'Hybrid power projects of wind and solar will be most successful in Indian states with good wind and solar profiles. As such, a suitable regulatory framework needs to be announced to maximise gains from the National Wind-Solar Hybrid Policy," asserts Amit Kumar, Leader, Renewable Energy, PwC India. Kumar particularly states that the policyÆs fundamental objective is to encourage the integration of installed wind and solar capacities for their better management.
What are some of the key advantages of a hybrid power project over a standalone wind or solar project?
Wind-solar hybrid power projects have several advantages over standalone solar or wind power projects. The first advantage is the optimum utilisation of transmission infrastructure, which is often a challenge when it comes to especially, getting the right of way and sizing up the transmission line capacities and internal or pooling sub-stations for power evacuation. The second advantage would be complementing the intermittency and improving the voltage regulation, as both wind and solar are unpredictable sources of energy with their generation profile varying according to the speed of the wind or the intensity of solar radiation. By combining the two projects, a steady power supply can be ensured for a longer period in a day as well as for the improvement in the overall Plant Load Factor (PLF). Wind speeds are usually at their highest in the morning and night, particularly during monsoon, while sunrays are available only during the day. The combined performance of wind and solar energy will, therefore, offer a stable supply. With 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 the utilisation of infrastructure and land.
But the intermittency of solar and wind energy can also be taken care of to a large extent through the development of a robust storage infrastructure. Please comment.
Energy storage and wind-solar hybrid are fairly different technologies and have different applications. Bulk energy storage predominantly used for grid stabilisation applications like Peak Load Management (PLM), Power Quality Management (PQM) and Outage Management Systems (OMS) can account for the ancillary services markets in the near future. However, the objective of the current policy on hybrid wind and solar is to optimally utilise the existing transmission and distribution infrastructure to encourage complementarity. It is also evident from our experience that energy storage capacity required to stabilise the grid in hybrid wind and solar will be less compared to individual wind and solar plants. This can also help discount the overall capex and thereby, reduce the Levelised Cost Of Electricity (LCOE) from the hybrid energy generation systems integrated with storage.
However, the question of hybridising the existing wind and solar plants or integrating them with storage will also depend on various other factors like intermittency at the site in solar irradiation and wind profile, infrastructure utilisation, generation profile, topography and wind turbine technologies. A detailed due diligence and a feasibility study has to be conducted to determine the extent to which both the technologies can be integrated optimally with the energy storage capacity to assess the technical and commercial viability of the overall system. In India, the hybridisation concept will be more feasible from a techno-commercial perspective in states like Rajasthan, Karnataka, and Gujarat as well as parts of Andhra Pradesh and Maharashtra that have good wind and solar profiles. Energy storage will play a key role in intra-day markets as a part of ancillary services that are yet to open up in the Indian market.
Does India presently have the requisite technology and expertise to achieve the targeted hybridisation of new as well as existing plants?
The current policy focuses on the integration and synchronisation of solar and wind plants based on wind turbine technology for both AC and DC currents. The converter or inverter topology and system design are fairly mature in India, with a few developers even experimenting with hybridisation to scale up their existing capacities. From a technical perspective, the market is well-equipped with system designers and manufacturers to enable achievement of the targeted hybridisation. The overarching challenge will be the mapping of solar and wind power with the current available forecasting tools and techniques and handling the quantum of power from solar and wind plants. The focus should be on improving the evacuation infrastructure at the same pace of renewable energy capacity addition that is critical to integrating hybrid systems into the grid. Issues will also arise with the dispatch of renewable, which will have to be dealt with at load dispatch centres. A clear-cut regulatory framework should therefore, be in place preferably with deemed generation for hybrid power plants at the state-level. Here, the extensive efforts made by Andhra Pradesh in promoting such plants by issuing a hybrid policy in 2016 need to be commended.
Increased access to cheap capital for developers, declining equipment costs and defaulting state electricity boards failing on their Power Purchase Agreements has led to power tariffs declining to new lows. Can hybrid units of wind and solar help improve yields for investors?
The objective of hybridisation in the current Indian context is not to improve the yields for investors but to utilise the existing infrastructure and manage installed and integrated wind and solar capacities in a better manner. Hybrid power projects will have the same outlay for solar modules and wind turbines but can help reduce overall capital costs involved in land acquisition and setting up of evacuation and transmission networks. It is important to understand the additional costs that would be incurred on the converter and inverter architecture as well as generation management infrastructures like capacitor banks, energy storage, bi-directional power flow controls, protection mechanisms, metering infrastructure and forecasting tools. The current policy on hybrid plants will attract the same investors and developers, who are active in solar and wind energy installations, with the hybrid segment witnessing competitive bidding similar to that of solar and wind projects earlier.
Presently, states utilise renewable power for backup and avoid implementing it mandatorily. How can this situation be best remedied?
Electricity distributors often follow economic load dispatch pattern to cut down their Aggregate Technical and Commercial (AT&C) losses. Most Indian states have long-term PPAs, which include fixed and variable tariffs with conventional power generators who are technically stable and often respond to the energy demand from distribution companies. Conversely, renewable energy PPAs only have a variable component and generation is often unpredictable and intermittent. Therefore, it is technically and economically feasible for electricity distributors to utilise conventional, including large hydropower to serve base load, with the renewable power as an add-on source to meet the variable demand.
However, the growth in conventional energy is almost stalled with limited new capacity addition, whereas renewables are on a strong growth trajectory. The distribution companies might find it economical with the current falling tariffs for solar and wind plants, but various technical challenges have dented the growth of renewable energy procurement. Therefore, the primary focus should be on improving the efficiency of the distribution networks and reducing network congestion to leverage an increase in power demand. Improved coordination among the State Load Despatch Centres (SLDCs) and Renewable Energy Management Centres (REMCs) to strengthen the power flow in intra and inter-state networks is the need of the hour.
"The primary focus should be on improving the efficiency of the distribution networks and reducing network congestion to leverage an increase in power demand."
- Manish Pant
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