Carbon nanotubes are surprisingly ubiquitous in their use for renewable energy applications as well as for environmental protection and remediation. Hence, this is the motivation for the current review, to investigate into their usefulness. The characteristic properties of these nanotubes are a result of their large surface areas, and their unique mechanical, electrical, and chemical properties, and in no small part, due to its relatively easy manufacturability. Research has been done using carbon nanotubes for hydrogen storage, although it does not seem logical that carbon nanotubes would be very useful for this purpose. Carbon nanotubes used for solar collectors are used mainly for their improved thermal and electrical conductivities. Organic solar cells do not have a long life since they deteriorate in the sun. Research into long-lasting, yet inexpensive organic solar cells is an active area, and should continue to be so for some time. Carbon nanotubes are activated by certain chemicals. They may be used to react with solids, liquids, and gases. Hence, they are employed for waste water treatment, liquid, and gaseous cleanup. They may be used to remove metals as well as life pathogens. As the number of new pollutants and pathogens entering the environment multiply, research should continue to study the use of carbon nanotubes with regards prevention and remediation.