2019-08-28 / HFE Team
India’s First Wind-Solar Hybrid Project
A feather in our cap, the wind-solar project developed by Hero Future Energies at Kavithal village in Raichur district Karnataka is India’s first large-scale commercial, wind-solar hybrid project. This project created history by adding a 28.8 MV solar PV site to an already existing 50 MV wind farm.
The real challenge in this entire process was to combine all resources at one node and automatization of logical decision to choose the right generation resources to fulfil the need of consumption load and charging of battery.
To design the wind-solar hybrid system as a first step we studied the available renewable resources and diurnal & temporal consumption load of the said plant. By fixing the average availability of wind speed and analysing wind data of last 10 years, the tentative generation was plotted for a year. By referring to historical solar irradiance data for the last 10 years during the same period, we calculated solar generation pattern and by superimposing and optimising the yield, optimum capacities for both the plants were finally calculated.
Graph 1 indicates a sample pattern for wind speed & Irradiance for particular location
Graph 2 indicates superimposed power output from both sources using wind speed and irradiance data
The consolidated combined power sufficed 50% to 60% of the consumption requirement and still did not succeed as infirm power. Thus evolved the need to introduce the third element. In recent times battery storage technology has developed substantially and it qualified as one of the best options to fill this gap in providing power in case of non-availability of any renewable resources thus contribute in converting infirm power to firm power evacuation.
By stacking two battery systems in parallel, one could get charged during excess energy generation from renewable sources and other stack remains available to support the fulfillment of load requirement thus making the grid more stable as compared to single renewable energy source.
Graph 3 indicates the Plant load factor for Hybrid resources (Wind & Solar) reaching a maximum of 71% in a month as compared to individual resources as wind 59% & solar 16%.
Graph 4 & 5 indicates space for including battery storage and evacuation of excess power in case both wind & solar resources are not able to evacuate due to power evacuation limits.
Cost savings due to hybrid
Our one of the philosophies is to be the first in the market with new technologies and the firm is constantly looking at how to innovate.
Not only does the hybrid system share the transmission infrastructure, but the operations are also shared by the same teams, thereby reducing costs even further.
However, operations and Maintenance (O&M) teams are different since the solar system requires manual, water-based cleaning twice a month, in this extremely dusty region. The barren land is naturally dusty, but there are two types of dust that impact solar. Dry dust, as in the arid, desert state of Rajasthan, can be easily wiped off or blown off by the wind, but dust in humid conditions tends to stick the panels, which can impact irradiation on the panels and cause soiling in the long-term.
There are two main benefits of wind-solar hybrids. The first one is, obviously, there is better and more efficient use of the land and transmission infrastructure, which reduces the capital cost by something like 5-7% and that is parked through and results in overall lower tariff. So, the discom and the power purchaser should actually be keen on hybrid projects.
Secondly, hybrid power project also makes the power output a little bit more reliable than a standalone solar or standalone wind project so that again from a discom's point of view or from a transmission grid stability point of view should be actually better for the entire eco system.
An unsung benefit of hybrid systems is that by choosing a location with naturally high wind resources, the temperature of the solar modules is also reduced by the breeze, thus increasing the PV generation. Year-round lower temperatures on the solar panels from the wind also reduces the rate of degradation in the modules.