Hybrid power plans heat up in India
Combining wind and solar power at dual-use plants could ease land acquisition and variability issues—which would impact the country’s renewables market growth
India's renewable energy ministry published a national policy on 16 May that envisions a national grid of "hybrid" power plants integrating both solar and wind power, a concept that potentially addresses threats to renewables' dominance of the energy mix such as inconsistent output and land shortages. But geographical challenges and design complications suggest hybrid power may not be the silver bullet that it envisions.
The country's renewable sector has made major strides in recent years, rising to 20.1% of the energy mix as of 31 March, from 12% five years earlier, according to the Central Electricity Authority. However, growth towards the government's goal of 175 gigawatts of installed renewable capacity by 2022—from just 36.6 GW last year—is being kept in check by issues such as land acquisition.
Researchers at Delhi-based TERI School of Advanced Studies have estimated that going by current land usage trends, about 150,000 hectares of land would be required to support 50 GW of ground mounted solar and 30 GW of wind capacity—a huge ask considering that more than two-thirds of the 1.3 billion-strong population still depends upon farmland. Under a much-criticized law, officials have said it takes 59 months on average to acquire land, and protracted conflicts with local communities often turn violent.
The Ministry of New and Renewable Energy (MNRE) sees hybrid energy as the solution. Its finalised "Wind-Solar Hybrid Policy" outlines plans for a grid of integrated power plants across the country that can generate power day and night, as well as during dust storms and monsoons. Just days later after its approval in mid-May, President Ram Nath Kovind also sanctioned a programme to set up 2.5 GW of hybrid projects on build-own-operate basis.
Rather than focusing on new projects, the ministry's hybrid strategy recommends adding solar PV capacity to existing wind projects, and vice versa, maximising the usage of land that has already been acquired. It has identified sites for hybrid stations by superimposing wind and solar resource maps, saying "large areas" of the country have "high to moderate potential ".
According to the MNRE, hybrid power's versatility means it can reduce variability in renewable power generation, and create overall better grid stability.
However, not everyone is convinced that the implementation of hybrid technology will be as easy as the MNRE projects. Those who've worked on the existing projects say simply superimposing maps isn't enough to find viable locations for hybrid projects that have both strong winds and good solar radiation.
"If you want to optimise on both, there are very few places" says Rahul Munjal, chairman at Hero Future Energies. "Wind power is available in only eight states in the country. Solar is everywhere. It is possible to get a great wind site with decent solar, but it will be rare to get a great wind site with great solar as well."
Munjal adds that his experience has shown that the design considerations involved in preparing a site for hybrid power are much more complex than stand-alone solar or wind plants, as the shadows cast by wind turbines can potentially stunt the production of solar power.
But the early signs are positive. In partnership with Siemens Gamesa, Munjal's Hero Future Energies completed the first large-scale solar and wind energy hybrid project in Karnataka in April, adding a 28.8MW solar PV site to an existing 50MW wind farm. An even larger project is planned for Anantapur in the state of Andhra Pradesh, which will have 120 megawatts of solar power and 40 megawatts of wind energy capacity installed.
While other countries such as Jamaica, Australia and China have launched hybrid projects, none reach the scale of India's ambitions, and other developing countries will be watching the performance of these new plants closely. Ultimately, the future success of the initiatives depends on their actual ability to produce the steady, reliable and affordable energy needed to power India's frenetic growth, whatever way the wind blows.