Actually, it is savings and investment which powers economic activity. Consumption is the using up of goods. Production must occur before consumption can take place. And handing out cash to everyone in the form of UBI payments will just result in price inflation, because sellers will raise their prices according to new demand. Kind of like how the government got into the student loan business and tuition increased dramatically. Let markets work, and prices will come down on their own, making more goods available to more people.