Get the carbon out of natural gas

Turning natural gas into hydrogen might sound like the alchemists dream of turning lead into gold but the technology has been around for decades.

image: FuelCellsWorks

It’s long been the dream of our fossil-fuel hungry society that we can continue to burn fuel without the consequences of climate change. We’re totally hooked on fossil fuels and the future of reliance on renewable energy sources is decades away.

One proposed solution is to extract CO2 out of the air by sequestration: capture and store CO2. But that technology is unproven and even if it worked, would require billions of dollars to build. 

It would help a lot if we could, at least, remove the carbon from the natural gas used to heat our homes, cook our meals, and heat water. Fifty per cent of Canada’s household energy needs come from natural gas, with electricity at 45 per cent in second place, and heating oil at 4 per cent.

As far as gas goes, hydrogen is the fuel of the future. When burned, it produces nothing but water.

The feds are big on hydrogen. Last year, the federal government released its Hydrogen Strategy for Canada. It’s an ambitious plan to get Canada to net-zero carbon emissions by 2050 and make Canada a global leader in hydrogen technologies.

There are a number of ways of producing hydrogen including the electrolysis of water using green sources of electricity. There are even pockets of hydrogen beneath the ground that could be mined.

And since a massive system of natural gas pipelines already exists, the hydrogen could be sent through those pipelines.

However, sending hydrogen through natural gas pipelines is a bad idea, says professor Michael E. Webber of the University of Texas at Austin:

“Moving and storing gaseous hydrogen is also a challenge. Because of hydrogen’s low density, it takes a lot of energy to move it through a pipe compared with denser gases such as methane or liquids such as petroleum. After several hundred kilometers the inefficiency makes moving hydrogen more expensive than the value of the energy it carries (Scientific American, April, 2021).”

A better solution would be to convert natural gas to hydrogen at the end of the pipeline -at home. The process is called pyrolysis. It breaks down in natural gas into hydrogen and solid carbon. The method is efficient and eliminates CO2 emissions. It’s been known for decades. Pyrolysis takes conventional natural gas and converts is to nearly zero carbon.

However, pyrolysis is not magic. It requires heat which would have to come from renewable electricity sources. On the plus side, the solid carbon produced is a valuable industrial product; more valuable than any other product we place at our curbsides. It could be collected with other recyclables. Also, the gas jets in our appliances would have to be replaced to burn hydrogen.

The installation of home pyrolysis generators would be expensive but compared to the billions of dollars being put into carbon sequestration, not prohibitive. The sale of the valuable solid carbon collected would partially offset costs.

Home-based natural gas converters would allow us to have our fossil fuels and burn them too. And feel good about doing so.

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B.C. firm extracts fuel from air

It may sound like alchemy but Carbon Engineering Ltd based in Squamish captures carbon from the atmosphere and turns it back into automotive fuel.

Carbon Engineering,
Squamish, BC. Image: Google maps

It’s not just wishful thinking. Investors with deep pockets are putting money into the project, such as Microsoft’s Bill Gates.

Co-owner of Carbon Engineering David Keith describes the technology as “direct air capture” (DAC). They’ve been running a pilot plant since 2015 and hope to build a commercial-scale operation soon. The plant has been producing a variety of fuels, such as diesel, gasoline, and Jet-A since 2017.

Carbon capture technology is not new but the price barrier has been too high to make it feasible. Previous processes have cost US$600 a tonne. Professor Keith says they have broken the price barrier:

“At Carbon Engineering, we now have the data and engineering to prove that DAC can achieve costs below US$100 (Globe and Mail, June 8, 2018).”

Former processes haven’t worked, as Saskatchewan found out. At higher cost and lower reliability, they extract CO2 and store it into the ground. Former Premier of Brad Wall had high hopes that his province could avoid a federal carbon tax by carbon capture. However, these plants are only operational 45 per cent of the time. The old technology has been tried globally and abandoned; China cancelled theirs.

Professor Keith researched his DAC technology at the University of Calgary. The process is relatively simple in theory. First CO2 is extracted from the air. Then hydrogen is created from water through electrolysis using any energy source, preferably renewable. Solar cells, for example, could create hydrogen by breaking water into its component parts. In the final stage, hydrogen and CO2 are combined to produce hydrocarbon fuels.

The novelty of Professor Keith’s technology is that it solves three problems: rising levels of CO2 in the atmosphere, drilling for fossil fuels, and the storage of renewable energy sources such as wind and solar.

Of course, if you are going to extract CO2 from the air only to convert it back into fuels that will put the CO2 back in the air, that hardly seems like a solution. But at least it is not producing any more CO2. And mining the air for fuels is certainly better than fracking shale deposits.

Using renewable energy sources such as wind and solar to produce automotive fuel seems counterintuitive at first. The problem with renewable energy sources that they produce energy when it’s not needed and none when is -it has to be stored somehow.  The surplus electricity could be stored in batteries for use later. Or it could be used in conjunction with other renewable sources such as hydroelectricity.

Storing renewable energy as fuel is a good idea because the engines to burn the hydrocarbons already exist. There is no need to build new vehicles with electric motors.

The fuel produced is expected to cost 25 per cent more than traditional gasoline but it would fetch premium prices.

“It’s not a magic bullet, it’s not too cheap to meter,” says Professor Keith, “but it’s something that really we think could be built out, and could be built out at relatively low technical risk. So we hope it is really a turning point.”

 

Smart water and you

We’re told to turn off lights to save electricity. But when you move up the energy chain, turning off the lights means saving water.

In turn, more water means more food. Nowhere is that more obvious than in California which grows one-half the fruit and vegetables in the U.S. and for much of Canada. The recent drought has prompted the California governor to order a 25 per cent reduction in water consumption.

As well, water produces electricity for many parts of North America. Water behind a dam is a versatile resource: energy, food, potable water. Turning off the lights can mean more food. In other words: energy = water = food.

Smart water can be achieved in a number of ways. One of the problems with renewable energy is storage. Solar panels and wind turbines produce electricity but not necessarily when it’s needed. What’s to be done with the surplus?

Sure, surplus renewable electricity can be stored in batteries or other devices.  Another option would be to store the surplus energy as water. Once the water is pumped behind a dam, it can be used for electricity when it’s needed, or for food. Another option would be turn unusable groundwater into potable water. Michael Webber at the Energy Institute, University of Texas at Austin, puts it this way:

“We can also rethink how to better use energy and water to grow food in unlikely places. In parts if the desert Southwest, blackish water is abundant at shallow depths. Wind and solar energy are also plentiful. These energy sources present challenges to utilities because the sun does not shine at night and the wind blows intermittently. But that that schedule is fine for desalting water because clean water is easy to store for later.”

As climate change drives drought into parts of the Canadian prairies, that calculation applies here. Surplus renewable electricity could provide water to prairie towns that would otherwise dry up, providing drinking water and even irrigation for crops.

As well as turning off the lights, we could throw away less food to save water. It takes 15,000 litres of water to produce one kilogram of beef, 1,600 litres per kilogram of bread. Yet, we throw away about one-third of the food we buy. When you throw away 1/2 kilo of over-ripe apples, you’re throwing away the 400 litres of water it took to grow them. That represents more energy than a couple of lights turned off.

Too many perfectly good fruits and vegetables are thrown out because they have minor imperfections. Restaurants throw out tonnes of food from the plates of customers who order more than they can eat. But even if more cosmetically imperfect food was consumed and plate portions were reduced, some waste may be unavoidable.

Instead of throwing waste food into landfills, it could be placed in anaerobic digesters along with other agricultural waste such as manure to produce methane, which could be used to produce electricity, which could be used to pump water, which could be used for . . . well, you get the idea.