The ability to run the generator on natural gas is interesting. When the car is parked it could be plugged into the electric grid as well as the natural gas grid and thus be able to deliver vehicle to grid services using its generator running on natural gas. A more refined system could also make heating water using excess heat from the motor generator.

It is interesting because it provides a very cost effective solution to massive grid-leverage-services in a grid where nearly all power comes from wind power. Specifically, a country like the US uses 3900 billion kWh per year and therefore on average need 445GW (=(3900/(365*24))*1000) of power.1) If just 6% of the 300 million US vehicles had this ability to use natural gas to generate 35kW of electricity this compares to 630GW (=300*0.06*35) or plenty to run the entire US grid if needed.2)

The cost of electricity generated this way will not be high because the PHEV vehicle has no capital cost as a power plant because the car is already paid for by the vehicle owner. Indeed, the vehicle owner could make substantial money selling expensive electricity at the few days during the year were the wind blows to little to deliver the demanded power. Nevertheless, on average electricity will still be affordable because most of the year it is delivered inexpensively from wind turbines.

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1) Consumption of 3900 billion kWh in USA, click economy to confirm data

2) 300 million US vehicles

As analysed by Henrik, the natural gas fueled electric car is indeed interesting. There is no need for such a car owner to even have a charging system if he has natural gas. Many households have gas grills connected to the natural gas "grid", so there is no reason not to have a connection available for an automobile parked in an open carport or driveway to charge the battery or to supply the electric grid with electricity from the battery and ultimately from the generator operating on natural gas.

In the long run, cars will likely be powered from the grid but natural gas can be made with many energy sources as it is now from coal in North Dakota or from biomass all over the world. There probably can be found organisms that will make methane and CO2 from coal and a little bit of oxygen dissolved into water in very small concentrations. Sulphur, Sulphur trioxide or dioxide may be used to supply oxygen for energy as well. ..HG..

Henrik: natural gas is the most expensive generating fuel, and vehicular ICEs are among the least-efficient sytems which can run on it. Even if you can get 30%, they will be up against the likes of GE H-series gas turbines at 46%. Hooking up in parking spaces also creates many more chances for leaks and explosions, asphyxiation and fire. Cars can be emergency generators, maybe; for regular use, no.

Cogeneration with cars is simply not practical. I've worked with vehicles designed with quick-disconnects in the cooling system, and they were all taken out because of headaches involving small leaks and inability to purge air from the system. You can learn this lesson yourself, at your own expense. Until you have a proven prototype, suggesting it as a mass-market idea is ridiculous.

HarveyD: that's only about half the vehicle fleet. Unless you are going to replace most of the chemical fuel with electricity (which is the only way to go), it's far from a complete solution.

E-P:

I assumed that the rest of the fleet would have other power plants, including pure EVs, Fuel Cells, heavy duty ICE etc.

A 100% pure EVs fleet would be ideal but would require much higher performance, lower cost batteries that may not be available for 2+ decades.

Secondly, it would be a good way to get rid of mountains of unwanted wastes, using known technologies. Of course, the Wastes to Gas converters could be upgraded to produce electricity for EVs if and when required.

EP

The nominal capital costs and the nominal operational costs of a power plant is the same each year whether your capacity factor is 0.1 or 0.9. However, when measured per produced kWh these costs are 9 times larger per kWh with a capacity factor of 0.9 compared to producing at a capacity factor of 0.1.

If wind power does exactly 90% of all the electricity production then the average capacity factor of all the fuel based power plants (coal, gas and nuclear) will be exactly 0.1. I have a spreadsheet model that return prices per kWh for various power sources and when you change the capacity factor to 0.1 for the fuel based plants the price per kWh of respectively nuclear, coal and natural gas becomes 0.192USD, 0.122USD and 0.086USD. A PHEV can generate a kWh for 0.07USD regardless of the capacity factor so it will be preferred despite only being 30% efficient. I assumed 60% efficiency for the natural gas plant and 40% for the coal power plant.

By the way I was wrong about the cost of wind power. It is 4 cents per kWh today for onshore parks with a capacity factor of 0.3. However, coal and natural gas can also deliver for less than 4 cents today if their capacity factor is high enough. The wholesale price of electricity is also about 4 cents per kWh. See http://www.bloomberg.com/markets/commodities/energyprices.html

I think the future grid in most countries will be based on 90% generation from wind power with the remaining 10% coming in the form of fuel based backup power from PHEVs (preferable biogas). Eventually this will be the least costly form of power grid using the least possible amount of fuel.

V2G is interesting, but not a solution. It is a form of distributed generation that can be beneficial, but not THE solution. Peak shaving has been done for decades and has its place. Let's say by 2020 we have more than 2 million EVs on the road and half of them actually use V2G on a regular basis, that does not add up to much more than 1 small power plant.

MG

There is less emissions from this engine than your own or you neighbors gas heater as this engine has an exhaust unit which is probably not required for residential gas or oil heaters.

The noise from the PHEV could be an issue buy it is easily fixed by legislation limiting how much noise it is allowed to make in a generator mode. To give an example, VW is now selling a motor generator that house owners can install inside their house and that generate electricity and heat at a combined efficiency of 90%! Obviously they have solved the sound issue with that engine or people would not install it inside their houses. See http://www.lichtblick.de/uf/pdf/091000_Technische_Daten_ZuhauseKraftwerk.pdf

As you can see the VW engine generator emit less than 50 DB at one meters distance (much less than playing kids!).

Cooling the PHEV motor could be done by circulating water from the house’s heating system through the PHEV engine. If it generates too much hot water you can simply waste it in your garden or in the drain. The ability to make money selling electricity at prices above 7 cents/kWh as well as free hot water will make it attractive for PHEV owners to pay the extra money that a PHEV cost when compared to a pure electric vehicle with a 100 miles range (the Volt will cost several thousand more than Nissan’s LEAF I am almost certain).

Also, I don’t expect private house owners to generate more than max 20kW from their PHEVs as this could be done with an inexpensive level II charger. Commercial fleet owners will however have level III chargers in their garages and they could use therefore use bigger generators at about 100kW which would probably be normal for busses and trucks of all kinds.

SJC

Pure battery EVs will never be used for V2G services as the batteries durability will be shortened and they do not contain enough energy to deliver significant backup energy for the grid. Not so for PHEVs where you only need some 1500 hours of engine use for vehicle use in the lifetime of the PHEV while the remaining about 4000-6000 hours of motor life are free to use for V2G services.

SJC

You are right. To use the expression ‘never’ without restriction is unwise. What I should have said is that at the current high prices, battery limitations and consumer behavior it will never happen. If the battery prices one day drop to 50 USD per kWh (down from 500) and they are good for 2000 cycles then the cycle costs of battery backup become 0.025 USD/kWh and that will make good economic sense in many situations. In that case it could actually pay to do V2G services by a BEV but it is still not likely to happen as people would want their BEVs to be fully charged whenever they go somewhere. The beauty of using a PHEV for V2G services is that it will be fully charge and not have used any fuel from its regular tank because it can take the energy from gas grid.

Henrik, shallow battery cycles do not appear to affect lifespan significantly. AC Propulsion's V2G test actually increased the capacity of the Panasonic lead-acid cells in the battery. AC Propulsion was testing regulation rather than peaking (which would involve much deeper cycles), but if the services can be provided for next to zero cost in depreciation, EVs become the preferred supplier of regulation (because other sources cost quite a bit more).

The synergies are fascinating, because the system both gets cheaper to run and more efficient.

Regarding the cost of NG-fuelled vehicles providing grid power, you're ignoring the capital cost of delivering fuel to the vehicles, the safety issues with flexible piping and quick disconnects, and systemic capital and infrastructure issues involved with having to deliver 50% more NG per kWh to car-generators than the best gas turbines. That's a win/lose proposition, and you have to look at the losses very carefully.