To present our future generation with a clean and green Earth, all the nations have united with an aim to make this world a better place to live in and India has taken a centre place in that. Present NDA Govt., led by visionary Shri Narendra Modi has put renewable at the core of its energy policy and elevated our renewable energy generation target from MW to GW level. A realistic implementation plan has been laid out to achieve 175 GW of renewable energy capacity by the year 2022 – 100 GW from Solar and 60 GW from Wind.
Past researches reveals the fact that solar and wind energy are almost complementary to each other and hence any move to try and combine the two is a commendable effort. Ministry of New & Renewable Energy (MNRE), through its recent Draft policy, has tried to provide a framework for promotion of large grid connected wind-solar PV hybrid systems for optimal and efficient utilization of transmission infrastructure and land.
Although, on paper, the marriage of wind & solar power looks a promising concept, in reality, there are certain nuances that have to be examined in detail. Without these clarities, the policy may fail to gain momentum and raise interest among the serious investors.
- The biggest point that has captured the industry’s attention is the capacity limitation imposed on such hybrid systems. As mentioned in the policy, “The hybrid power injected in to the grid will not be more than the transmission capacity/grid connectivity allowed/sanctioned for existing wind/solar project”. Putting such limitations, primarily because of bottlenecks in transmission system, may fail to unlock the true potential of the concept and can create roadblocks for implementation going ahead. Investors may not be willing to take up the project due to structural deficiencies. This clause is a safeguard for the existing transmission system which needs revamping over short to medium to allow play for such new concepts.
- There are other technical challenges that need to be addressed when opting for hybridization of existing power generation units. Wind power developers acquire only a small area of land for siting the turbine, usually the footprint area – covering the sweep zone of the blades. This footprint area may not provide enough space that is free of the shadow cast by the tower to put up substantial solar capacity. On the other hand, the location of the solar power plant may not necessarily provide a location that would prove favourable while micro-siting the wind turbine. Both these scenarios would mean additional land acquisition for hybridization, which would again drive up the capital cost.
- Even if these challenges are overcome in the due course of time, another dilemma lies before the developer community. Apart from the small savings in the cost of an additional substation & transmission system, there is no additional incentive for setting up a hybrid plant. Incentives proposed in the policy document are same to that of a standalone wind or solar PV plant. Considering the limitation imposed by the draft policy, the developers may as well opt to set up separate wind and solar power plants which may end up being equally profitable, if not more profitable than a hybrid system. Hence, the policy would need to bring in stronger incentives for the developers to invest for such for Hybrid plants.
- The hypothesis driving the need for such hybrid systems is that this would help in minimizing the variability in generation by mixing the sources of power. But this idea neglects the fact that both these sources being mixed are inherently uncontrollable. This means that while these sources may work in harmony to minimize the variability, there may also be times when the combo, being uncontrollable, may increase the variability of generation. Keeping this in mind, at the present point in time, the promotion of storage solutions would prove to be much more worthwhile. Storage systems would bring in a level of certainty to the variable nature of the renewable generation system, at roughly the same cost of hybridization.
However, this is a noble concept for optimizing the infrastructure utilization including land and transmission system and may partially help to address grid stabilization issues which is arising due to increasingly higher share of renewables in the country’s energy mix. Going ahead, the policy makers need to work on the nitty-gritties and introduce programmes / schemes / incentives that may address the above mentioned challenges to make this policy robust and practically implementable.