Nonrenewable resources such as coal, petroleum, natural gas and uranium cannot be replaced within human lifetimes because they take significantly longer to form than the rate at which they are consumed. Renewable resources like solar, geothermal, wind, biomass and hydropower can be replenished within short time periods and include resources that are continuously replenished like sunlight, wind and flowing water. Examples of nonrenewable resources are coal and uranium, while solar and hydropower are examples of renewable resources.