Although the industry has generally welcomed the newly-enunciated Wind-Solar Hybrid Policy, review of its certain aspects may be necessitated on the back of some serious concerns. Also, the role of States will be crucial in ensuring the policy-s overall success.
As part of its aggressive target of achieving 175 GW of installed capacity from renewable energy sources, the Ministry of New & Renewable Energy (MNRE) issued the draft Wind-Solar Hybrid Policy in mid-2016. Following several discussions with the stakeholders over a two-year period, MNRE unveiled the final policy document in May 2018.
Given their intermittency, solar and wind power present certain challenges on grid security and stability. Therefore, expert studies advocate hybridisation of these two technologies not only to minimise the variability, but also to improve complementarities through better utilisation of land and transmission infrastructure.
According to the policy document, "The main objective of the policy is to provide a framework for the promotion of large grid-connected wind-solar PV hybrid system for optimal and efficient utilisation of transmission infrastructure and land, reducing the variability in renewable power generation and achieving better grid stability." This industry wholeheartedly agrees with this contention.
"Dual-energy generation from the same parcel of land with common evacuation should provide significant benefits," opines Uday Bhende, Managing Director, Kirloskar Solar Technologies, from the firm-s headquarters in Pune. He cites an example of States such as Gujarat that has extended relief from cross-subsidy, energy and wheeling charges. Bhende would now like to see other industrialised States such as Maharashtra to adopt similar measures.
Welcoming the move, Sanjeev K Ahuja, Head - Marketing at the Gurugram-headquartered equipment maker Su-Kam Power Systems, feels, "In order to achieve the renewable energy target, the Indian Government needs to step up its game, and wind-solar hybrid plants are the perfect way of achieving it. Another reason why hybrid projects make sense in India is that they allow power producers to make better use of the land and the electricity transmission infrastructure."
However, he adds that it will take a few more years before the concept can take-off as there are several technical challenges in the integration of the two systems.
Ivan Saha, Business Unit Head, Solar Manufacturing & Chief Technology Officer at another Kolkata-based equipment maker Vikram Solar, avers that the growth of hybrid plants would facilitate enlargement of renewables in India-s energy mix, ensure grid stability and encourage optimal use of land and other resources to make the sector cost-competitive. "Currently, there are only a few hybrid plants in the country. Only with sufficient fiscal incentives and favourable regulatory measures can this policy help hybrid plants to take-off in a significant manner."
As analysts point out, the hybrid plants of wind and solar have an edge over standalone renewable energy projects in several ways. They enable optimum utilisation of transmission infrastructure, which can be an asset since getting the right of way can often be a challenge and so is pooling of sub-stations for evacuation of electricity. Moreover, such units help in addressing the intermittency of wind and solar by combining the two projects to ensure a steady electric supply. While around 80 per cent of solar energy generation takes place between 9.00 am to 3.00 pm, more than 75 per cent of wind generation is typically received between 3.00 pm and 9.00 am. Furthermore, wind generation peaks in monsoon season, when solar energy generation markedly decreases.
"The combined performance of wind and solar energy will, therefore, lead to a stable form of supply, and with proper due diligence, we can identify solar and wind-rich sites to effectively design hybrid plants to improve grid stability, regulate voltage, reduce intermittency in the electric supply and optimise utilisation of infrastructure and land," asserts Amit Kumar, Leader, Renewable Energy, PwC India.
However, Surbhi Singhvi, an Analyst with the renewable energy consultancy, Bridge to India, emphasises that setting up hybrid projects would not only require efficient design and planning capabilities for conversion of existing units but also in allocation of new projects on account of land acquisition hurdles. "Moreover, sites at which both wind and solar energy sources are abundantly available and commercially viable are mainly limited to a few areas of Gujarat, Tamil Nadu, Maharashtra and Andhra Pradesh. This may become a limitation to scaling up hybrid capacities in India," she claims.
The policy also seeks to promote new technologies and approaches for a smoother integration of wind and solar plants. Especially, provisioning of the evacuation of electricity through the same system has gone down well with developers. However, like some of his other industry peers, Kirloskar-s Bhende chooses to remain cautious. "It remains to be seen whether the grids can support this additional evacuation as there are already cases where such permissions are being refused by distribution companies due to grid instability," he remarks.
Talking with specific reference to Tamil Nadu, Badrinarayanan Thirumalai, Head of Solar Business, Anchor Electricals, informs that State has the potential to harness the maximum wind velocity of up to 25 m/s between April and June each year. "Unfortunately, the grid is not suitable to take the additional generation and, hence, unable to tap the excess energy. While new Wind-Solar Hybrid Policy would benefit the renewable energy target, focus on the grid capability is of utmost importance," he declares.
Talking about some of the main technical impediments in the integration of wind and solar, Krishnan Rajagopalan, Director, Business Development at the renewable energy developer Statkraft BLP Solutions India, in Bengaluru says, "Some of the major hurdles might be encountered in the substation capacity during evacuation of power. Although the policy is very progressive, difficulties with respect to synchronised working with grid voltage and frequency, and hybrid inverter behavior are key." He is hopeful that with the government-s focus on encouraging the adoption of new technologies, advancements happening in the inverter space would get incorporated in the systems to resolve this concern.
The technological interventions also include the addition of battery storage to a project to minimise variability in power from the hybrid plant to effectively provide for higher energy output from the bidden or sanctioned capacity at points of delivery and ensuring of firm power for the period specified. This led POWER TODAY to ask domain experts if it would have made far more sense to curtail the intermittency of solar and wind energy through the development of a robust storage infrastructure that is presently lacking in India.
Although in agreement with the assessment, Bridge to India-s Singhvi points out that it comes at a high cost to the environment, as in the case of pumped hydro, and a company-s bottom line, as in the case of battery storage. She says, "In the existing policy framework and at the current battery prices, storage is not a commercially-viable option though battery prices have already shown a sharp decline of more than 75 per cent in the past seven years, and are expected to fall further." She says that integrated installation of solar and wind helps reduce the capacity of storage required, which is a far better option for both developers and grid operators.
Elaborating this further, PwC-s Kumar explains, "Bulk energy storage predominantly used for grid stabilisation applications like peak load management (PLM), power quality management (PQM) and outage management systems (OMS) could account for the ancillary services markets in the near future. Whereas, the objective of the current policy on hybrid wind and solar is to optimally utilise the existing transmission and distribution infrastructure to encourage complementarities."
With less storage capacity being required to stabilise the grid in a hybrid plant, compared to a standalone plant of wind or solar, the cost of electricity would also get reduced.
But other key concerns continue to persist. In an exclusive interaction with POWER TODAY, Vikram Kailas, Vice Chairman & Managing Director, Mytrah Energy India, a leading independent power producer, terms the policy a reaffirmation of the federal government-s commitment to support new and emerging technologies. However, he was quick to enumerate, "The policy lacks a clear framework for converting existing wind or solar projects into hybrid projects, instead focusing solely on procurement by government agencies from new projects, which is a shortcoming."
Moreover, for a wind-solar plant to be recognised as a hybrid plant, the rated power capacity of one resource needs to be at least 25 per cent of the rated power capacity of the other resource. Informs Animesh Damani, Managing Partner, Artha Energy Resources, the country-s only investment bank entirely focused on the renewable energy space, "Most windmills - barring those of 1.5MW and above - have an area of only one acre. The area is enough to set up 250 KW of solar power assuming there is no shadow of the windmill. But this is a difficult proposition and many existing windmill owners may not be able to take up this opportunity." He recommends reducing the ceiling to 20 per cent to in order to expand the scheme to make it more inclusive.
With developers having increased access to cheap capital, declining equipment costs and default by state electricity boards on their power purchase agreements, power tariffs have weakened. Against this backdrop, it is being suggested that hybrid units of wind and solar might improve yield for investors. Singhvi believes that with yields of hybrid projects likely to increase and grid stability becoming easier to ensure, the reduced cost of power and better grid management would lead to states- enhanced interest in hybrid power plants. "In our view, free market forces would decide uptake of a particular source of power rather than regulations, which could be used to give an initial push to a particular market."
But Damani offers another perspective. "We believe that the new Solar Energy Corporation of India (SECI) Ltd auction has a ceiling tariff of Rs2.93 for a wind-solar hybrid plant. Going by recent trends, this means that most of the projects will be auctioned in the range of Rs2.44 to Rs 2.70. As it is, we have our concerns on the viability of these tariffs for a pure-play wind or solar project." He feels that creating a hybrid structure does not necessarily mean better yields as areas with high wind density might have dramatically lower solar irradiance levels and vice-versa. Therefore, wind density and solar irradiance levels need to be thoroughly examined at each site before arriving at a conclusion.
Adds Kumar, "The objective of hybridisation in the current Indian context is not to improve the yields for investors but rather to utilise the existing infrastructure and better manage installed and integrated wind and solar capacities." He feels that the current policy on hybrid plants will attract the same investors and developers who are active in the solar and wind energy installations. Consequently, the hybrid segment may also witness competitive bidding similar to that seen in the wind and solar projects earlier.
Developers insist that the policy must, therefore, must also look at conceiving options for the absorption of additional capacity that would be created. Maintains Mytrah-s Kailas, "When it comes to the incremental capacity added to existing wind and solar projects, offtake of power by respective distribution companies should be made mandatory and a separate feed-in tariff mechanism should be adopted for such projects."
It is now up to the States with robust wind and solar profiles to work out a suitable regulatory framework to leverage the policy recommendations to maximise gains. For only then, together with a review of its certain aspects at the federal level, can a sustained long-term traction be ensured for India-s renewable energy sector.
- Manish Pant.
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