@ECI, The average electricity cost at 13 cents/kWh is $2.20 gge compared to 52 MPG gas car. $4k per kg of H2 at 67 MPGe Mirai would cost $3.1 to go the same 52 miles. L2 and faster public charging are also more expensive.

"They begin by observing that the EU’s goal of 95 gCO2/km fleet average emissions by 2020 can only be met by means of extended range electric vehicles or all-electric vehicles in combination with the integration of renewable energy (e.g., wind and solar)." I am surprised nobody pointed this out. Gen3 Prius achieved 89g/km 5 years ago. Gen4 should be 18% lower. Auris HSD emission is similar.

The HEV used in this paper is rated 45 MPG and 59 MPGe for FCV. Prius is 50 MPG while (Gen4 could be 55-60) while Mirai is rated 67 MPGe. NG to electricity conversion rate is high (55% used). I believe the current US NG powerplant efficiency is around 40%.

53 miles at 106 MPGe would consume 16.85 kWh. Take out 15% charging loss and you get 14.3 kWh used from 18.4 kWh battery pack. That's 78% depth of charge, very deep. Is it charging to 100% and drained to 22%? Or 90% to 12%?

Hopefully the rating was tested on the 5 cycles test rather than derived from 2 cycles, like Fusion hybrid.

EPA estimated 48% EV so that sounds about right.

Great to see the ball rolling on this. Toyota, Hyundai and a few others are aiming 2015 for the release of their FCVs. How about the plan to increase the hydrogen stations?

Since it generates electricity and provides hot water, you'll need to subtract the cost of a traditional water heater before calculating the payback. Natural gas water heater is like $500, nonetheless. It looks like the last gen unit has max output of 1kW. http://www.tokyo-gas.co.jp/tgminutes/64.pdf

Yes PiP has 4.4kWh (energy) Li-ion battery and it can discharge 41kW (power). 1.31kWh (energy) NiMH in a regular Prius can discharge 27kW (power). If PiP has 4.4kWh NiMH, it should be able to discharge 91kW but then it'll be much heavier. Anyway, PiP lithium battery is tuned to balance the required power and energy density for specific application. Another thing to look at is the regen. PiP can absort 31kW (max) when SOC is around 50%. When it is fully charged, it can regen only 10 kW. NiMH HV battery can capture more regen energy (relative to the battery size). For the hybrids NiMH is hard to beat.

@Kelly - Hybrids need high power cells. Prius has 168 battery cells that makes 27 kW power. EVs need high energy cells. Tesla battery pack has over 7,000 cells low power cells to make 310 kW. 168 of those cells would make 7.4 kW power. For a hybrid, you need a small battery that can charge/discharge at very high rate. NiMh is very good with that and it is very cost competitive. I wouldn't be surprised if IS300h uses the same NiMh pack as ES300h.

Great to hear that Prius PHV had a good start in UK.

It should be mentioned that PiP went on sale late March, 2012 and it was available only in the launch states. Volt and Leaf have been available nation wide.

Bob, natural gas is fossil fuel. It is a lit cleaner than coal. PiP is the cleanest PHEV, per EPA beyond tailpipe emission site. It is the only plugin hybrid with a flat cargo floor and 5 seats. I have it for about two months and I have been averaging 264 Wh/mi (128 MPGe) on electric miles (charging loss included) and 55 MPG on gas miles. It is amazingly efficient and I am thrilled with getting those numbers in a midsize.

Per GM's ticker, about 62% are on EV. I wonder what caused the discrepancy. Any word on how many kWh was used for 100 million miles? http://www.chevrolet.com/volt-electric-car.html

I purchased my PiP in October. So far I am averaging 258 wh/mi on electricity (charging loss included) and 54 MPG on gas. 34% of my miles are on EV and 66% on HV (gas). Since majority of my trips are short, they are driven on EV and I am getting about 12 miles per charge (3 hours).

Right. It has to be engineered to ensure durability and reliability to sell in all states. As for EV, I think they will sell more if they are required to have the same warrenty as hybrid battery.

These are surely not automotive grade which requires 10 years warranty.

It is obvious that Kit P has never driven a Prius. A closer comparison is the Matrix, which starts around $20k comparably equipped.

Yes, really Kit P. I saved all my gas receipts. 53 MPG was my personal real world data measured at the pump. You should go test drive a hybrid instead of relying on the internet misinformation. Hybrids do get great mileage even on the highway. You are right that not all PHEV reduce CO2 emission. For example, EPA rated the compact Volt at 260 g/mi which is an increase from a regular midsize Prius (222 g/mi). A well designed PHEV like Prius plugin (with optimal battery size) lowers the CO2 beyond a regular Prius can achieve. EPA includes PM, NOX, CO and other emissions and convert them to CO2 equivalent to derive their CO2 figures. It is not just the emission from the tailpipe. They include fuel production as well so the upstream emission is included. Jetta TDI wagon auto is rated 390 g/mi.

@Kit P - In case you are not aware, modern diesel cars void warranty if you use 100% biodiesel. VW limits to B15 under warranty. These modern diesel emission system also need regular maintenance. Having said that, any technology that saves petroleum and reduce emission should get its own fair share of incentive.

@Kit P - Regarding your other comment... Combining trips and living closer are common sense and people do that if the choice is available. There are other things to consider in the entire quality of life equation. Emission is a global issue so it does not matter where you live. 25-30 MPG in city driving is unacceptable by my standard. My Prius PHV can drive 190 miles with a gallon of diesel equivalent electricity. On the highway, I use the gas engine and have been getting 55 MPG. Using the fuels that is superior in different driving conditions is what the hybrid synergy drive is all about.

@Kit P - In my old commute (mostly highway), 2006 Prius served me well with average 53 MPG. It still has the original brake pads and the original traction battery required no maintence. I think you and I are on the same page, together with the author. The incentive needs to aim at the goal and not a specific technology (battery size). Diesel and regular hybrid also save gas and there are no incentive. Yet we are spending $4.5 per gallon in a compact 4 seater Volt. Check my posts on priuschat to understand my position better.

@Kit P - I used to have a long commute and put 30k miles a year (for 5.5 years). 2006 Prius has 164,000 miles and my brother bought it from me to replace his truck. Now, majority of my trips are very short. A regular Prius doesn't get great mileage due to the initial warmup. Plugin Prius addressed it by allowing me to drive those frequent trips in EV. When I make long distance trips in the weekend, the gas engine is still rated at 50 MPG despite the 150 lbs extra weight. So, using electricity for short frequent trips and the most efficient gas engine for long trips, I am able to get the best of both worlds. Yes, I am using $2,500 tax payer money but every $1.25 will save the nation a gallon of gas (per the paper above). Pretty good bang for the buck. I have 416 miles on it now. 30% on EV and 70% on HV (gas). The car is reporting 80 MPG with 25 kWh of electricity used. Per EPA, I have lowered my emission from 222 gram of CO2 per mile to 190 g/mi. The Prius PHV drives better and the gas engine shutdowns are so smooth. It is an upgrade I am extremely satisfy of. I understand your criticism and I think it should be directed toward Volt. It uses $7,500 tax payer money and every $4.5 saves a gallon. It is also heavier than the Equinox SUV.

It is like Honda IMA with a clutch. Instead of using CVT, they are using DSG.

Common sense would say the bigger battery would save more gas. However, if you put cost into the equation, $4.5 per gallon saved by 16kWh plugin hybrid is not saving at all. By keeping the plugin battery small and maintain 50 MPG gas engine, every gallon saved cost just $1.25. The effect of the bang for the buck is counterintuitive.