Magnetohydrodynamics (MHD) is the study of electrically conducting fluids in electric and magnetic fields. Examples include plasmas, liquid metals, and salt water. MHD was pioneered by Hannes Alfvén, who won the Nobel Prize in Physics in 1970 for his work. MHD power generation has high efficiency and low pollution and is used widely in advanced countries, though in developing countries like India construction of MHD generators is still ongoing, such as a joint project by BARC and BHEL in Tamil Nadu. An MHD generator directly converts the heat energy of a fuel into electrical energy without a conventional electric generator.