Are there any back up techniques?

Wind Turbine systems are available in several designs according to the way they store surplus power generated. For example:

Grid Connected Off Grid Stand alone Hybrid System etc.

Incidentally the applications of each of the above types will depend on the;

Availability of the National Power Grid within an economically viable distance. Ability to sell back surplus power to the National Grid. Buy-back price of unit energy uploaded Whether a reasonable and consistent wind flow is available at the site through out. Availability of a stand-by battery bank of adequate capacity and maintenance of it.

Of these the Grid connected and Stand Alone systems possess the ability to provide continuous power supply to the end user. A hybrid system will possess the same capability subject to it works as a stand alone system.

Stand Alone Small Wind Turbines

Stand Alone systems are Wind Turbines not connected to the Grid Supply but uses a battery bank to store surplus energy generated when the optimum wind velocity is available. The Electrical Energy stored in the battery bank will supplement the power needs of the home as Direct Current (generally below 5 kw) or in the case of higher capacity generators (generally above 5 kw, as Alternating Current.

In the case of the low capacity DC generators the surplus power generated will be directly stored in the battery bank. If the appliances and the power distribution of the home is AC oriented an inverter will be used to convert the power to AC prior to feeding the home distribution.

If the Wind Turbine is generally over 5 kw the electrical energy generated will be alternating current and cannot be stored in the Battery Bank direct. The inverter in this instance will be converting AC to DC for this purpose after stepping down the voltage from 230V (415V if it is 3 phase) to 12 V DC (nominal) generally and stored in the Sealed Lead Acid Battery bank. The inverter will convert the stored energy to AC again when the home demand dictates so.

Hybrid Wind Turbine Systems

A hybrid system will be similar in general to the above stand alone system but will incorporate Solar Powered PV Panel arrays (or diesel Generator Sets) to supplement the wind generated power in situations where the wind velocities decrease due to climatic or geological reasons during the year. The PV panel arrays have purpose designed inverters. Controls for matching the two systems are too necessary. Therefore one must be careful as to what he has to order additionally. Professional assistance in all these cases is therefore strongly advised.

Storage Battery Banks

The battery bank will require quite a few safety devices (such as over charge cut-out, Over current and voltage regulators etc) and controls which are generally solid state. The battery bank is located in a well ventilated (preferably air conditioned) room which is isolated from living areas. (This is because they release corrosive fumes and also pose an explosion hazard to some extent).

Adequate space for regular maintenance is a must. The batteries are of the deep cycle type (regular charging and discharging up to 80% of it’s capacity is possible). Automotive batteries (shallow Cycle type) are not suited for this application.

Grid Connected Small Wind Turbines

A grid connected Wind Turbine Power System does not need such a huge array of additional components. It requires only an inverter to make the generated electricity supply compatible with the grid supply along with the necessary power cabling and controls. When the wind generated power is not adequate all it has to do is to draw the additional demand from the power grid. A kwh meter is of course required whether you want to buy the short supply or sell the excess production to the utility.

The cost of power cabling and installation may be high if the distance it has to be drawn is far. As you see it is possible to obtain a consistent power supply from small wind turbines. Under proper guidance these could be made very cost effective too.

Wind turbines are not capable of providing uninterrupted steady power by themselves simply because the wind velocities incident on them fluctuate widely.

Small Wind Turbines are good for power generation as long as the wind velocities 4.5m/s upwards is available. What if wind velocities drop below 4.5 m/s or rise above 16 m/s?