NEDO, IHI to Begin Long-term Test of Ocean Current Power Generation System

2019/07/30 01:00
Sousuke Kudou, technical writer
The "Kairyu" test machine of an underwater floating ocean current power generation system (source: NEDO and IHI)

New Energy and Industrial Technology Development Organization (NEDO) and IHI Corp will start a long-term (one-year or longer) verification test in an actual sea area by using the "Kairyu" 100kW-class test machine of an "underwater floating ocean current power generation system."

The test machine will be shipped from IHI's Yokohama Office (Yokohama City) to a sea area off the coast of Kuchinoshima (island), Toshima-mura, Kagoshima Prefecture, Japan, in early August 2019.

The underwater floating ocean current power generation system moors a floating power generation unit from a weight (sinker) set up on the seabed and generates electricity by using ocean current energy, which does not fluctuate much.

There is an abundance of ocean current energy in Japan, which is surrounded by the sea on all sides. Especially, the country has good geographical conditions for ocean current energy. For example, the Black current, which is one of the most powerful ocean currents in the world, is flowing in sea areas near the country.

The Kairyu is a test machine of an underwater floating ocean current power generation system with a rated output of 100kW (50kW x 2 units). The diameter of its turbine is about 11m. The length and width of its floating body are both about 20m. The rated flow velocity is 1.5m per second (3 knot). The floating depth is about 30-50m.

The test machine was completed in fiscal 2017, and a short-term verification test was conducted in a sea area of the Black current off the coast of Kuchinoshima.

In the short-term verification test, it was confirmed that the test machine can realize an expected performance while controlling the posture and depth of the machine with an autonomous control system. Also, test data that were collected in an actual sea area and are necessary for future commercialization were obtained (e.g. detailed examination of ocean current characteristics and installation/removal methods).

Based on the results of the short-term verification test in fiscal 2017, in preparation for the long-term verification test, NEDO and IHI (1) improved an autonomous control program that adjusts the angles of the turbine blades and floating body at the time of operation, (2) installed additional current plates for preventing the disturbance of ocean currents and (3) improved heat rejection performance inside the test machine.

Also, from fiscal 2018, NEDO and IHI started to (1) measure ocean currents off the coast of Kuchinoshima (test area), (2) conduct research for grid connection and consider it and (3) conduct negotiations with local communities. They will start installation work off the coast of Kuchinoshima in mid-August 2019, aiming to start operation in the fall of 2019 after test operation, etc.