Several studies have suggested that in most of the locations with good wind and solar potential, the two generation sources generally complement each other well on a daily as well as seasonal basis — basically the sun shines when the wind is weakest and vice versa.
The studies suggested the complementary generation profiles could not only be beneficial from a grid-balancing perspective, but could also allow better utilisation of transmission assets, effectively helping early recovery of transmission infrastructure costs.
Shared land, infrastructure and operation-and-maintenance strategies could also offer benefits in terms of capital and operational costs compared with separate wind and solar projects. The levelling of the hybrid generation profile could enable better generation scheduling and help save on regulatory penalties for forecast deviations.
The Ministry of New and Renewable Energy (MNRE) published a draft wind-solar hybrid policy in June, inviting public comments. The draft targets 10GW wind-solar hybrid capacity by 2022.
Not to be left behind, the coastal state of Andhra Pradesh, which had identified wind-solar hybrid as a thrust area in its wind-power policy released last year, published a draft policy for wind-solar hybrids in August, targeting 3GW by 2020.
Like the MNRE policy, it also allows existing wind or solar projects to go for hybridisation. The generated power can be used by the project owner themselves (captive use), be sold to a third party or to a utility at a rate determined by the regulator.
Some of the measures suggested include waiving statutory and regulatory charges and shifting the onus of system augmentation on to utilities.
Going a step further, Andhra Pradesh floated an expression of interest (EOI) inviting corporates to partner with the state government in setting up a 500MW wind-solar-storage hybrid, expandable to 1GW, in the next three to five years.
The award for the EOI has not been announced yet, but it is understood that at least four Indian renewable-energy developers expressed interest.
In late 2015, the state of Rajasthan signed a memorandum of understanding with Suzlon to develop 1.5GW of wind-solar-storage hybrids, with about 500MW to be developed by the end of 2017.
The private sector is also looking into wind-solar hybrid projects. NTPC, India's largest public-sector generator, recently floated a tender to develop 3.5MW of joint wind and solar capacity at the site of one of its thermal power projects in the state of Karnataka.
Suzlon, which has already ventured into solar engineering, procurement and construction contracts, has announced plans to work on developing wind-solar hybrids with storage and market it as an integrated offering to customers.
Other players interested in wind-solar hybrids include wind-turbine manufacturer and developer ReGen Powertech and generators such as Mytrah Energy and Adani Green Energy.
ReGen Powertech undertook the first wind-solar hybridisation by combining a 1.5MW commercial turbine with a 200kW solar PV system in 2014.
This new focus on wind-solar hybrids has also helped ease competitive pressures as many in the industry were seeing wind and solar as adversarial.
Although the wind-solar hybrid policies are yet to be passed, the intent is clear, and the initiative by these states to partner with the industry clearly shows the commitment and support for large scale wind-solar hybrids in India.