Tokyo Electric Power Co. (TEPCO) announced that the company completed the
construction of Unit 1 (capacity of 470,000 kW) of Kannagawa Hydropower Plant
(in Ueno-mura, Tano-gun, Gunma-ken and Minamiaiki-mura, Minamisaku-gun,
Nagano-ken), and started in commercial operation.  The construction of the
plant was commenced in May 1997.
This power plant is TEPCO's ninth pumped-storage power plant.  Once the plant
is completely up, it will have the world's largest generation capacity of
2.82 million kW(including Units 1-6) as a pumped-storage power plant, being
able to cover 900,000 households.

Pumped-storage power plants pump up and store water during night hours when
the electricity demand is small, and drop the stored water for power
generation during daytime hours when the electricity demand is large.
  Kannagawa Hydropower Plant has introduced the first "splitter runner" in
the world that was jointly developed by TEPCO and Toshiba Co. as the
pump-turbine runner(Note 1) that has  both functions of a pump and a
turbine (see Reference 1).
With the splitter runner, the power plant could increase its power generation
with higher efficiency than with the conventional one.  This is the same
effect to construct a new power generation plant equivalent to the increase
in generating capacity.  Therefore, it can achieve a significant cost
reduction effect.  In the future, moreover, the improvement of power
generation and pumping operation is expected to reduce  CO2 emissions.
For the civil work, the "full-face tunnel boring machine (TBM) was introduced
to excavate the full-round section of the penstock tunnel (steep angle of 48
degrees, 6.6 meters in diameter and about 1,000 meters in length) between the
upper and lower dams in order to drastically reduce the time and cost of
construction (see Reference 2).  Moreover, the ultra-high tensile strength
steel (HT100) was applied as the materials of the steel penstock for the first
time in Japan, and the cost could be further reduced (see Reference 3).

We would like to express our deep gratitude to the local residents and all
parties concerned for their kind understanding and cooperation to the
construction works to date.
We will do our best to maintain the safe and stable operation of the power
plant, and would like to ask for your continued cooperation and support.

(Note 1) The pump-turbine runner has both functions of a pump and a turbine.
  Power generation operation and pumping operation are switched by reversing
the direction of rotation of this turbine.


1.Outline of Kannagawa Hydropower Plant
(1)Location:       Ueno-mura, Tano-gun, Gunma-ken and Minamiaiki-mura,
                   Minamisaku-gun, Nagano-ken.
(2)Name of river:  Minamiaiki river of the Shinanogawa river system
                   (upper dam), and Kannagawa river of the Tonegawa river
                   system (lower dam).
(3)Capacity:       Unit 1 has 470,000 kW (commencing commercial operation
                   on December 22, 2005).
                   Unit 2 also has 470,000 kW (to be operated in July 2010).
                   Units 3-6 have a total of 1,880,000 kW (to be operated
                   in and after 2015).
                   Units 1-6 have a total of 2,820,000 kW.
(4)Effective head: 653 meters
(5)Plant discharge:510 cubic meters per second (Units 1-6)

(7)Power plant
  Type:           underground type powerhouse
  Major equipment:pump-turbine (vertical-shaft Francis-type pump-turbine)
                  (482,000 kW x 6 turbines), and generator-motors
                  (three-phase AC synchronous generator-motors)
                  (525,000 kVA x 6 motors)



4.History of Construction of "Kannagawa Hydropower Plant"
July 1993:     Kannagawa Hydropower Field Survey Office was established.
July 1995:     The construction of the power plant was approved by the 130th
               meeting of Electric Power Development Coordination Council.
July 1995:     The office was reorganized into Kannagawa Hydropower Plant
               Construction Preparation Office.
February 1997: The office was reorganized into Kannagawa Hydropower Plant
               Construction Office.
May 1997:      The construction work of the power plant began.
October 2003:  Water storage to the lower dam (the Ueno Dam) began.
September 2004:Water storage to the upper dam (the minamiaiki Dam) began.
December 2004: The test run of Unit 1 began.
December 2005: Unit 1 (470,000 kW) of Kannagawa Hydropower Plant started
               commercial operation.

Reference 1:Splitter Runner
Reference 2:Full-Face Tunnel Boring Machine (TBM) Method
Reference 3:Ultra-High Tensile Strength Steel (HT100)
Expenditure