Natel advances small-scale hydropower turbines

Natel, a company at Alameda Point, is developing small-scale turbines that can harness water flow to produce electricity without a dam.

Water enters white chute at bottom left and exits against the cups, forcing the conveyor to turn a generator shaft. Natel photo.

Rivers have been harnessed for the production of electricity since 1882.  That’s when the world’s first hydroelectric dam was built across the Fox River in Appleton, Wisconsin.  But dams are costly public works projects with negative environmental consequences, including the flooding of vast watersheds and blocking fish migration.

Natel has taken an invention from the dawn of hydropower called a Pelton Wheel and flattened it out.  Natel’s Linear Pelton hydroEngine is able to capture more of the water’s energy than the original wheel design, employing a dual series of cups on a conveyor system connected to a generator shaft. Continue reading “Natel advances small-scale hydropower turbines”

Google wind energy kite nears launch date

Google-owned Makani, a wind energy company at Alameda Point, moved one step closer last week to full-scale testing of its flying electricity kite. The novel invention made a rare public appearance at the company’s test site near the USS Hornet to fine-tune the docking maneuver. It will be deployed at a test site being readied in Hawaii where it will reach an altitude of 1,100 feet.

Makani energy kite undergoing testing at Alameda Point on October 1, 2015. Kite is suspended by mast on right. Tower on left is where the kite will be docked with propellers facing upward.
Makani energy kite undergoing testing at Alameda Point on October 1, 2015. Kite is suspended by mast on right. Tower on left is where the kite will be docked with propellers facing upward.

The wind energy craft was pioneered at Alameda Point. It employs the same principle as a stationary wind turbine, using the wind to rotate a blade connected to a generator. But unlike a traditional wind turbine, the tethered energy kite can soar to twice the height, accessing stronger wind force, while using a fraction of the materials. Electricity is transmitted to the base through the tether.

One of the big engineering challenges has been to design how the kite will launch itself into the air from a docking tower and then return when the wind dies down. An earlier prototype was tested on the former Navy airfield while tethered to a truck-mounted base.

The new model has three times the wingspan and twice as many motors and generators as its predecessor. The 84-foot carbon fiber craft uses eight motors to vertically take off and land on its base tower. Once airborne, the motors turn off, and the blades begin driving generators as the kite rotates in the wind.

Makani energy kite on transport trailer at Alameda Point test site.
Makani energy kite on transport trailer at Alameda Point test site.

Makani found an ideal spot to launch its kite at Parker Ranch in Waimea, Hawaii. The 250,000-acre cattle ranch is diversifying into clean energy projects. At a workshop on alternative energy hosted by Parker Ranch in July 2015, they referred to the local wind corridor on the Big Island as a world-class resource. A traditional wind turbine farm is on the drawing board.

Before Makani can send its kite into the sky, it must first gain approval from the Federal Aviation Administration (FAA). Makani representatives have met with local pilots in Hawaii to get their input, according to a story published on October 2 in West Hawaii Today, a daily newspaper circulated on the west side of the Big Island. The test site is five miles from the Waimea Airport.

“Makani has laid out its plans to local groups on the Big Island, including pilots last year who wanted to make sure every measure possible is taken to make sure the kite and tether are visible,” wrote West Hawaii Today’s Bret Yager. Citing Makani project manager Alden Woodrow, Yager stated, “Woodrow said on Thursday the kite will be lighted, the tether will be marked for visibility and that the FAA may provide other guidance for how the kite’s visibility should be enhanced.”

Kite with tether cable extending from tower to belly of kite, with mast suspending the kite during testing. Vertical platform extending from tower is the docking pad for the kite when not flying.
Kite with tether cable extending from tower to belly of kite, with mast suspending the kite during testing. Vertical platform extending from tower is the docking pad for the kite when not flying.

Google’s experimental product division acquired Makani in 2013. Last year they signed a leasing deal with the city for Building 400, the hangar across the street from their office in the old Air Control Tower, where the company is betting on producing a commercially viable clean energy product.

The company’s website points out that conventional wind turbines are limited by height and the available locations where prevailing winds make economic sense. “The wind moves faster and offers exponentially greater power at higher altitudes,” states Makani’s website. “When the wind speed doubles, the amount of available power increases eightfold.” One kite will produce enough electricity to power 300 homes.


Originally published in the Alameda Sun.

Additional reading:

“Google’s Makani:  From Regulatory To Technical To Wildlife Challenges”  by Mike Barnard, February 19, 2014, published on the CleanTechnica website.


“Finally, a little about wildlife. While the Makani device will be better than fossil fuel generation for wildlife, the reality is that they require a thin, invisible cable to be flying from ground level to 350 meters (1000 feet) for the onshore model or 650 meters (2000 feet) for the offshore product. That cable will be flying through a cone at a speed of around 130-140 kph near the wing, and slowing as it nears the ground. This is likely to be much more difficult to perceive and avoid than any wind turbine blade for birds. The best evidence is that many species of birds including seabirds and many raptors simply adapt to wind farms and avoid them, as there are highly visible masts and blades that they perceive as they do jutting islands and trees. There is no evidence to suggest that this is true for Makani’s relatively small masts, long tethers, and flying wings. The tethers will cover a much, much greater volume of airspace than wind turbine blades. It is difficult to not see greater avian mortality as a likely outcome, with resultant challenges for safe siting.”

Makani submission to Federal Aviation Authority

Smart grid power storage system being tested at Alameda Point

A small company based in Union City is quietly conducting underground field tests of their flywheel energy storage system at Alameda Point. The mechanical device seeks to accomplish the same result as battery storage, only cheaper and with completely recyclable materials. The system is ideally suited for storing electrical energy created by commercial size solar facilities.

Alameda Point test site
Alameda Point test site

Working with the City of Alameda, Amber Kinetics is leasing space on an old tennis court next to the O Club at Alameda Point. The two concrete vaults that they installed in the ground to house their flywheel system go down seven feet. That’s how far they were able to dig before hitting the layer of hydrocarbon residue called the Marsh Crust. Digging into the Marsh Crust would have complicated the testing and created added expense. Since there is no electrical service at the site, they brought in their own generator to perform the tests, which they store in a shipping container.

Their test is being partially funded by the U.S. Department of Energy (DOE) under the Smart Grid Demonstration Program. The DOE Project Description says in part: “The goal is to deliver a cost-effective prototype flywheel system that can be grid connected and electrically charged and discharged. The flywheel stores energy in a spinning rotor that is connected to an electric motor that converts electrical energy into mechanical energy. To recover the energy, the motor is electrically reversed and used as a generator to slow down the flywheel converting the mechanical energy back into electrical energy. Amber Kinetics will improve the traditional flywheel system by engineering breakthroughs in three areas, resulting in higher efficiency and radically reduced cost: bearings, low-cost rotor, and high-efficiency motor generator. This technology can also be used to optimize existing infrastructure.”

Alameda Municipal Power substation at Alameda PointAccording to a DOE report on energy storage from December 2013, so-called distributed storage facilities like the type being tested at Alameda Point can improve the efficiency and reliability of high power transmission lines. They would do so by reducing “line-congestion and line-loss by moving electricity at off-peak times, reducing the need for overall generation during peak times. By reducing peak loading (and overloading) of transmission and distribution lines, storage can extend the life of existing infrastructure.” The report also notes the value of distributed electrical storage for emergency preparedness.

Photovoltaic solar panelsAccording to the company, benefits of their system would be:

  • Green job creation
  • Electricity costs lowered
  • Renewable energy integration
  • U.S. energy security strengthened
  • Greenhouse gas emission reduced