This document discusses direct energy conversion through photovoltaic cells and fuel cells. It provides details on: 1) How photovoltaic cells convert solar energy into electrical energy through a module of approximately 30 cells producing around 15V and 1.5A of current. Applications include water pumping, commercial and residential power, and consumer electronics. 2) What fuel cells are, how they convert hydrogen and oxygen into water and electricity through electrochemical reactions. Types are classified by temperature and electrolyte used, with hydrogen-oxygen and fossil fuel cells discussed in detail. 3) Advantages of fuel cells include high efficiency and low emissions, while disadvantages include higher costs and difficulties with hydrogen production and storage.