Methane promising route for storage of renewable energy from sun and wind

**Methane promising route for storage of renewable energy from sun and wind
Credit: Utrecht University

Storing renewable electricity in molecules can solve two problems at once: first of all environmentally harmful CO2 can be used as a feedstock, and secondly it can enhance the capacity to store renewable electricity in chemical bonds for long periods of time. The latter is necessary because traditional batteries do not yet have the capacity to ensure enough flexibility, stability and security to store wind and solar energy on a large scale for extended time periods. Utrecht University researchers published a Perspective article on the status quo of "power to methane" earlier this month in Nature Catalysis.

First author Charlotte Vogt says, "Aside from understanding fundamental physical and chemical concepts behind catalytic reactions, I'm especially interested to know if and how the research I am doing can impact society. That's why I wanted to start this societally relevant, but still fundamental research project."

Ten times cheaper

Another process that can be used to store electricity in molecules is the conversion of water to hydrogen via electrolysis. This process is cheaper than methanation, because it involves fewer reaction steps. The researchers have now calculated that despite this higher cost of the process, it can still be beneficial to make methane out of CO2 because storage of methane is ten times cheaper than hydrogen. This way, we can store electricity for seasons in a potentially cheaper manner than by using only hydrogen.

"The important part of this idea is that we do not send the methane to houses, where it gets re-emitted as CO2, but rather to recycle this carbon again and again in a closed-loop process," says Vogt. "This process of using methane as a chemical battery has an overall efficiency of roughly 34%, so we need a lot of CO2 to ensure that our 'battery' gets big enough." Another option is to make methane out of sustainably resourced biomass or municipal waste. In this case, the methane could be sent to houses through our natural gas network. However, without a carbon tax this synthetic natural gas (SNG) will be more expensive than fossil methane, so it is unlikely that this process will come to fruition in the near future.

Charlotte Vogt explains more about the CO2-to-chemicals process she is studying in her PhD Credit: Utrecht University

Promising research direction

The researchers thus conclude that 'Power to Methane' is indeed a promising research direction for certain geographical sweet spots in the world where there are many CO2emissions (near large scale industry for example, called point sources), together with the production of . Examples of such CO2 point sources are petrochemical and metallurgical industries, both present in the Netherlands. The researchers finally conclude that the future of non-fossil fuel dependent energy supply is mainly dependent on how fast we can make the conversion of water to hydrogen much cheaper, and in the long run directly convert water and CO2 into hydrocarbons, which we can directly use in the energy transportation grid, being an example of it.

The work involved a close collaboration between Prof. Gert Jan Kramer of the Copernicus Institute of Sustainable Development at Utrecht University, and Charlotte Vogt, Matteo Monai, and Prof. Bert Weckhuysen, who are chemists at the Inorganic Chemistry and Catalysis group of Utrecht University.

Bert Weckhuysen: "We have a responsibility as scientific researchers to be aware of the socioeconomical impact of our science, and catalytic chemistry in particular. By collaborating in this way, we utilize our combined knowledge to help determine what research and technology directions society should put emphasis on."


Explore further

Production of renewable gas from waste wood

More information: Charlotte Vogt et al. The renaissance of the Sabatier reaction and its applications on Earth and in space, Nature Catalysis (2019). DOI: 10.1038/s41929-019-0244-4
Journal information: Nature Catalysis

Citation: Methane promising route for storage of renewable energy from sun and wind (2019, April 1) retrieved 20 June 2019 from https://phys.org/news/2019-04-methane-route-storage-renewable-energy.html
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Apr 01, 2019
environmentally harmful CO2


Liars.

Apr 01, 2019
environmentally harmful CO2


Liars.


So back up your statement with facts.

Apr 01, 2019
So back up your statement with facts.


There'd be no plants on Earth without CO2. Harmful? That's teaching children lies.

Apr 01, 2019
So back up your statement with facts.


There'd be no plants on Earth without CO2. Harmful? That's teaching children lies.


They aren't teaching children anything. This is a scientific proposal, in a scientific paper. They are talking about recycling CO2 produced by anthropogenic means.

Apr 01, 2019
They promote an agenda by claiming CO2 is a poison, it's not.

Apr 01, 2019
They promote an agenda by claiming CO2 is a poison, it's not.


Nobody said anything about poison. Now you are making things up.

Apr 04, 2019
Methane is more valuable than electricity or hydrogen.

Consider: people in the EU already pay €1.24 per liter average prices for gasoline. For a modern gasoline engine, that corresponds to an energy price of 47.2 cents per kWh at the wheel.

If your renewable power costs 6 cents a kWh to produce, and you apply the same motor efficiency to run the car's engine on the converted methane, the minimum cost to the end user is 35.7 cents per kWh. There's even a profit margin compared to market prices - it's cheaper than the gasoline even when the process wastes 83% of the energy. (better efficiency is possible)

Hence, it makes much more sense to turn renewable electricity into motor fuel than it is to return it to the power grid. People find the fuel more valuable than the electricity, and you can actually make profit on the scheme while reducing CO2 output instead of inflating electricity prices needlessly.

Apr 04, 2019
For improving the round-trip efficiency, fuel cells instead of piston engines can be used, which reduces the end cost to around 18 cents a kWh and would make the methane-electric car unbeatable in terms of cost. You could even double the price of the input electricity, or to cover the infrastructure costs, and it would still be cheaper than gasoline.

Process heat can be captured to heat buildings etc. and the methanation process itself can be improved on. There's also value in the oxygen that is generated as a byproduct of the hydrogen - there's all sorts of side streams that make the system practical and economical entirely regardless of the poor efficiency - in fact the apparently poor efficiency just doesn't capture how much energy it saves elsewhere.


Apr 04, 2019
environmentally harmful CO2

Know what's environmentally harmful?
All the bullshit from the AGW Cult. Like bio-fuels from food crops.

Apr 04, 2019
environmentally harmful CO2

Know what's environmentally harmful?


Idiots like you.

Apr 04, 2019
Bio-fuels from food crops

Sound attractive
that is
if
you are a farmer
because
market your crop as bio fuel instead of food
and
guess what
you get more readies selling it as bio fuel
so
farmers inadvertently put the price of edible food crops up
that effects the poor struggling natives in far flung territories
and
in Tesco's and Walmart
not only that one and all
farmers by selling their food crops for burning
reduce the food supply
increase the food price
creating poverty and starvation
to
The down trodden workers

Apr 12, 2019
Of course, the comparison has to be made to pure electric cars.

Assume an electric car like a Tesla Model S with a 100 kWh battery pack for a comparable range to the gasoline vehicle. That battery costs around $150/kWh -> $15,000 which is already the price of a low-end cheap car or a fairly good second hand vehicle. Nevertheless, a person would drive about 20,000 km a year and consume roughly 220 Wh/km or 4400 kWh per year, for the lifespan of the battery which can be assumed to be 10 years. Hence, $15,000 / 44,000 kWh = 34 cents/kWh and that's just from the battery alone. Add up electricity cost, let's say 11 cents average consumer prices, and that makes 45 c/kWh which is perfectly on par with buying gasoline. It doesn't actually come any cheaper: you pay more up-front.

In other words, regardless of the abysmal efficiency, turning renewable energy into methane and burning it in cars would be superior to battery-electric vehicles as well.

Apr 12, 2019
farmers by selling their food crops for burning
reduce the food supply


There isn't a problem of starvation in the first world countries. If anything, the poor people are eating way too much stuff that's just subsidized corn processed into simple sugars - biofuels are just the latest excuse to increase subsidies for the large industrial corporations that run massive monoculture farms that outcompete the actual farmers. The ethanol they produce is matched very closely 1:1 in fossil fuels used in the process, and the mandate to mix it in fuels causes worse air pollution and tremendous damage to public health due to the chemicals released in incomplete combustion of alcohols, such as formaldehyde.

The individual small time mom & pop farmers commonly don't run biofuel operations because the profit margins are so slim that making money over it would require more acreage than they could ever hope to farm.

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