Depends.sendler2112 wrote:Very interesting. It is misleading if total energy is always quoted as thermal. So how do we correlate the total electrical production from your graph with the total energy from mine? Obviously all thermal manufacturing and most transportation and heat is not electrical so the total energy consumed will be much more than the total electrical.
Using primary energy has its uses. let's say for CO2 emissions or usage of resources, because it counts what you "burn".
If you want to show the usage / "usefulness" of energy I suggest using the "Endenergieverbrauch" (gross final energy consumption???). This also has its limits because 1 liter of diesel is counted as 10kWh, the same as 10kWh of electricity. But for running a car 10kWh of electricity is compareable to 40kWh of Diesel.
There is also the option to compare "Nutzenergie" (useful energy???) where you would compare 1kWh of heat to another 1kWh of heat or 1kWh of mechanical energy to drive a car to 1kWh of mechanical energy to drive a car with another engine. But this is difficult and also has its disadvantages because oyu do not see the efficiency of energy production.
Important is that you know what you look at.
It is not illegal or "false data" to count 1kWh nuclear electricity as 3kWh nuclear power, it is just how counting nuclear power production is defined for "primary energy" data.
The point is, that 1kWh primary energy of solar or wind energy can replace much more than 1kWh of nuclear or coal in power plants and also much more than 1kWh of oil if used in a electric car or in a thermal heating pump for room heating.
So sure, if you look at the whole picture (which is a good thing) solar+wind is still just a small part, either in Germany and also worldwide. As nuclear has always been just a small part. So there is still a long way to go, but it is possible and not so difficult as many people predict.
We have lots of analysis about the German grid and today at almost 40% RE share there is NO urgent need for storage, the opposite is true, actually there is not much money in the arbitrage market (buy cheap -> store -> sell expensive).
Most experts say that we neen more storage at around 80% RE share, before that we need more flexible thermal power plants (which we already retrofit) and a morre powerful grid.
what you do after 80% RE is up to debate. There are several options. A very intersting one would be a large grid, but there are others, too. You most likely would not use battery storage for 24h storage capacity. Batteries (today) are much better suited to store for 30-60 minutes. Germany now has around 200TWh of storage capacity in methane and we are adding another 140TWh. Some people say making hdyrogen or methan from electricity and using them in gas power plants / fuel cells / trucks would be a wise option. Efficiency is low and in case of methane you have the end of pipe problem with CO2 , but it is an option...
Today there are several projects in Germany to build better PEM electrolysis systems in the MW class that can operate highly flexible and with better efficiency. Still very expensive, but solar PV has been very expensive just 15 years ago, too...