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A New Look at the Hydrogen Economy

Introduction:

The concept of a “hydrogen economy” took a hit in the first years of the new century when hydrogen was touted as the clean transportation fuel of the future. Prolonged failure to deliver on that vision tarnished popular perceptions. The concept didn’t die, but it receded from public attention.

In the past few years, interest has revived. That’s in part because practical fuel cell vehicles may finally have arrived. (I’ve started seeing hydrogen-fueled Toyota Mirais on the roads in the San Francisco Bay area.) But there’s also a lot of interest — notably in Europe — in the use of hydrogen for buffering the irregular energy output of wind and solar PV resources. Hydrogen would be produced by electrolysis when the supply of electricity exceeded demand, and then used to meet demand during shortfalls.

That particular use of hydrogen is controversial, due to the low 40% round-trip efficiency of P2G2P (power to gas to power) when electrolytic H2 is used for energy storage. Advocates don’t dispute the low efficiency, but contend that renewable energy will soon be so cheap that low efficiency won’t matter.

However there’s no avoiding the fact that 2.5 kWh of electricity would need to be generated for every kWh delivered from storage. In a 100% renewable energy economy, a large fraction of energy must be delivered from storage: 50 – 75%, depending on geographical region and on the state of transmission systems and demand side management. That means a rough doubling of the RE capacity that would have to be installed. The average cost of electricity would more than double.

There is an alternative that could be quicker and more economical. That alternative is hydrogen made using the chemical potential energy of fossil fuels, but with no CO2 emissions.

Avoiding CO2 emissions

There are two general ways the chemical energy of fossil fuels can be tapped without emitting CO2 to the atmosphere:

  1. Thermal cracking. H-C bonds are broken, yielding hydrogen and carbon. Solid carbon has commercial value, and is easy to store;
  2. Steam reforming. High temperature steam converts hydrocarbon feedstocks to hydrogen and CO2.

The pure carbon side product makes cracking an attractive alternative — in principle. Quite a lot of R&D has been devoted to improving the energy efficiency and economics of this approach. A recent DOE report provides a good overview. However, almost all of the work seems focused on carbon black as the primary product. Carbon black has significant value as an industrial product, but the market would be quickly saturated if cracking were employed at the level needed to address energy markets. In most cases, that wouldn’t be possible anyway; the overall energy efficiency of most cracking processes is too low. They consume more energy than the resulting hydrogen can supply.

An exception is found in some of the more recent work to crack light hydrocarbons — methane in particular — using molten metals as both a catalyst for the cracking reaction and a medium for separating the resulting carbon and hydrogen. The process is energy efficient, but so far the reactors are too expensive for the modest production rates they’ve been able to demonstrate. Commercial feasibility may yet be realized, but it doesn’t seem immanent. Hence, I’ll set aside further consideration of cracking and focus on reforming.

Steam reforming of hydrocarbons to yield hydrogen and CO2 is well established. It’s widely used to produce hydrogen on an industrial scale for oil refinery and fertilizer plant operations. But as the foundation for a prospective hydrogen economy it has two drawbacks. One is that, for economic efficiency, current processes need the economies of scale that come only with large chemical plants. They’d work in an all-out national program to implement a hydrogen economy, but are complex and not practical for small seed projects in local communities.

The second drawback is that steam reforming produces CO2. It thus depends on some form of CCS or CCU to avoid releasing CO2 to the atmosphere. The “carbon capture” part or CCS / CCU is no problem; the SMR process can be — and often is — engineered to deliver a nearly pure CO2 side stream. Nor would the “storage” part of CCS be a technical problem; there are proven methods. However it would face political hurdles. Greenpeace and some influential “climate hawks” are firmly against it.

CCU (“U” for “utilization”) has the inverse problem. There are no political hurdles; everybody likes the concept. But all of the uses implemented or proposed to date are limited. They’re niche applications that couldn’t begin to handle the amount of CO2 that large scale H2 production by reforming would create.

Before we can adopt national energy policies supporting CCS, Greenpeace and like minded organizations must be willing to relax their opposition. They’ll need to drop their insistence on “keep it in the ground” as the only acceptable policy for slashing carbon emissions. If they do so, they can — in my opinion — expect to see adoption of robust pricing on carbon emissions, an end to industry-sponsored campaigns to undermine climate science, and much more rapid progress overall toward an emissions-free energy economy.

Those will strike some as wild assertions. I’ll explain shortly below why I think they’re justified, but first I need to say something about recent technical developments. They have a lot to do with my optimism.

Better approach to steam reforming?

A promising new approach to steam reforming might soon be commercially available. It’s being advanced by CoorsTek, a high tech ceramic materials company with an interesting history.

Research sponsored by CoorsTek has led to the development of a new type of hydrogen permeable ceramic membrane. Although hydrogen permeable ceramic membranes are nothing new, this one is different. Other membranes with selective permeability to hydrogen have been passive. They rely on diffusion of hydrogen across the membrane from a region of higher H2 partial pressure to a region of lower partial pressure. This one is active. It uses an applied electric potential to actively transport hydrogen across the membrane. That enables it to scavenge hydrogen present in a reaction chamber at low concentration and compress it for delivery as a pressurized H2 output stream.

The beauty of that is something that perhaps only a physical chemist can appreciate. I’ll try to explain anyway. It has to do with the thermodynamics of equilibrium reactions. Readers with no interest in chemistry may skip ahead. In the next section, I’ll take up the practical implications.

Equilibrium reactions

In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time. That’s quoted from Wikipedia. It’s a fair definition for chemical equilibrium, but doesn’t capture what is meant by an “equilibrium reaction”. The term refers to a reaction that takes place at or near equilibrium conditions. When equilibrium is approached, the concentrations of reactants and products approach stability, but not because the reactions themselves actually stop. Rather, reactions and their corresponding counter reactions balance. The distinction between reactants and products blurs, as the reactants for one reaction are the products of the counterreaction.

If the concentration of one of the species in a chemical equilibrium is disturbed — say by adding more of that reactant species from an external source — the rate of reactions that consume that species increases. It continues until a new equilibrium is achieved. Conversely, if one of the species is systematically withdrawn, the rate of reactions consuming that species slows. The reactions that produce it will continue at the same rate, with the net result being an excess of production over consumption. The surplus production of the species in question offsets what was withdrawn.

That’s just what happens in the case of withdrawal of hydrogen from a reaction chamber — or tube, more likely — fed with high temperature steam and methane. At the high temperature in the tube, the steam partially dissociates into oxygen and hydrogen. As the initial mix of steam and methane entering the tube flows, dissociated hydrogen is steadily withdrawn through the membrane running the length of the tube. That leaves oxygen to react with the other gases in the tube.

The flowing mix becomes increasingly depleted in methane, enriched in CO2. Carbon monoxide (CO) is also generated, but the concentration never gets high. The CO gets oxidized to CO2. At the end of the tube, what exits is a stream of nearly pure CO2 and steam, with only traces of CO, hydrogen, and methane. The steam is easily condensed and the CO2 can be compressed to a liquid. Any residual hydrogen, methane, and CO are then recirculated.

A key point is that for this type of progressive quasi-equilibrium reaction process, there is very little increase in system entropy and loss of exergy. Being endothermic, the overall reforming reaction:

CH4 + 2H2O + heat ⇒ CO2 + 4H2

requires an input of thermal energy to drive it. That thermal energy converts to increased potential energy in the produced hydrogen over and above that of the input CH4. Thus, the electrical energy expended to pump hydrogen across the membrane does not end up as waste heat; it supplies the high temperature thermal energy needed for the endothermic reaction.

To quantify, one mole of CH4 (methane) has a combustion energy of 890 kilojoules (kJ); four moles of H2 yield 1,144 kJ. The difference, 254 kJ, is what must be supplied to drive the reaction.

Another point worth noting is that the electrical energy supplied to the membrane also serves to maintain a low concentration of hydrogen within the reaction gases. That speeds reforming and eliminates the need for the complex multi-stage reaction process that conventional SMR requires. So the electricity serves triple duty — thermal energy, H2 separation, and acceleration of the reforming reaction. That triple duty contributes to the low capital cost and to the energy and economic efficiencies that the process promises for even small implementations.

Practical implications

In terms of hydrogen out to electricity in, the new process is about six times more productive than conventional electrolysis. If the hydrogen produced is subsequently converted to electricity in a fuel cell or a combined cycle gas turbine, it will give roughly four times more electricity out than was consumed in making it — an effective 400% return on electrical energy invested. Compare that to the 40% return for the P2G2P scheme often proposed for long term storage of renewable energy. Leveraging the chemical potential energy in methane makes the process literally ten times more productive.

The process should also be quite productive in terms of capital. Its simplicity means that the equipment should be cheap enough for economical operation at low capacity factors. It could be run from cheap surplus power on an as-available basis. Moreover, the process can be throttled over a wide range under real time control to provide regulation service to the grid. It would thus make an ideal discretionary load.

As a consequence of these factors, a hydrogen-fueled power system using these reformers could operate equally from H2 made using cheap surplus power and stored temporarily, or from natural gas reformed in real time to meet demand. The latter requires a portion of generated power to be diverted back to the reformer; it’s less desirable than using stored H2 made from surplus power, but it’s only needed when H2 stores have been depleted by an extended period of sub-normal power production from other sources. The fallback option means H2 stores could be optimized for typical rather than worst cases. Dunkelflaute weather or seasonal variability would not be problems.

Speculation

Of course, all this is speculative. To date, the new reforming process has been demonstrated only in the lab and in small prototype. But CoorsTek appears to have big hopes for it. They project its use in private refueling stations for hydrogen vehicles in homes supplied with natural gas. That may sound radical, given the internal 800 ℃ operating temperature and the safety concerns surrounding hydrogen in general. But the reformer would be stationary and well insulated, while small hydrogen tanks can be isolated below ground. So it could work.

Regardless of whether this advanced SMR takes off at the home level, there is little doubt that it would be practical at a neighborhood level. It would provide an ideal backup supply for local microgrids. Hydrogen fuel cells of the type developed for the auto industry have been projected by DOE to cost $53 per net kilowatt in mass production. That’s incredibly cheap; $1000 per kilowatt is usually the low end of capital cost for the least expensive class of commercial power plants.

The $53 figure is admittedly a projection for production levels that have not yet been reached. But current costs can’t be very much more than that. The fuel cell system in the Toyota Mirai is spec’d at 113 kW, and Toyota is selling or leasing a few thousand cars per month at a pre-subsidy price point of roughly $60,000. Even if the fuel cell system were to account for as much as 25% of the vehicle’s MSRP, it couldn’t be costing Toyota more than $130 per kW.

The low specific capital cost of these hydrogen fuel cells means that it wouldn’t be a problem to maintain a large reserve capacity idled much of the time. The ramp rate of automotive style fuel cells is better than the most responsive type of gas turbine power plants. They’re not as fast as batteries, but are in the same class. Hence they can easily be paired with variable renewables or with baseload generation to follow the load curve.

Use of hydrogen in neighborhood micro-grids would be self-contained. Making H2 by advanced SMR avoids the need for hydrogen pipelines. Other gas users need not switch from natural gas to hydrogen. The waste heat from producing power could be used to supply district hot water and boost overall energy efficiency. A nice perk is that the process is insensitive to the specific hydrocarbon being reformed.

Operating from natural gas might be the normal mode, but the process should work equally well for bottled propane or natural gas liquids, or from tanks of methanol, ethanol, or even gasoline. The only proviso is that the fuel be free of sulfur or halides that might degrade the membrane. Hence the system could operate from local stored fuel reserves if cut off from its NG supply.

That just leaves the question of how to dispose of the CO2 from the reformers.

Disposition of CO2

Different solutions for disposition of CO2 from the reformers are available depending on the scale of operations. The first couple aim to minimize the capital expenditure for demonstration projects:

  • For small neighborhood demonstration projects, CO2 from the reformer could simply be pumped into pressure bottles and sold into the merchant gas market. Small delivery trucks would visit the reforming station nightly, pick up a load of filled bottles, and leave off a load of empties.
  • For somewhat larger district level demonstration projects, CO2 from the reformers could still be handled by pumping into pressure bottles, but the bottles would need to be of the larger type permanently mounted on semi trailers.
  • For deployment at the level of small cities or suburban counties, the merchant gas market is inadequate to accommodate the amount of CO2 that would be created. In states with oilfields, the EOR market should be large enough. Oil prices permitting, the CO2 price operators would be willing to pay could be sufficient to fund collection and distribution even without credits from carbon pricing. But to keep operational costs low, it might be necessary to build pipeline links from CO2 collection centers to the oilfields.

For large scale H2 deployment or in states with no oil fields, even the EOR market would be inadequate for the amounts of CO2 created. Long term geological storage in depleted oil and gas fields or in deep saline aquifers would be needed. An extensive network of pipelines for delivery of CO2 to injection wells would have to be built, with a robust price on carbon emissions to pay for construction and operation.

The good news is that with hydrogen from reformed fossil fuels used only to provide flexible backing power for renewables or peaking supply for base load generation, the amount of CO2 created would be an order of magnitude less than it would be for handling CO2 from the current fleet of coal-fired power plants.

The political landscape

I said earlier I feel that if Greenpeace and like-minded environmental organizations were to drop their insistence on “keep it in the ground” as the only acceptable way to cut carbon emissions, robust pricing on carbon emissions would be adopted fairly quickly, and the net rate of CO2 emission reductions accelerated. What aspects of the political scene support that conclusion?

I believe that much of the popular opposition to CCS stems from its usual association with the concept of “clean coal”. The surface mining methods employed to minimize the cost of coal are devastating to the environment; there’s good reason to oppose coal apart from CO2 emissions. But at least within the US, coal is losing out to natural gas for economic reasons, even without pricing carbon emissions. Its competitive position would be weakened, not helped, by carbon emissions pricing with credits for carbon sequestration.

CO2 emissions per MWh of electricity from coal are double what they are from natural gas to start with, and post-combustion carbon capture adds far more to the energy and financial cost of coal than reforming adds to natural gas.

“Keep it in the ground” is a rationale for opposition to CCS, but it’s counterproductive for ending coal use while being a loaded gun aimed at other parts of the fossil fuel industry. It threatens the economies of oil exporting nations. The oil and gas leases that would have to be abandoned and the reserves that would have to be left in the ground have present values measuring in the tens of trillions of dollars. No wonder we see well-funded think tanks that challenge climate science and project dire consequences for the economy from carbon pricing. Given what’s at stake and their financial firepower, is it any surprise that fossil fuel interests have been able to defeat policies that threaten them?

Some 3500 years ago, the legendary Chinese military strategist Sun Tsu, in his treatise on “The Art of War”, wrote that one should always leave one’s enemy an avenue of retreat. Not out of benign concern for the enemy’s welfare; it was simply that cornered enemies fighting for their lives and fortunes fight very hard. It may still be possible to defeat them, but it will be costly. In general, the less an enemy stands to lose, the easier the victory over them.

CCS is an avenue of retreat for non-coal fossil fuel interests. It removes the gun to their heads that “leave it in the ground” represents, and offers a prospect of profitable redirection of business. They are, after all, uniquely positioned with the skills and equipment that large scale CCS would employ. But a robust price on carbon emissions, coupled with a corresponding credit for sequestration, is absolutely essential to enable that redirection.

Opponents of CCS need to figure out whether they are more interested in slaying enemies or in achieving their war’s core objectives. I know what Sun Tsu would advise.

Roger Arnold's picture

Thank Roger for the Post!

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Discussions

Roger Arnold's picture
Roger Arnold on April 9, 2018

Somewhat relevant: I just posted a comment to Schalk Cloete’s article on BEVs. I suggested the idea of autonomous rolling recharge trailers, fueled by H2, for extending the range of BEVs.

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

Congratulations.  You just re-invented AC Propulsion’s charger-trailer, circa 1998.

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

I am reminded of the “four miracles” required for the hydrogen economy:

1.  Generating it.
2.  Shipping it.
3.  Storing it.
4.  Utilizing it.

The cost of HFCs is down far enough to consider #4 pretty much solved, but #3 is still a major issue and #2 is such an extreme headache that HFC vehicles are limited to driving in small “islands” around the handful of places offering fuel.

Generating H2 from NG or coal, with or without emissions, can solve #1 but leaves #2 and #3 festering.  The New England cold snap severely over-taxed natural gas pipeline capacity and ran backup fuel oil supplies down almost to minimum operating levels.  Storing H2 is vastly more difficult and expensive than oil, and maintaining a large overcapacity in the production system is costly also; in an H2 economy, what is going to provide that essential stockpile of energy which keeps people from freezing in the dark?

My take on this is that it hydrogen is the fuel of the future, and always will be.  We’ll see methanol and dimethyl ether instead, and maybe ammonia.

Bob Meinetz's picture
Bob Meinetz on April 10, 2018

Roger, not sure what you see in hydrogen to recommend it as a transportation fuel. Its energy density is awful. Storage? Problematic, and you haven’t even broached the costs, both energy and financial, of transferring it in pressurized, refrigerated tankers to where it can be sold to consumers.

Using hydrogen to power cars was a whimsical fantasy until 1997, when oil producers recognized in GM’s EV1 the potential of electric vehicles. In 1999, after envisioning their 50,000 U.S. service stations sold for pennies on the dollar to be repurposed as tomorrow’s convenience stores, Shell, Chevron, and BP in joined together to form the California Fuel Cell Partnership. They pumped $millions into the goofy idea liquid hydrogen might make a practical fuel to replace gasoline, asking consumers to accept the simpleminded logic that water coming from their exhaust pipes would be its only environmental impact.

To this day – though most casual observers do accept it, you know better. So what about hydrogen is worth going through your Rube-Goldbergian machinations to try to revive it from life-support? With Gibbs free energy there’s no free lunch, and the well-to-wheels carbon and financial footprints of any possible hydrogen pathway, including the ones you outline above, are abysmal.

Lately I’m finding I have more in common with Sierra Club and Greenpeace than I thought: fossil fuel carbon is the start and end of our climate problem, and we’ll solve it only when we accept there are no shortcuts. Leave it in the ground.

Roger Arnold's picture
Roger Arnold on April 10, 2018

Doesn’t producing hydrogen locally from fossil fuels dispose of your second point? Natural gas is already widely distributed. Even in the absence of an NG pipeline connection, LPG is easy to ship. Reforming from that — or from methanol or DME — is no different with this process than reforming from NG.

For that matter, active membrane reforming should be compact and cheap enough that an HFCEV could carry an on-board reformer and be fueled with methanol. Or any other light, sulfur-free hydrocarbon that happened to be available.

Unless the high temperature core were deemed an unacceptable hazard in a crash. It might need to be armored and kept isolated from spilled liquid fuel.

Roger Arnold's picture
Roger Arnold on April 10, 2018

you haven’t even broached the costs .. of transferring it in pressurized, refrigerated tankers to where it can be sold to consumers

But that’s the point; by producing it at the refueling station, the only transfer is from the station’s small holding tank to the vehicle. Because the power consumed for producing it is only a sixth that required for electrolysis, the refueling station doesn’t require megawatt level electrical service.

Using hydrogen to power cars was a whimsical fantasy until 1997, when oil producers recognized in GM’s EV1 the potential of electric vehicles.

Yeah, I thought so too until last year. When I saw the announcements of various HFCEVs going into production, I was surprised and a bit skeptical. But then I saw them turning up on the roads here, and looked up the sales figures. This is not just some greenwash PR campaign by Toyota, Honda, and Hyundai. They’re serious.

But forget about FCEVs. They may or may not succeed, but that’s not what I was writing about. I was writing about dispatchable power generation that would be cheap enough (capital cost) to operate at low duty cycles and wouldn’t release CO2 to the atmosphere. I’m interested in any comments you might have about that.

Roger Arnold's picture
Roger Arnold on April 10, 2018

So what about hydrogen is worth going through your Rube-Goldbergian machinations to try to revive it from life-support?

The carbon capture is free, that’s what. And far from being “Rube-Goldbergian” and inefficient, the new reforming process appears to be elegantly simple and ultra-efficient. The electricity input makes the chemical potential energy in the produced hydrogen 25% higher than the energy in the natural gas input. Plus, that chemical potential energy can be converted to electricity on demand at 60% efficiency — comparable to a CCGT. And the conversion is accomplished using HFCs that appear to be about 5% of the cost of CCGTs. For the cherry on top, HFCs are also far more flexible than CCGTs. They support much faster ramp rates and have infinite throttling range.

Bob Meinetz's picture
Bob Meinetz on April 10, 2018

Roger, every analysis I’ve seen put FCVs (forgive me for not buying into the greenwashed “FCEV” acronym) at slightly-lower CO2e emissions than contemporary hybrids, and after the half-$trillion financial and energy investment in infrastructure, well over gasoline. And because hydrogen can’t be poured into a tank like Perrier, I’m adding in the carbon footprint of obligatory pressurization to 10,000 psi, refrigeration to 20K, or a little of both – otherwise, a full tank in your FCV might take you 240 ft, much less 240 miles.

SMR process can be — and often is — engineered to deliver a nearly pure CO2 side stream. Nor would the “storage” part of CCS be a technical problem; there are proven methods.

You’re overlooking a critical component of SMR, and that is the “S” – steam. Because SMR requires thermal input, are we using coal, natural gas, or oil to boil our water? If the mainstream CO2 emissions are captured, how?

Grid battery storage is not a technical problem, either, but both it and CCS remain wildly impractical, with CCS entirely geography-dependent and impossible to verify. About a year ago, I had an email exchange with a rep at the California Fuel Cell Partnership on this very topic. After I confronted him on it, and his claim Shell and Chevron haven’t been part of CFCP for almost a decade (a lie), he must have misplaced my email address – I never heard back.

From both an economic and environmental standpoint, hydrogen-powered transportation and electricity are non-starters – we’d be better off sticking with gasoline and coal.

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

To put it bluntly, despite the abundance of natural gas it is still not sufficiently available to even beat electricity for highway driving.

Doesn’t producing hydrogen locally from fossil fuels dispose of your second point? Natural gas is already widely distributed.

Given the inability of a Honda Civic GX to drive coast-to-coast along I-90 (and probably a lot more routes, I haven’t looked recently), that distribution is way short of wide enough to do the job.  Note that you CAN drive a Tesla along that route.  If your goal is to sequester the CO2 you also have to have disposals nearby all the major production points.

active membrane reforming should be compact and cheap enough that an HFCEV could carry an on-board reformer and be fueled with methanol.

What does it do with its CO2?  If it doesn’t carry that massive quantity for disposal, the vehicle is no better than a direct-methanol FCV dumping to the atmosphere.  Probably worse because of the extra step wasting energy.

At some point you are better off burning a fuel in something like an Allam-cycle plant exhausting to a CO2 dump to charge your PHEV, and burning very low-carbon fuels in the combustion engine of the PHEV.  If most or all of that fuel is renewable, good; if it’s all renewable and some of it goes to feed the Allam-cycle generating plants, it can be carbon-negative.

Or any other light, sulfur-free hydrocarbon that happened to be available.

The least-effort path looks to be light, sulfur-free alcohols because they embody the most energy per atom of carbon of liquids at STP.  Methanol tops that list at 726 kJ/mol carbon; EtOH is considerably lower at 650 kJ/mol C.  Ammonia is carbon-free but not liquid at STP.

Roger Arnold's picture
Roger Arnold on April 12, 2018

despite the abundance of natural gas it is still not sufficiently available to even beat electricity for highway driving.

The abundance of natural gas is an interesting issue. By some reckonings, methane is the world’s most abundant fossil fuel. But I think that counts methane clathrates, not currently exploitable reserves. There are others who believe that the North American gas boom is a Ponzi phenomenon that will soon go bust. NG wouldn’t run out within this century, but prices could quadruple. That would cause electricity prices to double or triple, and potentially reverse the decline of coal and nuclear. I’m not taking any position about that.

I don’t know if that’s the issue you’re talking about. It doesn’t have a lot to do with the economic competitiveness of hydrogen vs.batteries, since electricity prices will tend to follow NG prices. It has almost nothing to do with their relative carbon emissions. Hydrogen is zero — assuming that it’s made by reforming fossil fuels, and that the reforming process is coupled with CCS. Equivalent emissions for batteries depends on the mix of sources.

If you’re referring instead to the immediate availability of NG at locations where one would want to have refueling stations, that’s pretty much a non-issue for hydrogen. If there’s no gas pipeline nearby to tap into, then truck in methanol or LPG. Active membrane reformers won’t notice the difference.

If your goal is to sequester the CO2 you also have to have disposals nearby all the major production points.

Not a goal, I’d say, but a requirement. That’s why I’m not advocating for a hydrogen-fueled transportation system as a near term priority. The use I’m advocating is for low duty cycle dispatchable power and discretionary loads for demand side regulation. That application is an order of magnitude smaller — at least initially — than transportation. It avoids the chicken-and-egg problem of widespread availability before the market can be viable. At the same time, once the feasibility of reforming coupled with CCS is well proven, widespread availability for transportation becomes a relatively easy leap to make.

Bas Gresnigt's picture
Bas Gresnigt on April 12, 2018

Interesting. A few remarks.

… large fraction of energy must be delivered from storage: 50 – 75%, depending on geographical region…

For Germany that fraction is in the range of 10%-25%. Considering further that:

– storage occurs when electricity prices are extremely low (when the wind blows & the sun shines);
– biomass, etc. plants which were paid as base load will gradually act more as peakers due to their gradually changing reward structure (only subsidy for amounts produced when the electricity price is high, check their new EEG2017);
– the flexible loads such as alu smelters that run only when the price is low;

the higher price of electricity from stored energy (battery, H2, pumped storage, etc) will have only a small influence (<10%) on the average electricity price in an 100% renewable situation.
Btw The Germans have major PtG developments.

… these reformers could operate … from natural gas reformed … only needed when H2 stores have been depleted …

Little chance that the large cheap gas stores in deep earth cavities (in Germany now ~30% of annual electricity production) become depleted. Especially since it’s cheap to use more of those cavities. But it will be an interesting nice application.

Keep it in the ground
Its chances increase greatly when something useful can be done with the CO2.
Storing CO2 in the ground may be nice, but too many people reason that what is stored will come out some day.

They will be remembered to the final nuclear waste store in stable salt at Asse2, 600meter below the surface. It’s leaking since a few decades, making the mine galleries inaccessible for humans. The leaked radio-activity is predicted to reach the surface in a few thousand years making the fertile area unsuitable for agriculture or worse…
And CO2 is a lot more agile than nuclear waste…

Engineer- Poet's picture
Engineer- Poet on April 12, 2018

It’s not the resource, it’s the (lack of) distribution.  If you go to the CNG Now station map you’ll find there is NOTHING on either the I-90 or I-94 corridors between Seattle on the west and Fergus Falls ND/Fairmont SD on the east.  Maybe a Civic GX could make it along I-80, I’d have to check.  Until this problem is fixed, CNG vehicles are close to useless except for local travel.

Petroleum and LPG can be carried by tanker trucks, so they’re available pretty much everywhere.  NG has to travel by pipeline, which requires a separate right-of-way and a considerable amount of revenue to make it pay.  Why the absence of CNG stations over the Bakken shale?  Obviously, the business isn’t there.  Electricity is ubiquitous even where NG is unavailable, so Teslas can boldly go where GX’s literally run out of gas.

Bas Gresnigt's picture
Bas Gresnigt on April 15, 2018

Your 4 miracles are gradually happening here in NW-EU.

1. Generating. The Germans have major PtG(H2) pilot developments. They want to start with regular roll out in 2024.*)
They also pilot unmanned PtG plants at petrol stations, e.g. Berlin, Hamburg, Stuttgart.

This page shows the direction of developments; a series produced standard sea-container which contains the PtG installation together with H2 storage. So those can easily be added to existing petrol stations (assuming the presence of water and a good electricity connection). The waste heat can be used to warm the station and associated restaurant.

Investment estimations for series produced unmanned PtG plants run at ~€500/KWh.

2. Shipping is a non-issue as it can easily be generated where needed as demonstrated by the info in previous links.
Local H2 production via PtG is becoming competitive in areas with a lot of wind+solar due to the frequent very low power prices. Last year a chemical firm in Hamburg opened an 8MW PtG(H2) plant. Until then its supplier used natural gas to produce H2.

3. Storing. Mass storage to bridge seasonal wind+solar dips (during winter) is a non issue as it can be injected in the natural gas piping and storage system.**)
Local storage is in or near the PtG(H2) plant as also indicated above.

4. Utilizing .
In addition to chemical plants and projects partially driven by idealistic motives (e.g. the buses of Hamburg), competitive H2 driven cars are needed. H2 cars have the benefit of longer range and much faster refill.

The long range, such as the new Hyundai Nexo (up to 500miles), partly overcomes the sparse distribution of H2 refill stations.
In NL govt set the target to have 20 H2 refill stations running in 2020, assuming other countries do the same, the refill problems will be solved. I checked and found that I can now already easily drive into the alps with an H2 car…

With mass production H2 cars should become cheaper than petrol cars as they are less complex (less moving parts, no extreme high temperatures which create wear, etc).
A more serious issue is the price of H2 which should be lower as H2 produced from renewable has a much lower climate footprint and the cars don’t emit NOx’s and CO2.
__________
*) Considering that 25% of their electricity production is now by wind+solar, their planned expansion rate of wind+solar, the flexibility of their load and fossil plants, they won’t need it until ~2030 when renewable share will be ~70% (wind+solar ~60%).

**) H2 injection up to 5% without upgrade of the natural gas piping system. German natural gas consumption is ~1000TWh/a. The storage capacity of ~200TWh (in deep earth cavities) is easily expandable. Electricity consumption 600TWh/a.
So present situation allows for 50TW/a H2 production to be injected + the H2 consumption. It implies that there is enough capacity available until at least 2040.

Engineer- Poet's picture
Engineer- Poet on April 16, 2018

The amazing thing about the Green/Energiewende narrative is how immune its believers are to factual criticism.  They’re always claiming energy will be cheap, even as the costs from their woefully-inadequate efforts thus far continue to escalate.  Take the 2018 price structure of electricity.  The VAT, renewables surcharge and electricity tax alone total €0.1354/kWh.  Given that it takes about 46 kWh to generate 1 kg of H2 in a pretty good modern electrolyzer, the energy input alone costs around €6.23/kg just for taxes and fees.  This is double the retail price of gasoline in the USA per unit energy.  As it takes 8.69 kg of H2 to deliver 1 million BTU of energy, this comes to $54 per million BTU.  This is roughly 7-8 times the delivered residential price of natural gas in the USA and multiples of the delivered price of LNG to Europe.

Road taxes would roughly double that again.  Perhaps it’s affordable for FCEVs, but if people were forced to use it for heating and cooking all but the rich would be reduced to eating raw food in freezing-cold houses.  It’s certainly not cheaper than what we have today.

This page shows the direction of developments; a series produced standard sea-container which contains the PtG installation together with H2 storage.

How much storage, Bas?  A day?  750 kg would fill about 150 FCEVs.  750 kg of H2 gas is a lot of volume.  That station is going to have to have electricity delivered pretty much on a just-in-time basis, whereas the system as a whole requires energy storage on the scale of seasons, not hours.

This means that the PtG fueling station would have to be powered by electricity that is itself produced remotely from H2 made from last windy/sunny season’s electricity.  The round-trip efficiency of PtGtP is about 40%, so the net efficiency of 2 rounds of this (plus transmission losses of 6.5%) comes to about 15%.  At an initial energy cost of €0.1354/kWh just for taxes and fees, the end-use cost would come to a whopping €0.905/kWh without considering O&M, amortization or anything else.

The waste heat can be used to warm the station and associated restaurant.

It’s much more expensive to store heat than hydrogen.  If that heat isn’t being produced right when you need it, it will go to waste.

3. Storing. Mass storage to bridge seasonal wind+solar dips (during winter) is a non issue as it can be injected in the natural gas piping and storage system.

5% H2 by volume in methane is about 1.7% by energy.  Anyone who thinks this is a solution to anything is either innumerate or crazy, and of course the people who tout it as a solution while knowing it isn’t are frauds.

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