Modified Prius gets up to 180 Miles Per Gallon 907
shupp writes "The NY Times (free reg. required) reports in that some folks are not content with the no-plug-in rule that both Honda and Toyota endorse. By modifying a Prius so that it can be plugged in, Ron Gremban of CalCars states 'I've gotten anywhere from 65 to over 100 miles per gallon'. The article also reports that 'EnergyCS, a small company that has collaborated with CalCars, has modified another Prius with more sophisticated batteries; they claim their Prius gets up to 180 mpg, and can travel more than 30 miles on battery power.'"
Plug in.... (Score:5, Informative)
It can help in other ways, perhaps the power plant where you are getting the electricity from is cleaner burning (or nuclear) than your car, and it reduces overall air pollution.
Words words words.. (Score:5, Informative)
Still, it's a claim to be approached cautiously. Perhaps improved batteries can improve hybrid milage -- but by a factor of 3? In any case, the "up to" is a hint that this is one of those meaningless "gee whiz" statistics, as with "The IQ of Slashdot users is as high as 300."
Re:Misleadning (Score:5, Informative)
Re:The benefit of that is... (Score:4, Informative)
Re:Obligatory (Score:3, Informative)
17.17 - 26.42 miles per litre,
27.63 - 42.51 km per litre,
3.619 - 2.352 litres per 100km, or about
LXXVIII - CXXI stadions per sester,
depending on what measuring system you like.
Re:Cost goes UP! (Score:1, Informative)
However the conclusion that its cheaper to run your car on gasoline does not follow. You're missing a critical step, the efficency of converting your stored energy to mechanical energy. A very good combustion powered car can achieve 20% efficency, however electric motors can convert electrical energy to mechanical energy with 90% efficency.
This yields:
Cost per mechanical kilowatt hour (weird unit but applicable):
1 gal gas $2.00 equals 34KWh.
At 20% conversion efficency this gallon gives us 6.8KWh of mechanical energy for $2.00 or 3.4KWh per dollar.
At 12cents/KWh, $2 of electricity is 16.7KWh.
At 80% (lets be conservative) efficency we'll get
13.3KW/h of mechanical energy or 6.7KWh per dollar.
At current energy prices, it looks like it costs about half as much to run your car on electricity.
Re:Is this energy-efficient? (Score:3, Informative)
Re:Park and charge (Score:5, Informative)
"The energy content of a gallon of gasoline ranges from about 109,000 to 125,000 Btu. The average is about 114,000 Btu."
and this:
"1 kW = 3413 BTUs"
so, one gallon of gas (on average) = about 33kW
Electricity ranges from about 5 - 10 cents per kW, so a gallon of gas (more than $2) has as much energy as $1.65 - $3.30 of electricity.
Clarifications: we encourage you to read our docs (Score:5, Informative)
Also look at the new section at our vehicles page where we document the benefits of PHEVs even when they're recharged from a dirty (coal-fueled) grid.
We've added a link to this discussion at http://www.calcars.org/kudos.html [calcars.org]
Felix Kramer, Founder, CalCars
Re:Cost goes UP! (Score:3, Informative)
However, from a fuel usage standpoint, electric power is only about 50% efficient (the best plants reach 60%, most are less), whereas a car is maybe 25%. So let's consider fuel -> mechanical for both systems.
Charging batteries is not very efficient when the batteries are more than say 50 or 60% full already. Your 80% figure is off considerably [sandia.gov] when you consider that the battery is probably not discharged more than about 50% due to the onboard prius electronics kicking in to keep it from being too low.
With say 60% efficient battery charging, and 80% efficient motor/transmission system you're talking about 48% efficient electricity from wall -> mechanical output efficiency.
With even 60% efficient fuel->wall electricity power plant (ignoring transmission losses), the net fuel-> mechanical efficient of the entire system is about 28%, only marginally better than the 25% you'd expect from a good honda or toyota engine. Interesting. Now the fuel burned at a power plant is cheaper and requires less refining so that's an issue. But it's interesting to see these numbers.
If you just look at dollars, then you've got about 48% efficiency wall electricity -> mechanical and 25% efficiency gasoline -> mechanical so you're using about 2 times as much fuel energy as electricity, so you do save a small amount of dollars, by my calculations around 2 cents per kilowatt hour output. Of course that gets eaten up by the over-baseline charge they put on the excess electricity you're using (over baseline electricity here costs about $0.17/kWh I think.)
At best, considering the time value of money and the premium on hybrids, you're not likely to break even vs buying a reasonably efficient gasoline only car, and you can't really reduce carbon emissions this way without changing the electric generation mechanism.
Now if you want to heat your house with the waste heat of a diesel engine while charging the car battery at night, you could do quite well, in a cold climate.
Of course, as they say, your mileage may vary.
Re:total energy cost (Score:3, Informative)
Re:Nuclear energy is unsafe (Score:1, Informative)
Re:Oil industry? (Score:2, Informative)
That's a pretty rough environment (Score:2, Informative)
Actually, corrosion is a problem for all compressed gas containers. Hydrogen powered cars will have to solve this as well. I have seen a compressed air car using liquid nitrogen as its power source but liquid hydrogen storage is more difficult (-250C versus -80C) This technology is interesting, but remember that filling the tanks is not an efficient process. Heat generated during compression is lost to the environment.
Scuba tanks for instance (operating at about the pressures you described) are visually inspected every year (inside and out) and must be hydrostatically (pressurized to much higher than the typical working pressure and strain measured) tested every five years. I do not know the rational for those particular time periods, but believe that they are DOT regulations (and that there is some logic behind it).
I would assume that these tanks would be filled and drained more frequently than most scuba tanks and so increased frequency of inspections might also be warrented. (though some kind of swappable design may mitigate this)
AFAIK the 747 is one of the more efficient designs (in terms of lbs of fuel per passenger mile). Bigger planes get better efficiency in that regard. I don't believe that the hybrid approach would be useful to planes as it is not useful to cars on the highway either. The two main benefits of the hybrid system in cars is that the engine can be allowed to run at its most effective rate regardless of road conditions (many engines are more efficient at 3000 rpm than 2000 rpm if you can take advantage of it) and regenerative breaking. A vehicle which does not vary its speed or make frequent stops will see no benefit from the hybrid system seen in automobiles.
In fact, a perfectly designed hybrid car should be mass independant: it should not matter how much the car weighs. Only it's cross sectional area into the wind and rolling friction should affect mileage since the energy lost in accelerating would be gained back on breaking.
On a side note, I find it humorous that a french company would be using psi to measure the pressure in the tanks and km to measure the distance travelled.
in SI units, this would be 24,131 kPa(240 atm) - 150 km
or in standard units, 3500 psi ~ 100 miles.
Leaving out, of course, the capacity of the tank.
Re:Park and charge (Score:1, Informative)
Re:Misleadning (Score:3, Informative)
My commute times are so ridiculous that I'm seriously thinking of making the change. I actually think it'd reduce my commute time as I wouldn't have to wait in bumper to bumper traffic. I've done my normal bike sometimes and it wasn't bad but I don't like showing up to work sweaty.
Re:Two beds (Score:3, Informative)
Re:Two beds (Score:2, Informative)
Wrong.
The design the RUSSIANS used in Chernobyl is NOT the design we use in the US. WHat happened there can't happen here, simply because of the different designs.
If you have a Coal plant, and lose it - you might burn to the fence line
Coal plants require coal. Which means mines. Which means mine disasters, including mine fires and collapses.
Oil plants need oil. Need I refer to pics of the Gulf War oil wells burning?
Both of those produce literally tons of soot and ash that needs to be dealt with. CO2 is produced in LARGE amounts, too.
True- a nuclear plant requires uranium, which means mines too. But uranium, having a higher energy density, is needed in smaller amounts, and therefore, there are fewer mines, fewer disasters. The 'waste' of a nuke plant is a few tons of solid materials than can basically be thrown into the back of a truck and sent for disposal, instead of being released into the air and drawn into people lungs like oil/coal smoke and soot is.
Re:Call me when... (Score:3, Informative)
Re:Nuclear energy is unsafe (Score:5, Informative)
Wow. How then thousands die each year in cities like Toronto from smog? I guess their quiet deaths are not heard. Nothing spectacular like freaking out the uninformed about the dangers of "radiation".
Just because US has scaled up their submarine reactors to be used as energy producting reactors doesn't mean all reator types are that unsafe. CANDU (Canadian heavy water) and pebble-bed reactors are inherently safe. In the CANDU reactor, if the cooling fails and the pipes explode from too much pressure, the reaction stops. This is nothing designed by humans. It is part of physics of this type of nuclear reaction.
The amount of waste produced by a nuclear power plant is miniscule. The tons of crap we have are all good fuel that can be reused if it is reprocessed. But as of now it is cheaper to dig up Uranium from the ground.
A reactor can work for 5-7 years and the amount of actual waste produced will fit in a small bucket. And this waste is contained. With coal, it just spreads everywhere killing all of us, slowly.
Anyway, fusion reactors are around the corner (ie. they work now). All we need is will on the part of the governmnents to fund the development of the commercial fusion reactor.
Re:Nuclear energy is unsafe (Score:1, Informative)
Um, I mentioned what to do with it in my previous post. You conveniently didn't quote that part:
The only 'problem' is disposing of the waste. Which is really a non-problem, if the greenies would simply allow us to bury it in a remote location. But, people fear what they do not understand, and most people are too stupid to understand nuclear energy. So they fear it.
There, I bolded it for you this time.
For another, there have been so many near catastrophic accidents.
I bet I can quote 5 oil refinery fires or coal mine disasters for every nuclear plant accident you can come up with.
The was one case (Brown's Ferry, IIRC) where a moron inspector used a candle to see if a cabling hole thru a wall was airtight. It wasn't, and the airflow pulled the flame into the hole, where it ignited some foam insulation. Long story short, they played Keystone Kops for a while before calling the fire department (after findignthe number), and the fire was (eventually) extinquished. The reactor was up and operational the whole time.
Now, imagine if an idiot inspector used a candle in an oil refinery. Would it remain up and operational? Or would it explode, killing who knows how many people??
You mention "near catastrophic accidents". By "near", you mean "non-". Nuclear plants have layer after layer of saftey devices and procedures. And so far, they have worked.
You don't have to evacuate a city when ANY pipe breaks for a coal plant.
Nor do you when a pipe breaks at a nuke plant. There are multiple loops of coolants. The water that turns the turbines/generators is NOT the same water that runs over the core. The 'outer' loop is NOT radioactive. It's just ordinary water. It can leak out all over and not be a concern (other than the fact that it would need to be replenished). The 'inner' loop is mostly inside the reactor building, which is heavily sheilded anyway.
You did not mention this, but it has also been extremely expensive compared to everything else.
Re:The biggest surprise... (Score:4, Informative)
The Prius is not a small car. It's not an Expedition, but it's at least as big as a Camry or Accord, both of which are considered mid-sized sedans. 50mpg (about normal for the Priuses I've seen) is excellent for a car of that size. My Corolla (a typical "small" car, and quite a bit smaller than the Prius) averages 35mpg. Where are you finding all these "normal" gasoline cars getting 65mpg?
Re:Misleadning (Score:3, Informative)
That's a heck of a lot cheaper than providing health insurance and the electric car might even be cheaper than providing free coffee. Maybe the boss will care about the price and maybe he won't. But since the cost is so low the more probable outcome is he wont even notice unless everyone all of a sudden started showing up with EVs.
BTW, the gasoline cost for many gasoline vehicles to travel 30 miles is about $2.00 (30mpg, one gallon of gas @ 2.00 per gallon). SUVs can usually double that, but the Prius can almost cut it in half. The Prius, based on energy cost per mile, is probably very close to as efficient as EVs.
And one last point: Almost off this subject, but kind of important. The cost per mile traveled, including cost for infrastructure, energy and the vehicle itself, is the only real way of determining if gasoline, hybrid, or plug-in electric is more efficient. If efficiency is important to you, find out this number. However, polution costs also need to be factored in. These are very difficult to calculate. My advice would be for government to try to calculate this cost and simply charge for it. The result would be that the greener energy would have a price advantage and consumers will go for the cheaper energy. We'd all be happier and healthier in the long run.
TW
Re:Oil industry? (Score:3, Informative)
It's also a greenhouse gas which brakes down into large quantities of CO2 which is another greenhouse gas so I know it's all that safe either.
Approximate Figures (Score:4, Informative)
It turns out that electricity is extremely cheap per unit of energy. According to these folks [electroauto.com], it takes about
The national average for electricity is around $ 0.10 per kwh, so this is a phenomenally cheap way to power a car. If we wanted to go 100 miles in a purely electric car, it would take 40 kwh, or $0.40.
I rented a Dodge Neon recently and got only 20mpg from it. (It must have had an old or badly tuned engine). Going 100 miles in the Neon would have taken 5 gallons of gas, at about $ 2.50 a gallon. That's $12.50! Even if I could get the peak mileage of non-hybrid cars, or 40mpg, that's still over $6 to run the car the same number of miles electricity would power for $ 0.40. Even if electric rates doubled, electricity would still be phenomenally cheaper than gas.
So why haven't electric cars taken over the world? Because often you need to go further than the charge range in a day. When I went to Sacramento a year or so ago to visit the Capitol, I decided to try renting an electric car. All it had to do was go about 20 miles, the round trip to and from the Capitol. With extra excursions to find parking and the like, I barely got there and back successfully. On the other hand, I had completely free "fuel". The rental company didn't account for it in any way, because it was, truly, too cheap to meter.
So it seems clear that if you can squeeze a big enough battery into the Prius, you could have the best of both worlds: The economy of having a purely electric car, combined with the "get home" ability of the gas engine.
I should briefly address a specious argument against this idea which seems to have gotten wide currency. Once we Californians got through our tiresome power crisis, we thought that anything that plugged in was Bad. Well, true, during the day when we run hefty air conditioners and the like. But once we've cooled down, demand for power plummets and there is no problem at all with plugging in something like an electric car. In fact, the power companies dearly want this to ramp up demand and enable expensive power plants to run at a higher duty cycle.
Once you express this idea in terms of costs, it becomes, well, pretty obviously a brainy scheme. I wonder why Toyota wants to shut it down, since it seems like a wonderful idea for everyone involved, and really, an amazing PR coup for Toyota.
Hope this helps.
D
Re:Park and charge (Score:5, Informative)
Electric Power ain't the answer (Score:2, Informative)
A. Your hacked and modded Prius
B. Your Grandpa's 1950 8-cyclinder Station Wagon
well?
The correct answer is B. .
Everyone seems to take great pleasure in blithely ignoring the fact that it takes energy to build new cars
Even if battery powered cars were the wave of the future, they will merely shift vehicular pollution from gas fired engines to.... coal fired power plants.
If you really want to be a greenie, buy absolutely anything other than a new car.
To appeal to the /. love of numbers, if you're driving a 50 year old car, then the "energy cost" to produce it has been spread out over 50 years.
Even the most inneficient, smoke belching, catalytic converterless relic causes less net pollution compared to building a brand new car.
Most of these hybrids don't even pay for themselves in gas money. They're all small cars. People pay at least $3000 premium over the regular version.
Why? You'd spend what $500~ish per year filling its non-hybrid version up, which means that it'll take years before the premium is worth it.
Re:Misleadning (Score:3, Informative)
Second, your comparison would be quite a lot more useful if you actually used similar units. A kwh is 3.6 MegaJoules, a gallon of gasoline corresponds to about 130 MegaJoules of energy, assume a moderate conversion efficiency of 20% and call it 26 megajoules. So $.06/kwh is $16/GJ, while $2.50 per gallon is $96/GJ.
Re:Two beds (Score:4, Informative)
Politicians are currently deciding where to build ITER, the prototype reactor. Europe and Japan both want it. It costs 4.6x10E9 euros in parts and will take about 10 years to build. Running it for 20 years will cost about the same.
ITER will provide the knowledge for DEMO, the first model fusion reactor, to be operational 5 years after. Followed by commercial reactors.
According to this EFDA folder.
Re:Park and charge (Score:4, Informative)
And, indeed, if only economics (and not governments) were in play, gasoline should be much cheaper than it is now---it's not as bad in U.S., but in Europe and Asia, more than half the gasoline price is tax.
Nevertheless, this comparison shows... well, that the prices are nearly equal (with the order of magnitude) and there are no economic incentive or disincentive to use electricity on its own---only coupled with either environmental or political incentives.
Re:Plug in.... (Score:1, Informative)
Consider a particulate filter.
Re:Two beds (Score:1, Informative)
There's no such thing as a "deadman's switch" on a nuclear reactor; it needs cooling circulation for days even after a total shutdown. Most of TMIs problems happened after the reactor had been stopped. (BTW, the Chernobyl core exploded because they tried to instantly stop the reactor by hitting a switch after they had put it into a state where that couldn't be done.)
Look at what happened at Three Mile Island. Place suffers failure, and the safetys mean that there aren't any casualties.
That's only because the designers of the reactor finally got through to the clueless operators after nearly 24 hours and told them what to do.
TMI was within a couple of hours of a *total meltdown* before they finally figured out what was going on. It's not a given that the containment building would have stopped a liquid pool of molten nuclear fuel from eating through down to the water table.
Re:Block Heaters are much less power (Score:3, Informative)
So, in the winter, use electricity to store heat in a heat sink, and in the day, charge up the vehicles.
In the summer, use electricity to cool down your heat sink (which now becomes a "cold sink"), and in the day you can still charge up the cars.
Or switch your heating and cooling to heat pumps.
There are always solutions. Especially when if you can find a way to make it profitable.
Re:Oil industry? (Score:2, Informative)
Usually the appeal of a large engine is torque -- i.e., more bottom end horse power. This is why driving a manual-equipped Honda S2000 in a city is a pain in the ass -- the engine has absolute gobs of top-end horsepower (240 when it was introduced, as I recall), but it's all in the top end.
From the top Google search result for "honda s2000 torque curve", "from idle to 3000 rpm, the car feels pokey but acceptable. From 3000 to 6000 rpm, acceleration is not particularly inspiring but satisfying and enjoyable nonetheless."
This is the appeal of a large engine -- a large engine generally provides more torque, which means that horsepower comes at lower engine speeds. This is appreciable in the fact that my 170-horsepower 1989 Crown Vic actually accelerates faster from a dead stop than my girlfriend's 2002 Accord which sports 150 horsepower but weights only 60% as much. Until the Accord's engine hits about 3000 RPM it's a gradual acceleration because its small engine has very little low-end horsepower.
This is in part why auto manufacturers advertise V6 or V8 engines instead of raw horsepower. This is also why I find it rediculous to put tons of money into a Honda -- while a 400HP Mustang can be had fairly reasonably and will practically pick the front end of the car off of the road, a 400HP Civic would cost a mint and would be less able to maintain proper traction as strong acceleration would remove weight from the drive wheels, making it much more likely that they slip. The Civic also would end up with less acceleration from a stop, as generally increasing overall horsepower decreases overall torque. Once the car got running, it would move nicely, but it would be working to catch up to the V8 ahead of it.
This is on top of the fact that the 400HP four-cylinder would still sound like a busy Taco Bell bathroom while the 400HP V8 would have to try damned hard to sound anything other than damned tasty.
I generally agree with your assessment that a large beefy engine appeals strongly to my American sensibilites. However, there is a huge difference between top and bottom end power, which is exactly why a large engine is so appealing despite its inefficiencies.
Re:The biggest surprise... (Score:3, Informative)
My car gets forty rods to the hogshead, and that's the way I likes it!
Re:The biggest surprise... (Score:4, Informative)
It's interesting to look at the [toyota.com] actual [toyota.com] numbers [toyota.com]. The Prius is shorter lengthwise and heightwise then both the Corolla and Camry, but the wheelbase is almost that of the Camry (106" to 107", with the Corolla at 102"). The luggage capacity of the Prius (16.2 ft^3) is much closer to a Camry (16.7) than a Corolla (13.6). Curb weight and passenger volume for the Prius are about halfway between the Corolla and Camry. Interior dimensions are all over the place - the Prius has less headroom than the Corolla (and Camry), but more legroom than either. Overall - I'll agree with you that the Prius isn't quite as big as a Camry, but it's definitely larger than a Corolla.
Re:Park and charge (Score:4, Informative)
Power plants are much much more efficient than an engine that has to fit into a car and run at a wide range of RPMs. So even with coal this is a much better alternative.
Toshiba's new nano-battery should make this an even more attractive technology. A quote: [linuxinsider.com]
"For example, the battery's advantages in size, weight and safety highly suit it for a role as an alternative power source for hybrid electric vehicles."
Re:Two beds (Score:5, Informative)
Um, no. The Chernobyl people had turned off most of the safety equipment in order to conduct a test. The reactor was almost at zero power. They were pulling out control rods in an effort to start the reaction up. But they made a fundamental mistake with reactors. The control rods control rate of change, not the absolute power rating. So when the reaction did start up, it rapidly overloaded the reactor. On top of that, the reactor was designed with a positive thermal coefficient. English translation: the hotter it gets, the faster the reaction runs. No wonder the damn thing exploded. Its like Windows, when you see how well it was designed, its no wonder it gets hacked.
But this is old technology. Look at the more recent technologies like pebble reactors. They figured out the maximum temperature a reactor could hit, and then designed the ceramic shell to melt at a higher temperature. It can't melt under its own power. Its passive safety, which I trust a lot more than active safety with all its pumps and valves and moving parts that can fail.
TMI was within a couple of hours of a *total meltdown* before they finally figured out what was going on
According to the Kermey (sp?) report, the reactor actually melted down about 25-50%. The reactor designers were quite conservative. They assumed that steam would not cool the reactor core at all. In reality it cooled about half as effective as water. So in spite of the operators turning off the ECCS (emergency core cooling system) pumps, the absolute wrong thing to do, the reactor didn't completely melt down.
it's not a given that the containment building would have stopped a liquid pool of molten nuclear fuel from eating through down to the water table
Kermey report actually goes into that. TMI-2 had a relatively new reactor load, therefore had few waste products built up. It would not have penetrated the containment building. I think the doc even questions if it would eat through the reactor vessel. Its been years since I've read those docs, so memory fades a bit.
Re:Misleadning (Score:3, Informative)
Oil is FAR worse than Nuclear power! (Score:5, Informative)
Then address the actual problem, i.e. use less coal powered electricity stations.
Hydro, solar and to a lesser extent wind as well as of course nuclear are great options here.
As far as nuclear power goes, I wonder what's better, relying on oil or nuclear power?
Then you should probably hold off on expressing an opinion before you wade into the discussion. Any 10 year old should be able to tell you the answer to that is very clearly Nuclear.
If one persons electricity needs for their entire life time were met using electricity generated from a Nuclear power plant, the total amount of nuclear waste generated as a result would be approximately the size of a tennis ball.
You then simply collect large amounts of it together, encase it securely (in reality quite easy to do, large amount of concrete come in handy here) and dump it somewhere, e.g. in the sea. Given 3/4 of the planet's surface is water and it has valleys several miles deep, finding space to put isn't going to be a problem). If you think this is bad, consider that each of us in the western world uses more landfill space than this on a DAILY basis, and it's easy to see how trivial the problem of disposal of the tiny amount of waste generated is. The result is something that's completely inert too!
Let's take a long hard look at the safety aspect too...
The worst nuclear disaster in history was Chernobyl, which has killed 30 people.
The worst coal disaster in history (to my knowledge) was at Benxihu Colliery which killed over 1500 people.
Oil, as we know from very recent events, is also far more dangerous (as seen from events in Texas). The Piper Alpha disaster alone killed over 150 people (and that was in a supposedly well maintained modern Western environment).
Across the world, have been quite literally hundreds of coal and oil retrieval & power-plant related disasters in the last century, with tens of thousands of people killed. Gas and oil are inherently extremely dangerous to handle, coal mining especially so. Nuclear disasters make for far more sensationalist news though, so one disaster at a very poorly run nuclear power plant (which should never have been allowed to run, and wouldn't in any Western country) and so people who can't be bothered to do any research, decide that nuclear is 'bad'.
Nuclear power isn't the only answer, in particular it's not a great solution for unstable regions of the world (politically or geologically), but for Western regions, like North America and Europe it's far and away the best solution we have for a sustainable reliable energy source, that is by and large environmentally friendly to boot.
Re:Oil is FAR worse than Nuclear power! (Score:3, Informative)
The worst nuclear disaster in history was Chernobyl, which has killed 30 people
Sure, only 31 people died from acute radiation exposure, but that doesn't mean only 31 people died. Although I totally agree with Nuclear power in favor of Coal (I'm an Illinois resident), something like 1800 children alone had thyroid cancer at the age of 14 in the affected area. Although maybe not all of these kids didn't die, I don't really think ignoring all of the long term affects of what happened at Chernobyl is the correct thing to do.
http://en.wikipedia.org/wiki/Chernobyl_accident%2
Anyways, if you're going to rant, at least present it in a manner such that people that are actually working on fixing these problems don't pass you off as blindly biased.