Hybrid vehicles: Plugin vs regular and storing renewable energy, a novel combined cycle approach

Hybrid vehicles: Plugin vs regular
This is the follow up post to the original hydrogen economy post. I have read up a bit topic and there are definite advantages to using plugin hybrids since the production of energy by a power plant is more efficient than using a gasoline engine. However, the problem is that using the predictions of the plugin hybrid proponents once they are mass produced they will still cost $5K more than a regular hybrid which are ~$5K more than a regular car. So driving 25 miles a day, the pay back period of a plugin is 10 years with $3 a gallon gas (assuming it never uses any gas, at all and you're buying electricity at $0.08/kWh), versus the 8 year pay back of a regular hybrid that gets double the mpg of a regular car. You can say well the environment is worth it regardless of the cost, but the problem is that to get to the $5K from the current $30K it has to be worth it because of the cost alone!

Do I think it could work at all?
I think a plugin hybrid bus could work, however it would work better if at the bus stops there were overhead chargers so the bus could recharge, and not drain the batteries to run the electrical loads while it idled at a passenger stop. An added advantage is that the biggest load for a vehicle is getting off the line, so if the bus was fully electric coming out of the stop you save a lot of drain on the batteries and/or not have that huge cloud to diesel exhaust as it starts up. In addition you don’t have to string wires over every road on the route, just selected and permanent locations, so you retain most of the flexibility of having buses versus electric trolleys. Fleet vehicles might work as well (but not police or fire vehicles since they need total flexibility and go too many miles per day), perhaps even taxi cabs, since they could charge while idling at the airport, and at distributed stations waiting to be dispatched.

Now I did read a very interesting article that the batteries in plugin hybrids could be used for peak shaving, since the electric company can sell them cheap off peak power then get it back to met peak demand. I think that is a brilliant idea except, the conversion (AC/DC then DC/AC) and transmission loses would eat up the savings. However if it was individual companies that did it, and then they could have special DC chargers for the cars and DC air conditioning equipment so they could cut the loses and maybe save money, plus the employee benefit of giving them free fuel for the commute in. Well that is does make a very nice model till you consider that peak demand is: 3 to 6 in the afternoon. Well this is also when most cars are on the road, and when they get home the batteries will be in no condition to provide power. Plus, if you want to store wind energy (sun up to ~10 am) you will be trying to charge batteries that have already recharged all night, or are on the road already.

Storing renewable energy, a novel combined cycle approach
Ok since wind power is now cheaper than even combined cycle natural gas utilities are investing heavily in it, but since renewal isn’t on demand, most wind power is wasted. The problem with electric is that it has to be used as it made, so in my previous post I suggested we use excess energy to make hydrogen gas. I still think this is an excellent idea, since hydrogen has many uses that command a premium price (ie more than the company could get for selling the electrons) but I wish to consider alternatives too. The most obvious is store power in either flywheels or batteries but the cost and maintenance issues make that impractical. So I suggest a combined cycle system, it is complex but I believe workable. Making ethanol is limited since yeast require simple sugar for food, but most plants convert sugar to cellulose which yeast can’t process, and is even difficult for most bacteria. However, acid can readily break down cellulose to sugar but the process is plagued by high acid costs, and difficultly of getting rid of spent acid. One of the main acids for the process is HCl, which can be produced by electrolyzing salt to sodium metal, and chlorine gas, then reacting the chlorine with hydrogen (which can be made from reacting sodium metal and water and yields NaOH aka lye). This provides a feed stock gas to turn useless biomass into yeast food, (which is neutralized with you guessed it lye) then finally biofuels. Unlike the traditional process the spent acid is not recovered from the waste solution it is instead reacted in situ with iron or nickel to produce FeCl or NiCl. Since one you can make a whole day’s worth of chlorine with a few hours of power, the process is well suited to being discontinuous.
Now here is the cool part there is a battery technology the uses a sodium metal (anode) and either finely divided FeCl or NiCl as the cathode in a molten salt electrolyte. While currently this is sealed cell technology, since it uses liquid electrodes in permeable ceramic containers it is well suited to conversion to a continuous process by having the reactants flow in and out or semi-continuous flowing only sodium and having the reduced metal coat the anode so you recover rods to neutralize the acid solution again and regenerate the finely divided metal chloride. Since the parts are cheap and while liquid sodium isn’t as safe it is considered safer than high pressure stream, these cells could complete against high temp fuel cell technologies. Plus since they use industrial waste instead pure hydrogen, they save money (especially the part about not having to recover spent acid).
Some will criticize me and say the production sodium and chlorine is not efficient if the cell isn’t continuous, (due to heat lose while idling), and so it must be done wet which produces NaOH not sodium. I agree there may be issues, but if sodium metal production is not possible that is still not a problem since sodium is the cheapest metal at >10 cents a pound. At that price it cheaper than hydrogen gas on a W/kg basis (Na 23 g/mol versus H 1g/mol.)
Is it cheap enough for peak shaving in a competitive market? It might be if the plant was built near a big city in the interior of the country, in a windy area, next to a paper mill. Even without the combined cycle to get work out of the intermediate products simply making and storing sodium metal and using chlorine to directly make FeCl/NiCl is easier and cheaper than making and storing hydrogen and oxygen (compressors and chillers require huge amounts of power you can’t get back, plus hydrogen has a low energy density.)