Colonization of the outer Solar System the Solar System's gas giant planets for exploration and possibly mining of helium-3, which could have a very high value per unit mass as a thermonuclear fuel. The Jovian system in general has particular disadvantages for colonization, including its severe radiation environment and its particularly deep gravity well. Its radiation would deliver about 3,600 rems per day to unshielded colonists on Io and about 540 rems per day to unshielded colonists on Europa. Exposure to about 75 rems over a few days is enough to cause radiation poisoning, and about 500 rems over a few days is fatal. Jupiter itself,
Solar energy use in rural Africa In the article by Burney et al. (2010) another use for solar energy that has been proposed is the Photovoltaic- (or solar-) powered drip irrigation (PVDI) system [which] combines the efficiency of drip irrigation with the reliability of a solar-powered water pump… [Where the] PV array powers a pump (either surface or submersible, depending on the water source) that feeds water to a reservoir. The reservoir then gravity-distributes the water to a low-pressure drip irrigation system. No batteries are used in the system: The pump only runs during the daytime, and energy storage is in the height of the column