02-23-2016, 09:59 PM
|
#41 (permalink)
|
Dreamer
Join Date: Nov 2013
Location: Australia
Posts: 350
Thanks: 95
Thanked 214 Times in 151 Posts
|
Quote:
Originally Posted by RustyLugNut
But if throw away electricity is available, why not use it?...
|
Use it yes, waste it, no. Using lots of energy to create a little hydrogen just because the energy would otherwise be wasted doesn't sound like a good idea. That excess energy could be channelled into other processes that unavoidably need lots of energy. Like say aluminium production or water desalination.
Or even powering the manufacture of additional green technology.
And if electric cars were commonplace then there probably wouldn't be that excess geothermal energy available to throw away.
|
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
02-23-2016, 10:13 PM
|
#42 (permalink)
|
home of the odd vehicles
Join Date: Jun 2008
Location: Somewhere in WI
Posts: 3,891
Thanks: 506
Thanked 867 Times in 654 Posts
|
You do realize compressed air is actually more efficient than hydrogen?
It too is a carrier of energy and could carry a car about 100 miles if appropriately designed.
Especially in hot environments.
For example, exhaust from a power plant near specific parts of the ocean could be compressed using the waters pressure at over 90% due to the temperature loss and gain.
Now do you see why I don't really support hydrogen?
|
|
|
02-24-2016, 02:10 AM
|
#43 (permalink)
|
Master EcoModder
Join Date: Nov 2012
Location: San Diego, California
Posts: 982
Thanks: 271
Thanked 385 Times in 259 Posts
|
I don't think you see the advantage of hydrocarbon liquids.
Quote:
Originally Posted by Astro
Use it yes, waste it, no. Using lots of energy to create a little hydrogen just because the energy would otherwise be wasted doesn't sound like a good idea. That excess energy could be channelled into other processes that unavoidably need lots of energy. Like say aluminium production or water desalination.
Or even powering the manufacture of additional green technology.
And if electric cars were commonplace then there probably wouldn't be that excess geothermal energy available to throw away.
|
There IS an excess of electricity in my region and regions such as Iceland. Electric cars are nice for you if you don't expect to go much more than 200 Km or so. Can you show me the numbers for taking an 80,000 lb tractor trailer 600 miles in a day using batteries? A disproportionate amount of that load would have to be batteries. How about airliners? No dice with batteries of ANY formulation. You can store hydrogen in hydrocarbons and power both.
Care to argue that point? Because truthfully, you have not provided a solution for heavy load transport. Trains can only go where tracks go.
Iceland has a disproportionate amount of geothermal and hydro electric power. The politics being what they are, they embarked several decades ago on a hydrogen pathway. They built out their power production to embrace the hydrogen buses and vehicles that were to be powered by hydrogen from electrolysers. Currently, they only have one electrolyzer feeding a handful of buses as the power has been turned to aluminum production and ammonium nitrate. The failure is not hydrogen so much as the politics of money. The local population could continue to use expensive imported gasoline and diesel just as long as they could export more valuable nitrate and aluminum. But, it doesn't change their ability to produce hydrogen in abundance and, like the nitrates, they could store it as hydrocarbons to be used in local ships and boats and aircraft. If the price for such products was high enough , they could export it. Can they export the electricity? No, but they could switch the majority of their personal vehicles to batteries and their larger vehicles could use hydrogen or hydrocarbons. There is simply no battery that can match hydrocarbons for energy density. Call it a waste of energy? It is a necessity.
|
|
|
02-24-2016, 02:27 AM
|
#44 (permalink)
|
Master EcoModder
Join Date: Nov 2012
Location: San Diego, California
Posts: 982
Thanks: 271
Thanked 385 Times in 259 Posts
|
So what?
Quote:
Originally Posted by rmay635703
You do realize compressed air is actually more efficient than hydrogen?
It too is a carrier of energy and could carry a car about 100 miles if appropriately designed.
Especially in hot environments.
For example, exhaust from a power plant near specific parts of the ocean could be compressed using the waters pressure at over 90% due to the temperature loss and gain.
Now do you see why I don't really support hydrogen?
|
Your compressed air car is not my 80,000 lb truck or my 200 passenger plane. It is not my 1000 hp tug. I am not arguing the use of hydrogen in every niche as being the best solution. But, if I can take nuclear energy and store it as a hydrocarbon I can power loads too heavy for batteries alone to move any great distance.
Now you see why I don't support a singular solution? Care to race me to Las Vegas in your compressed air car?
|
|
|
02-24-2016, 08:30 AM
|
#45 (permalink)
|
Dreamer
Join Date: Nov 2013
Location: Australia
Posts: 350
Thanks: 95
Thanked 214 Times in 151 Posts
|
Quote:
Originally Posted by RustyLugNut
There IS an excess of electricity in my region and regions such as Iceland. Electric cars are nice for you if you don't expect to go much more than 200 Km or so. Can you show me the numbers for taking an 80,000 lb tractor trailer 600 miles in a day using batteries? A disproportionate amount of that load would have to be batteries. How about airliners? No dice with batteries of ANY formulation. You can store hydrogen in hydrocarbons and power both.
Care to argue that point? Because truthfully, you have not provided a solution for heavy load transport. Trains can only go where tracks go.
...
|
i'm not trying to argue, just give a different point of view. I don't imagine either of us have much involvement in what the auto industry, fuel industry and the governments eventually decide to do. So it is just a discussion.
I have little first hand experience with heavy industry but i expect they would follow the path of least financial resistance.
I don't know what it would cost to convert heavy industry from diesel to hydrogen but i wouldn't expect it to be cheap.
Simply swapping to bio-diesel as a way of being greener would also allow them to keep their existing investment in diesel machinery.
The aviation industry would need heavily redesigned planes to store and use hydrogen. Imagine what a plane ticket would cost after the aviation industry completed paying for that sort of transformation.
Again a swap to a greener fuel that has the same properties as their current fuel is a much more likely move. Aviation bio-fuel is already being tested.
These bio-fuel technologies could be very green and very low impact.
If some countries or regions have an energy surplus they may be able to use it to intensify production on their algae farms to boost bio-fuel production without increasing the amount of land allocated. This may give them enough production capacity to create export opportunities. Transporting diesel is an existing activity, transporting bio-diesel should be no different.
But I was talking mainly about cars and using hydrogen as their fuel source. Hydrogen still has a lot of issues. Many of which rely on future innovations to completely solve.
There is promising technology currently in labs that may come to fruition but there is also a lot of promising technology that never makes it out of the lab.
Whereas electric cars are already in production and in use on the roads. No waiting for possible future technology to make them happen. Their fuel is available just about everywhere. Even the garage they are stored in overnight has a readily available source of fuel. They are as green as the grid. Greening the grid will benefit not just the transport sector but all areas of society, environmental, manufacturing, agriculture, etc, etc.
Electric cars will not suit everybody, no car will.
But if i can have a car that is super cheap to run, requires almost no maintenance, is quick and quiet, can carry the passenger and cargo load that i have become used to with ICE vehicles and is available today. Then why wouldn't i choose it.
And for those occasional trips where 200klm is not enough range and i can't organise a 30 minute stop along the way. Well i could always hire a car that would normally be well outside my price range and travel in luxury that day. Or that beautiful classic car that i keep for special occasions could be rolled out and given the chance for a road trip. Everyone will come up with different ways of organising their transport.
Lots of people ride a bicycle to work each day yet still have a car for longer trips. They don't throw away the bicycle just because it doesn't work for every trip.
|
|
|
02-24-2016, 01:57 PM
|
#46 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,907
Thanks: 3,475
Thanked 2,950 Times in 1,844 Posts
|
Hydrogen fuel cell vehicles are electric cars. They use a small battery - or capacitors in this case, and a fuel cell and hydrogen to generate electricity on the fly.
This will always be lower efficiency than a EV with a bigger battery. Currently, the FCEV is ~1/2 the efficiency of a BEV.
Then there is the energy to get the hydrogen, and energy to get the hydrogen into the car. Take a look at this:
If the hydrogen is made from natural gas, it is even less efficient.
|
|
|
02-24-2016, 02:03 PM
|
#47 (permalink)
|
...beats walking...
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,525 Times in 1,126 Posts
|
NOTHING is 100% efficient, so:
99% × 99% = 98.01% efficiency
95% × 95% = 90.25% efficiency
90% × 90% = 81.00% efficiency
Q: Recognize any *trend* in the above sequence of numbers?
A: The more times anything has to be translated/converted/changed, the LESS the total efficiency has become!
|
|
|
02-24-2016, 06:21 PM
|
#48 (permalink)
|
Master EcoModder
Join Date: Nov 2012
Location: San Diego, California
Posts: 982
Thanks: 271
Thanked 385 Times in 259 Posts
|
We are having a conceptual problem.
It is obvious to me that most of you are stuck in the classic modes of thinking.
Hydrogen is perceived as useless because it is inefficient in production and use. As Niel Blanchard has pointed out in no uncertain terms, hydrogen and fuel cells are no competition to direct battery powered vehicles when efficiency is of great consideration.
The cascade of percentages illustrated by Old Tele man applies directly to hydrogen production and use in fuel cells.
And , Astro is right in that industry and market follow the easiest, most economical financial path.
But, consider this concept - long term storage of unused/unusable energy. Also, consider the transport of that same energy.
Batteries perform very poorly in both catagories. Discharge rates being what they are, storage of electrical energy in batteries for years down the line is not reasonable. Transmission of energy via electric cables has losses proportional to distance.
But chemical storage is excellent for doing both. Chemical storage allows us to use the stored energy many years down the line. The bulk transport via heavy terrestrial modes or pipeline is economical on a per unit basis.
Fossil fuels are essentially the energy of the sun stored chemically eons ago. This is currently the dominant primary power in our modern culture and will be for a bit of time more. Formation of fossil fuels is very energy inefficient. Collection via photosynthesis, burial and entrapment then the addition of heat and pressure plus time. Finally, it is ready for extraction, transport and use in a heat engine. The energy efficiency of the fossil fuel cycle from sun to my gas tank is a small fraction of 1%. And yet, at the current low prices, this fossil fuel beats your current and future battery solutions for energy density by a considerable margin. Because of it's advantages, even at much higher fossil fuel prices batteries cannot compete with fossil fuel on a cost/energy performance basis.
This whole cycle is what I and others are proposing - to mimic the hydrocarbon cycle but with carbon that is currently in the biosphere.
Astro, you simply missed what I am proposing - to synthesize fuel that is an analog to what is used today. Diesel and gasoline are already in wide spread use and can be closely mimicked or matched via several pathways. The pathways need carbon and hydrogen as the input plus energy added as the reactions are essentially reverse oxidation ( reverse combustion ) and are highly endothermic. Thus, cheap energy is needed. Or unused energy. These hydrocarbon fuels can be produced in times of energy excess as found in most current power generation. If we build out enough nuclear energy as I have mentioned, we can build to the point that Iceland is at - several times the energy capacity of it's population of 300 thousand people will need. Then you can use this excess electrical and heat energy to feed your hydrocarbon plants. The fuels can be stored indefinitely.
This synthetic fuel will not be as cheap as fossil fuel because we are actively adding effort at each step, thus we must use it more efficiently.
For personal light transport, putting the electricity directly into batteries for immediate use is by far the best solution for that niche. Our personal transport should not be using our synthetic fuel stream.
For heavy payloads such as 18 wheeled trucks, they can continue to use advanced diesels until LT-SOFC reach the 350 deg C operation range. At this operating temperature a LT-SOFC has a 60% thermal efficiency. This exceeds current and future diesel tech and will allow trucks to go further on each liter of synthetic diesel.
Aircraft can continue as before but flying on synthetic fuels.
All the above is not unicorn science. It is very basic. The complexity is in the need to change public opinion towards nuclear power. But, while waiting for that change, we can leverage excess electrical sources and start the storage of that power in hydrocarbons. It does not have to be efficient per energy calculations. But it must be efficient by market calculations.
At some point fossil fuels will cease to be the standard for primary power. Batteries are not a primary power. But they, along with hydrocarbons can store the energy of a nuclear age for short and long term transport use as well as the basic materials for our plastics consumption.
In the short/near term, renewable power can still be used on a personal scale. I tutor university students in science classes. Many move on to research in masters and doctoral efforts. One highly fascinating endeavor was an idea from India to use solar electricity, solar heat and carbonaceous plant waste. In an effort to provide concentrated and storable fuel on a local level a system the size of a large freezer box was fed with solar panel electricity, solar hot water and several kilograms of pulp wood. A few minutes of processing time resulted in several kilograms ( a gallon ) of liquid methanol. A long summer day might result in several gallons of methanol. Not an economic success by western standards but it allows the long term storage of energy for use at a later date. The efficiency is not near as good as storing the solar power in batteries, but it can be stored easily and cheaply. If my plug in LT-SOFC car is charged in half a day of solar connection, I can store the excess energy as methanol. I do have to provide the yard trimmings. My daily route may not see me go more than a few miles never draining my battery but my excess energy piles up as methanol as my energy "still" continues to plug away. A few weekends later, my wife wants to blast up to Lake Arrowhead. I just fill up the fuel cell with more than enough methanol to make it there and back. My methanol fuel cell is not near as energy efficient solar panel to wheels as a battery pack. But it is using that energy in a form that is concentrated and long lasting.
Just a remark on bio-fuels, specifically algae bio-diesel. The problem with this solution is the need for concentrated CO2 sources to make it worthwhile. Thus the need for flue gasses from current fossil fueled power plants. As someone has mentioned, at least the secondary use of this CO2 is essentially a halving of greenhouse gasses. But, once fossil fuels fall by the wayside, we will have to find waste CO2 streams. Places like Iceland have geothermal venting of CO2 gasses and can thus tap these emission sources. We can also trap the CO2 streams of municipal dumps and sewers.
|
|
|
The Following User Says Thank You to RustyLugNut For This Useful Post:
|
|
02-24-2016, 06:31 PM
|
#49 (permalink)
|
Master EcoModder
Join Date: Nov 2012
Location: San Diego, California
Posts: 982
Thanks: 271
Thanked 385 Times in 259 Posts
|
I have considerably more invested in this topic than you do.
Quote:
Originally Posted by Astro
i'm not trying to argue, just give a different point of view. I don't imagine either of us have much involvement in what the auto industry, fuel industry and the governments eventually decide to do. So it is just a discussion.
|
My business deals with diesel emissions technology development. We also build industrial electrolysers for product gasses. I am active in the sense I sit in and make my voice heard in California Air Research Board (CARB) legislation in subjects that pertain to transport and power generation.
|
|
|
02-25-2016, 04:04 AM
|
#50 (permalink)
|
Dreamer
Join Date: Nov 2013
Location: Australia
Posts: 350
Thanks: 95
Thanked 214 Times in 151 Posts
|
I have obviously misunderstood what you have been saying.
I thought you were advocating creating a hydrogen (H) fuel infrastructure and using fuel cell powered vehicles. This seemed like a less than optimum solution given the inefficiencies in the hydrogen fuel cycle and the likely source of the hydrogen.
Using hydrogen as a type of battery for the production stage and long term storage is very different. Then we are talking about bulk storage, large scale fuel cells and the production of bio-fuels.
No vast new infrastructure, simply producing electricity, diesel and jet fuel from stored hydrogen rather than fossil fuels.
As i mentioned a few posts ago using bio-fuel to replace existing fuels will be the most likely route for existing diesel powered vehicles and jet fuel powered aircraft.
If that bio-fuel can come from stored hydrogen derived from electricity production rather than from agriculture then even better as it won't seem like it is stealing food from people and driving up food prices. If it can be done efficiently then even better again.
|
|
|
|