Our civilization has managed to consume an average energy per person 50 times higher than that of our food and although this energy is ridiculous compared to the energy that comes to us from the sun, and almost 20 times less than nature’s capacity to sequester, it is much higher than the differential of sequestration/emission of CO2. We live in an ecosystem where CO2 is measured in ppm, and where CO2 increases by 2ppm/year in the atmosphere, which supposes a 5% per year!
Fossil fuels are finite and although the hydrocarbon reserves known today, allow us to endure only 50 years, despite the new explorations, we must consider that the shortage will be an obstacle, as it was before the Great Crisis, which made us change the paradigm of its “termination”, that the hydrocarbons would not end, but would stop burning.
If the power consumption continues increasing it is foreseen that in 100 years we will reach values similar to those of Jurassic period, and long before than that we will undoubtedly observe its effects, and then a disruptive change will take place, with a real disruptive limitation of burning fossil fuels. Beside fossil fuels we may also consume biofuels, however, these fuels remove from the market land fertile area needed for food.
Renewable energy can be produced taking advantage of the bad soil. This will mean profit a 3-4% of uncultivated land to satisfy our power demand.
Dominant renewable energy sources are wind, and sun.
Wind energy on shore is almost has been fully developed in Spain, best locations are already in use and others has been discarded due to environmental issues. The present and future of wind energy is at sea where the conditions to profit from it are even better (more speed, longer gust, better quality). Therefore it is obvious that it can be used on a large scale.
Energy density form different sources
The learning curve for offshore wind is still steep, as it has been for all other renewable energies for several decades. In this case, it is the scale factor that is most relevant in reducing costs, together with the development of the industry that has allowed manufacturing and installation costs to be reduced in very significant percentages.
Nevertheless, if today we can produce renewable energy on land at costs competitive with fossil energy, it is true that with its contribution to the network is guarantee offshore wind energy still requires significant support, with a price per Kw-h higher than the market demand.
Only few countries, such as Denmark, the United Kingdom or Germany are making the economic effort that will result in improvements for everyone in this field.
If we talk about Spain, we had the commitment more than ten years ago, to have 3000 MW of offshore wind when the photovoltaic and solar thermal were 400 MW and three times the price of offshore wind. Almost ten times more than the programmed solar power was installed, but no offshore wind, and not because there were no projects!
Nowadays in the next plan, it is intended to multiply by three the renewable energies onshore and there is no mention about offshore.
Wind energy density in Spain
There is no doubt that a great part of the energy should come from offshore wind, not only because of the reasons set before, but also because it reduces the storage needs which imply 4 times the cost of renewable.
So that, which is the total power to be installed in Spain? Mathematical models will have the answer, however 10000MW of offshore wind will are envisage.
Offshore solar is not an option, even 2/3 of the planet is water. However, the option of cover swamp and other fresh water reservoir onshore with photovoltaic it could be a great advantage that allows to easily correct the azimuth and increases the performance.
Tidal and currents energy is usable with remarkable efficiency in certain locations, ranging from the Florida Straits or locations such as the French Coast, with the storage of the tides.
Wave energy use, despite its high energy density or perhaps because of that, will continue to be the subject of countless mechanisms, almost all of them capable of recovering energy, but all of them victims of the stresses produced by the cycles.
Wind energy density in Spain