The aim of the studies was to determine to what extent a 100% replacement of fossil fuels by solar and wind energy is technically possible and can be justified in terms of cost and landscape use, taking into account the advancing climate change.
The production and consumption of the world's primary energy is explained. The basis for this is an energy flow image of the USA 2018 (Sankey diagram).
The main sources of renewable energy are photovoltaics and wind power. These can be used as direct current or as electricity-generated fuel. For the 4 resulting variants solar direct electricity, solar fuel, wind direct power, wind fuel, the production costs/ kWh were calculated as well as additional costs and grid distribution costs before tax.
For the assumed special case 100% generation by each of the 4 possible variants, wind direct current and wind fuel are cheaper than the variants solar. The landscape consumption of wind power is significantly larger than photovoltaics, the investment amounts slightly lower. Therefore, the special case 100% solar direct power would be the best alternative. However, since only a mix is technically feasible, the order in which solar direct power, wind direct power, solar fuel and then wind fuel should be taken into account.
The scenario World is technically and cost-wise with a landscape consumption of 2.19 % realizable, the 100% variant Germany self-generating scenario is not realizable because of the high landscape consumption of 12.33%. This is due to the ratio of energy consumption to land area compared to the world average. In the case of Germany 100% electricity generation by renewables, 2.39% of landscape is consumed, which would still be feasible. Even the addition of the replacement of fuels for transport leads with 3.99% landscape consumption rather to the necessity of importing energy, which would be possible technically and in terms of costs.
If one considers the current activity World and Germany in the conversion of primary energy production by renewable energies, the goal world will only be reached in 323 years. For Germany, this is 292 years in case 100% (not feasible due to landscape consumption), 71 years for replacement only electricity generation and 122 years for the replacement sum electricity generation plus fuels transport.
Climate change can only be contained if all efforts are made together across the world to force the growth of solar power and wind power in such a way that in a time of 20 years the calculated values of the world will be reached. Until then, the electricity supply should be supplied by robust gas-fired power plants (combined-cycle power plants), combined with district heating (and thus an overall efficiency above 90%). These power plants must be designed in such a way that they can later be operated with suitable green fuels. At the same time, the existing nuclear power stations should not be decommissioned prematurely and should be used as a buffer for the transitional period.
The costs can be financed, but a reasonably increased price for fuel must be accepted. In terms of the world situation, this challenge would offer the following advantages. Firstly, the generation of energy via solar and wind power in developing countries and poorer countries with relatively low population density and large unused land areas, and the creation of jobs for the construction and maintenance of the necessary equipment. Secondly, technical development and production of high-quality plant components in the highly developed countries with relatively high population density, also creating new replacement jobs for the decommissioning of oil and coal production.
The content of the listed websites on this website is not my own work. I have checked and verified the calculations to the best of my knowledge through multiple checks, but I cannot completely rule out errors and am grateful for any meaningful hint or contribution. My own assumptions may differ somewhat from current developments, but this has relatively little impact on the overall result. Whether we reach the target in 150, 200 or 250 years is, in any case, too late. The whole thing is a challenge for humanity.
I hope that many interested people will read and understand the message of this site, and that the expert teams of many countries and their leaders will also find this an incentive to accept the challenge. If a significant proportion of the countries consuming a lot of primary energy can agree on an agreement, the world has a chance of surviving in its current state. If not, there will be end scenarios that have already been filmed. It is still time to limit the damage, but it's already 5 minutes after 12.
The chart below is showing a simplistic timeline of what the implementation to a CO2-free energy procurement would look like in 20 years. The fossil fuels oil, coal, gas would be reduced to zero. The existing energy sources biomass and the existing renewable electricity production will remain in place (in the end, nuclear power can also be reduced to zero if more capacity is built up accordingly by solar, wind or others). The shares of the 4 alternatives Renewable Solar and Wind are raised from 0 to the calculated values. The amount of primary energy is lower than in the year zero, because the proportions of direct electricity in particular are significantly more efficient.
Implementation in this period is unfortunately unlikely, since on the one hand not all countries participate in it and on the other hand the necessary annual increase in investments in renewable energies (factor 15 to 2019) is difficult to achieve (but not technically impossible). The fact is, however, that annual investment needs to increase significantly.
Germany must concentrate on switching at least 100% of electricity production to renewable energies and at the same time, importing the remaining primary energy in form of hydrogen (or similar). There are too few suitable land areas for the production of large quantities of green hydrogen in Germany. From today's point of view, this means an import of about 50 million tons of hydrogen/year.
If Germany succeeds in doubling its annual investments in solar and wind and importing parallel these quantities of green hydrogen from suitable countries (with technical support), Germany should be CO2-free in 30-35 years (1 generation).
The Chart below shows a simplistic linear development of primary energy production in Germany for this case.
Once again, briefly.
1. The international community is working towards carbon neutrality.
2. However, investment activities are far too low and the target is only reached very late.
3. In terms of cost and land use, the target could be achieved in 20 years, but investment activities need to be increased by a factor of 15. As this cannot be achieved in a short time, alternatives must also be used. Some countries are betting on the retention or expansion of nuclear energy. In Germany, the existing nuclear power plants should not be shut down until the 100% CO2-free target is within reach. Unless one accepts the increased risk of power outages.
4. The most efficient variant of renewable energies is the direct use of the energy generated.
5. The conversion into hydrogen or other fuels is very suitable as a buffer for periods without wind and sun, but is much less efficient.
6. The electric car is thus at the forefront because it uses the CO2-free current directly with a high efficiency. Approximately 80% of the electricity generated is used.
7. If the electric car is still powered by electricity from fossil fuels during the transitional period, that is still the better alternative. The overall efficiency of approx. 55% (average modern gas turbine and coal-fired power plant) and 80% would be above 40% and would therefore be better than the use of the internal combustion engine with its high heat losses. However, the total capacity of electricity generation is not sufficient for this purpose.
8. If there is sufficient capacity, the vehicle (fuel cell or combustion engine) operated with the buffer medium hydrogen or similar fuels is an alternative, but only with green hydrogen from excess green electricity. This especially for trucks and buses with long journeys.
9. In order to form a buffer for night-time with lows, a corresponding part of the CO2-free electricity must be converted into fuel. This can then be converted into electricity with suitable gas turbines using the waste heat.
10.There is room for improvement, but this is countered by an unbridled increase in the world's population and a further increase in electricity consumption.