3. Conclusions and Policy Implications
From the data published by Eurostat, it emerges that Austria is the state with the highest RES production; however, it is not the state that has obtained the greatest growth, indeed, over the years, as energy production has shown a fluctuating trend, even if the level starting points were higher. This could depend on the fragmented nature of energy policy, since a similar trend characterized by low constancy is also found in Germany, where energy competence is also divided between central power and Länder. In the context of energy policy, therefore, the principle of subsidiarity, as the basic principle of the European Union, does not seem to fully unfold its effects. The subsidiarity principle is defined in Article 5 of the Treaty on European Union. It aims to ensure that decisions are taken as close as possible to the citizen, verifying that the action to be taken at the community level is justified with respect to the possibilities offered by the action at the national, regional or local level. However, in countries where energy policy is not fragmented, the yield in RES has been higher; for example, this happened in Luxembourg, where RES production growth has increased significantly in recent years. Therefore, surely to obtain a higher yield, it is necessary that the energy policy adopted is unified throughout the territory.
It should also be noted that in the states where more and various forms of subsidies are foreseen, growth seems to be greater. For example, in France, although the population density is higher than in Luxembourg, the production growth of RES H&C has been higher. Therefore, more clean energy is produced for a higher population density. It is believed that the main difference is due precisely to the greater number and greater variability of incentives. This is also evident compared to Belgium, which, by combining green certificates with FIT and FIP subsidy systems, could achieve greater results in terms of energy efficiency. Belgium has a position of merit, however, for the amount of incentives provided for research; it would be necessary for each state to invest in research, particularly Germany, where it could be possible to make more use of the resources of the territory, especially solar energy. Renewables in some situations have reached record levels compared to other states, but much remains to be carried out to decarbonize the country, above all avoiding job losses: investing in research could help remedy the problem and increase the use of resources from neglected energies, such as solar energy. On the other hand, the German RES-T results are excellent. In this regard, there seems to be no great variability, since almost all the sample states make use of a quota system as with Germany; indeed, Germany has been the subject of criticism from both the IEA and the RES LEGAL database, yet the results obtained are commendable 
. This is believed to be due to the loan system by KfW. Such a loan system should be used in all states, as it appears to lead to good results. Additionally, in Holland, which seems to hold the primacy for the whole of Europe in terms of RES-T, the forms of subsidy for the purchase of electric cars not only for citizens but also for public transport lead to an increase in the use of renewable resources and a decrease in CO2
Belgium also appears to be currently engaged in a progressive elimination of nuclear power, but the policy on this matter is not unanimous, and most scientific reports recommend extending the nuclear license in order to reduce the current pressure on supply uncertainty 
Having said this, it was previously reported that the member states of the European Union have published new national energy–climate plans. The European Commission has finished analyzing them, and ad hoc assessments have been carried out for each European nation (also collected and summarized by the IEA) which should be integrated into the definitive national energy plan for 2050. As of today, according to Brussels, the documents still make insufficient contributions to achieve the energy efficiency targets for 2050.
Moreover, if energy plans are not carefully designed, they can distort the functioning of the energy market and entail higher costs for European families and businesses 
In addition, support schemes should be flexible and respond to falling production costs. As technologies become obsolete, the patterns should gradually be removed. For example, feed-in rates should be replaced by premium feeds and other support tools that incentivize manufacturers to respond to market developments, and it has been seen that not all states have provided or are replacing incentive tools now obsolete for the needs of their national market. At the same time, the economic and financial crisis has blocked investment in new construction generation capacity. Low demand, combined with increased deployment of wind and solar energy, has also pushed down wholesale electricity prices in some member states such as Germany, Belgium or Spain, putting pressure on public service yields.