Hybrid wind-solar projects explained

Wind and solar are often thought of as separate technologies with separate projects. But in many parts of India, their generation patterns complement each other: solar produces during the day and peaks in the dry season, while wind is often stronger in the evening, at night and during the monsoon. Combining the two in a hybrid project can deliver steadier output and use grid infrastructure more efficiently.

What a hybrid project is

A hybrid project combines wind and solar generation, connected so they share infrastructure — most importantly the grid connection. There are several configurations:

• Co-located hybrid — turbines and solar arrays on the same site, sharing land, internal infrastructure and a single connection point.
• Adjacent or nearby sites — wind and solar on separate parcels feeding a common pooling substation.
• Hybrid with storage — battery storage added to shape output further.

Definitions and eligibility for hybrid status are set by applicable policy; check current MNRE and state provisions.

Why combine wind and solar

Complementary generation

When one resource is weak, the other is often stronger. The combined profile can be smoother than either alone, which suits buyers who want more consistent supply.

Better use of grid capacity

A grid connection used only by a solar plant sits idle at night. Adding wind lets the same connection carry energy for more hours. Because the two rarely peak at full output simultaneously, the combined installed capacity can sometimes exceed the connection capacity, with only small curtailment — though how much depends on the site and what regulations allow.

Shared costs

Land, roads, substations, security and O&M facilities can be shared, which can reduce cost compared with two separate projects.

What makes a good hybrid site

A good hybrid site needs both resources at useful levels, which narrows the options:

• Wind resource strong enough at hub height. See evaluating a site for wind.
• Solar resource with good irradiance. See irradiance explained.
• Land that can accommodate both turbine positions and solar arrays.
• Grid access with enough capacity for the combined output.

Some of Tamil Nadu's wind regions also have good solar resources, which makes them candidates for hybrid development — subject to site-specific assessment.

Layout challenges

Placing solar arrays near turbines raises specific issues:

• Shadows — turbine towers and moving blades cast shadows on solar arrays, which must be modelled.
• Access — turbine maintenance needs crane access and clear areas, which constrain where arrays go.
• Setbacks — safety distances around turbines may restrict array placement.
• Cabling — two different electrical systems must be integrated.

These usually lead to solar arrays placed in zones that avoid the heaviest shading and keep turbine access clear.

Modelling a hybrid

Hybrid energy yield must be modelled with both resources together, ideally using time-series data at hourly or finer resolution. This shows:

• Combined output profile through the day and year
• How often combined output exceeds the grid connection (and how much is curtailed)
• The optimal ratio of wind to solar capacity for the site

Modelling each technology separately and adding the results can significantly misstate the benefit.

Land considerations

Co-located hybrids involve two different land uses on the same site. Solar arrays occupy land continuously, while turbines use smaller footprints with surrounding land often still farmable. Lease structures need to reflect both. Landowners should understand exactly which parts of their land will hold arrays, turbines, roads and cables. See land requirements for solar, wind and industrial projects.

Hybrids for industrial consumers

For industrial buyers, a hybrid supply can match daily consumption better than solar alone, especially for facilities running night shifts. Hybrid supply through open access or group captive arrangements depends on state rules. See open access vs group captive and matching solar to your load profile.

Adding solar to an existing wind farm

Some owners add solar to an operating wind farm, using spare connection capacity. This can be attractive, but check:

• Whether the existing connection agreement allows added capacity
• Whether land leases permit solar use
• How the existing offtake agreement treats the new energy
• Whether current policy treats the combined project as a hybrid

Operating a hybrid

Once running, a hybrid needs a single view of both technologies. Monitoring should show combined output at the connection point, as well as each technology's contribution, so curtailment, faults and underperformance can be traced to the right source. O&M may be split between a wind provider and a solar provider, which makes coordination — shared access roads, outage planning and safety rules — an ongoing task rather than a one-off.

Common mistakes

• Assuming complementarity without checking local data
• Ignoring turbine shadows on solar arrays
• Oversizing combined capacity beyond what curtailment rules allow
• Using separate leases that conflict over the same land
• Underestimating the complexity of integrating two electrical systems

How we help

Through our hybrid wind-solar work, we help developers identify sites with both resources, assemble land for combined layouts, and coordinate EPC partners for each technology. Engineering and construction are delivered through specialist partners.