Can this satisfy the world's energy needs? High-altitude wind power.

[Astronuc]

Interesting article from Purdue Engineering -

The Energy Challenge for Our Generation’s Engineers
https://engineering.purdue.edu/Impact/Energy/

Modern civilization has coasted on fossil fuels, but Earth's supply will peak—then decline. We need a sustainable energy future. Purdue Engineering with support from its partners is taking solving this predicament to heart.

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Somewhat related:

Purdue part of new $21 million fluid power energy research center
http://news.uns.purdue.edu/html3month/2006/060519.Ivantys.ERC.html

WEST LAFAYETTE, Ind. — Discovering ways to reduce fuel consumption, developing devices for people with mobility impairments and designing state-of-the-art rescue robots are just three of the goals of a new multimillion-dollar research center involving the Discovery Park Energy Center, Department of Agricultural and Biological Engineering and School of Mechanical Engineering at Purdue University.

The National Science Foundation announced a $15 million, five-year grant to support the new Engineering Research Center for Compact and Efficient Fluid Power. Industry partners will augment the funding with $3 million, and seven universities involved in the center will contribute an additional $3 million. The center will be based at the University of Minnesota Twin Cities campus, and Purdue will house one of the center's research labs in its MAHA Fluid Power Laboratory.

"This center will advance fundamental knowledge, providing a platform for technology that will spawn new industries," said Lynn Preston, leader of the Engineering Research Centers Program at NSF. "We are impressed with the ambitious goals of the center for research and education and the strong partnership with industry."

Fluid power is a $33 billion industry worldwide. Industry areas include aerospace, agriculture, construction, health care, manufacturing, mining and transportation. Fluid-power technology encompasses most applications that use liquids or gases to transmit power in the form of pressurized fluid. The complexity of these systems ranges from a simple hydraulic jack used to lift a car when replacing a tire to sophisticated airplane flight control actuators that rely on high-pressure hydraulic systems.

 

[Astronuc]

Let's not forget Russ's thread - YOU!: Fix the US Energy Crisis

https://www.physicsforums.com/showthread.php?t=42564

It probably should be stickied as should this thread.

 

[Ivan Seeking]

New Zealand Company Produces World’s First Sample Of Bio-Diesel From Algae

New Zealand-based Aquaflow Bionomic Corporation announced today that it had produced its first sample of home-grown bio-diesel fuel with algae sourced from local sewerage ponds.

“We believe this is the world’s first commercial production of bio-diesel from algae outside the laboratory, in ‘wild’ conditions. To date, bio-diesel from algae has only been tested under controlled laboratory conditions with specially selected and grown algae crops,” explains Aquaflow spokesperson Barrie Leay. [continued]

http://www.dieselforecast.com/WireReportDetails.php?wireID=142

 

[Ivan Seeking]

And, a story indirectly related to the FEGs concept:

... Multimax is one of several defense companies pouncing on the military's renewed interest in using high-flying, unmanned, helium-filled balloons -- sometimes tied to the ground with a long rope -- as possible weapons. Lockheed Martin Corp. is developing a blimp that it says will reach an altitude of 65,000 feet, while Raytheon Co. is developing one designed to reach 10,000 feet and be tethered to the ground. Blackwater USA, better known as one of the largest security contractors in Iraq, expects to finish its prototype, which aims to reach an altitude of 5,000 feet to 15,000 feet, in December.[continued]

http://www.washingtonpost.com/wp-dyn/content/article/2006/08/06/AR2006080600499.html

 

[dansydney]

I think there are many viable clean power solutions out there its just a matter of people willing to build and fund the required plants, machines etc. I think its much harder fighting the greed and politics associated with world energy usage than the actual making/finding etc of a clean energy source.

 

[Ivan Seeking]

Last night on a re-broadcast of Scientific American Frontiers, they did a spot on the Algae project at MIT.
http://www.pbs.org/saf/1506/segments/1506-3.htm
http://www.pbs.org/saf/1506/

Note that at the top of the page [under "Hydrogen Hopes"] is the option to watch online.

 

[turbo]

Great link, Ivan! I love it. I have wondered for the past few years if photovoltaic technology would ever allow the production of hydrogen on small (my house and personal vehicles) scales so that we could free ourselves from the petro industry. This gives me some hope. Sure, people in apartments and in the city might have to use commercial retail sources, but what if I could buy or build my own hydrogen generator and supply my own enegy. Right now the only thing that the south-facing side of my roof does is keep out the rain and reflect the Sun's energy. What if it could provide enough energy to keep the house cool in the summer and supplement the heating requirements in the winter?

 

[joema]

...I have wondered for the past few years if photovoltaic technology would ever allow the production of hydrogen on small (my house and personal vehicles) scales so that we could free ourselves from the petro industry...the only thing that the south-facing side of my roof does is keep out the rain and reflect the Sun's energy...

Average solar insolation for much of the US population area is 4-5 kilowatt hrs per square meter per day: http://www.windsun.com/Solar_Basics/Solar_maps.htm

Normally you wouldn't convert to hydrogen for local household use -- that would add considerable conversion loss. You'd just use the electricity directly.

How much solar cell roof area and how many hours would it take to produce enough hydrogen to refuel a fuel cell vehicle with comparable performance to a Honda Accord?

Hydrogen electrolysis is about 70% efficient, vehicle/depot storage about 80% efficient, fuel cells about 70% efficient, electric motors about 92% efficient, for total end-to-end efficiency of about 42%.

A 15-gal tank of gasoline holds 1.86E6 BTUs or 545000 watt hours of energy.

Assume your solar-useful roof collecting area is 20 by 40 feet (74 square meters). Note you can't count the whole roof area, just that portion that receives direct sun.

Your roof receives (74 m^2 * 4500 watt hr / m^2 / day) or 333,000 watt hours per day, on average. At 15% solar cell efficiency, it produces 49,950 watt hours per day. Running it through the hydrogen/fuel cell cycle, the delivered hydrogen energy is 42% of this, or about 21,000 watt hrs per day. So it would take 545000 watt hrs per tank /21000 watt hrs per day or 25 days to fill up your hydrogen car with equivalent energy to a tank of gasoline.

If you live in Yuma, Arizona, you have about a 2x advantage in solar insolation, which lowers the time required to about 12 days.

It appears the solar/hydrogen/fuel cell vehicle refueled by your solar roof panels isn't practical.

I enjoyed the Scientific American Frontiers videos, but such programs never do the above pragmatic math, so constantly leave viewers with unrealistic impressions. Then years go by and people wonder why hydrogen cars aren't here yet. The reason isn't a conspiracy, but the physics work against you, and these items are rarely adequately explained by programs like this.

 

[turbo]

Thank you very much joema for keeping practicality at the forefront.

 

[Ivan Seeking]

Although I agree in principle, not completely. First note that the efficiency of the gasoline engine wasn't considered. The actual energy demand is about 18% of that indicated. Also, this is for a full tank of gasoline, so a few days isn't so bad.

Also, I keep seeing 50% as the practical number for electrolysis efficiency.

 

[joema]

Although I agree in principle, not completely. First note that the efficiency of the gasoline engine wasn't considered. The actual energy demand is about 18% of that indicated. Also, this is for a full tank of gasoline, so a few days isn't so bad.

Also, I keep seeing 50% as the practical number for electrolysis efficiency.

Thanks for catching that. However it doesn't make a huge difference, when you factor in a few other items I omitted:

The energy in a 15 gal tank of gas is about 545000 watt hrs. A modern internal combustion engine is about 25% efficient, so it can actually convert 25% * 545000 watt hrs to mechanical energy.

The question is how long would a residential-roof-size solar PV array take to produce sufficient hydrogen for equivalent mechanical energy from a fuel cell vehicle.

Let me repeat the numbers, with a few changes:

Hydrogen electrolysis efficiency: 70% (maybe optimistic, but based on actual electrolyzers available today)
Hydrogen storage efficiency: 80% (unlike gasoline there's boil off loss)
Hydrogen liquefaction efficiency: About 70% (I omitted that before -- you have to either compress or liquefy it for storage in a car).
Real-world fuel cell vehicle efficiency: About 40%. See http://www.evworld.com/view.cfm?section=article&storyid=730

Now, the fuel cell vehicle is more efficient -- about 40% vs about 25% thermodynamic efficiency. So you don't need 545000 watt hrs in the tank, but about 60% of this or 327,000 watt hrs of hydrogen.

How long does a residential roof full of PV cells take to produce this much hydrogen in a form the car can use?

327,000 watt hrs needed / (49,950 watt hours per day * 70% electrolysis efficiency * 80% storage efficiency * 70% liquefaction efficiency)

= 16.7 days for useable energy equivalent to one 15 gallon tank of gasoline.

If you're satisfied with about 1/2 the range of your gasoline car, you could fill up your hydrogen car from your home's solar array in about 1 week, assuming it's not cloudy and you dedicate 100% of your solar array output for that task.

 

[Ivan Seeking]

The energy in a 15 gal tank of gas is about 545000 watt hrs. A modern internal combustion engine is about 25% efficient, so it can actually convert 25% * 545000 watt hrs to mechanical energy.

However, there are additional losses through the drive train, but I was coming back to up that number a bit as the one that I used is an average, and a Honda Accord is obviously a more efficient choice. Also, I'm not sure how much drive train is avoided in a typical electric car today.

The question is how long would a residential-roof-size solar PV array take to produce sufficient hydrogen for equivalent mechanical energy from a fuel cell vehicle.

Let me repeat the numbers, with a few changes:

Hydrogen electrolysis efficiency: 70% (maybe optimistic, but based on actual electrolyzers available today)
Hydrogen storage efficiency: 80% (unlike gasoline there's boil off loss)
Hydrogen liquefaction efficiency: About 70% (I omitted that before -- you have to either compress or liquefy it for storage in a car).
Real-world fuel cell vehicle efficiency: About 40%. See http://www.evworld.com/view.cfm?section=article&storyid=730

Now, the fuel cell vehicle is more efficient -- about 40% vs about 25% thermodynamic efficiency. So you don't need 545000 watt hrs in the tank, but about 60% of this or 327,000 watt hrs of hydrogen.

How long does a residential roof full of PV cells take to produce this much hydrogen in a form the car can use?

327,000 watt hrs needed / (49,950 watt hours per day * 70% electrolysis efficiency * 80% storage efficiency * 70% liquefaction efficiency)

= 16.7 days for useable energy equivalent to one 15 gallon tank of gasoline.

If you're satisfied with about 1/2 the range of your gasoline car, you could fill up your hydrogen car from your home's solar array in about 1 week, assuming it's not cloudy and you dedicate 100% of your solar array output for that task.

According the the Sci Am article "Questions about a Hydrogen Economy"from May 2004, for a grid electric hydrogen fuel cell powered auto, the fuel chain efficiency is about 22% [from your solar/hydrogen example we get 39%], the vehicle is about 38% efficient, and the total efficiency is about 8%.

Edit: The most efficient option of all is steam reforming - hydrogen from methane using steam - and a H2 fuel cell powered auto. This has a "well to wheels" total efficiency of about 22%.

 

[Ivan Seeking]

Not that this applies to the home brew solar hydrogen idea since you have included the fuel chain losses in considering the cycle times, but if looking at the big picture we need to include that the fuel chain efficiency for gasoline is about 81%. So the well-to-wheels efficiency of the gasoline internal combustion engine is about 13%-14%, on the average. Petro-Diesel does a little better at about 18%.

 

[civil_dude]

Here is a very interesting article about lunar helium 3 isotopes that one shuttle payload could fuel the U.S. for a year.

http://www.space.com/scienceastronomy/helium3_000630.html

 

[turbo]

Here is a very interesting article about lunar helium 3 isotopes that one shuttle payload could fuel the U.S. for a year.

http://www.space.com/scienceastronomy/helium3_000630.html

Lunar soil has been returned to Earth, and presumably, some of it has been hemetically sealed until it can be used to test some theories about the moon's composition. Where is the He³?

Edit: For instance, do we really know deep the He³ deposition layer is? What is the concentration for a given soil type and at what depths? I don't get the impression that we know that critical information yet, except from surface samples and shallow excavations. After all, you can't just start strip-mining any place on Earth and expect to find gold, uranium ore, or coal. And how are we going to get the equipment to the Moon to strip-mine it, process the He³, compress it, and return that shuttle-load of the gas to Earth? It's not like we can go shovel a shuttle-load of lunar soil and be done with it. All of the excavating equipment, the transporters, the furnaces, extraction, compression and storage facilities would have to be located on the Moon, with crews, living quarters, food, air water and other supplies for operators. Compare this to what we have managed to put in LEO over the past few decades. I think (hope, anyway!) that we will have viable, sustainable sources of energy right here on Earth long before we develop the capability of putting heavy industry on the Moon.

 

[Francis M]

However, there are additional losses through the drive train, but I was coming back to up that number a bit as the one that I used is an average, and a Honda Accord is obviously a more efficient choice. Also, I'm not sure how much drive train is avoided in a typical electric car today.


That's difficult to say becasue there aren't any "typical electric cars" that I've seen.
I looked on the web for research on electric cars because I was curious as to what was out there from car manufacturers, kits, conversions, etc...
From car manufacturers there's hybrids but you don't avoid the drive train at all.
Kits and conversions could go either way I suppose, but I haven't seen too many direct drive electrics out there. It's been done to save weight/space for more battery banks (increase range?)and reduce drive train maintenence/complexity.
AS hit upon in another thread though, most of the electric "car" kits I've seen don't fall under the definition of a passanger car a far as DOT and NTSB specs, they're more of an enclosed two passenger trike (and don't look as if they'd hold up well in an accident even at 30MPH on the back roads that they're primarily designed to travel).

 

[Ivan Seeking]

I have been investigating the options to produce biodiesel from algae. As I had suspected, the good information is all proprietary. This comes from one of the leaders in the field.

As we and others are still developing the technology, and having to do so under intellectual property protection (since we're relying on funding from private companies, as there's no government funding for this), we're having to keep everything confidential. So, for now, you likely won't be able to find much information on the technical side of doing this. We anticipate it will be perhaps another 2 years before we have our systems ready for commercialization.

 

[denni89627]

Interesting idea. How about this. Getting your generators in the air using dirigibles. You can anchor it to a ship directly below, lift any amount of weight you want to any altitude (within reason). Than imagine another tether forming a hypotenuse with the sea and vertical anchor tether which can help hold it in position and steer it into the wind.

 

[denni89627]

correction. you would have to be able to be able to rotate the inlet for the moving air on the balloon and maybe have 4 tethers forming a square in the ocean to hold it in place. With the collection facility directly below the balloon.

 

[Ivan Seeking]

...Biofuels, long a cornerstone of the quest for greener energy, may sometimes produce more harmful emissions than the fossil fuels they replace, scientific studies are finding.

As a result, politicians in many countries are rethinking the billions of dollars in subsidies that have indiscriminately supported the spread of all of these supposedly "eco-friendly" fuels, for use in power vehicles and factories. The 2003 European Union Biofuels Directive, which demands that all member states aim to have 5.75 percent of transportation fueled by biofuel in 2010, is now under review.

"If you make biofuels properly, you will reduce greenhouse emissions," said Peder Jensen, of the European Environment Agency in Copenhagen. "But that depends very much on the types of plants and how they're grown and processed. You can end up with a 90 percent reduction compared to fossil fuels — or a 20 percent increase." [continued]

http://www.iht.com/articles/2007/01/30/business/biofuel.php

 

[Ivan Seeking]

...The first rigorous, worldwide study of high-altitude wind power estimates that there is enough wind energy at altitudes of about 1,600 to 40,000 feet to meet global electricity demand a hundred times over.

The very best ground-based wind sites have a wind-power density of less than 1 kilowatt per square meter of area swept. Up near the jet stream above New York, the wind power density can reach 16 kilowatts per square meter. The air up there is a vast potential reservoir of energy, if its intermittency can be overcome.

Even better, the best high-altitude wind-power resources match up with highly populated areas including North America’s Eastern Seaboard and China’s coastline.

“The resource is really, really phenomenal,” said Cristina Archer of Cal State University-Chico, who co-authored a paper on the work published in the open-access journal Energies.”There is a lot of energy up there, but it’s not as steady as we thought. It’s not going to be the silver bullet that will solve all of our energy problems, but it will have a role...”

http://www.wired.com/wiredscience/2009/06/highaltitudewindpower/

 

[ray b]

what % loss does tesla air system suffer vs microwave vs powerlines for high volt ac

H or He balloon shaped wings?

balloons every 1000m to hold up the cables?

jet streams shift around
could a railroad based system follow the shifts

 

[Topher925]

How is it that I missed this thread? I used to work on the skywindpower project (now called Baseload Energy).

what % loss does tesla air system suffer vs microwave vs powerlines for high volt ac

Tesla and microwave power transmission techs both have ridiculously poor efficiencies. Also, all HAWG concepts require a tether to either hold the HAWG in place or have something to pull on to drive the winch.

The Magenn concept uses helium.

Jet streams do shift around but their capacity factor is still extremely high when compared to terrestrial based winds so extracting power from them still makes sense. Maybe not financial sense, but makes sense in some ways.

 

[Ivan Seeking]

Jet streams do shift around but their capacity factor is still extremely high when compared to terrestrial based winds so extracting power from them still makes sense. Maybe not financial sense, but makes sense in some ways.

What are the major problems? Do you mean that it becomes cost prohibitive because of the changing jet streams?

 

[Topher925]

What are the major problems? Do you mean that it becomes cost prohibitive because of the changing jet streams?

No, I mean that operating a wind turbine of any type at 15,000+ feet may not make financial sense when compared to other alternatives such as nuclear. The technology proposed by all of the HAWG companies is still in its very early stages of development so its difficult to gauge what kind of capital and maintenance costs high altitude wind generation would have. However, all of the designs require exotic components such as cables or tension members which will have extremely high costs and low MTBFs, which may make high altitude wind generation not financially competitive to other alternatives.

I have yet to see any in depth cost analysis in terms of $/kWh from any of these venture capital companies, only empty promises.

 

[Ivan Seeking]

No, I mean that operating a wind turbine of any type at 15,000+ feet may not make financial sense when compared to other alternatives such as nuclear. The technology proposed by all of the HAWG companies is still in its very early stages of development so its difficult to gauge what kind of capital and maintenance costs high altitude wind generation would have. However, all of the designs require exotic components such as cables or tension members which will have extremely high costs and low MTBFs, which may make high altitude wind generation not financially competitive to other alternatives.

I have yet to see any in depth cost analysis in terms of $/kWh from any of these venture capital companies, only empty promises.

Going way back to the beginning of the thread, even back-of-the-napkin calculations make it clear that the tether is a key challenge. But it did appear to be doable using commercial products. It was looking like the power transfer was an issue as well, but with off-the-shelf 500KV generators now available, the power wire could be relatively small and light.

It seems to be a bit like tidal power: It is fairly easy to do in principle but challenging from a practical point of view. However, the energy density is hard to ignore.