Energy Alliance in English

SMALL HYDRO
AS AN ALTERNATIVE SOURCE OF ELECTRIC POWER

A.V. Astafyev, Technical Director , Company "Energo-Alliance", St- Petersburg, Russia

Power availability and a share of electric power determines in many ways the engineering progress, contributes to the development of high-precision techniques and helps to provide prosperity and comfort to the lives of people. At the same time the rise in price for natural sources of energy (coal , oil and gas) leads to permanent increases in electric power tariffs and consequently has a negative effect on the activity of small and medium enterprises and farms.
There are entire regions where employment and material benefits of the people directly depend on timely
delivery of organic fuel to steam and diesel electric stations, while the most part of such regions have vast reserves of reliable and renewable sources of electric power - water.

The realistic way out of the existing situation can be found in the increase in the importance of hydro electricity
as an alternative source of electric power. Up-to-date level of engineering makes it possible to develop for micro
and small hydroelectric power plants, such equipment that provides the electric power quality (on isolated load) superior as for its parameters than the quality of electric power generated by existing big steam and hydraulic power plants.

The list of potential sources of electric power for small hydro is extraordinarily wide. It includes rivers, small
rivers, streams, natural differences of heights on lake spillways and irrigation channels.
The turbines of small hydroelectric power plants can be used as energy dampers at the differentials of
elevations of portable water and other pipelines intended for pumping of various liquid products.
Furthermore, for partial compensation for electric power consumed by production from the power grid, the
hydro-units of small power plants can be installed on technical stream flows, industrial and sewage spillways etc. Small hydro should primarily be used in remote and hard-to-reach regions where there are no power
transmission lines, as construction of such lines is often more expensive than construction of a small
hydroelectric power plant.

One of the urgent targets for consists in the development of the effective, reliable and cheap equipment for micro and small hydroelectric power plants.. As an engineering project for production of such equipment, it is possible
to use practically all types of classic hydraulic turbines. However, the analysis of their possibilities from the viewpoint of used heads, discharges, overall dimensions of the hydro-units, the cost of manufacturing of the equipment and construction revealed that it is not always rational to use classic hydraulic turbines for this
purpose. Hydro-units with classic turbines designed for low heads ( from 2m to 15m) are of complicated design, expensive in manufacturing and require considerable expenses for construction of hydraulic-technical structures.
At the same time, construction of dams at such stream flows for increasing of heads and use of other types of classic turbines leads to flooding of vast territories, i.e. is unreasonable from economic and ecological
viewpoints. Experience suggests that automatic extension of the principles of equipment designing and
technical solutions from large to small hydro power engineering is radically incorrect. Development of the equipment for micro and small hydroelectric plants requires a quite different approach.

The optimum way for solving the above problem lies in the development of highly effective water passages of cross-flow or two-stage turbines or their optimized designs based on a Banki-type turbine.
Over the years the water passages and design of cross-flow turbines have been permanently enhanced as for their efficiency and operating characteristics. At the present time, maximum efficiency of such turbines obtained
in the world is about 90%. Along with the simplicity of the design, reliability in operation and relatively low cost,
the above efficiency give grounds to consider cross-flow turbines as the preferable type of turbines to be
installed at micro and small hydroelectric power plants.
Under the same conditions (head, output), the cross-flow turbines have smaller size and smaller cost and expenses for construction of hydraulic-technical structures as compared to classic turbines.

Those turbines can be actually operated at heads starting from 1m and deliver considerable outputs if there is sufficient water discharge, as contrary to the classic turbines, it is possible to vary the discharge and
consequently the output at the same head by changing not only runner diameter but also its length. It should be noted that the range of application of the cross-flow turbines is unusually wide. For micro and small
hydroelectric plants the cross-flow turbines can be used at heads ranging from 1.5 m up to 180 m.There is an actual possibility to develop the unified equipment based on cross-flow turbines for refurbished and newly constructed micro and small hydroelectric plants operating over a wide range of heads and outputs.

Russian company "Energy-Alliance" specialises in the design and production of up-to-date cross-flow turbines. As distinct from the designs of foreign companies, the turbines developed by "Energy-Alliance" are equipped
with a guide vane mechanism which forms the optimum water flow (from power/efficiency characteristics) upstream of the runner inlet, the device for smooth control of water discharge during the course of operation.
The device for water discharge control can be equipped with manual, electric-mechanical or
hydraulic-mechanical drive for automatic remote control of the hydro-unit. The turbines are also equipped with automatic overspeed protection device to prevent the hydro-unit from runaway in case of a sudden
disconnection of electric power consumers.
Owing to its design, the device for water discharge control does not bring about flow disturbance and practically does not experience the influence of force loads and hydraulic torques as it is the case with the guide vanes of classic turbines. As a consequence, the device does not require any powerful drive. The design of turbine bearings is environmentally safe.

At the present time, our maximum turbine efficiency is about 85%. The company works on the further
improvement of water passages of cross-flow turbines with the aim of optimizing their efficiency and output characteristics. The company specialists have been working at Leningradsky Metallichesky Zavod (LMZ) for
many years and have a wide experience in design and production of hydraulic turbines.
Now the company can effect a serial production of the turbines intended for heads ranging from 1m to15 m and rated from 4.7 kW to 315 kW. Based on available technology, the company is able to manufacture the turbines
for any parameters of stream flows of the Customers.

"Energy-Alliance" can deliver complete equipment for the hydro-units, performs erection and commissioning works. The hydro-unit comprises of : cross-flow turbine, reducer of batch production, synchronous or asynchronous generator and automatic control system to provide operation of hydro-units of up to 200 kW
output both in the power grid and on isolated load. Production of more powerful equipment and the equipment intended for higher heads is possible.

"Energy-Alliance" is also working on the development of submerged free-flow hydro-units using stream flow velocity for power generation and requiring no dam across the river, thus providing free passing of fish to spawn. Technical solutions used when developing the designs of hydraulic turbines and hydro-units are protected by the patents of the Russian Federation.

If you have any inquieries please do not hesitate to contact 'Energy - Alliance':
E-mail: mail@energy-alliance.spb.ru