From UPSC perspective, the following things are important :
Prelims level : Nothing much
Mains level : Hybrid solar wind
Two recent auctions for wind/solar hybrid projects conducted were under-subscribed. However, we can believe that renewable hybrids can play a key role in helping India accelerate the decarbonization of power generation and lowering the cost of electricity in the medium term.
- Bids totaling 1.56GW were awarded against a total of 2.4GW on offer. The discovered prices were marginally below the ceiling tariff of₹2.70.
- India added 65-70GW of wind and solar capacity so far, with wind and solar contributing 9.5% of generated energy in 2019.
- If the government target of 175GW is achieved by 2022, this share could exceed 15-16%.
Renewable energy – inherent challenges
- It relies on intermittent sources, producing energy only when the sun is shining or the wind is blowing.
- Its output is constrained to specific hours of the day.
- Its use leads to lower utilization of transmission lines. This can create issues in matching peak power demand with renewable output and raise the costs of transmission.
- Countries with renewable energy penetration of 15% indicate that flexible energy resources that can rapidly ramp up or down are needed. These could include hydro or gas-based power, or energy storage solutions.
Renewable hybrids can be a solution
- A hybrid system can combine wind, solar with an additional resource of generation or storage.
- In India, solar output is maximum between 11am and 3pm, while wind output is highest in the late evening and early morning.
- Peak demand for power is reached in the evening hours of 6-9pm, which cannot be catered to by either wind or solar.
- If we can store some energy during excess renewable generation hours and release it into the grid during peak demand hours, the combined “hybrid” system can produce 24×7 clean energy as per varying levels of demand in the day.
- The storage can take many forms, such as batteries, pumped hydro or mechanical storage through the flywheel.
- The intermittency of wind and solar could also be balanced by adding a fast ramping source of power such as an open cycle gas turbine.
- Hybrid systems are driven by reducing costs of battery storage and solar energy.
- An optimal combination of solar, wind and storage can deliver stable round-the-clock power at today’s costs of around ₹6-7/kWh. Though this is significantly higher compared to baseload coal plants, lithium-ion battery costs are expected to fall from current $220-240/kWh to below $100 in the next 3-4 years.
- Costs of solar energy have fallen from ₹4.63/kWh in 2016 to ₹2.50/kWh in the latest auctions and may fall as low as ₹2/kWh in the next 3-5 years.
- McKinsey’s proprietary modeling suggests that if the above improvements are factored in, wind-solar storage hybrid systems could generate round-the-clock power with cost as well as reliability levels comparable to existing coal-fired power plants in the next 4-5 years.
Ministry of new and renewable energy’s solar-wind hybrid policy, 2018 provides a framework to promote grid-connected hybrid energy through set-ups that would use land and transmission infrastructure optimally and also manage the variability of renewable resources to some extent.