Direct solar thermal energy can be used to power solar cook stoves, which can save time, work, money, and combustible fuel in suitable circumstances. Unlike solar photovoltaic energy, which requires expensive PV cells to convert sunlight into electricity, solar thermal energy can be captured instantly and directly with a solar cooker, which generates zero emissions heat for cooking food and boiling water. By comparison, a one hundred square foot PV array would be needed to power a single hotplate. Solar thermal energy can also be used for solar hot water heaters, sterilizers and food driers.