A point that is discussed by the government of Baden-Württemberg is whenever or not it should be mandatory to use photovoltaic systems in all new buildings. Especially the "Die Grüne", "Klimaliste" and "Die Linke" parties support and promote this idea. A critical point is that introducing a law what forces all architects to use photovoltaics would violate the free market rules. The state would interfere into the market because everyone would have to buy photovoltaics. That would be unfair for companies who do not produce photovoltaics but compete in the same margin as companies who do sell photovoltaics do. Liberals claim that it is against the right of liberty to tell people what they have to adjust to their houses. The supporters of an obligation for photovoltaic systems argue that it is necessary to involve CO2-neutral energies into our ever day life. If photovoltaic systems become mandatory, the big factory buildings would produce "green" energy on the side. In debates with critics they also remark that we already have laws about the design of buildings in Germany. You are not allowed to paint your building for example in neon colours. The parties which support the photovoltaic systems in their election advertisement often compare this new law to old ones. An example is that you h ave to dispose your trash. You can not throw it into nature but you have to use the disposal service or keep the trash. That is also an environmental law. A member of the "Klimaliste" also reasons that the photovoltaic systems are not big enough to be seen and that it barely is a intervention into private home designs. In my opinion the Obligation for photovoltaic systems is a great development in german politics. It forces big companies to take to the their CO2 emissions into account and become more "green". I do not think that it violales my liberty rights.