Solar PV-DG Hybrid System: A cost effective proposition for diesal abatement
[ezcol_1half]The cost decline in Solar PV has already brought this technology to a preferred option as compared to the DG (Diesel Generator) set based power generation. The cost of electricity generation through the conventional DG sets is of the order of Rs. 15/kWh, as compared to the cost of solar PV which is in the range of Rs. 7-8/kWh. Since the electricity generation cost of solar PV is half the cost of DG electricity clubbing solar PV with the DG set and thus minimising the diesel consumption in your existing DG set becomes an attractive proposition to the industrial and commercial consumers who heavily rely on the DG based power generation. In some of the cases the power is supplied through the standalone DG sets, and in some cases the power generation through the DG sets is for back up power to the grid outages and the hours of operation go up to 16-18 hours per day.
While DG power is expensive and price per kWh are bound to go upward as the diesel prices are rising every year, it makes a strong case to evaluate your existing fuel mix and identify whether installation of solar PV can displace your diesel consumption. Considering the fact that solar is a variable resource and integration with the DG generation becomes challenging to handle the variability of the solar PV generation. A mix of solar PV DG in the range of 20:80 is easier to handle, however the larger proportion of solar PV required some other protective and peak load control features so that variability of solar PV can be absorbed in a dynamic fashion. The inverter used for typical grid connected application needs to be different which can operate at a larger voltage and frequency range to handle the variability of the solar radiations in tandem with your standalone DG set.
[/ezcol_1half] [ezcol_1half_end]Companies such as SMA has launched a dedicated fuel save controller which is connected with the solar inverters and diesel generators via a communication interface and continuously monitor the mains parameters (electricity/voltage) at the connection point of the loads. As soon as the diesel generator load approaches the minimum load, the controller reduces the power output of the solar inverters in order to maintain the load of the generators above the minimum capacity. The diesel generators respond indirectly since they supply the residual load, defined as the electricity demand minus the photovoltaic output. If the Solar PV -DG hybrid is combined with a dedicated battery bank, then the solar can contribute up to 70-80% of the load. There are specific applications where there is no grid electricity available, for example in mining applications the power is supplied through the DG sets only and large open area are available for PV installations. While the electronics has addressed the need of the controllers to integrate the solar PV and DG sets to meet the requirement of the variable loads, it is equally important for assessing the loads and evaluate some of the variability options to the load side to integrate the solar PV in a cost effective way,[/ezcol_1half_end]