President Barack Obama shows off his newly acquired T-shirt after learning about the energy storage research conducted by Professor Alexander H. Slocum ’82. MIT President Susan Hockfield accompanied Obama during his tour through the labs at MIT on Friday. Slocum explained a system for harnessing excess wind energy. When the wind is not blowing, water flowing into the storage area through a turbine produces electricity. When the wind is blowing, excess power is used to pump water out of the storage area.