Mazda Says Its Upcoming Gas-Powered Cars Will Emit Less CO2 Than Electric Cars 330
cartechboy writes: "One of the arguments for electric cars is that we are reducing greenhouse gases and emitting less CO2 than vehicles with an internal combustion engine. But Mazda says its next-generation SkyActiv engines will be so efficient, they'll emit less CO2 than an electric car. In fact, the automaker goes so far as to say these new engines will be cleaner to run than electric cars. Is it possible? Yes, but it's all about the details. It'll depend on the test cycles for each region. Vehicles are tested differently in Europe than in the U.S., and that variation could make all the difference when it comes to these types of claims. At the end of the day whether future Mazdas with gasoline-powered engines are cleaner than electric cars or not, every little bit in the effort to reduce our carbon emissions per mile is a step in the right direction, right?"
Re:Mazda is not open (Score:5, Informative)
Mazda abuses copyright to stop 3rd parties from publishing manuals. Can't get a Haynes or Chilton manual for any Mazda newer than about 1995.
http://www.haynes.com/products... [haynes.com] 2 seconds on Google.. come on, man.
Re:Ummm.... (Score:5, Informative)
So the only real way to reduce CO2 emissions per mile is get more miles per gallon of fuel.
No. My ~40mpg motorcycle pollutes far more than my ~27mpg car. It's all about how well the engine burns the fuel and handles the emissions before they leave the pipe, not necessarily just the volume of it.
Re:Ummm.... (Score:5, Informative)
CO2 emissions are directly proportional to fuel consumption (for a particular fuel). It's the other emissions - CO, hydrocarbons, nitrogen oxides etc. that can vary dramatically.
Re:Do electric cars actually produce CO2? (Score:3, Informative)
If you really needed the shale oil and you didn't have fossil fuels to do the extraction you could run the extraction process using a nuclear plant.
http://web.mit.edu/newsoffice/... [mit.edu]
The last of these ideas would locate a nuclear plant near a deposit of oil shale -- a type of deposit, technically known as kerogen, that has not been used to date as a source of petroleum. Heated steam from a nuclear plant, in enclosed pipes, heats the shale; the resulting oil can be pumped out by conventional means.
At first glance, that might sound like a "dirty" solution, enabling the use of more carbon-emitting fuel. But Forsberg suggests that it's quite the opposite: "When you heat it up, it decomposes into a very nice light crude oil, and natural gas, and char," he explains. The char -- the tarlike residue that needs to be refined out from heavy crude oils -- stays underground, he says.
Today, the heating of the rock is usually accomplished by burning fossil fuels, making the process less efficient. That's where the excess heat from a nuclear plant comes in: By coupling the plant's steam output with a shale-oil well, the oil can be recovered without generating extra emissions. The process also does not need regular heat input: The nuclear plant can operate at a steady rate, providing electricity to the grid when needed, and heating oil shale at times of low electricity demand. This enables the nuclear plant to replace the burning of fossil fuels in producing electricity, further reducing the release of greenhouse gas.
The world's largest oil-shale deposits are concentrated in the western United States. "We lucked out," Forsberg says. "This has the lowest carbon footprint of any source of liquid fossil fuel."
The resource that could be unlocked is enormous, he says: "Some of these deposits would yield a million barrels per acre. There's no place else on Earth like it."
Actually you could view the current extraction process as being a sort of pump priming - right now fossil fuels are used to run things. Counter intuitively it becomes more economic when fossil fuel prices are high. Now if fossil fuel prices fell you could imagine using a nuclear plant to supply the heat. Or, if fossil fuels became unavailable - e.g. due to a major war in the Middle East - you could use nuclear too. Once people have started to make money out of extracting shale oil the odds are they will use that money to stay in business.
It seems like if you could use the waste heat from a reactor to extract oil you can get even better energy efficiency than merely using the heat to generate steam to generate electricity. Also thorium means that we're not in any danger of running out of fuel for nuclear reactors.
Re:Do electric cars actually produce CO2? (Score:5, Informative)
The 300 Wh is also the electrical energy stored in the battery (the Tesla S has an 85 kWh battery rated at 300 miles, so that works out to 283 Wh/mile). If you're going to factor in production costs of gasoline, you also need to factor in production costs of electricity. Charging the battery is about 75% efficient. Transmission to the home is about 98% efficient. And coal plants are about 45% efficient. So to produce the 300 Wh/mile the EV uses, the power company actually has to burn 300/(.75*.98*.45) = 907 Wh/mile. Factor in coal mining and transport costs and you're probably up around 1 kW/mile.
So the energy cost to refine gasoline is probably more likely enough to drive the EV only 2-3 miles.
Re:Do electric cars actually produce CO2? (Score:5, Informative)
Breeding means generating more nuclear fuel from stuff that is not fissile material in the first place. For example, in a classic nuclear fuel rod only a few percents of the uranium is of the 235 isotope variety, which is fissile (= radioactive, potentially dangerous and useable as nuclear fuel), the rest is the 238 isotope and is not fissile... but is intead "fertile", because once it gobbles up a passing neutron (= beta radiation), it quickly transmutes into the 239 isotope of plutonium - and this kind of plutonium, in turn, is fissile.
And, fortunately, you can have it so that while the 235 uranium "burns" it produces the right neutrons for the 238 to turn into 239, or "breed" into plutonium. Or breed the fertile 232 thorium into fissile 233 uranium, too. That's the principle of a breeder reactor. And you may use your fresh new fuel to breed yet some more fuel, too, so that potentially, all the uranium and all the thorium in the world may be converted into nuclear fuel - that's called "supergeneration", because then you are not even limited by the tiny amount of starting fissile material anymore.
For every amount of starting fuel you can have various ratios of breeding happening. In fast breeder reactors you can have three or four times more breeding than consuming, so that every unit of fuel spent generates, on the side, three or four units of additional fuel from fertile material. In molten salt thorium reactors this ratio is projected to be 1-on-1 to limit the risks of nuclear proliferation (= using the breeding process to make a lot more fissile material, in order to make weapons).
Re:Do electric cars actually produce CO2? (Score:4, Informative)
The figure came from articles like this [greentransportation.info]. The issue is that the 6KWhr/gallon is energy loss and not energy use. Some of that loss is in heat and other waste. If you look at just electricity consumption it is closer to 89Whrs/gallon.