This is what I figured, if you add some H2 you can use more CO and get more fuel. You could gas shift and get more H2 but end up with more CO2, this seems like a better method.

Currently 1.5 acres of good farm land are required to make enough agro-fuel for one average gas guzzler and 0.5 acres (min) are required to feed one human. (NB: large beef eaters require much more because beef (like plants) are very poor energy converters, less than 9% efficient, i.e. require 11+ units to produce one unit.

Recent solar cells, with up to 30% efficiency, could do a much better job and could be installed in desert land, unused roofs etc and not use any farm land. Wind energy is another good source that would not compete with food production.

clett: The only problem with PV is the high cost energy storage required for low or no sunlight hours. The same applies, to a lesser degree, for Wind turbines. Short of affordable e-energy storage, those two clean energy sources need complementary replacement energy. Hydro is ideal because it can be turned on and off at will and the huge water reservoirs are excellent low cost storage units. NG power plants can also be used to supplement Sun and Wind variable power sources. Managing the power mic may be a challenge. Eventually, PHEVs and BEVs could help to supply some of the needed energy.

PV to EV payback starts to look good when you compare it to fuel costs. Sure you put the power on the grid during the day and charge at night, but is a good deal if you can get an affordable system in the future.

The answer isn't PV there is insuficient doping material available to supply all the silicon arrays world wide.

The solution is low tech Solar Thermal with fused salt storage. Hundreds of megawatt plants of this sort are already in operation in Calif. A new very large one is planned in Algeria to be built by Siemens. This will export electricity to Europe using DC transmission lines.

Lets not forget the price of good farm land ($10,000 to $20,000) an acre or about $15K to $30K per average gas/ethanol guzzler. That alone would buy a large long life storage battery, The other associated agro-fuel cost would buy most of the PVs required. In other words, PVs + storage batteries may be cheaper than farm land + all other ethanol production and delivery cost.

Grain ethanol is certainly not the answer.

The most efficient route of renewable energy utilization is still solar and wind to electricity. The surplus of this electricity can be stored locally in the form of H2 for direct use as vehicle fuel, home heating, CHP, or backup electrical generation.

The future consumers will be presented with choices of whether to use higher-cost, less-efficient and more polluting carbon-based fuel, or lower-cost, more efficient, and non-polluting H2.

Most families in USA and Canada have 2 or 3 vehicles. One EV per family (by 2020?) could be a goal to achieve on the way to total electrification by 2030. The family member who does more in city travel should use the EV. Polluting ICE vehicles could be progressively banned (or have to pay a special fee) for city center areas.

@HealthyBreeze,
Hydrogen is a big industry even right now, and H2 is stored under pressures right now. There are thousands of industrial applications for stored H2. With increasing advancement in H2 adsorptive materials, we will be able to store more and more H2 with less and pressures.

Leakage and explosion are engineering issues for any kind of fuels, for which there are ways to prevent. Petroleum and Natural Gas do leak and explode as well, but we have learned to deal with those risks. Even lithium battery have risk of fire, and lead-acid battery have risk of explosion.

How come Nickel-Iron battery is not in popular use, if it is so good?

@ HarveyD,
http://www.beutilityfree.com/pdf_files/NiFeFlyer.pdf shows a price list and specs on on page 2. They are quoted in Ah, not Kwhr, with a 1220 Ah cell going for $1008.

@ Roger Pham,
NiFe batteries are more expensive than lead-acid batteries, and in vehicles their decades-long life was not needed, so they never really took off. Also, they don't do well below freezing temperatures. Their characteristics are better suited for stationary, getting-off-the-grid, indoor applications which may improve their economies of scale.

@ Roger Pham

"How come Nickel-Iron battery is not in popular use, if it is so good?"

These batteries have poor self-discharge characteristcs and high internal resistnce. Their main advantage is extremely long life and rugged construction.

For advanced Nickel Iron batteries the energy density is projected as 55 Wh/kg and 110 Wh/L. Expected production cost is 250 $/kWh.

These are hardly stellar characteristics for traction applications.

The diagram looks odd to me. The bottom orange block, H2, appears directly from the sun.

But H2 doesn't come directly from the sun. I have to assume they omitted two boxes like those shown for Electrolytic H2 into the H2Bioil Process.

The diagram may have been made that way to avoid clutter???

Mannstein reminds us solar thermal concentration with salt/storage is alive and running. That strikes me as the best approach for utilities.

The world has a lot of empty desert, and in North Africa, at least, the NIMBY voters won't stop it.

Biological organisms are energy harvesting and utilizing entities. We, ourselves, use plants as the basis for providing energy for our body systems, and plants are poor harvesters of solar energy. Photosynthesis is only about 4% efficient.

But the advantage of plants is that they do the hard job of concentrating nutrients for us and are comparatively easy to manage and at low cost. Harvesting solar energy directly at higher efficiency and using that energy to synthesize carbohydrates and amino acids for biological use would be much more costly.

There is a lesson here for biofuel production. Absolute efficiency is not an end all or be all. Cost, established infrastructure, an entrenched knowledge base, and the quality of energy form are factors that have greater importance than efficiency.