A competition held by nonprofit ImagineH2O highlights the close connection between water and energy.

ImagineH2O, a not-for-profit company formed to foster innovation around water, last week announced that the three winners to its Water-Energy Nexus Prize, a competition for the best business ideas to reduce the energy needed to move and treat fresh water and wastewater. Winners out of the more than 50 participants were awarded $100,000 in cash and in-kind services.

Hydrovolts CEO Burt Hammer shows off the company&39's turbine designed specifically for manmade canals. The company plans to build these turbines in three sizes, with the largest able to fit into a shipping container.

The top prize went to Hydrovolts, a Seattle-based company that makes a hydrokinetic turbine designed specifically for manmade canals. Flowing water turns adjustable wings to generate electricity.

The company's plan is to sell the turbine to landowners and facility operators that have a steady-flowing canal. One advantage of this approach is that there shouldn't be a need for environmental reviews because it's an artificial environment, according to the company.

The runners-up were Philadelphia-based Blackgold Biofuels, which has a process for converting fat, oil, and grease from wastewater treatment facilities into biodiesel fuel' and Oakland, Calif.-based Fogbuster, which is also separating fat, oil, and grease (FOG) from wastewater without using chemical plants.

Other companies in the competition focused on different areas, such as membranes that improve the efficiency of desalination plants or drawing usable energy from water distribution systems.

ImagineH2O, which was started by people from Harvard Business School, organized the competition to bring attention to energy in water distribution and treatment. California, which has to pump much of its water long distances, uses 19 percent of the state's energy on water.

Different forms of power generation have wildly different water requirements as well. Nuclear power uses 720 gallons of water per megawatt-hour of energy produced, compared to 140 gallons for natural gas, 30 for solar photovoltaics, and 1,060 for concentrating solar power plants, according to Dow Water and Process Solutions.

Supplying fresh water to people around the world, the focus of today's World Water Day, is obviously vital. But water technologies tend not to attract entrepreneurs and investment in part because in industrialized countries water is relatively inexpensive as a resource and facilities are run by cash-strapped municipalities.