Renewable sources have been gaining more and more sympathies of common people and governments too. Their shares have been growing, especially in Europe and Northern America. You can make sure of it looking through Fig. 1 below
Fig. 1 – Shares of renewables in 2005 and 2020
But first of all, renewables are very expensive. Relative costs of generating electricity from different sources, which are shown on the next graph, support it with evidence.
The costs are calculated taking into consideration several internal cost factors. These factors are as follows:
Comparative costs of electricity produced by different source of primary energy and calculated, using the above mentioned factors, are depicted in Fig.2.
Fig. 2 – Comparative costs of electricity
USA Generating costs in May 2008 given in Fig. 3 also support this fact.
Fig. 3 – US Generating costs in 2008
Nonetheless, in long term context the costs should equal according to different forecasts – see, for example Fig. 4.
Fig. 4 – Long term cost trends
Besides high costs the other serious problem connected with renewables concerns their intermittence. It means that a wind power installation generate electricity when wind blows and similarly a solar plant produces electricity when the Sun shines. But consumers require and consume electricity when they need it, e.g. in the mornings, evenings i.e. mostly at the time quit different from the time when wind blows or the Sun shines. So, means for energy balancing, which is limited, in order to meet consumers´ demands (see a detailed analysis of the issue in Renewable energy – our downfall? by Ralph Ellis and in posts If we don´t interest in the energy future, we may see its collapse and Is the „green“ energy really free?). Nowadays, some gas power plants or hydro power plants are used to balance the variation … With more intermittent renewables in the electricity grid they will have to do this much more often and situation could become intricate, maybe unsolvable.
The problem is not lack of wind or solar (etc.) energy, it is a fact that at times there may be too much wind or sun. Different operational and economic conflicts will arise, especially at time of low electricity demands. Energy storage (e.g. pumped hydro) and export through new inter-connections could help (for teach-in how serious the situation is see Renewable energy – our downfall?).
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