Renewable energy is enough for everyone and is cheap
The discussion about the energy revolution and the possibilities and costs of a CO2-free energy supply has been conducted vehemently for many years. Renewable energies are often questioned with false or outdated arguments. Therefore first a few basic facts to the renewable energies:
- A worldwide energy supply with renewable energies will not fail due to limited potentials. The huge amount of solar radiation that hits our planet is about 10,000 times greater than the total current world energy consumption. It is sufficient to capture and use a fraction of this energy in the form of solar and wind energy, hydroelectric power or biomass.
- A 100% CO2-free energy supply does not fail because of the costs and affordability of renewable energies. Already today the production costs for wind and solar power are lower than those of new coal or gas power plants, not to mention nuclear power plants – and in this calculation the costs for ecological consequential damages are not even taken into account.
Which hurdles have to be overcome for the energy transition?
So if there is enough renewable energy at a reasonable cost, why is the energy turnaround slow and far too slow? There are several reasons for this:
Renewable energies (or rather the final energies generated from them) are usually produced in decentralised plants. This does not fit into the concept and business model of large energy groups. For years and wherever possible, they have tried to hinder the expansion of renewable energies. In view of the dramatic nature of climate change, however, this blockade attitude can no longer be socially justified today.
- Renewable energies have different system requirements and are not compatible with traditional generation systems based on baseload power plants. The new infrastructure necessary for renewables, such as the expansion of electricity grids, has been sleepy and hampered for years.
- Fossil and nuclear power generation plants are still heavily subsidized by governments, worldwide at around US$500 billion per year. And, to an even greater extent, they generate costs through environmental and health damage for which they are not responsible. Without this double subsidy, fossil energies would not be competitive.
Fossil energy use is physically changing our world: it pollutes soil, air and water and causes dramatic climate changes. For many people, however, these changes are not (yet) visible.
Renewable energies change our world optically: due to the mostly smaller outputs, many more plants are needed compared to coal-fired and nuclear power plants. As a result, these plants are also seen and perceived by many people. The illusion that electricity somehow comes out of the socket and its generation has nothing to do with one’s own living environment can no longer be maintained with renewable energies. But as long as you don’t think the comparison through to the end and judge according to the scheme: „coal electricity comes from the socket and doesn’t affect me otherwise“ and „renewable electricity comes from ugly wind power plants, which change my familiar picture of the landscape'“, the cleaner and more environmentally friendly renewable energies unfortunately lose out.
The renewables are not environmental angels and they do not lead to an ecological paradise. Renewable energy plants also require rare raw materials for production that can only be obtained with environmental damage, and of course they also have their side effects during operation. However, these are far lower than those of coal-fired and nuclear power plants. This consideration between the possible alternatives, not an idealised and side-effect-free dream world, is the main reason for the energy turnaround. It is therefore also inadmissible, however, to no longer pay attention to energy saving and energy avoidance when referring to clean power generation. Renewable energies provide us with some air with the current dangers, but they alone do not solve the problems of our excessive consumption of resources.
- Wind power and solar plants are not always available. They do not always deliver power when it is needed, and they may deliver power when it is not needed. Opponents of wind power often use this fact to justify their claim that the energy revolution could not work at all due to the lack of storage capacity. It cannot be denied that larger storage capacities are indeed becoming increasingly important with a very high proportion of renewable energies. However, there are already high flexibility reserves that have not yet been used due to the low monetary incentives. No bottlenecks are therefore to be expected in the foreseeable future, even with an increasing share of renewable energies.
Which energy storages do we need?
Although the storage problem does not yet play a significant role in the energy system transformation, it has been regarded as a prerequisite for the success of the energy system transformation in the political debate and in the public for years. The most promising storage technology currently cited is the use of renewable electricity for the production of hydrogen, possibly with a further processing step towards methane. How promising are these technologies, and what can generally be expected from this power-to-gas?
When using power-to-gas, excess electricity from renewable energies is to be used in a hydrolyzer to generate hydrogen. In this way, the idea is that electricity that can no longer be used elsewhere can be stored in the form of hydrogen and reused in times of low electricity production from wind and solar power plants. At first glance, this concept sounds plausible and tempting. A closer look, however, reveals a number of problems. The conversion of electricity to gas and later back from gas to electricity entails considerable losses in efficiency. Depending on the technology used, only 20 to 40% of the electricity used is recovered. P2G is therefore a storage facility with a very high loss that would only be technically and economically viable if the electricity used were really energy that would otherwise no longer be usable, and if in this way appreciable quantities were collected that could not or would not be dispensed with for supply reasons.
Are these requirements met with Power-to-gas? Unfortunately, the facts speak a different language than the often full-bodied promises of the protagonists. Because in Germany there are no significant amounts of grid-connected surplus electricity. The often cited quantities of regulated electricity that are alleged to be available for P2G (in 2017 it was 5.5 TWh or approx. 2.5% of the renewable electricity) come almost exclusively from wind power plants in northern Germany and are related to the lack of grid connection to the transmission grid.
There is no nationwide surplus electricity from renewable energies. Therefore, P2G systems operated in central or southern parts of Germany cannot use surplus electricity. In reality, these plants use electricity (mostly from wind turbines) which is either produced exclusively or predominantly for these plants, but which could also be used elsewhere without any problems and could be used more sensibly and efficiently there because of the efficiency losses in the P2G plant. Or electricity is used from negative control energy, which also consists to a large extent of coal and nuclear power and is therefore neither surplus nor renewable.
Power-to-gas is often still a cheat package
In addition, P2G systems from so-called surplus electricity have a fundamental, irreversible problem: they only have very short operating hours because this surplus electricity only exists for a few hours a year, if at all. This makes hydrogen from German P2G plants very expensive, and because of the fundamental problems, it is not to be expected that prices will fall significantly, as was the case with photovoltaic plants.
In addition, there is another problem with domestic P2G plants: for a complete energy turnaround in all sectors, i.e. including mobility, heat supply, manufacturing industry and carbon-dependent chemicals, about 4 to 7 times the current electricity demand would be required. It is immediately apparent that no major losses in efficiency can then be allowed in electricity generation. If the electricity were to be generated to a considerable extent via P2G plants, then the necessary primary production would have to be significantly increased again. Since this is not only possible and sensible with photovoltaic plants (in winter we would have hardly any electricity), an additional immense number of new wind power plants would be necessary. It seems unlikely that there would be broad social acceptance for such a scenario.
Importing hydrogen?
It is more likely that hydrogen will in future be produced in regions with high solar radiation or very good wind conditions, where there is also an actual surplus of electricity that cannot be used locally or nationally. At such favourable locations, the power generation costs from wind and PV plants are very low, and due to the size of the P2G plant, hydrogen could also be produced there at low and competitive prices.
This leads to the conclusion that there will be a worldwide market for hydrogen in the future, but that most of it will not come from Germany. It would therefore be desirable for the success of the energy system transformation if the creation of the necessary infrastructure for the import and use of hydrogen were to begin today. At the same time, of course, the expansion of renewable energies and electricity grids is also necessary.
As an alternative to a hydrogen economy, there is also the possibility of fully converting energy use to the final energy carrier, electricity. This would certainly be possible with the help of continental and intercontinental electricity grids. However, a number of questions remain open for such a scenario, such as the availability of resources for the large storage capacities required. The future will show which system will prevail. In any case, however, we do not have to worry about security of supply and the amount of our electricity bill.