest area of highest insolation on earth. Insolation measurements take sandstorms into account.

2) Thermal storage is a well-known and demonstrated process. Either largetanks of the thermal collection fluid are stored at high temperature, or the fluid is used to heat insulated tanks of dry sand and gravel (much cheaper). Nobody's putting any development money into it as long as all present solar electricity output can be efficiently sold into the peak market.

3) Thermal vacume desalination using the heat from the condensers of a generating facility is clearly logical, esp. with low-efficiency solar-steam plants where as much as 83% of the heat in goes into the condensers. It's already common in the middle east to do de-salination with the waste heat from combined-cycle gas plants, see Dubal Aluminum's 1,200 MW generating plant.

4) Your last scare tactic is just that, nothing more. I could as well ask why doesn't Iran close off the Straights of Hormuz to oil tankers, something they could logically do quite easily with some determination? Answer, of course, is that they need the cashflow from the oil sales. Ditto electricity from Tunisia, Libya, Algeria, Egypt. I think you perhaps have no concept of how many separate HVDC transmission cables would be involved in "replacing all enegry use in Europe".

1b) And the studies have been done of the effects of sandstorms on the collector mirrors. Result was normally the units are easily defended by turning them over away from the wind direction, with the cost of any reduced performance and/or required replacements easily handled by insignificant insurance premiums.

So what could a smart investor do with unlimited available electricity generation in Tunisia at $0.035 / kwh, and with Italy's $0.15 / kwh wholesale market, determined to NOT use nuclear, just a short shallow undersea hop away, no worse than Spain's undersea cable to Mallorca.

NiMH store better than lead acid. Panasonic made a "good enough" battery, the EV-95, which was used in Toyota RAV-4 EVs. These were built around the same time as the GM EV1. Some of them are still running today! The NiMH technology got fouled up with patent rights, so carmakers abandoned them in favor of Lithium Ion, but I'm not sure they have the overall best performance (including lifetime) as a battery.

The RAV-4s have gotten 200,000+ miles out of their battery packs. I'm not sure Li Ions have demonstrated that track record yet.

Len, Most of Europe is dependent on Russia for its natural gas supplies so my argument about relying on a foreign country for your energy is not a scare tactic but a harsh reality the implications of which you need to better understand. Ask the Ukranians what they feel about that. When the Kremlin feels the desire to cut you off it can - at the flick of a switch - and they did just that. The very reason that Japan has invested and continues to invest billions in to nuclear power is for that very same reason. You cannot be dependent upon other nations for your energy supply especially ones that don't like you very much.

So planting all of Europe's energy supply in the middle of the Sahara is just plain stupid. And I agree it is just as stupid as becoming dependent on foreign supplies of oil some (by no means all) of which flows through the Straits of Hormuz). As far as I know not a drop of Canadian oil moves through that route.

And yes I do know enough electrical theory to know that many hundreds of DC links would be required - but it still remains sitting duck infrastructure for anyone who wanted to knock it out.

Much easier to build a string of nuclear plants like France has done. I really cannot see France investing a cent in such an ill-conceived. It reminds me a bit of the scheme the British conjured up to grow peanuts in the jungles of Africa. Great idea but.....didn't work.

Malcolm