Solar energy into a pipe

Compared with electrical energy networks, the use of existing gas networks is more conducive to the storage and transmission of solar energy and wind energy after conversion. An expert in the field of plasma at Eindhoven University of Technology (TU/e) in the Netherlands is trying to develop a new technology for converting renewable energy (and carbon dioxide) into methane and methanol. This will provide a new possibility for the long-distance transport of renewable energy including solar energy and wind energy.

Large wind power plants far from the coastline and solar power plants in the Sahara desert can efficiently produce a large amount of renewable energy. Unfortunately, there is little demand for electricity in the region, whether it is the Ocean Center or the desert hinterland. These electrical energy must be delivered to densely populated load centers in various ways. Just as power distribution network specialists from Alliander (a well-known Dutch energy company, one of the distribution network operators) are aware, the long-distance transmission of electricity is not easy because of the huge losses. At the same time, the output of electricity generated by all solar power plants in the Sahara desert will be transported to Europe. The cable trench width needed is about two kilometers.

It seems like a good idea to use existing gas networks and other infrastructure to solve energy transmission. Alliander is responsible for gas network operations in parts of the Netherlands, including Eindhoven. Two gas pipelines are enough to connect Europe and the Sahara. At the same time, the Netherlands has a well-developed gas pipeline network and can store huge quantities of gas that generates 100TWh of electricity for the entire year in the Netherlands. The long-term storage of such a large amount of electric energy is almost an impossible task.

With the gas network to deliver new energy, the biggest challenge in this plan is to convert solar or wind energy into a high-energy density gas, such as methane, a major component of natural gas, and natural gas is being transported continuously through pipelines. To all parts of the country. It has been technically possible to use electricity to produce methane, but one step in this process is the electrolysis of water, which requires a rather complicated and expensive treatment process.

Another way to produce methane is to use plasma to convert carbon dioxide into carbon monoxide, which in turn reacts with water to produce methane. Renewable electrical energy is used to power a machine that is similar to the microwave oven principle, generating plasma. Through this roundabout process, solar energy or wind energy can be stored indirectly as methane. When the conversion efficiency of electricity to methane is sufficiently high, this new type of energy delivery is very obvious: it avoids the need for new transmission lines and greatly reduces investment.

"My first reaction is: This is impossible!"

As a potential technology, last summer STW and Alliander jointly decided to fund the project to convert carbon dioxide using plasma technology.

The project was jointly attended by several universities and research institutes in the Netherlands. “My first reaction was: This is not possible!” Dr. Van Dijk and Dr. Peerenboon, who participated in the study of two of these topics, initially thought so. Dr. Van Dijk acknowledged that he was surprised when he first heard about the project: “My first reaction was: This is not possible. But

Later, when I heard that Alliander was also funding this project, I realized that this should be a serious idea. After careful consideration, he and Dr. Peerenboon decided to meet this challenge that will have a wide range of social impact.

"The goal of both subprojects is to use plasma to make methane from recycled carbon dioxide," Dr. Van Dijk said. "The main difference is the timing of the addition of water vapor." The essence of the plasma technology that we hope to adopt is the decomposition of carbon dioxide into carbon monoxide and oxygen. Because the carbon dioxide molecule and the electron flow formed by the plasma collide rapidly, the former acquires enough internal energy and will release oxygen atoms. “This is equivalent to a reverse combustion process,” explains the plasma physicist. “This is why the most important aspect of this technology is to remove oxygen from the oxygen before the carbon monoxide is reconverted into carbon dioxide. To achieve this goal, we plan to use thin-film technology. Because of this, from the University of Twente (-Twente University's experts also participated in the project research."

In the generation of carbon monoxide, of course, it is better to lose as little energy as possible. "In order to achieve this goal, we need a plasma with perfect characteristics," said Dr. Van Dijk. To determine the optimal environmental conditions for generating this plasma, researchers from the University of Technology in Eindhoven (TU/e) in the Netherlands will combine computer simulations with field experiments. "There are too many variables that need to be regulated, so we must combine computer simulations with actual experiments to advance research."

Finally, because this technology will be adopted on a large scale in practice, it also puts higher requirements on researchers. “We must keep in mind the entire reaction conversion chain. The conversion process cannot be run for a long period of time in a situation where there is a large amount of carbon monoxide released and no oxygen separation method is used. Therefore, it is important to have regular discussions with all parties involved – for example, including End-users like Alliander."

"The mechanism of interaction between plasma and catalyst has not been fully studied."

Although participating in this research project are all academic personnel from the University of Technology in Eindhoven, Netherlands (TU/e), the research strategy is slightly different: Dr. Qi Wang’s research plan does not actually include making methane, but Produced into liquid methanol fuel. However, the first step is the same: that is, carbon dioxide is converted to carbon monoxide. “In order to produce methanol from carbon monoxide, we use the technology of our industrial partner Evnoik. The basic method is also to add hydrogen. With the right catalyst, we can efficiently produce methanol.” Using plasma to convert carbon dioxide to methanol is not A new idea, this researcher from China explained. However, this process has not been widely studied, and its benefits so far are very general. "Effect depends on the synergistic mechanism between plasma and catalyst, which unfortunately has not yet been thoroughly studied. In addition, nobody knows how to use this technology on a large scale to the industrial application level."

Dr. Wang's research goals in the next few years are to solve the above mentioned problems. To this end, she will work closely with Prof. Hensen and Prof. Toschi, experts in the field of catalysts. "Because this project is an interdisciplinary field, we must maintain communication with scholars who come to the fields of physics and chemistry. I am confident that we will achieve positive results," Dr. Wang added finally. ([Li Yu, graduate student of Eindhoven University of Technology])