HansMMN October 14, 2011 09:32 AM Someone is confused. 85 kW in 34 liters. For how long? 1 second or 1 hour or 10 hours? Or did you mean 85 kWh? Remember the 125 million US$ Mars Lander that crashed because the engineers fouled up on the units. Robert Newman October 14, 2011 01:26 PM With hydrogen, you have a chicken vs. egg adoption scenario which is often very slow. Why not design around methane (natural gas) as the fuel? It already has a wide distribution network. Methanol would also be a better choice than hydrogen since it has a high storage density compared to hydrogen gas. Sure, hydrogen leaves no CO2 behind, but given then costs and time to roll out a hydrogen network, it may be a while before you can buy a hydrogen car. These fuel cells would be ideal for home power use, especially when supplemented by solar or wind generation. Stewart Mitchell October 14, 2011 01:40 PM This is a fuel cell. The power will be constant as long as the fuel last. Eletruk October 14, 2011 02:42 PM You are confusing power density with energy density. What they are saying is that the powerplant can put out 85kW of power, and the volume of space it takes to do that is 34 liters. So that translates to 2.5 kW/liter. How long that is output for depends on how big your Hydrogen tank is. EinSascha October 14, 2011 03:02 PM @HansMMN. This is a hydrogen fuel-cell, not a battery. The energy (kWh) is in the hydrogen. The fuel-cell only converts it into electrical power (kW). Stewart Mitchell October 14, 2011 05:41 PM An electric bike is 500 watts. That should be 200 ml inverter. Sounds good Eric Grant October 14, 2011 05:57 PM The article is refering to power density which is kW per Liter, not efficency which would be kWh per Liter. A Fuel cell does not store energy like a battery so it\'s not measured in kWh. The 85 kW in 34 liters is akin to saying my car has a 300 bhp 4.6 Liter engine. In an internal combustion engine the volume is the engine displacement but for a fuel cell I believe that it is the volume of the stack.The reason they find power density important is because cars need a small fuel cell that put out a large amount of power, as opposed to industrial sized fuel cells that don\'t need to move and can be as big as they want. Facebook User October 14, 2011 06:55 PM I think you are right they have their volume units a wee bit wrong. Now if that was 3.4 litres that is impressive.Natural gas /methane doesn\'t work in low temp pem cells. It does work quite nicely in SOFC types that run at much higher temps. Michael Mantion October 14, 2011 07:17 PM Hans they are reffering to the volume of the fuel cell not the fuel. Just like the displacement of an engine, not the size of the gas tank offthegrid October 14, 2011 08:32 PM Why is the expected cost such a big secret? Einstein himself after reading this never ending parade of stories couldn\'t say how much \"thereby reducing cost of the Next Generation Fuel Cell Stack to one-sixth of the 2005 model\" is. Can the writer or anyone else tell me how much in dollars one-sixth of the 2005 model is? Bullfreathers! This is yet one more smoke and mirrors look what\'s coming happy things. Good job reporters, another article about what is \"not here on sale yet, look what tomorrow will bring story. And you can forget a 200ml pack for your bike being on the shelf any time soon. Poor people, keep peddling, you wont be able to afford it if one if it ever comes out.