Energy Field's Long Shots Show Off Their Stuff ARPA-E, the Energy Department's program for betting on long-shot technologies, is holding a convention in Washington this week, and several dozen teams working on unusual ideas showed up to hobnob with potential investors and potential government customers. None of the technologies are ready for the market, but that is as it should be, said Arun Mujamdar, the program's director. The notion is that the technologies should "swing for the fences," he said. Most will not reach commercialization, program officials say. In fact, some have already failed and returned unspent federal money to the government. Yet some show interesting progress. Makani Power of Alameda, Calif., had the most visible one, a mockup of its flying wind turbine. The device, which is made of black carbon fiber and looks a bit like a stealth drone, is a wing with four propellers, a thin fuselage and a tail with a rudder and an elevator, the same two surface control surfaces that an airplane has. But the Makani bird does not fly from place to place. It is tethered to the ground with a cable, and it flies in circles in a path like the outer diameter of a Ferris wheel. While the passing wind may be only 10 or 15 miles an hour, the Makani device is circling at speeds of about 100 miles an hour as its propellers are turned by the wind. That makes it possible for the device to generate electricity at wind speeds that are too low for ordinary turbines to produce much. Each propeller makes about 7.5 kilowatts of power that flows back down the cable to the earth. The prototype flies in a circle about 165 feet in diameter, with its center about 655 feet in the air. In that sense, it follows a path a bit like the tips of a conventional wind turbine, yet it is supposed to be far cheaper to build. To take off, the machine draws power from the grid and uses the blades as propellers; once it is operating, it switches to drawing energy from the passing wind. Makani's Web site shows the device taking off from dry land, but Corwin Hardham, the company's chief executive, said that the better location might be the ocean, where winds are stronger and it would not require a tower, a costly feature of offshore wind machines. "All it needs is a buoy," he said. Makani received a $3 million ARPA-E grant. Some of the exhibitors at the convention did not win grants but are still hoping to do so. Cefco Global Clean Energy, for example, was showing off a relatively energy-efficient method of scrubbing the pollutants and carbon dioxide out of the flue gases from incinerators, cement kilns or power plants. The process involves zapping the dirty gases in a chamber with a supersonic shock wave that sharply raises their temperature and injecting a chemical into the chamber to bind with the pollutant. The Energy Department has used the technology to capture bits of radioactive cesium at a nuclear waste incinerator, said Robert E. Tang, Cefco's president and chief executive, and the Army has used it to capture chemicals that are not consumed when it incinerates nerve gas canisters. The technique also works on more pedestrian pollutants like oxides of sulfur and nitrogen, which are big problems at coal plants. And it can be used to turn carbon dioxide into a solid bicarbonate. Another exhibitor was Agrivida, which received $4.6 million for an effort to grow crops with an odd group of genes that help free the sugars in which a plant stores energy. When the plant is heated and placed in an alkaline solution, these genes cause it to secrete enzymes that break down some of its structure so that the sugars flow out. The sugars can then be converted into alcohol or hydrocarbons for use as vehicle fuel. When I visited the company at its Medford, Mass., laboratory in May 2010, it was experimenting with scores of seedlings. Recently it has begun delivering "gram quantities" of sorghum, switchgrass and corn to customers for processing, and next year it hopes to be delivering biomass by the kilo, said David Agneta, a vice president. The corn is of interest not just for the kernels but also for the stems, leaves and other inedible parts, he said. Agrivida has raised some money in the private marketplace and will be looking for other sources of funds, Mr. Agneta added.