Picture: A canola field. The biomass can be used to manufacture green fuel. However, such a solution is not scalable.

What we need: Synthetic Green Fuel

We need to substitute usage of fossil fuel. The problem of the increased CO2 concentration in our atmosphere arises from man excavating fossil carbon-based fuel – in form of coal, oil or natural gas – and burning it and releasing the contained carbon in form of CO2 into the environment. We therefore assume that the increased CO2 concentration is man-made. If it is right that CO2 acts as a greenhouse gas and that it captures heat in the atmosphere by the greenhouse effect, the increased CO2 concentration will lead to global warming. At least a portion of global warming is then also man-made.

As a logical consequence mankind needs to replace the usage of fossil fuel with a substitute. Fossil fuels are used in all three energy sectors:

Cooking & heating/cooling

buildings & water heating/cooling, industry process heating

Mobility and transport

in cars, buses, trucks, trains, airplanes

Electricity

in coal, oil or gas power plants, block heat and power plants (BHKW) and micro-turbines

For all energy sectors, fossil fuels provide a constant and reliable energy supply. In simple words: We are used to having the energy source available at any time when we want it or need it. Any substitution technology therefore also needs to be constant and reliable, next to its scalability to live up to the full energy demand.

Substitution technologies in the electricity sector

In the electricity sector there is a substitute, which fulfils these criteria. Nuclear energy can provide constant and reliable electricity. But on the downside it carries the risk of disaster and radioactive pollution of our environment. Further, the safe and long-term disposal of the radioactive waste is not resolved. In any case, nuclear energy can neither cater for cooking and the widespread heating of buildings or water, nor for mobility and transport.

Thermal solar power plants or photovoltaic power plants, combined with short-term storage technologies to get over the night, can deliver constant and reliable electricity in regions with reliable sunshine, such as deserts. So these power plants can bring a local solution for supplying energy within the electricity sector. But then, many of these regions are far away from the hotspots of electricity consumption: Most of Europe, most of Asia, or most of America. Therefore their utilization is limited.

Wind turbines or photovoltaic facilities produce electricity, but they cannot meet the criteria to deliver constant and reliable energy, not even for the electricity sector. Their delivery is intermittent and non-predictable. To be able to replace fossil fuel just for the electricity sector one would need to combine their energy production with huge long-term storage capacities. This kind of storage is not available today. Building this would be very expensive. Using pump storage power plants would lead to massive nature conservation issues, for instance through building massive dams in mountain regions.

Long-range transportation of electricity from and to areas, where one can suitably produce or store electricity to areas of current demand is only a theoretical solution, because of efficiency loss and political dependence, not to speak of the ugly and expensive power lines.

Substitution technologies in the heating and mobility sector

Renewable biomass can substitute fossil fuels in the heating and mobility sector to a certain extent. While growing and storing biomass brings a constant and reliable energy supply, it is unfortunately not scalable. Growing biomass for direct burning or for processing into liquid fuels or gaseous fuels, like for instance ethanol or methane gas, competes directly with the production of food or animal feed. Food prices increase, leading to increased poverty, social unrest and human migration. It is simply unethical to grow fuel on the agricultural fields instead of food, in a world where many people have barely just enough to eat.

But production of biogas from waste is certainly a substitution technology. Only it has limited capacity.

Substitution technologies for all three energy sectors

Only synthetic fuel gained from renewable energy sources can truly substitute fossil fuels. Fuel contains stored energy, so unlike with electricity from renewable sources there is no storage problem. Transport and distribution does also not pose a problem, it is identical with the transport of fossil fuels today.

Fuels can be in solid, liquid and gaseous form. The latter two are most convenient to handle. Liquid fuels can be transported in tanker ships, tanker trucks or pipelines. Gaseous fuels follow the same principle. Storage is usually only ‘the flip side of the transport coin’ – it happens in tanks and pipe networks. In gas networks, storage can even take place simply by increasing the gas pressure. So often specific gas storage tanks are not even needed.

Power-to-Gas and Power-to-Liquid Technology

Renewable electricity, unless consumed directly because it concurs with current demand, can be transformed into synthetic fuel for long-term storage and, if needed, for long-range transport.

Power-to-gas technologies can transform electricity by electrolysis into hydrogen. Because we lack a hydrogen infrastructure and because hydrogen is rather difficult to handle, subsequent methanation or hydrogen-to-liquid technologies often make sense. During these processes one adds CO2 to hydrogen. The result of methanation is synthetic natural gas – SNG. It is almost pure and clean methane gas. This resembles natural gas, but it’s even cleaner because SNG does not contain any residual unwanted substances, only methane gas CH4, some unprocessed hydrogen H2 and some unprocessed CO2.

synthetic_green_fuel

Renewable electricity can also be transformed into synthetic liquid fuels, also called bio fuels. Again, the first step is to produce hydrogen by splitting water H2O into H2 and O2 through electrolysis. Thereafter comes the synthesis of hydrogen via the Fischer-Tropsch process by adding CO and CO2. This process is a collection of chemical reactions that converts a mixture of carbon monoxide, carbon dioxide and hydrogen into liquid hydrocarbons. It can create a number of hydrocarbon fuels. The result can be as diverse as synthetic diesel, synthetic methanol or synthetic kerosene (also called bio-diesel, bio-methanol or bio-kerosene) up to synthetic lubrication oil.

Burning synthetic fuels is completely clean, green and CO2 neutral

All synthetic fuels have in common that we can burn these in any quantities without remorse and damage to our earth. With synthetic fuels, the CO2 cycle is closed. When burning these fuels, we only release CO2 into the environment, which has been taken out of it before, during the production process. Molecule by molecule. If you want so, the production process resembles the growing process of plants and their photosynthesis. Burning synthetic fuels is clean, it does not smell and it does not harm the climate.

Synthetic fuels can be easily stored and transported, and therefore they constitute a constant and reliable energy source, just like fossil fuels. Synthetic fuels, such as SNG, are a fully-fledged substitution for fossil fuels. They therefore have the potential to replace fossil fuels, to resolve the problem of increased CO2 concentration in the atmosphere at its root, and therefore to relieve the problem of man-made global warming and unwanted climate change.