The best energy is that which is not consumed in the first place. Logical, all critics of common bon mots may now object. But how is that supposed to work in a globalized world and an increasingly digital economy? Industry needs energy, cars need fuel and the home needs to be heated. You may be reading this text right now on the screen of your PC. As you can see, reducing energy consumption is one thing. But it has to work. Above all, the primary energy consumption of fossil fuels must be reduced. But what is primary energy? A common definition of primary energy states that it is the usable energy content of a naturally occurring energy source.1 It is the energy that occurs directly in the sources. As it is with definitions, especially that of primary energy definition, they are rather bulky. Probably an example will make it clearer. Primary energy sources include lignite, petroleum, and natural gas, but solar energy, wind power, hydroelectric power, geothermal power, and tidal energy are also primary energy examples. Thus, primary energy includes both fossil fuels and renewables.
Primary energy is therefore energy that has not yet been converted. This is quite the opposite of secondary energy.2 It includes all energy sources that have been further processed. These are substances that do not occur naturally in this form. For example, numerous secondary energy sources such as gasoline, liquid gas and heating oil are produced from the primary energy petroleum. The situation is similar with the primary energy wind. Wind turbines are needed to harness the power of the wind for human use. However, it is a long way until the electricity finally flows out of the socket. The energy has to be converted several times and sometimes transported over long distances. Hydrogen and fuel cell technology, for example, can act as converters and storage systems. If the energy transition and the achievement of climate protection targets are to succeed, hydrogen is the means of choice. Green hydrogen in particular plays a major role in storage technology. It is produced in a climate-neutral way by electrolysis of water, using only electricity from renewable sources – such as wind power.3
The climate-neutral hydrogen can be delivered decentrally to where it is needed: to the consumers. On site, a fuel cell then converts the fuel back into electricity. Both hydrogen fuel cells and direct methanol fuel cells are part of SFC Energy’s wide range of environmentally friendly power generators. Far away from the conventional power grid, they make an important contribution to supplying, for example, measuring stations, traffic control technology, or civil surveillance systems with environmentally friendly electricity. Fuel cells also hold great promise for more sustainable mobility concepts and more efficient power and heat supply in private households. As a combined heat and power system or combined heat and power plant, fuel cells generate electricity and heat. This is not only particularly efficient, but even saves money for the operators. And saving money is not only the order of the day in pecuniary terms. A steadily growing number of end devices in the household, more and more vehicles on the roads and the enormous increase in the global trade in goods associated with this have led to a sharp rise in energy consumption.
According to an observation by the International Energy Agency (IEA) and the German Federal Agency for Civic Education (Bpb), primary energy supply increased from 6,115 million metric tons of oil equivalent to 14,282 million metric tons of oil equivalent in a 45-year period – between 1973 and 2018. This represents an increase of nearly 134 percent.4 It should be noted that the share of primary energy from fossil materials in total primary energy supply has been declining in relative terms. For example, while the share of oil was still 46.1 percent in 1973, it was only 31.5 percent in 2018. In contrast, the shares of coal and gas in global primary energy supply increased by 2.3 percentage points and 6.8 percentage points, respectively, to 26.8 percent and 22.8 percent. As pleasing as the relative decline in the share of oil in primary energy supply is, however, it says nothing about the absolute volume of oil supplied. During the period under review, it increased by 59.7 percent. In the case of the primary energies coal and gas, the volume supplied actually increased by 156 percent and 233 percent respectively.5
So there is still a lot to do when it comes to making primary energy production more sustainable, and to transporting, storing and using the energy. The German government has also set itself ambitious targets in this area. Primary energy consumption is to be reduced by 20 percent by 2020, by 30 percent by 2030 and by 50 percent by 2050 compared with 2008 levels.6 To this end, it has formulated the Energy Concept 2010 and the Energy Efficiency Strategy 2050. In 2019, the decrease in primary energy consumption was 13 percent compared with 2008, with renewable energies in particular increasing their share of primary energy consumption in relative terms. This is largely determined by the economic cycle as well as prices for raw materials and technical developments.78 Weather conditions also play a major role. If there is a severe winter, the demand for heating is high. At the same time, of course, the weather also affects conversion technologies. If there are extended periods of darkness, solar panels cannot convert solar energy into electrical energy. If there is no wind, the wind turbines also stand still.
The efficiency of individual primary energies in conjunction with the associated conversion technology provides information on this. This is the ratio of useful energy to the amount of energy supplied. The former comprises the total energy potential that consumers can use. Here is an example: A car engine has an average efficiency of 20 percent. Of 100 percent of the fuel (diesel or gasoline), only one-fifth is converted into kinetic energy. The rest is lost in the form of waste heat. Vehicles with electric motors, on the other hand, achieve efficiencies of 90 percent and more. The electric unit generates a mechanical drive power of 0.9 kilowatts from one kilowatt of electrical energy. The situation is similar in the home. Heating systems that rely on fossil primary energies are less efficient than cogeneration plants, for example. The latter produce electricity and, through cogeneration, simultaneously ensure that the resulting heat can be used for heating. In this area, too, the fuel cell can be used as a key technology for successfully finalizing the energy transition. It ensures higher efficiency and environmentally friendly energy generation in stationary and off-grid applications. In this way, it makes an important contribution to reducing the consumption of fossil primary energies.