@ Davemart, for a PHEV to get you to 60 mph, it's more like a 4.4 Kwhr battery pack, but I take your point. I'd heard the regenerative braking on a Prius wasted ~80% of the potential energy because it couldn't take in the power fast enough. I dunno. I still have a bad taste in my mouth about FCEV because during the G.W. Bush administration they were used as a cynical way to stall more plausible BEV research, and with the presumption that the oil industry would ultimately fix the H2 from methane, so they wouldn't be renewable energy powered. I know innovation can bring the price and size of Fuel Cells way down, but if you want to scale your transportation system, solar panels and batteries scale much more than flue gas. It's like how I used to be stoked about biofuels, until I realized that an acre of jatropha/palm/soybean oil would take you a few hundred miles per year, whereas an acre of photovoltaic panels can take you tens of thousands of miles per year. We're on the cusp of affordable electric cars. There's a race for the $35K price slot. In 5 years, it will be a race for the $25K price slot. Once we can get away from liquid fuels vehicles that travel less than 200 miles per day...why ever would we go back?

@ SJC, What is the well-to-wheels efficiency of this https://phys.org/news/2016-02-proven-one-step-co2-liquid-hydrocarbon.html process? It sounds energy intensive? My problem with fuel cells has always been the horrific inefficiency of isolating, compressing, transporting, and converting to electricity their fuel. This (http://phys.org/news/2006-12-hydrogen-economy-doesnt.html) is an older chart referring to H2 well-to-wheels being 1/3rd of BEV. If your initial input is renewable electricity, I have yet to see any chemical intermediary that doesn't flush 50-70% of the energy before it gets to the wheels. Even if you are getting your chemicals from waste streams that are already hot (which usually have scalability limits), I still strongly suspect the well-to-wheels conversion efficiency is poor compared to BEV. Also, Fuel Cell Vehicles need to have big batteries to handle acceleration and regenerative braking, so, why not just go all the way to BEV?

These are the same doofuses who, when polled, mostly thought Hydrogen fuel cells are going to be the big thing in 10 years, and BEV is a passing fad. Never mind that BEV is 250%-300% more efficient than Hydrogen from well to wheels, per http://phys.org/news/2006-12-hydrogen-economy-doesnt.html.

Question: Is 14% conversion efficiency good? Don't heterojunction cells usually cost a lot more, and have conversion efficiencies in the 24-30% range. If half the energy is still being lost in conversion, H2 is still a very inefficient storage medium, right? Lithium Ion batteries convert ~90% to stored energy, right?

In the short term, this doesn't change much. In the long term, this is HUGE. This is the positronic brain for your I Robot. This is the energy efficient system to interpret interface signals for cybernetic augmentations. This is the smartphone that can record, understand and tag all of your external and internal experiences for later replay. This pours through petabytes of unstructured data, forms 1 billion hypotheses, makes 1 billion predictions, observes the data awhile longer, and fundamentally advances our understanding of the natural, economic and social world. This could be very good or very bad, and will likely be both. Do I win the prize for spookiest speculation?

Has anybody come up with a way to mass produce graphene?

@ SJC, you're right. There's a carbon-policy simulator at https://www.energypolicy.solutions/ that lets you see the CO2 emission impact of various efficiency, regulatory, subsidy, and technology and tax policies. I've fiddled with it a bit, and it seems that the 3 things that change our trend line the most are retiring coal plants faster, reforrestation, and carbon tax.

This is so frustrating. While they compare the sodium 18650's to to iron phosphate lithium cells, but potentially cheaper due to the abundance of sodium, it's pretty fuzzy that they left out so many crucial details. Even so, they do say 2,000 cycles. If we suppose that they have low conversion losses when power makes a round trip in and out of these sodium cells, and that they are cheap in bulk, and therefor attractive for stationary storage...what do they cost per watt hour stored over their lifetime? Ok, researchers can only estimate costs in bulk, but that's ultimately what will make these successful or not, since they will always be behind lithium on the mobile priorities.

Saying the reactor is 3.3M across is a bit like saying the cylinder in the car engine displaces 1.7 Liters. It's true, but the total system is a much bigger. Heat exchangers, turbines, and lots of other system elements still make this large, not portable, and plenty pricey. I've been waiting for this breakthrough most of my life, and getting net energy out is really, really hard. Getting cost-competitive energy is much, much harder. Lockheed has a compact fusion project (http://www.lockheedmartin.com/us/products/compact-fusion.html). EMC2 has done a number of contracts for the Navy on compact fusion (http://www.emc2fusion.org/). Everybody has a story for why this time it's different. I support almost every one of these avenues being pursued. However, I do not get my hopes up because, you know, it's really hard.

http://www.upi.com/Science_News/2015/06/25/New-technology-could-spur-a-graphene-driven-industrial-revolution/2391435246627/ This is good, yes?

@ Gryf, One of those PDF's says an objective was to "• Develop in-situ measurements of electronic and ionic transport vs. Li concentration using binder-free sintered electrode design" which is worrisome, because sintering does not lend itself to high-throughput production as the recent article claims. Maybe they moved on from that to their "wet" process. Laszlo's article says Lithium Iron Phosphate chemistry for stationary storage markets...which I guess makes sense, since Iron Phosphate was always about faster charge and recharge but sacrificing energy density...so, make that cheap and yep, you get stationary storage. I guess other chemistries could be suitable for cars, but the stationary market is less demanding.

They don't mention watt-hours per Kg, or Liter, or cost. There's an argument to be made that a combined battery and supercap could be really good for a PHEV that captures all the available regenerative braking energy and has a fairly low HP engine which almost always runs at optimum RPM for efficiency, but is only running half the time because it's constantly refilling the supercap. Dunno if that gets us much above the Plug-in Prius' ~55 mpg, but it might.

@ Roger Pham, So, your contention is that Fuel Cells will make energy sense when someone else pays for the electricity to reform the Hydrogen? I mean, c'mon. Conversion from (Power Source X) to H2 (lose 30% of energy), then storage losses, then convert from H2 to electricity (lose 40% of what energy is left) is way too energy expensive. The motor ends up with less than 42% of the energy (from Power Source X) you started with. Use good batteries and the motor will receive closer to 75% of the energy you started with. Batteries also seem to be improving faster than FC. How can you, as an engineer, get fixated on FC in the face of such numbers? FC only apparent advantages are refueling time (although not if you plug in the car and reform on board as you suggest), and potentially range depending on how store your H2. Partial recharge of batteries (from a pair of 220v chargers) is pretty quick now. Range on premium electrics is pretty good now, too so it comes down to price. How long before FC cost dramatically less than the battery pack that can produce similar peak power output?

Am I reading this right, that what they are announcing is "as efficient as platinum catalysts" so they will still instantly lose 30% of the energy they put in due to conversion losses? This is a cheaper catalyst material. That doesn't make it more efficient from well-to-wheels than BEV though.

@ Davemart, Leave solar out of the well-to-wheels equation and most FC are still suspect. Cogeneration natural gas plants can convert at up to 80% efficiency. Put that into, and out of a battery and it's still likely better than the 60% claimed for an FC. There are conversion losses for refining fuels for FC which that 60% number probably doesn't include.

This is perhaps the most exciting BEV research announcement since Silicon Nanowires...except even more so. 1. It seems to solve the dendrite problem that high-theoretical-density chemistries such as Li-Sulfur and Li-Air have. 2. It seems to allow applicable chemistries to charge faster and harder. 3. It seems to offer a more compact and cheaper packaging. 4. It is offered by a reputable national laboratory. We need tests of large-form-factor batteries suitable for BEV ASAFP.

The Gen 1 Volt disappointed me on price, electric-only range, gas-only fuel economy, weight, and interior cabin space. I try to figure out why GM stubbornly sticks to 4-cylinder engines for the generator, and while there may be esoteric torque at optimum RPM curve issues, given all the other ~50Kw gensets, I've got to beleive it's because they want the ICE to matter, to seem complex and valuable, to justify a higher price. I think they've got it backwards. The simpler and leaner the whole drive train is, the more affordable the whole vehicle becomes, and then maybe it will outsell the Leaf or even the Prius if they really hit a grand slam.

In my mind, the long-term energy solution would be one that takes a renewable source of energy and stores it in a very clean, easy to store and transport medium, with minimal conversion losses. My impression is that biofuels and synfuels all have relatively poor "round trip" conversion losses. This fairly reasonable analysis suggests almost 70% of energy content is lost with synfuels today. http://theenergycollective.com/schalk-cloete/459401/seeking-consensus-internalized-costs-synfuels As a result, I keep thinking that cheaper solar power and better, cheaper batteries are the long term answer.

If money was no object, what would be your preferred battery technology?

@ RP 50C gets you more efficient regenerative braking, right? I'd had the impression the current Prius only recovers about 20% of the energy from braking because it just can't absorb that much energy into its battery on a downhill or hard braking. Is that about right?

@SJC, Any idea if Alta Devices (acquired last winter by Hanergy) is going to bring their 30% efficient flexibly thin-film cells to market? They had the thin film efficiency record, probably closer to 25% as part of a module, but apparently hadn't worked out how to scale the assembly line before running out of money. If they can scale, their cost per watt should be considerably lower, with no need for concentrators.

I'll make a judgement on Hydrogen tanks. They leak. H2 molecules are so small that it's very difficult to completely seal them in. What happens over decades if just 2% of all Hydrogen fuel used eventually ends up in the upper atmosphere? Oh, and the word "Hindenberg" comes too readily to people's minds. Mostly, I just don't like the conversion losses with electrolysis, and reforming methane is still releasing greenhouse gases into the atmosphere, so that's a bait-and-switch. Hydrogen is a storage medium, not an energy source, and compared to near future batteries, H2 is probably a disadvantageous path to go down.

I think they're targeting luxury sports car drivers because their fuel cell and capacitors are probably very expensive. @RP, they need a source tank and depleted fuel tank, so 2x200 liters. The volume doesn't have to be crazy...think a 1-meter square, 40 cm tall, plus structure. I don't much like the idea. I'd like it better if they could reprocess their fluid with a completely reversible process. Also, how do the conversion losses compare to lithium batteries? I'm guessing that's also a problem.

I'm curious about the conversion losses into and out of the flywheel. This avoids rare-earth magnets and may be cheaper and lighter as well. Energy recovery provides gretest return on large vehicles that stop frequently (think garbage trucks and buses), but CVT is best suited to lighter vehicles. If this is durable enough it could be good on taxis and light-weight delivery vehicles.