Sustainable Energy Successees

   

Small Hydropower Neglected for three Decades
In 1999, the share of renewables in the primary energy supply of Estonia was 12%, and 92 % of the electricity supply was fossil fuel based, produced by big thermal power stations in the North East of Estonia, fired by oil shale. Therefore, a very strong effort is needed to change the governing fossil dominated situation in the energy sector, switching from oil shale to renewables as primary energy source. There are several choices available for this conversion but recently hydropower has proved to be one of the most successful options on commercial basis.
Hydropower has been a forgotten thing in Estonia for almost 30 years, starting from the 60's and up to the regaining of national independence in the beginning of 90's. In the 60's, the bulk of small hydropower stations that had survived the destructive powers of the Second World War, were closed as not corresponding to the central energy supply doctrine of a totalitarian regime. Only the 2 –3 smallest were left to supply local space heat. After the economic upheaval of the early 90's, some enthusiasts started to refurbish small existing hydropower stations that were neglected for a long time and in a deep disrepair.

A New Start for Small Hydro
Today, the situation is radically changed due to the following circumstances which have launched a genuine boom in commercial hydropower application in Estonia:
a) The new Energy Law, which was passed in the Parliament in 1997, opened new opportunities for the use of renewable energy. It obliges the big energy monopoly Eesti Energia, covering practically all the electricity production and distribution in Estonia, to buy electric energy from small renewable energy based electricity producers at the cost of 90% of the electricity price for household consumers.
b) The oil shale based electricity price has increased steadily during the recent years, equalling at the moment to 0.06 EUR/kWh and in April 2002, it will increase to 0.07 EUR/kWh. The renewable energy plants receive 90% of this price for power sold to the grid.
c) Eesti Energia has launched a Green Energy Programme in co-operation with Estonian Fund for Nature, attracting various firms to promote renewable energy applications through buying the renewables based energy at a higher price with the bulk of the profit going to the Estonian Fund for Nature to support environmental projects.

Many Small Sites
The number of rivers and creeks in Estonia is large, more than 700, but the bulk of these are short and with a scanty volume of water flow. As Estonia is rather flat, the tilt of rivers is small and therefore the head for waterpower is usually 2 – 6 m. The technical potential of hydropower does not exceed 30 MW in Estonia. The number of existing hydropower stations in disrepair but considered to pay off the refurbishing, is about 25, with the total rated output power of some 6 MW. The number of old watermills in ruins is big as well, being around 700 with more than 500 turbines installed. About 200 of these are more or less suitable for refurbishing. In addition, there are  100 water dams that can be provided with turbines. The number of potential brand new hydropower stations is about 20. The refurbishing of old hydropower stations would make the restoration of the dammed waterbodies for their esthetical and recreational values economically viable as well.

Successful Projects
A small stock company Generaator Ltd was the first to start refurbishing old hydropower stations, having by now under its belt already stations in Saesaare (180 kW), Leevaku (60 kW) and Kotka (150 kW).
In 1997, Estonian Water Power Ltd in co-operation with Nordic Investment Bank and specialists from the company DriveTech International AB made an inventory list of 20 old hydropower stations that can be refurbished on commercial bases with the bank loan pay back period within 5 – 8 years. The evaluation for finding the most suitable turbines for the refurbished power stations gave the preference to the fully automated remote controlled propeller type compact turbines from the Finnish company Waterpumps WP OY. The peculiarity of these turbines is that the turbine and the generator are mounted on the same shaft with no need for a gearbox, closed into an underwater hermetic capsule and lowered into the water channel. This results in environmentally improved installation, reduced investment cost and improved efficiency, avoiding the need for a large building for the station.

The first pilot project for using contemporary high technology while refurbishing hydropower stations, was Kamari station (water head H = 5.1 m, water flow Q = 5 m3/sec, output power of 200 kW) in 1999. The output voltage of the generator is 400 V and the generator is linked to the 15 kV grid through a transformer. The undertaking was initiated and conducted by Estonian Water Power Ltd with co-operation of Nordic Investment Bank and Finnish Ministry of Environment. The annual energy production of this station is going to be within the range of 1.5 – 1.7 GWh and the profit level for the year 2000 was 64 000 EUR. The construction work took one year plus one year for preparatory works. The overall refurbishing cost of Kamari was 204 500 EUR and the bank loan from the Nordic Investment Bank was 179 000 EUR at the interest of 8% and with 8 years payback-period. The annual maintenance cost of the station would be about 3200 EUR. The photos on this page show the Kamari power station in full operation.

Following Kamari, the next refurbished hydropower stations have been Tudulinna (150 kW) and Joaveski (300 kW). The refurbishing process is under way for Koseveski (40 kW), Torva (80 kW) and Linnamae (1.1 MW) hydropower stations with the latter belonging to Eesti Energia. The current situation is the refurbishing process is characterised by 4 power stations with restored hydro aggregates and 3 power stations with a new fully automated remote controlled equipment from the company Waterpumps WO OY. The average cost of hydropower aggregates has been in the range of 900 - 1300 EUR/kW.

Smallest Sites Needs Pilot Project
Concerning watermills, the situation is more complicated as the cost of control system is too high compared with the turbine - generator system and therefore it is needed to either work out simplified control systems or organise a serial production of turbines, bearing in mind the high number of micropower stations. A pilot project in this power range would be Torva project with two turbines, both having 40 kW output power.

Viable and Profitable
The practical experience shows that the refurbishing of existing hydropower stations in Estonia is viable and profitable. The pay back period remains within the limits of 5 – 8 years. Often the refurbishing requires to raise the water level of dammed water bodies and therefore it is needed to carry out environment impact evaluation prior to the project start up. Very important is to provide all the refurbished power station with the fish ladders. An important asset of the refurbishing process of existing hydropower stations in Estonia is that it contributes at the same time to the restoration of the beautiful Estonian agricultural landscape, broadens the recreational area and serves to make the environment more healthy and picturesque.
Within the next five years all old hydropower stations in disrepair but viable concerning refurbishing could be refurbished.