There are at least three basic parts to powering a motor vehicle.
1. An energy source
2. An energy carrier
3. A motivation system
Energy Source
A natural resource that we can exploit in order to generate work. Without trying to get too cosmic, all energy sources in the universe that we are aware of are finite and will eventually run out. It is important that we choose our energy sources carefully in order to not pollute the environment (heat, carbon, radiation, etc…) and to not run out.
Examples: solar power, geothermal power, fossil fuels, wind, hydroelectric, nuclear fission, nuclear fusion, etc.
Energy Carrier
A method that allows stored energy to be moved from its energy source to its destination where work needs to be done.
Examples: electrochemical conversion (batteries and fuel cells), fossil fuels, flywheel, polonium, the electric grid, etc.
Motivation system
A device that turns energy into kinetic work.
Examples: electric motor, internal combustion engine, pneumatic pump, turbine engine, rocket engine, etc.
Fossil fuels and radioactive materials such as uranium are somewhat unique in that they are both an energy source and an energy carrier. The disadvantage of using these sorts of resources are obvious. They will run out sooner than later (10’s or 100’s of years vs. millions’s of years for other resources), they often cause pollution and they often cause political turmoil because of their geospatial location.
Hydrogen falls into the second category, it is an energy carrier. Many people who are used to dealing with fossil fuels often mistakenly believe Hydrogen is an energy source. Also unfortunately, since fuel cells operate most efficiently with pure hydrogen and because there are virtually no environmental byproducts when using Hydrogen it has been identified and championed as the future energy carrier. But, it’s a really terrible energy carrier. It requires an energy source to produce, energy for transportation to move it locally, and energy and expensive containers to store it.
Hydrogen is the LEAST dense element on the periodic table. There are no other elements with a lower density, why would we choose this as the ultimate way to store energy?
Regardless of which energy source we use, what we need is a technology that can store energy with very little loss, in a compact package, repeatedly, and with low or no environmental impact.
Energy Carrier Candidates
- Kinetic energy – flywheels, springs, etc.
- Burning liquid fuels – fossil fuels
- Burning gaseous fuels – fossil fuels, hydrogen
- Electro-chemical conversion:
- Batteries – NiCd, NiMh, LiFePO4, Limn2o4, Licoo2, Lipf6, etc…
- Fuel cells – hydrogen
- Radioactive decay – uranium, polonium, etc…
- Pure electricity – capacitors
Best Long Term Solution
If we are to pick a technology with the most promise and the most long-term benefits personally I think capacitors are the way to go. Little or no losses, extremely high power (how much energy you can use per unit of time), quick charging (<5mins with the right hookup), virtually unlimited cycles (long lasting), and density on par with 2x modern lithium ion (think 450+ mile range). EEStor claims to have ultra capacitors with the density equivalent to twice lithium-ion batteries. If this is true it is truly game changing.
Best Short Term Solution
If we want to pick a solution for the interim to improve over fossil fuels I’d have to choose batteries. Fuel cells are merely batteries that instead of recharging (storing chemical energy) they re-fuel the cells with additional liquid chemical fuel and the cell is merely a catalyst (hence fuel-cell). Unfortunately, they are not ready for commercial production and sales yet. So it has to be standard chemical batteries for the time being. In the past 5-10 years there have been huge technological improvements in lithium-based batteries. There are at least half a dozen commercially viable lithium-based battery chemistries available today that can charge quickly, last much longer, are much safer, and are cheaper than traditional lithium cobalt.
Additional Considerations
It is more than likely that there will be a mix of technologies used for various modes of transportation for the foreseeable future (hybrids, biodiesel, CNG, ethanol, pure EV’s, etc). Hydrogen is often touted as some sort of panacea energy solution when in fact it’s expensive to produce, difficult to store, and difficult to use. Existing oil companies and automobile manufacturers who have vested interests in the status quo like hydrogen because of these reasons. It favors the usage of fossil fuels for the time being and it also favors the same large companies who will build the large infrastructures needed to support the hydrogen economy.
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