Aluminium, salt water and coffee produces ..... hydrogen?????

From Science Daily

MIT engineers have found that when the aluminum in soda cans is exposed in its pure form and mixed with seawater, the solution bubbles up and naturally produces hydrogen -- a gas that can be subsequently used to power an engine or fuel cell without generating carbon emissions. What's more, this simple reaction can be sped up by adding a common stimulant: caffeine.

In a study appearing today in the journal Cell Reports Physical Science, the researchers show they can produce hydrogen gas by dropping pretreated, pebble-sized aluminum pellets into a beaker of filtered seawater. The aluminum is pretreated with a rare-metal alloy that effectively scrubs aluminum into a pure form that can react with seawater to generate hydrogen. The salt ions in the seawater can in turn attract and recover the alloy, which can be reused to generate more hydrogen, in a sustainable cycle.

The team found that this reaction between aluminum and seawater successfully produces hydrogen gas, though slowly. On a lark, they tossed into the mix some coffee grounds and found, to their surprise, that the reaction picked up its pace.

In the end, the team discovered that a low concentration of imidazole -- an active ingredient in caffeine -- is enough to significantly speed up the reaction, producing the same amount of hydrogen in just five minutes, compared to two hours without the added stimulant.

The researchers are developing a small reactor that could run on a marine vessel or underwater vehicle. The vessel would hold a supply of aluminum pellets (recycled from old soda cans and other aluminum products), along with a small amount of gallium-indium and caffeine. These ingredients could be periodically funneled into the reactor, along with some of the surrounding seawater, to produce hydrogen on demand. The hydrogen could then fuel an onboard engine to drive a motor or generate electricity to power the ship.

"This is very interesting for maritime applications like boats or underwater vehicles because you wouldn't have to carry around seawater -- it's readily available," says study lead author Aly Kombargi, a PhD student in MIT's Department of Mechanical Engineering. "We also don't have to carry a tank of hydrogen. Instead, we would transport aluminum as the 'fuel,' and just add water to produce the hydrogen that we need."

The study's co-authors include Enoch Ellis, an undergraduate in chemical engineering; Peter Godart PhD '21, who has founded a company to recycle aluminum as a source of hydrogen fuel; and Douglas Hart, MIT professor of mechanical engineering.

The MIT team, led by Hart, is developing efficient and sustainable methods to produce hydrogen gas, which is seen as a "green" energy source that could power engines and fuel cells without generating climate-warming emissions.

One drawback to fueling vehicles with hydrogen is that some designs would require the gas to be carried onboard like traditional gasoline in a tank -- a risky setup, given hydrogen's volatile potential. Hart and his team have instead looked for ways to power vehicles with hydrogen without having to constantly transport the gas itself.

They found a possible workaround in aluminum -- a naturally abundant and stable material that, when in contact with water, undergoes a straightforward chemical reaction that generates hydrogen and heat.

The reaction, however, comes with a sort of Catch-22: While aluminum can generate hydrogen when it mixes with water, it can only do so in a pure, exposed state. The instant aluminum meets with oxygen, such as in air, the surface immediately forms a thin, shield-like layer of oxide that prevents further reactions. This barrier is the reason hydrogen doesn't immediately bubble up when you drop a soda can in water.

In previous work, using fresh water, the team found they could pierce aluminum's shield and keep the reaction with water going by pretreating the aluminum with a small amount of rare metal alloy made from a specific concentration of gallium and indium. The alloy serves as an "activator," scrubbing away any oxide buildup and creating a pure aluminum surface that is free to react with water. When they ran the reaction in fresh, de-ionized water, they found that one pretreated pellet of aluminum produced 400 milliliters of hydrogen in just five minutes. They estimate that just 1 gram of pellets would generate 1.3 liters of hydrogen in the same amount of time.

But to further scale up the system would require a significant supply of gallium indium, which is relatively expensive and rare.

"For this idea to be cost-effective and sustainable, we had to work on recovering this alloy postreaction," Kombargi says.

In the team's new work, they found they could retrieve and reuse gallium indium using a solution of ions. The ions -- atoms or molecules with an electrical charge -- protect the metal alloy from reacting with water and help it to precipitate into a form that can be scooped out and reused.

"Lucky for us, seawater is an ionic solution that is very cheap and available," says Kombargi, who tested the idea with seawater from a nearby beach. "I literally went to Revere Beach with a friend and we grabbed our bottles and filled them, and then I just filtered out algae and sand, added aluminum to it, and it worked with the same consistent results."

He found that hydrogen indeed bubbled up when he added aluminum to a beaker of filtered seawater. And he was able to scoop out the gallium indium afterward. But the reaction happened much more slowly than it did in fresh water. It turns out that the ions in seawater act to shield gallium indium, such that it can coalesce and be recovered after the reaction. But the ions have a similar effect on aluminum, building up a barrier that slows its reaction with water.

As they looked for ways to speed up the reaction in seawater, the researchers tried out various and unconventional ingredients.

"We were just playing around with things in the kitchen, and found that when we added coffee grounds into seawater and dropped aluminum pellets in, the reaction was quite fast compared to just seawater," Kombargi says.

To see what might explain the speedup, the team reached out to colleagues in MIT's chemistry department, who suggested they try imidazole -- an active ingredient in caffeine, which happens to have a molecular structure that can pierce through aluminum (allowing the material to continue reacting with water), while leaving gallium indium's ionic shield intact.

"That was our big win," Kombargi says. "We had everything we wanted: recovering the gallium indium, plus the fast and efficient reaction."

The researchers believe they have the essential ingredients to run a sustainable hydrogen reactor. They plan to test it first in marine and underwater vehicles. They've calculated that such a reactor, holding about 40 pounds of aluminum pellets, could power a small underwater glider for about 30 days by pumping in surrounding seawater and generating hydrogen to power a motor.

"We're showing a new way to produce hydrogen fuel, without carrying hydrogen but carrying aluminum as the 'fuel,'" Kombargi says. "The next part is to figure out how to use this for trucks, trains, and maybe airplanes. Perhaps, instead of having to carry water as well, we could extract water from the ambient humidity to produce hydrogen. That's down the line."

All very nice.  But the key question is this:  how much energy does it take to make the aluminium pebbles compared to what is released when the hydrogen in burned or used in a fuel cell?  In other words, what is its "round-trip efficiency"?  Producing hydrogen via electrolysis has a round-trip efficiency of 40%.  Lithium-ion batteries have a round-trip efficiency of 90% or higher.  Using old coke cans (where the aluminium has already been made) may mean it's better than 40%, in which case it's a goer.  

The article doesn't say what happens to the oxygen presumably produced as part of this price.  I'm presuming it combines with the aluminium?  If not, hydrogen and oxygen is a very explosive mix.

Iron and steel without fossil fuels

In electricity generation, renewables are these days much cheaper than coal, and heading towards parity with gas.  For example, in 2009 Lazard calculated that new solar cost 3.2 times new coal.  Now, that ratio is reversed.  New coal costs 3 times new solar.  Battery costs are plunging, by 15 to 20% per annum, which means it's getting cheaper and cheaper to "firm" renewables, so that large percentages of renewables can be introduced to the grid without affecting its stability.

At the same time, the falling cost of batteries mean that electric vehicles (EVs) will soon (2022-2024) reach sticker price parity with petrol/diesel cars.   By 2030, it will be technically and economically feasible to have 80 or 90% green electricity and a 50% (or more) electric vehicle fleet.  The Republicans and their oil-soaked billionaire friends will do their best to stop this trend, but it will be irresistible to most of the world.  Why use something that's filthy and polluting and kills millions globally when the alternatives are cheaper, cleaner, and carbon free?

But that still leaves the remaining sectors which produce CO₂, like iron and steel, cement, air travel and agriculture.

Of these, the iron and steel sector is making all the right moves (though it still has a long way to go)

First, steel made using green hydrogen (from en-former):

The EU is taking climate protection very seriously. Both increasingly stricter environment and climate protection regulations and rising costs through emissions trading are turning up the heat for the industry. By 2030, greenhouse gas emissions in the European Union are to be reduced by at least 40 percent compared the corresponding levels from 1990. By 2050, they are to be cut by as much as 80 to 95 percent.

This affects the steel industry in particular, given that it is considered to be one of the main industrial sources of the climate-damaging gas carbon dioxide. As a result, European steel producing companies are trying to fundamentally change their manufacturing processes through a number of pilot projects and test facilities in order to reduce these unwanted emissions.

The joint endeavours of a project of three Swedish companies, the steel group SSAB, the mining group LKAB and the energy group Vattenfall, are already coming along swimmingly. ‘Hybrit’, short for ‘Hydrogen Breakthrough Ironmaking Technology’, is set to produce zero carbon steel from 2020 onwards. At a plant in Luleå in northern Sweden, the conventional production method is being given a dramatic facelift.

The production of pig iron, which is later made into crude steel, uses iron ore as a basic material together with what is referred to as a reducing agent, which removes oxygen from the iron ore. Traditional pig iron manufacturing processes usually use coke as a reducing agent. However, in doing so carbon and oxygen produce the climate-damaging gas carbon dioxide.

The new production process uses hydrogen instead of coke, which also reacts with the oxygen in the iron ore, but the result is water vapour rather than carbon dioxide. The hydrogen itself is produced climate-neutrally with electricity from renewables. As such, the process could ultimately produce genuinely ‘green steel’.

Initially, Hybrit will only produce a comparatively modest amount of one metric ton of steel per hour. Moving forward, however, production is to be expanded to churn out the usual industrial quantities of around 100 to 200 times this figure. According to the feasibility study, the associated costs are currently still 20 to 30 percent higher than those of the traditional process, mainly because hydrogen production is complex and energy-intensive. 

[Wind costs are falling by 5% per annum, and solar by 10-15%, so that 30% cost premium will disappear within 5 to 6 years; plus the cost of carbon is only going to rise from her on out]

Difference between conventional steelmaking and the new Hybrit process: The Hybrit process uses hydrogen instead of coke, which produces no CO2 but only water (Source: Hybrit). 

Second, steel made using wind (E&E News):

For decades, access to cheap coal-fired electricity fueled industrial expansion across the Midwest, from auto plants to steel mills.

These days, a cleaner and cheaper energy source — winds blowing across the central Plains — is enabling new manufacturing investments, key sources of jobs and taxes for states hungry to grow their economies.

The latest example? A $250 million Nucor Corp. "micro" mill taking shape in Sedalia, Mo., that will be the first U.S. steel production plant that will run on wind energy.

The Sedalia mill's significance stretches beyond the state and represents the potential for greening the steel industry, which globally is a major source of carbon emissions, environmental advocates say. A report last year from the group Mighty Earth — "Cold Steel, Hot Climate" — noted that steel represented 7% of global carbon emissions worldwide in 2013, much of that from less efficient blast furnaces.

The plant is also indicative of what Midwest utilities and clean energy advocates alike see as new potential for economic expansion in the Heartland. While Appalachia has cheap shale gas driving big new investments, the Great Plains has an unlimited supply of even cleaner cheap wind.

The contract between Nucor and Kansas City-based utility Evergy Inc., which will bring new wind capacity online to supply the plant, is part of a broader national trend of corporate renewable energy purchases to achieve sustainability goals.

Nucor will be Evergy's largest Missouri customer when the plant begins operation. And the wind farm that will supply the plant, which has yet to be announced, will offset 100% of the mill's electricity supply.

The Sedalia mill will still rely on fossil from the regional Southwest Power Pool bulk power grid when it can't draw enough energy from wind on Evergy's system. Even then, the plant will be supplied at least partly by renewables as the power supply in SPP increasingly becomes greener (Energywire, Nov. 6).

In neighboring Iowa, wind energy has helped attract some of the biggest names in technology, including Google LLC, Facebook Inc. and Microsoft Corp. In Kansas, access to carbon-free wind energy was a key in the state landing a Mars Inc. plant.

[In this case, they are using scrap steel, not iron ore.  But the point is that wind costs have fallen so much that this steel-making method is now cost effective compared with traditional scrap steel operations, which use gas.  And gas is cheaper in the US than elsewhere.]

Third, steel made using the sun (CNN Business):

A secretive startup backed by Bill Gates has achieved a solar breakthrough aimed at saving the planet.

Heliogen, a clean energy company that emerged from stealth mode on Tuesday, said it has discovered a way to use artificial intelligence and a field of mirrors to reflect so much sunlight that it generates extreme heat above 1,000 degrees Celsius.

Essentially, Heliogen created a solar oven — one capable of reaching temperatures that are roughly a quarter of what you'd find on the surface of the sun.

The breakthrough means that, for the first time, concentrated solar energy can be used to create the extreme heat required to make cement, steel, glass and other industrial processes. In other words, carbon-free sunlight can replace fossil fuels in a heavy carbon-emitting corner of the economy that has been untouched by the clean energy revolution.

"We are rolling out technology that can beat the price of fossil fuels and also not make the CO2 emissions," Bill Gross, Heliogen's founder and CEO, told CNN Business. "And that's really the holy grail."

Heliogen, which is also backed by billionaire Los Angeles Times owner Patrick Soon-Shiong, believes the patented technology will be able to dramatically reduce greenhouse gas emissions from industry. Cement, for example, accounts for 7% of global CO2 emissions, according to the International Energy Agency.

Unlike traditional solar power, which uses rooftop panels to capture the energy from the sun, Heliogen is improving on what's known as concentrated solar power. This technology, which uses mirrors to reflect the sun to a single point, is not new.

Concentrated solar has been used in the past to produce electricity and, in some limited fashion, to create heat for industry. It's even used in Oman to provide the power needed to drill for oil.The problem is that in the past concentrated solar couldn't get temperatures hot enough to make cement and steel.

"You've ended up with technologies that can't really deliver super-heated systems," said Olav Junttila, a partner at Greentech Capital Advisors, a clean energy investment bank that has advised concentrated solar companies in the past.

That means renewable energy has not yet disrupted industrial processes such as cement and steelmaking. And that's a problem because the world has an insatiable appetite for those materials. Cement, for instance, is used to make the concrete required to build homes, hospitals and schools. These industries are responsible for more than a fifth of global emissions, according to the EPA.

That's why the potential of Los Angeles-based Heliogen attracted investment from Gates, the Microsoft (MSFT) co-founder who recently surpassed Amazon (AMZN) CEO Jeff Bezos as the world's richest person.

"I'm pleased to have been an early backer of Bill Gross's novel solar concentration technology," Gates said in a statement. "Its capacity to achieve the high temperatures required for these processes is a promising development in the quest to one day replace fossil fuel."

Heliogen uses computer vision software, automatic edge detection and other sophisticated technology to train a field of mirrors to reflect solar beams to one single spot.

"If you take a thousand mirrors and have them align exactly to a single point, you can achieve extremely, extremely high temperatures," Gross said, who added that Heliogen made its breakthrough on the first day it turned its plant on.

Heliogen said it is generating so much heat that its technology could eventually be used to create clean hydrogen at scale. That carbon-free hydrogen could then be turned into a fuel for trucks and airplanes.

Heliogen's biggest challenge will be convincing industrial companies using fossil fuels to make the investment required to switch over. Gross said the company has been talking to potential customers privately and plans to soon announce its first customers.

"If we go to a cement company and say we'll give you green heat, no CO2, but we'll also save you money, then it becomes a no-brainer," said Gross.

Its biggest selling point is the fact that, unlike fossil fuels like coal, oil and natural gas, sunlight is free. And Heliogen argues its technology is already economical against fossil fuels because of its reliance on AI.

"The only way to compete is to be extremely clever in how you use your materials. And by using software, we're able to do that," Gross said.

"If you can make hydrogen that's green, that's a gamechanger," said Gross. "Long term, we want to be the green hydrogen company."

[Even without fossil fuels, cement production involves cooking limestone to force the release of CO₂, so using CSP instead of fossil fuels won't completely cut its emissions.  But it's a big step in the right direction.]

Heliogen, backed by Bill Gates, has achieved a breakthrough that could allow cement makers to transition away from fossil fuels. The company uses artifical intelligence and an array of mirrors to create vast amounts of heat, essentially harnessing the power of the sun.

The writing on the wall for coking coal

Here ("Coal's last hope"), I talked about the crisis facing thermal coal, the kind used in power stations.  But coking (or metallurgical) coal, used to manufacture steel, also faces a potential crisis.

Via Kobad Bhavnagri of BNEF.

New research by @BloombergNEF  shows renewable hydrogen has the potential to cut emissions from steel making in half and hobble the market for coking coal at a carbon price less than $50/t by 2050. [The European carbon price is currently US$28.50/t]  

It is technically viable to decarbonize the entire steel making sector at a carbon price of just US$35-50/t CO2 by 2050 using hydrogen technologies. This would eliminate 7% of global greenhouse gas emissions.

A complete displacement of coal- and gas-based steel making is unlikely by 2050 due to the difficulty of writing down assets, but between 10-50% of global steel production could be from hydrogen if carbon pricing is widespread.

Hydrogen-based steel could first become competitive with coal-based production (without a carbon price) by 2030, where coking coal is $310/t. As hydrogen prices fall, it becomes competitive with coking coal at $200/t.

The technology to make fossil-free steel is already currently operating in many parts of the world. New plants can be constructed using Direct Reduction technology, first operate with natural gas and then transition to hydrogen once economics/policy allow.

The potential for hydrogen to displace coking coal at surprisingly low carbon prices should give investors serious pause for thought. Metallurgical coal is not immune from the changes sweeping the energy sector; hydrogen extends the reach of renewables into its front-yard.

I think the obvious symptoms of a climate emergency (drought, heatwaves, floods, hurricanes) will make the political imperative to do something about carbon emissions an irresistible force.  We have to reduce CO₂ and methane emissions to zero by 2050.  And the most practical way to encourage that is to introduce a price for carbon, which starts out low and rises steadily over time.  Countries or regions which already have a carbon price, and are making an effort to cut emissions, will not allow other countries to free-ride on their efforts.   The best recent example of this is the EU postponing ratification of a trade agreement with Mercosur, because of Brazil's burning of its Amazon rain forest.   The pressure is on, and carbon prices across the world will just get higher over time.  This spells the end not just of thermal coal but metallurgical coal too.

That leaves cement production, air travel, sea transport and, the elephant in the room, emissions from agriculture.  But does anyone think these sectors will be let off as the level of CO₂ in the atmosphere steadily rises and the climate emergency worsens?

[See also Iron and steel without fossil fuels]

A hydrogen-powered plane

From TriplePundit

The clean energy revolution means more than simply replacing fossil fuels with low-carbon alternatives. Clean technology can also provide extra benefits for companies in terms of productivity, comfort and convenience. A case in point is the hydrogen plane startup ZeroAvia. The company has just emerged from “stealth” mode to offer the world’s first commercial aircraft with a hydrogen fuel cell powertrain as its exclusive means of locomotion.

ZeroAvia’s business model is based on the premise that its hydrogen fuel cell powertrain will reduce the cost of flight on small, 10-20 seat aircraft, targeting short-haul journeys of up to 500 miles.

With the ability of the company's hydrogen plane to compete on cost for passengers against large conventional jets, ZeroAvia is anticipating that business travelers will be attracted by the opportunity to fly into smaller regional airports.

Ideally, the increased flexibility in choice of destinations will reduce the potential for delayed flights and long security lines that often bedevil larger airports.

Hydrogen fuel cell passenger cars have been slow to take off, partly due to their relatively high cost and lack of a mature fuel distribution network for motorists.

Those two issues are not significant barriers for ZeroAvia’s hydrogen fuel cell aircraft, however.

The company is anticipating a per-flight cost savings of about 50 percent for its powertrain compared to conventional jet aircraft. Higher power train efficiency is one key difference. Lower fuel and maintenance costs will also factor in.

To help reduce costs farther, ZeroAvia has adopted a “power-by-the-hour” engine lease model commonly used in the aircraft industry, in which customers pay only for the hours that they use the powertrain. The cost of fuel and maintenance will be picked up by ZeroAvia as part of the lease.

Hydrogen fuel cells produce no airborne pollutants. The only emission is water, resulting from the interaction of hydrogen with oxygen in the fuel cell.

Still, the supply chain for hydrogen is front-loaded with pollutants and environmental impacts because the primary source for hydrogen today is natural gas.

Air Liquide has committed to decarbonizing hydrogen production for energy-related applications through its Blue Hydrogen initiative.

For its short-term goal, the company has pledged carbon-free production for at least 50 percent of hydrogen in the energy category by 2020 -- in other words, by next year. Biogas, water-splitting (using electricity sourced from renewables) and carbon recycling are the three main pathways identified by the company.

Air Liquide’s timetable for renewable hydrogen improves the prospects for ZeroAvia to reduce its supply chain emissions.

ZeroAvia is looking at the year 2022 to introduce its new fuel cell aircraft to the market, and earlier this year Air Liquide announced it would ramp up carbon-free hydrogen production at an existing facility just across the border from the U.S. in Canada.

[Read more here]

Brown hydrogen is made from coal, blue hydrogen from natural gas and green hydrogen via electrolysis using green electricity.  The supporters of a hydrogen economy say that supporting blue hydrogen will lead to economies of scale which will then allow the introduction of green hydrogen.  For example, this page from Oz gas producer Woodside. 

I'm not altogether convinced.  The problem with blue hydrogen is not economies of scale.  It's cost, because the chemical bonds between oxygen and hydrogen in the form of water are so strong it requires lots of energy to break them apart during electrolysis.   ZeroAvia's relative cheapness, I suspect, depends on blue hydrogen, not green. 

That's doesn't mean ZeroAvia's project is completely pointless.  Green hydrogen produced by renewable electricity that would otherwise be curtailed because there is surplus electricity in the grid is cheap.  Curtailment will increase rapidly as we increase the percentage of renewables in the grid.  And it may be possible that the CO₂ produced as a by-product of the production of blue hydrogen could be dissolved in water and pumped into basalt where it turns into rock.  On the other hand, compressing and delivering the CO₂ to far-off locations increases the cost and energy usage.

For now, blue hydrogen is more efficient and much less polluting than petroleum or jet-fuel, so it is half a step forward.  Air Liquide's commitment to producing 50% green hydrogen as part of its total hydrogen production is good news.  Progress comes from small steps, as long as they're all in the same direction.

Cement produces more CO2 than trucks

From Bloomberg:

The most astonishing thing about cement is how much air pollution it produces.

Manufacturing the stone-like building material is responsible for 7% of global carbon dioxide emissions, more than what comes from all the trucks in the world. And with that in mind, it’s surprising that leading cement makers from LafargeHolcim Ltd. in Switzerland to Votorantim Cimentos SA in Brazil are finding customers slow to embrace a greener alternative.

Their story highlights the difficulties of taking greenhouse gases out of buildings, roads and bridges. After wresting deep cuts from the energy industry, policymakers looking to extend the fight against global warming are increasingly focusing on construction materials and practices as a place to make further reductions. The companies are working on solutions, but buyers are reluctant to pay more.

While architects and developers concentrate on the energy used by their buildings, it’s actually the materials supporting the structure that embody the biggest share of its lifetime carbon footprint. Cement’s contribution to emissions is especially immense because of the chemical process required to make it.

About two-thirds of the polluting gases that come from cement production stem from burning limestone. Kilns are heated to more than 1,400 degrees Celsius (2,600 Fahrenheit), about four times hotter than a home oven set to the self-clean cycle. Inside the kiln, carbon trapped in the limestone combines with oxygen and is released as CO2, the most abundant greenhouse gas.

A ton of cement yields at least half a ton of CO2, according to the European Cement Association. That’s more than the average car would produce on a drive from New York to Miami. And a single mixer truck can carry about 13 tons. Hundreds or even thousands of tons go into ordinary office buildings.

What comes out of the kiln is called clinker, the key raw ingredient of cement. It’s the substance that, when mixed with gypsum and water, binds with gravel to harden and form concrete. Many companies are working to cut the amount of clinker in their cement, which requires new and sometimes untested recipes.

Others are looking at substitutes. Those include fly-ash, which comes from the chimneys of plants that burn coal, or slag from steel-making blast furnaces. They trigger a chemical reaction and form what’s known as a geopolymer binder.

Geopolymer cement has performance advantages and a huge sustainability edge over traditional mixes, according to Cameron Coleman, chief executive officer of Wagners Holding Co., which is based in Toowoomba near Brisbane in Australia.


“This alternative eco-friendly binder technology reduces the carbon emissions associated with normal Portland cement by 80% to 90%, and also has a much lower embodied energy,” Coleman said by email. “We have been working with leading companies in South East Asia, New Zealand, India, Europe and the Middle East who are extremely interested in adopting this technology.”

That strategy won’t work for long in Europe and the U.S., where fly-ash is the main clinker substitute and coal plants are closing. There, the focus is on efficiency and using fossil-fuel alternatives for heat. The European Cement Association says its producers already get 44% of their energy from cleaner sources and wants to raise that proportion to 60% by 2050. Instead of using coal, it’s creating heat with used tires, mineral oil and industrial waste.

[Read more here]

I am very confident that the world will replace fossil fuels in electricity generation within 20 or 25 years, and will convert most land transport to EVs over the same time frame.  This will happen because people are getting frightened by global heating and the climate emergency, and because the costs of these new technologies are plunging. Why not do something about global heating when you'll actually cut costs by doing it?

But that will leave agriculture, iron and steel and cement, which by 2040 or 45 could make up 80% of emissions.  There are alternatives in cement production as this article discusses.  There are others: I talked about green concrete here.  Iron and steel could be produced using methane or hydrogen to reduce iron ore to pure iron.  Unlike electricity from renewables or EVs, these will not be cheaper than their high-carbon equivalents.

Clearly, to encourage the update of low-carbon cement and steel, we need a price on carbon.  In Europe, there is one, currently €24 (US$ 27) per tonne of CO₂.  It's only a question of time before Europe starts applying that price to the carbon content of imports from countries which do not have a carbon price.  The surge of Greens in the recent European elections makes that inevitable.  All the conventional parties are starting to feel how the breath of environmentalism is starting to become a breeze and then a gale.  What's more, the current extreme heatwave in Europe, as bad as or worse than last summer's,  will only harden attitudes.  With a carbon price, cement and steel will start to produce low-carbon products.  And the only remaining sector to de-carbonise will be agriculture.  But it will happen there too.  Because it has to.

More storage? Or more capacity?

When wind and solar first started to be used for generation on the grid, the aim was to use as much of the power as they created because their cost was so high.  Curtailing output would just make an expensive thing even more expensive.  But the costs of wind and solar have declined rapidly, and continue to decline.  "Wasting" some of the renewables output by curtailment is more acceptable, and indeed, as renewables penetration has increased, necessary, when good wind and/or solar conditions mean that otherwise there would be too much output, leading to the grid burning out.

Also, studies have repeatedly shown that although little storage is needed at low levels of renewable penetration as penetration rises, more storage is needed, and the need rises exponentially after penetration reaches 70%.  I wrote a long piece a year ago summarising some interesting research, here.  In a grid without baseload generation, such as hydro or nuclear, even with a mixed 50%/50% wind/solar generation base, we would need 32 days storage to take the grid from 90% to 99.99% renewables.  At that time, I pointed out that we wouldn't be getting to 70% penetration for 20 years, by which time storage costs would have fallen by 99% if current trends continue.  Which they prob'ly won't—but the current 20% per annum decline will very likely continue for another 10 years at least, which will mean by 2030, battery costs will have fallen 90%.

But what if we just added extra capacity, instead of or in addition to storage?  First, that won't work with a grid with 100% solar.  No matter how much capacity you have, the sun doesn't shine at night.  Outside the tropics, some night-time demand will be satisfied by wind.  Without wind, i.e., just solar, you would need at least 12 hours of storage.  I've assumed 8 hours of storage (1/3rd hourly daylight demand x 12 hours) will be needed, plus wind, to be conservative.  This will cover the day-to-day fluctuations.  But what about seasonal deficits?  I mentioned 32 days of storage above, which would be essential to give the grid 99.99% guaranteed supply even in prolonged cloudy, wintry calm, when demand is high and supply low.  Or during an Arctic vortex event, such as hit the N.E. USA earlier this year.

Let's have a look at a potential example.  I went to the ever reliable PVWatts (run by by NREL) and got them to tell me how much power is generated each month on average in Minnesota.  Solar panel output is lowest in December (229 kWh from 4 kW of panels) and highest in July (629 kWh).  December output is 36% of July's.  So if you were going to run all of Minnesota on solar electricity, you would need triple capacity to provide for that one month in winter, and would dump/curtail lots of power in summer.  Of course, at such a high latitude, no one would run a grid just on solar.  So let's assume 50% wind, and allow for some variability.  In that case double capacity of wind and solar  (plus 8 hours storage for nights) should be enough.  Double capacity, though, would more than double the cost, because some output would be curtailed.  By my calcs, about 1/3rd of the excess capacity would be curtailed in Minnesota if solar capacity were doubled, so doubling capacity would be 2.3 times as expensive.  I'll come back to that in a minute, below the chart.

In the chart below (I've shown variations before) I've taken the average LCOE estimated by Lazard from their latest report for each year since 2009 for wind, solar, coal and gas.  Wind+solar is the average of wind and solar individually.  I've assumed that the rate of cost declines for the last 5 years continues for the next 3.  I've estimated battery costs using battery pack prices, and in a change from my previous published estimates, assumed a 30% premium for the concrete base, connection etc.

The different green lines in effect show the different cost structures as renewables penetrate the grid.  The solid green line is a 50/50 average of wind and solar without storage, and would be appropriate for low penetrations of wind and solar in the grid.  That crossed the coal line in 2012.  The dotted green line adds the cost of 8 hours of energy, and would be appropriate for 40 to 60% penetration in the grid.  That combo became cheaper than new coal in 2015.  The dashed green line shows the costs of doubling capacity, still with 8 hours of storage, which is still though not for much longer, more expensive than coal.   However, that's a conservative estimate, as I'll explain below.

What would happen if large chunks of potential electricity generated were to be wasted via curtailment?  It would be "free" electricity.

First off, wind and solar farms would add more on-site storage so that when they were told to curtail output by the grid operators, they would divert production to their own storage for delivery later.  For example, wind blows all the time, but demand is mostly in the day.  In South Australia, with 50% renewables penetration, most of it wind, wholesale prices can go negative in the wee hours.  So why not store their surplus production then for delivery into the afternoon peak, when wholesale prices soar?  Of course, that's just what they would do.

And for prolonged periods of surplus output, say during summer, it would make sense to store that surplus energy as hydrogen or as synthetic natural gas.  Just to remind you, you take green electricity, use it to split water into hydrogen and oxygen, pass the hydrogen with CO₂ over a catalyst at high pressure and temperature, and that gives you methane.  This is called the Sabatier process, and I have talked about it often.  There is a 65%+ energy loss in this process, plus capturing the CO₂ from a gas power station flue adds $6-$34/MWh.  But if the energy is "free", the energy conversion loss is irrelevant.  And thus power-to-gas becomes much cheaper.  So instead of curtailing output from wind and solar when supply is excessive, that surplus supply would be used to produce hydrogen and methane, which would be stored to cover high electricity demand in winter.  Curtailed output would then have some value, reducing the cost of the extra capacity.

Note that the conservative costings for doubling capacity, i.e., ignoring any revenue from selling otherwise curtailed output for power-to-gas, cuts across the coal cost line in 2020, and the gas line in 2023 (not shown on chart).   And that's US gas, which is a lot cheaper than in the rest of the world.

The future grid will have:

• a mixture of wind and solar, varying by latitude
• plant-level and prob'ly grid-level battery/pumped hydro storage equivalent to a minimum of 8 hours storage and likely more
• long distance HVDC lines to bring power from other regions where the weather and the climate is different
• much more generation capacity to ensure supply at times when wind is low and the sun isn't shining
• seasonal storage using the Sabatier process to create synthetic natural gas, i.e., methane, to provide reserves for winter.

And. it occurs to me, hydrogen-cell cars may actually be a thing.  I've always dismissed them before because of the costly energy conversion losses caused by producing hydrogen from electrolysis.  But if we need extra capacity in the grid, and the result is cheap hydrogen, hydrogen-cell vehicles might yet work.   Ditto, methanol fuel cells.



[Hat Tip to CleanTechnica which started me thinking, with this article: No Joke: We Should Build More Solar & Wind Than Needed — It’s Cheaper]

Green methane in the gas grid

How power-to-gas works
(Source)
erneuerbare Energien=renewable energy;  Wasser=water; Wasserstoff=hydrogen
Erdgasnetz=natural gas grid; Strom=electricity; Wärme=heat
  Mobilität=mobility; Kohlendioxid=CO₂;Katalysator=catalyser; Elektrolysator=electrolyser

One of the ways we can reduce emissions is to produce synthetic fossil fuels.  We can do this by taking "green" hydrogen, running it with carbon dioxide at pressure and temperature over a catalyst, to produce methane.  "Green' hydrogen is produced by electrolysing water using surplus electricity from renewables.

This is an energy intensive process because the bonds between hydrogen and oxygen are very strong.  But, if you use power which would any way be "curtailed" (i.e., when the grid operator says there in too much electricity being generated and fed into the grid and forces wind or solar farms to temporarily disconnect from the grid) then the cost is low.  If, in addition, you don't need to concentrate CO₂ from the atmosphere. but already have a concentrated supply, for example, from the exhaust stack of a gas power station, then the cost is negligible.  Only the capital cost of the plant is relevant.

By the way, "brown" hydrogen is produced from coal, and "blue" hydrogen from natural gas.  Neither of these is carbon-neutral, and if they are used to fuel a hydrogen economy, then the hydrogen economy isn't carbon neutral either.  Which is surely the whole point! If, however, "green" hydrogen is used, although CO₂ will be produced when it is burned, it will have already been drawn from the atmosphere to create the synthetic methane in the first place, so will not be adding to atmospheric levels of CO₂.

Two points.

First of all, in high latitudes, there will be a need for seasonal storage, and batteries will likely be too expensive for a week or two of storage, for a couple of decades yet.   Gas via legacy peaker plants will be the obvious way to fill these gaps.  And the gas grid in most developed countries (a) already exists and (b) has several weeks of storage capacity.   Synthetic natural gas won't add to carbon emissions.

Second, there will inevitable be curtailment in any renewable grid.  Yes, we will have batteries, yes, high voltage connectors between regions will be built, but just as with the fossil-fuel grid now, there will be much more capacity than we will on average use, just to ensure that when demand is high (or supply low because of the weather), there is enough power.  This will mean that output from wind and solar farms—when for example there are strong winds or sunny days or both—will often be curtailed.  If instead of being curtailed, the unneeded electricity is used to create synthetic natural gas (SNG), the cost of SNG will be lower than natural gas, despite the energy cost.

From ArsTechnica:

A Düsseldorf, Germany-based energy company called Uniper announced last week that it sent methane made from renewable hydrogen into the local natural gas pipeline.

The methanation plant in Falkenhagen that made the synthetic methane opened in May 2018, and the plant's operators began testing the process to combine renewable hydrogen with carbon dioxide from a nearby bioethanol plant.

The synthetic methane is sent into the local natural gas pipeline, where it's used along with traditional natural gas. "Today, the plant produces up to 1,400 cubic meters of synthetic methane (SNG) per day, which corresponds to approximately 14,500 kWh [kilowatt hours] of energy," a Uniper press release noted. 

Uniper's Falkenhagen-based methanation plant combines the renewable H2 from Store & Go's nearby electrolysis plant with captured CO2 from the nearby bioethanol plant, combining the two molecules to create methane (CH4), the primary ingredient in natural gas. That process also creates heat as a byproduct, which is used at a nearby veneering plant.

A big advantage of this methanation project is that it can leverage existing natural gas infrastructure, allowing vehicles, residences, and other customers to indirectly use renewable energy for fuel and heat.

The methanation plant receives renewable hydrogen (H2) from a nearby plant that has harnessed excess wind and solar power for electrolysis-based hydrogen synthesis since 2013. The renewable-hydrogen project is run with help from Store & Go, a European Union-funded research program that recently partnered with CO2-capturing startup Climeworks to build a synthetic methane plant in Troia, Italy.

[Read more here]

From pv magazine:

Vattenfall-led consortium plans 50 MW power-to-gas project in Germany.

The energy company plans to build the “HySynGas” project in the Brunsbüttel Industrial Park with ARGE Netz and MAN Energy Solutions. The consortium wants to establish a power-to-gas hub for cross-sector decarbonization in northern Germany.

ARGE Netz, MAN Energy Solutions, and Vattenfall announced a plan on Thursday to set up a large-scale power-to-gas project in an industrial park in Brunsbüttel, northern Germany. The facility will produce green hydrogen and synthetic gases (SNG) from electricity generated by nearby solar and wind plants.
It is expected that the green hydrogen will contribute to cross-sectoral decarbonization. It could be used as fuel for buses or ships, as well as in gas power plants and other industrial sectors. 

The aim of the partnership is to establish a unique power-to-gas hub for cross-sectoral decarbonization in northern Germany, Vattenfall said in a statement. The partner companies have also applied for funding from the Federal Ministry for Economic Affairs and Energy to build a related R&D laboratory.

The aim is to increase the use of renewable energy and reduce CO2 emissions in a range of sectors with green hydrogen. “The project is a central building block for a holistic energy transition and at the same time lays the foundation for the power-to-gas hub in northern Germany,” said Frense.

The consortium has already secured a number of well-known customers, such as the Volkswagen Group, various logistics firms, municipal utilities and other local companies.

According to Oliver Weinmann, managing director of Vattenfall Europe Innovation GmbH, “the technology is ready for use and the companies want to invest in the green energy future.” He said that an electrolyzer for the production of green hydrogen with at least 50 MW of capacity will be built at the industrial park, as well as facilities for the production of synthetic methane, with a capacity of at least 40 tonnes per day.

In Rotterdam, the Gigawatt Elektrolysefabriek project was also recently launched. The researchers from that project aim to start generating green hydrogen at the the gigawatt scale from 2025.

[Read more here]