This book is focussed on forms of energy for the future, while maintaining climate neutrality, partly by drastically reducing, partly by recycling the resulting carbon dioxide emissions. Electric drive of cars and machines instead of combustion engines do not solve the conflict between energy and carbon dioxide, more efficient ways are described. The book presents hopeful forms of energy conversion without carbon dioxide such as photovoltaics, wind power and hydropower, with their advantages, but also with their disadvantages. More promissing is the energy generation maintaining climate neutrality: The water cycle nature-electrolysis-machine-nature is compared with the carbon dioxide cycle nature- photosynthesis in plant-machine-nature. The results of this analysis are largely surprising from such perspective.