Energy in Future  
Dr.-Ing. Dieter Bokelmann

Explanations and Tables

Primary Energy World 2018

The world's primary energy production in 2018 was 168693 TWh (Table Primenw). The aim is to replace the use of coal, oil and gas with a total of 136641 TWh with renewable energies. Biomass and electricity generated by nuclear, hydro, wind, solar, geothermal and other renewable sources is not taken into account.

Primary Energy World by type of use, efficiency conversion and useful energy

The conversion efficiency from primary energy to useful energy was derived using the Sankey diagram Energy Consumption USA in 2018 (USEn2018), thus creating the table Effi1 and building on this the table PrimINOUT. Although the USA does not necessarily match the world average in terms of consumption patterns, the accuracy of this study is not relevant due to a lack of some data. In table Effi 1, 5 efficiency values were derived directly from the diagram. For the other uses, an average of 37.34% was calculated, so that the total efficiency of 31.83% is identical to the value in the chart USEn2018 right side relative to 97.7 quads INPUT Energy and "Energy Services". 136641 TWh of primary energy is used with an efficiency of 31.83% 43492 TWh of useful energy. The renewables are not taken into account, the error is insignificant for the further investigation.


Calculation of the costs per kWh for the 4 generation types solar/direct power, solar/artificial fuel, wind/direct power, wind/artificial fuel net excluding taxes.

The size of the base (in the tables is this simplified the primary energy to be replaced in Twh) is irrelevant for the cost/kWh, because everything is rule of three calculation. In the same way, the base could have been for example 100,000 TWh, the result is the same. See 4+2 tables (2 special cases for Germany solar due to reduced irradiation instead of 1500kWh/ kWPxyear only 1100 kWh/ kWPxyear). A 20-year annuity loan is supposed for the repayment of the investment costs (Table Credit20J).

 In addition, based on 18) were taken into account 24.6% surcharge for repairs, maintenance and 112% for energy transport or construction of networks or conversion into artificial fuels such as Blue Crude or Hydrogen. Biofuel is not taken into account. Finally, 10% surcharge for pre-tax investment profitability was taken into account. In these 4+2 tables there is no surcharge for state taxes. The prices determined are net values. The costs per kWh are rising to


0.099 €/ kWh wind electricity directly used  (Table WindELW)


0.126 €/ kWh solar electricity directly used (Table SolELW), 0.172 €/ kWh , solar electricity directly used Germany (reduced irradiation, Table SolELD)


0.165 €/ kWh Wind Conversion Fuel (Table WindFW)


0.211€/ kWh Solar Conversion Fuel (Table SolFW), 0.287 €/kWh Solar Conversion Fuel Germany (red. irradiation, Table SolFD)


The prices for wind are cheaper than for solar, the fuels are logically higher than the direct use of generated electricity in relation to solar or wind (assumed losses about 40%) due to the conversion losses. The 4+2 tables also include the area requirement solar and wind equipment in % surface world per TWh generated energy. For the types of solar generation, the costs for Germany were calculated on the basis of lower real annual irridiation. This naturally results in higher costs, for solar direct electricity 0.172€/kWh (Table SolELD) and for solar conversion fuel 0.287€/ kWh (Table SolFD). .


Efficiency factors for determining the necessary energy generation by the 4 solar/wind alternatives based on the output of primary energy coal, oil, gas

Table Effi2 defines the conversion factors for the conversion of the required useful energy into the amount of electricity to be supplied by solar and wind. This is for use as direct electricity (1 factor 76-100) or for use as converted fuel (multiplication of factor 1 with value 60 for converting direcly used electricity into fuel and factor 2 depending on the mode of use).


Calculation for each of the 4 production alternatives for the extreme case 100% single source the necessary landscape and total costs net

4 tables with landscape use and total costs World

In the 4 tables (SolEL, SolF, WindEL, WindF) it is assumed that the required amount of electricity is generated 100% with in each case one of the 4 alternatives by combining the pairs of solar-wind and directly used electricity-conversion fuel. The annual production costs are calculated net, as well as the required surface world (based on land area excluding Antarctica).

Chart and rating

See diagram Dia4Alt. For the assumed special case 100% generation by each of the 4 possible variants, the annual production costs of the variants directly used electricity are significantly cheaper than the variants with fuel conversion. In the case of directly used electricity, the landscape consumption of solar is the better option. The production costs of the fuel conversion variants are significantly higher and also the landscape consumption. If possible, no fuel should be converted via wind, however the annual production costs are lower than with solar. Therefore, the special case 100% solar direct power would be the best alternative. However, since only one mix is technically feasible, the order for solar direct power, wind direct power, solar fuel (though more expensive than wind) and then wind fuel should be considered as a last resort.


Possible example of energy mix world, costs net excluding taxes and space requirements

The scenario is presented with 50% solar and 50% wind, each with 30% direct power and 20% fuel conversion. The landscape consumption is with 2.19% landscape world without Arctic within a tolerable frame (Table PossExaW).


Possible example of energy mix Germany, costs net excluding taxes and area requirements

4 scenarios were considered.

In Scenario 1 (FinTaxD), all primary energy is generated with solar power and wind power. Since in 2018 the share of solar energy in 100% primary energy was 1.3% and the share of wind energy was 3% 19),in the scenario the share of solar energy is estimated at 35% and the share of wind energy at 65%. In solar energy and wind, 10% of the 100% sum would be converted into fuel. Unfortunately, the scenario is not feasible because the required area is 12.33% of the area Germany multiplicated with 1.2 (offshore). At best, maybe 3% can be realized (?), the remaining electricity or fuel has to be imported, but this would be technically possible in terms of scenario world. In relation to the relatively small land area of Germany with 0.31% of the land area world without Antarctica, the share of primary energy Germany to the primary energy world is small but relative to the land area high (factor 7).

In Scenario 2 (FinTaxDEL), it was assumed that only all electrical energy is generated by renewables. Here, the required land area is 2.39%, which would be quite feasible.

In Scenario 3 (FinTaxDEL+TRANS), in addition to scenario 2, transport energy via renewables is to be generated. The required land area rises to a hardly feasible 3.99%.


Amount of the necessary tax rate to ensure that tax revenues are the same in the case of Germany

The net cost of electricity generation has already been explained. But it is not possible without taxes. Even if the scenario Germany with 100% self-generation is not feasible, the taxes rates were calculated in such a way to receive the same sum of tax revenues as in 2017. This is a necessary need. The tax rates are supposed in the FinTaxD table to receive 43.2 Mrd.€ tax revenues, as well as the resulting energy prices for kWh and litre of fuel. The stated tax rates for the 4 energy sources are chosen (and can of course be chosen differently) that the costs/ kWh correspond roughly to the actual costs, namely appr. 0.30 €/ kWh for private consumers and appr. 0.10 €/ kWh for industry.


Amount of the necessary tax rate so that tax revenues are the same for the world on the basis of Germany

In the World scenario, Germany's tax revenues were adopted as the basis for 2017 (rule of three calculation), with results see Table FinTaxW. The tax rates adopted are freely chosen. The world tax rates on energy and fuels are very different. It would go too far and would also be presumptuous to deal with individual countries. For Germany, this is possible, since the total is known and, apart from that, the tax rates are already relatively high.


When implemented in a period of 20 years, how much capacity building Solar + Wind per year is necessary, comparison with actual and evaluation

In the table Summary Data, the necessary yearly capacity increase in GW are compared annually to the current yearly capacity increase to meet the scenarios. Also the final necessary total capacity in GW is shown in comparison with the already existing capacity. In the end, the number of years have been calculated for the achievement of the target, the 100% avoidance of the use of fossil fuels. The result is unsatisfactory. These are 323 years for the world and for the scenarios Germany Scenario 1 it is 293 years (not feasible because of high space requirements), in scenario 2 it is 71 years and in scenario 3 it is 122 years. Once again the hint that the variant 100% replacement Fossil Germany is not accessible independently of the rest of the world realizable. Because of the relatively large required area of 12.33%. most of CO2-free energy Germany must be generated by importing direct electricity or importing fuel generated by electricity generated in other countries.

The calculation also negatively includes the fact that, firstly, the existing solar and wind equipment will have to be replaced in the next 20 years. Secondly, grey energy is generated in the construction of equipment, i.e. in principle the plants only produce CO2-neutral electricity after approx. 10% of the running time of approx. 20-25 years (but then they produce approx. CO2-neutral for approx. 18-23 years). Both are not taken into account here, but would simply have to be taken into account in the calculation. However, this contrasts with some potential for improvement and new developments in the coming years.


Potential for improvement

among others

1. Simultaneous use of land for solar and wind.

2. Improving the efficiency of solar. Either via multi-layer wafer or via multi-irradiation or other developments. In principle, photovoltaics can also be coupled with solar thermal energy.

3. Improving the efficiency of wind.

4. New development of power storage systems, for example environmentally friendly large-storage battery systems and auto-replaceable battery packs in standard sizes for electric cars or long-distance battery trailers at petrol stations.

5. Development of CC gas turbines (combined cycle gas turbines with coupled steam turbines for the use of the residual heat of the GT), which can also be operated with green fuels such as hydrogen, Blue Crude, etc. These are then also used to generate electricity in times of night-time wind slack periods using green fuel.

6. Efficient energy exchange across national borders and also better still continental borders (as from Africa to Europe) (export of energy to Germany).

7. Reducing private and commercial transport activities. Private through rethinking, conviction and fuel prices. Commercial target through more local production.

8. A Reversal of Population Growth

9. A change of the actual consumer behaviour

10. Production of longer-living recyclable quality products. Avoidance of cheap products with poor quality and short lifetime.

11. Reforestation of woods 

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.

The necessary reinforcement factor of the current annual investment measures for renewable energies is problematic, see sheet data compact. To switch the world to CO2-free energy production in 20 years, this factor is 16. €2932 Mrd. € (Mrd.=10 9) would have to be invested annually, which would have to be achieved in terms of costs and land use. However, it is questionable whether the production capacities for solar and wind can be increased to 16 times in the world scenario. Nevertheless, in order to achieve the goal in a reasonable time, a temporary investment in nuclear electricity supply would have to be accepted, which would be dismantled later as the target was achieved.

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 diagram below shows the only possible meaningful development for the Location Germany in order to reach the goal in 30-35 years.