Brian D.----------" Fred, it doesn't matter what the fracking fluids are, the heavy metals and potential water contaminants are in the shale layers. punching holes through the aquifers to get to the deep shale creates new paths for contamination."------------
I agree with you there Brian, however, I see things as a matter of progression. I believe we should make a change to methane as quickly as possible. Use fossil methane in the least intrusive means possible(propane fracking)----and build out anaerobic digestion capacity as we go along.
AD is the final goal in my estimation---I see fossil methane as just a step to get there.
Overall, I agree with you that AD is the best long term solution.
I also support production of CH4 directly from CO2 by means of the Sabatier reaction as is being done in Germany right now using excess wind power.
Mileage per charge is highly dependent on ambient conditions.
Electric motors are very efficient but changing electrical energy work. But to change electrical to chemical energy and then back again to electrical energy[in a battery] is not so efficient. And it becomes less and less efficient very quickly as the temperature goes down. You'll see this very quickly trying to start a car on a cold day. It also takes longer to charge when ambient temperatures go down.
@ Bill------" BUT, when dealing with rapid charging and fairly rapid discharging, there is an excess of heat generated anyway"-----------
That is proof of the lower efficiency. Heat is a sign that energy is being wasted.
So long as the ambient temperature is low, heat is expended to keep the batteries up to a higher temperature. The lower the ambient temperature, the higher the heat needed to heat them.
As a general rule---------it takes 2X the energy to heat per 20*F. For instance, if air is 100% RH at 80*F, it is only 50% RH at 100*F, 25% RH if heated from 60*F, etc.
I agree, it sounds more like a fuel cell. The question then becomes, how much of the energy recovered is in the form of electricity, and how much is in the form of heat.
What is needed is a battery that recovers all(or as much as possible) of the energy stored in hydrocarbons as electricity and as little as possible as heat. Useful energy / total energy = efficiency.
Bill Brandon-----------" Interesting article, and an area I am totally unfariliar with. If the sugar can be replaced (hence consumed) where does it go? What are the byproducts?- water and CO2 like combustion?"-----------
The same place it goes when you eat it----CO2 and H2O. There are no by products------just be careful, if you put in too much over a period of time, your battery will get so heavy you won't be able to pick up your cell phone after awhile.
It does the same thing any other living cell from the smallest bacteria to the largest elephant does.
Dr. A. Cannara ----------" Just because a bug kills a tree doesn't mean the tree should now be removed via ~30% efficient fossil-fueled machinery, transported & processed by similar, and burned for power at less than 50% thermal efficiency.
Leave the tree and its nutrients in the forest for the next trees. "----------
Leave the bugs that are killing the forest? You don't know anything about pine beetles do you?
Leave the trees and you leave the beetles. Eventually, you have no live trees----only dead trees as far as you can see.
-----------" In western North America, the current outbreak of the mountain pine beetle and its microbial associates has destroyed wide areas of lodgepole pine forest, including more than 16 million hectares in British Columbia"------------
---------" The current outbreak in the Rocky Mountain National Park began in 1996 and has caused the destruction of millions of acres of ponderosa and lodgepole pine trees. According to an annual assessment by the state's forest service, 264,000 acres of trees in Colorado were infested by the mountain pine beetle at the beginning of 2013. This was much smaller than the 1.15 million acres that were affected in 2008 because the beetle has already killed off most of the vulnerable trees (Ward).["------------
--------" It may be the largest forest insect blight ever seen in North America. Climate change has contributed to the size and severity of the outbreak, and the outbreak itself may, with similar infestations, have significant effects on the capability of northern forests to remove greenhouse gas (CO2) from the atmosphere."-----------
Companies drilling and fracking the Bakken and other shales are not the least bit interested in capturing and selling natural gas.
The entire focus is to drill as many wells as possible as quickly as possible since "wet" (liquid petroleum producing wells) are the object of the operations. Shales are typically low production wells, with low grade, thick viscous production that have low production and high refill rates. Thirty years ago they would have been called "strippers" and considered mostly a waste of time and money. The only thing that is changed is that now----with oil around $100/barrel, they can be used to at least get some small return on investment to keep the drilling pace up.
Natural gas is just an unwanted by product. Captured and sold if it is convenient but not considered a marketable product in itself. That is why it is flared.
Before the coming of the white man nearly led to the extinction of the species, the American Bison roamed the plains in numbers ranging from about 60 to 80 million. They fed solely on grasses(biofuel) of short grass prairies and adult animals ranged from 1500 to 2500 pounds each. They lived only on energy from short grass prairies that provided more energy than a car requires----a buffalo has to create enough energy to power a 1 ton air conditioner every hour per degree temperature drop from their normal body temperature. The buffalo's massive size and excellent insulation helped, but still, the only energy input was from grass.
The Native Americans practiced controlled burns to remove old growth and make way for new growth from time to time, but this was the only means of agriculture necessary to maintain the system. Nature and the natural herd migrations did the rest. The prairie management by controlled burns did the rest and brought the bison to the Indians as the herd migrations followed routes with the best grasses. The bison provided all the necessities of life for the Plains Indians in the form of food, shelter and clothing---all they had to do was harvest it.
Short answer. You will find prickly pear growing on mostly limestone karst bedrock that has an extremely thin to almost non existent soil layer with almost no water retention capabilities. It can also survive on very poor rocky or sandy soils with the same very poor water retention ability.
This gives prickly pear an environmental niche where the unique water catching and holding abilities it has evolved give it a distinct advantage over weedy species that could quickly overwhelm it in size and spread. Prickly pear survives and thrives BECAUSE of its adaptive evolution. It survives and thrives because it wins the war of survival because of the environment in which it is the dominant species.
Put it in an environment for which it is not adapted and it loses its edge that it has adapted for, it loses because the new environment is working against its adaptation rather than with its environmental adaptation. The competing plants quickly grow faster and taller crowding the prickly pear out.
All life is a competition for survival.
In other words----man as a farmer is limited to the prevailing conditions and must select the crops to fit the conditions, not try to fit the conditions to the crop. You select the crop according to the conditions that prevail. The adaptive evolutions of the plants are the tools you use to fit the prevailing conditions.
---------" and for sure with 1 kg dry matter it is impossible to produce more than 1255 kWh of electric energy (assuming 38% efficiency of the generator). "---------
You'd better check your numbers. One short ton of coal is generally equated to produce around 2500 kW.