From pv magazine Germany
A global energy turnaround without hydrogen is unthinkable. The cost and efficiency of hydrogen make alternatives appear more attractive in many sectors. In the building sector, for example, hydrogen will in principle not be used.
That is the verdict of a study that originated from the HyPat joint project. The Fraunhofer Institute for Systems and Innovation Research ISI, along with other institutes, including the Fraunhofer Institute for Solar Energy Systems ISE and the German Energy Agency (Dena), examined 40 recently published studies on energy systems and hydrogen scenarios and used 300 reduction scenarios from the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC) to determine a range of global hydrogen demand.
According to their forecasts, a scenario in which the greenhouse gas reduction is more than 80 percent by 2050 will require between 4 and 15 petawatt hours of hydrogen and synthesis products such as ammonia and methanol. One petawatt hour is equal to 1 million gigawatt hours.
Calculated on the basis of global final energy demand, that is 4 to 12%. The consumption of hydrogen is subject to strong regional differences. In relative terms, the EU will become the main consumer of hydrogen. The study calculates that up to 14% of the final energy requirement could be covered by hydrogen. In China, the authors assume a share of up to 4% in final energy consumption.
Calculated in absolute numbers, however, the relationship looks different. The major share of the EU will only lead to a consumption of 0.3 to 1 petawatt hour per year. In China, the demand will be between 0.6 and 4 petawatt hours per year.
“Our evaluations underline that hydrogen will play an important role in future global climate policy — but it will not be the dominant final energy source in the future,” says Martin Wietschel, professor at the Karlsruhe Institute of Technology (KIT) and head of the Competence Center for Energy Technologies and Energy Systems at Fraunhofer ISI. “In order to reduce greenhouse gas emissions globally, measures to save energy and direct electrification based on renewable electricity, such as through heat pumps, electric vehicles or in heating networks, are seen as the most important levers. Hydrogen, on the other hand, plays a relevant role in certain application areas in which other technologies cannot be implemented technically or economically.”
Broken down by sector, mobility shows the highest demand in absolute figures as well as relative to total demand. The study assumes that by 2050 around 16% of global energy in the mobility sector will be covered by hydrogen and its synthetic products. The authors forecast a share of 14% for the Chinese market. The EU stands out in this sector with an expected share of 28%.
The use of hydrogen in road traffic offers short “charging times” and long ranges compared to electric cars. However, the overall efficiency of fuel cell vehicles leaves a lot to be desired at just 34%. That is nevertheless still well above the 14% efficiency of vehicles that are fueled with synthetic fuels. Electric cars achieve a value of 77% in this metric.
The use of hydrogen is more conceivable for heavy-duty transport, since the weight of the batteries becomes a problem in this area of application. In addition, the long loading times are not always compatible with the way logistics companies work. In any case, hydrogen and above all synthetic products will be used in air traffic and shipping.
These technical and logistical uncertainties sometimes lead to very large bandwidths in the hydrogen demand in the 40 studies examined for the mobility sector. As a result, investments in production, transport and consumers are still avoided. In Europe, the individual studies predicted a hydrogen share of 13 to 36%. For China it was between 10% and 19%.
Compared to the mobility sector, lower demand is forecast for the industrial sector. However, unlike in mobility, there are often no alternatives here. Especially in the iron and steel industry, as well as in basic chemistry, it will not work without hydrogen, ammonia and methanol.
However, this does not apply to all areas of industry. When it comes to the provision of heat, for example, there are even greater uncertainties. This is mainly due to the available alternatives. According to the study, by 2050 hydrogen will account for between 2 and 9% of the world's total energy requirements in the industry. Here, too, there are strong regional differences. The majority of the studies examined expects a share of 3 to 16% for Europe in 2050. Individual studies even forecast a share of 38%. In China, on the other hand, the proportion will only be between 1 and 4% in 2050.
The more alternatives there are to hydrogen, the lower its use. This applies in particular to the building sector. According to the study, the share of building energy consumption in 2050 is likely to be less than 2%. Up to 1.7% is expected in the EU. Globally, the share is likely to be 1.6%. In China, only 0.5% of building energy requirements are probably covered by hydrogen.
The low use of hydrogen in the building sector is due to the other ways to save emissions, such as direct electrification with heat pumps and infrared heating. Alternatives are also significantly more efficient than fuel cell heaters, which are only 57% efficient. Even heating systems that burn compressed hydrogen directly for heat use only achieve an efficiency of 64%. Electric instantaneous water heaters, on the other hand, achieve 95%. The authors of the study assumed an efficiency of 300% for heat pumps.
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