1. Various types of Solar and hybrid power schemes for captive use:
By the combinational use of solar panels, micro wind turbines, Inverters and Batteries, a system can be
characterized into three types:
A. Stand Alone Solar PV system (with battery back-up):
A standalone system, as the name suggests is not connected to the grid, it is a combination of Solar
Panels with charge the batteries, which is are then used to power up the load requirement. This is ideal
from places with poor or no grid connectivity. Since the system uses battery back-up, the cost of the
system is higher.
B. Grid Tied Solar PV system:
Grid tied systems are usually based on intelligent inverters, which use the Solar Power Produced to
augment the utility based power. These inverters need a power source to match the voltage and
frequency of the grid and are cheaper because there is no requirement of batteries. The system can also
be used to supply any unused power back into the grid (“Net Metering”) but this is still not applicable to
Indian conditions, except in places like Gujarat, where the utility can buy all the power produced by the
system at a premium tariff. This is the most successful system in India because most of the corporate
installations use Solar Power to augment their grid supplied power. This improves reliability and is also a
green initiative which is cost efficient and money saving in the long run.
C. Wind-Solar Hybrid system:
This system consists of a combination of solar panels and micro wind turbines with battery back-up
system. This system is ideal to replace grid power and diesel power during power shutdown.
Economic Details of the Above Systems:
A. Stand alone Solar power systems (for 1 kW capacity) with battery back-up:
The system consists of a solar PV unit, inverter and battery back-up that may be used for powering a
lighting system or other linear loads. This system is ideal for places with poor or no grid connectivity.
S.No Parameter Value Unit
1 Space required 175 Sq.ft
2 Estimated generation 1200 Units/yr
3 Total cost (excl tax) 1.7 Lakhs
4 MNRE Subsidy 0.8 Lakhs
5 Accelerated depreciation benefit 80% in 1st year
6 Pay-back period @ 15/unit (Diesel 3 to 4 yrs yrs
replacement)

2. 7 Rate of Return over 20 yrs 22% %
B. 100 kW Grid-tied captive Solar power systems:
The system consists of a solar PV unit, inverter and controller and can be used for meeting captive
power loads in tandem with the grid power or DG power.
S.No Parameter Value Unit
1 Space required 20000 Sq.ft
2 Estimated generation 120000 Units/yr
3 Total cost @ 1.25 lakhs/kW 125 Lakhs
4 MNRE Subsidy@30% 37.5 Lakhs
5 Accelerated depreciation 80% in 1st year %
benefit
6 Pay-back period @ 6.50 6 to 7 yrs
Rs/unit
7 Rate of Return over 20 yrs 17 to 18% %
C. Off-grid Wind-Solar Hybrid systems with battery back-up (50 kW):
The system consists of a solar PV unit (18 kW) + micro wind turbine (32 kW), inverter and battery back-
up:
S.No Parameter Value Unit
1 Space required 5000 Sq.ft
2 Estimated generation 72000 Units/yr
3 Total cost @ 2.05 lakhs/kW 105 Lakhs
4 MNRE Subsidy, Deposit etc 60 Lakhs
5 Accelerated depreciation 80% in 1st year
benefit
6 Pay-back period @ 15 3 yrs Yrs
Rs/unit

3. 7 Rate of Return over 20 yrs 23% %
The above figures are indicative for a typical system. Actual figures may vary depending on customer
specific requirements.