An Israeli company made a deal yesterday to sell an innovative new system that can generate electricity from the motion of ocean waves. An Indian company agreed to pay $4 million to S.D.E. Energy & Desalination Ltd. for a wave-generated power plant. The company claims to have developed a relatively cheap and eco-friendly way to harness wave energy, and says that by 2020, the system could supply 15 percent of the world’s electricity. The system is well-suited to developing nations with sea exposure, the company says.