Originally Posted by Surestick
Originally Posted by Cujet
And yet we use Ethanol in large quantities. It may not qualify as a synthetic, but it certainly qualifies as way to transform "green energy" (sunlight) into liquid fuel. A liquid that pours into the tank in a minute or two, and delivers adequate overall performance, without the limitations of batteries.
Before we argue over ethanol's EROI, remember that methods exist to achieve an EROI of 6+ with ethanol. Brazil does it.
I really hope to see 800wh/kg specific energy in next decade's batteries, 3X+ better than today's best. Tomorrow, even Musk's best 200KWH battery Tesla pickup truck can't tow a conventional RV trailer for more than 100 miles. The truck also takes an hour or more to charge, and may not be chargeable at remote destinations.
Mercedes and VW may believe that filling a battery with sunshine is the best choice. I don't agree. It takes real power to do real work. There is a distinct reason why electric airplanes don't exist, despite 2 decades of attempts.
That's a bit of an apples and oranges comparison.
Energy density and available power are two different things.
Airplanes depend on the energy density of fossil fuels because range and low weight are high on the list of attributes.
A car used for commuting, shopping runs, etc. in an urban area can afford to sacrifice range and time to "refuel" because range and weight are a lot lower down on the attributes that type of vehicle needs. Short drives, stop and go traffic, and long idle times between uses mean that an electric vehicle is probably a better option for many due to cheaper running costs, less pollution, performance, and available time to recharge between uses.
It also depends on the application. Way back in my days riding bicycles, I remember that a larger, more muscular rider might be better at cutting through the wind because power relative to surface area presented to the wind was higher. However, for climbing hills, smaller riders typically had a higher power to weight ratio where the aerodynamics has a much lower impact.
There are many different applications, so specializing can be done. It's amazing how much empty space there can be in a bus. Sure one could double or triple the range of a public transit bus with a larger liquid fuel tank, but that's not needed when the bus already has an adequate range for a single day without refueling and it would add weight with little benefit. But when it's an electric bus (which are increasingly being used), placing in a larger set of batteries begins to make sense because then it provides the same range. There of course is going to be a weight penalty, but does it really matter when range in that application outweighs the weight penalty? I rather like electric (or hybrid) buses since they don't have that smelly exhaust (it's at least better with hybrids) and not as loud.
The hydrogen fuel cell buses in my area have found ways to store more hydrogen in order to have adequate range for a day. They've even gone to storage on the roof.
Originally Posted by Cujet
And yet we use Ethanol in large quantities. It may not qualify as a synthetic, but it certainly qualifies as way to transform "green energy" (sunlight) into liquid fuel. A liquid that pours into the tank in a minute or two, and delivers adequate overall performance, without the limitations of batteries.
Before we argue over ethanol's EROI, remember that methods exist to achieve an EROI of 6+ with ethanol. Brazil does it.
I really hope to see 800wh/kg specific energy in next decade's batteries, 3X+ better than today's best. Tomorrow, even Musk's best 200KWH battery Tesla pickup truck can't tow a conventional RV trailer for more than 100 miles. The truck also takes an hour or more to charge, and may not be chargeable at remote destinations.
Mercedes and VW may believe that filling a battery with sunshine is the best choice. I don't agree. It takes real power to do real work. There is a distinct reason why electric airplanes don't exist, despite 2 decades of attempts.
That's a bit of an apples and oranges comparison.
Energy density and available power are two different things.
Airplanes depend on the energy density of fossil fuels because range and low weight are high on the list of attributes.
A car used for commuting, shopping runs, etc. in an urban area can afford to sacrifice range and time to "refuel" because range and weight are a lot lower down on the attributes that type of vehicle needs. Short drives, stop and go traffic, and long idle times between uses mean that an electric vehicle is probably a better option for many due to cheaper running costs, less pollution, performance, and available time to recharge between uses.
It also depends on the application. Way back in my days riding bicycles, I remember that a larger, more muscular rider might be better at cutting through the wind because power relative to surface area presented to the wind was higher. However, for climbing hills, smaller riders typically had a higher power to weight ratio where the aerodynamics has a much lower impact.
There are many different applications, so specializing can be done. It's amazing how much empty space there can be in a bus. Sure one could double or triple the range of a public transit bus with a larger liquid fuel tank, but that's not needed when the bus already has an adequate range for a single day without refueling and it would add weight with little benefit. But when it's an electric bus (which are increasingly being used), placing in a larger set of batteries begins to make sense because then it provides the same range. There of course is going to be a weight penalty, but does it really matter when range in that application outweighs the weight penalty? I rather like electric (or hybrid) buses since they don't have that smelly exhaust (it's at least better with hybrids) and not as loud.
The hydrogen fuel cell buses in my area have found ways to store more hydrogen in order to have adequate range for a day. They've even gone to storage on the roof.