Clean Power

Published on May 1st, 2013 | by Tim Tyler


Solar–Wind Hybrid Power Plants Approximately Twice As Efficient

May 1st, 2013 by  

This article originally appeared on Solar Love.

A new study by the Reiner Lemoine Institut and Solarpraxis AG has found that solar and wind power generation complement each other better than previously thought.


Photo Credit: taryn_* / / CC BY-NC-ND

The study examined the surface area where solar photovoltaic systems and wind turbines were installed together. In that same surface area, twice the amount of electricity was being generated, and the shading produced by the wind turbines accounted for a mere 1 to 2% loss in the photovoltaic system — which is much less than previously thought would be the case.

One of the strong benefits is the construction of these types of power plants do not require grid expansion since the plants generate wind and solar power at different intervals and during complementary seasons. This helps ensure that the level of energy being fed into the grid is more steady than that of wind or photovoltaic power plants alone.

“Until now, it was thought that the shadows cast on solar plants by wind turbines led to high yield losses. The study shows, however, that these shading losses are much lower than expected, provided the hybrid power plant is well designed,” said Alexander Woitas, head of the engineering department at Solarpraxis AG, parent company of

In the study, they also calculated what effects combining photovoltaic and wind power plants will have on power grids on both a global and regional level.

The bottom line is: solar power plants generate more solar power in the summer, while wind turbines generally produce a lot more electricity during the colder parts of the year — this balances out the overall supply to the grid and keeps it more stable throughout the year.

To continue the research, a photovoltaic system will be  retrofitted with wind turbines in Templin (near Berlin). The pilot plant will be analyzed by Solarpraxis, the Reiner Lemoine Institut, and project partners. The data will be used for feasibility studies of future integration between wind and solar power. This is all part of the German government’s Zwanzig20 research initiative.

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About the Author

Holds an electronic's engineering degree and is working toward a second degree in IT/web development. Enjoy's renewable energy topic's and has a passion for the environment. Part time writer and web developer, full time husband and father.

  • Anumakonda

    Good option to compliment solar and wind. Solar gadgets work in day time and wind in day and night also depending on the site.

    Grid connected converters are required to transfer harvested
    green energy from wind and solar systems into the main grid. The importance of the single-phase grid connection for PV and wind power systems should not be underestimated. It is one of the key components when it comes to stable, and efficient power transfer from the solar or wind power system into the grid. Not only grid-synchronization, also EMI problems,harmonic regulations and efficiency are important design issues that have to be solved.

    Although it looks fairly simple at first sight, the transfer of DC power from the solar or wind power system to the grid can be categorized
    into various solutions. Depending on the size of the PV-system and the
    arrangement of the solar panels, the following combination of solar panels is possible:

    Solar Panel:

    Parallel and series connected solar cells.

    Solar Module:

    Parallel and series connected solar cells including bypass


    Solar Array:

    Parallel and series connection of solar modules.

    Solar string:

    Series connection of solar panels.

    Solar Multi String:

    Parallel connection of solar strings

    The PV inverters are categorized depending on the PV power

    plant configuration.

    50 – 500Watt:

    Here mostly one solar panel is used where the inverter is

    integrated into the solar module. Typically used for feeding

    on remote locations of Measurement Stations or traffic


    500Watt – 2kW:

    For small rooftop plants, one solar string is used.

    1.5kW – 6kW:

    Larger rooftop plants are configured either as solar string

    solar Multi String.

    6kW – 100kW:

    Three-phase grid connection is applied here with solar multi

    string or arrays.

    > 100kW:

    Three phase grid connection and central configured grid


    One more limitation for wind/solar vertical system which
    will be rotating. The incidence of solar light won’t be constant on a rotating surface.

    Infact Hybrid systems like Wind-solar,Wind Diesel,
    Solar-Diesel were tried in the past. Due to economics of power
    generation,maintenance,synchronization etc. these could not be popular.

    I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.

    – Thomas Alva Edison, 1931

    Dr.A.Jagadeesh Nellore(AP),India

  • I would like to ask, what happened with solar cell that is constantly “under shadow”, for example stopped blade, or pillar. Usually, In very sunny day, such local shadows destroys the cell. how this is solved in that case?

    • Bob_Wallace

      If each panel has its own inverter (getting more common) then while that individual panel will decrease wattage output as the blade shadow passes over its voltage will be maintained and not pull down the rest of the array.

      It seems to me that in most cases it would be best to locate the panels away from turbine shadow and simply let them share the same transmission lines. But if real estate is limited/expensive a 2% or less loss is pretty minor.

  • TigerGreen

    Excellent combination and one that might perhaps get past the ‘Naysayers’! There is plenty of wind around, and in UK the higher one goes, the more constant is the breeze. I was amused by an elderly anti-wind friend recently, when after moving to a flat, some stories above ground level, she remarked on the constant wind and for once did not have a reply to my suggestion that the top of the flats should provide an excellent surface for a bank of wind turbines – at least 3 HAWTs would fit over their flats, had they being designed with that in mind from the foundations up! Just a thought for all those architects out there:-)

  • Pingback: Hybrid Power plants: Renewable Energy’s Newest Trend | JBS News()

  • agelbert

    I have always thought this is the case as well. I might add that there are incredibly windy places on planet Earth high in mountains above the cloud layer most of the time. It just seems logical to set up a chain of combined solar and wind farms along the ridges.

    Another “way out there” thought I have had is to put floating wind turbines in the roaring forties, an area (around 40° South Latitude)
    in the southern hemisphere with 24/7 high winds and seas. Undersea cables could pipe the HUGE amount of energy to the continents north of Antarctica.

    Finally, on the low wind areas of Earth needing wind power, why not make kilometer sized vertical axis wind turbines that, because of the distance/torque arm energy formula, could generate enormeous amounts of power in a light and variable wind scenario? Add to that the inherent gyroscopic stability of a vertical axis wind turbine and you have a structure that would resist high storm winds in direct proportion to the strength of said winds. What’s not to like?
    Just thinking out loud. :>)

    • Bob_Wallace

      The math will decide. In general it’s probably cheaper to generate closer to point of use rather than transmit a long distance. That won’t hold in every situation. For example, we’re getting ready to extend HVDC lines into Wyoming and tie their excellent wind capacity to the existing Pacific Intertie and Mountain Intertie which will then supply the West Coast with great late afternoon and evening wind energy.

      If we had to build the entire transmission system rather than just adding on a bit it might not have made financial sense.

      Vertical axis wind turbines have been built many times and abandoned. No one has been able to make them work as well as HAWTs even with a lot of trying. We’re now manufacturing HAWTs designed for lower wind areas.

      • Brad Rouse

        Why not combine the two in the midwest of the USA with both a natural gas generator to completely firm up the power generation. Then add in storage and a syngas production facility and provide a degree of utility dispatchability as well. Ramp up the syngas over time and you have a completely versatile energy source 100% or close to it renewable. Scale up this idea across the grid and you have complete replacement of fossil fuel in electric generation over time. Really ramp up the syngas and convert the transportation system to electric and syngas and you can phase out fossil fuel use completely.

        • Bob_Wallace

          It could probably be done, but again, math will decide.

          Might it not be cheaper to gen the syngas close to point of use if that’s how we decide to fuel airplanes? Shipping electricity is pretty cheap.

      • Hi Bob – a couple of questions if you don’t mind?

        1) Vertical axis: does that mean the type where the blades have a tail that turns it into the wind?
        2) HAWT: High Altitude Wind Turbine?

        ok more than a couple….

        3) In the Northern Hemisphere, if you have the turbines to the north of the solar array, wouldn’t there never be a shadow? I guess the further north, the more shadow at morn and evg. in the summer time?
        4) If (according to my hydro bill) I use 2500 kW.h over the highest 2 month winter bill, and says that I am using on average 30 kwh daily average, what capacity system would I need? Obviously that would vary on sun and wind. Let’s just say it is generally cloudy/rainy windy all winter, and a reasonable breeze off the water and more sun during the summer.

        Appreciate any input.

        • Bob_Wallace

          Horizontal Axis Wind Turbine. Think “axle” in place of “axis” and then think about the axle in a bike wheel. If the axle is horizontal, parallel with the ground, then the wheel turns “up and down”.

          The turbine in the picture is a HAWT. Blades spin like a bike wheel rolling down the road.

          Vertical Axis Wind Turbine. Lay the bike on its side so that the Axle is in a Vertical position. Now the wheel turns like a merry go round. Most look like an egg beater at work.

          Almost every wind turbine will be a HAWT. Lots of VAWT designs have been tried, but they just don’t work as well as HAWTs. Over 200 large VAWTs were installed 20 or so years ago. I think they’re all gone.

          Shadow, yes. Putting panels north of a tower would put them in the turbine’s shadow. South would be better but they still could get some shadow when the wind is coming from the east or west and the blades have turned to face the wind.

          Overall this idea of packing solar panels close to wind turbines doesn’t make sense to me. Turbines need to be spaced out so that the turbulence created by one turbine doesn’t decrease the performance of another. It’s not like we take small pieces of land and cram it full of turbines.

          Sharing a transmission line, and possibly on site storage makes sense. Put the panels where they won’t get shaded. Maximize production.

          If you’ve ever farmed or raised cattle you’d know that not all parts of a field are equal. Some have poorer soil, more rock, bad drainage, etc. Put the panels on the least valuable land, farm/graze close to the turbines.

          Roughly, if you use 30 kWh on average you need to generate 30 kWh. The size of your solar system would be 30 divided by your average daily solar hours per year.

          Here’s a solar insolation map. Check the number of solar hours for where you live.

          Anywhere in Mississippi, for example, you’re in Zone 4 and get 4.5 solar hours. 30/4.5 = 6.7 so you’re looking at about 7,000 watts, 7 kW.

          There are other fine adjustments to be made to that number. Wire resistance loss, alternator loss, etc. But you can use 7 kW as a fairly close estimate.

          The idea with net metering is that you’ll generate a lot of electricity when it’s sunny and send most of that to the utility, to the grid, and then you’ll take back the power you need when it’s not sunny. The grid is acting like your storage battery.

          If you had a 7 kW solar system and used 30 kW/day when the Sun was shining you’d be producing 7 kW of power but using (on average) only 30/24 = 1.25 kW. That other 5.75 kW would be going to the grid and building an account you could use when the Sun stopped shining.

          (All that make sense? If not, let me know and I’ll try again. And work to get that 30 kW down. Efficiency is the cheapest route.)

          • TY much – i learned a couple of things. Do you work as a consultant on solar/wind systems? the 30kw was my highest use – winter running infrared electric heater that pretty much heated the whole place most of the time. Of course summer is very low. But I would think that the system would need to cover maximum use. I am planning on not being connected to the grid.

            I am wondering as well about those sun hours… I am North Vancouver Island – lots of rain/cloud almost all winter. Do you get anything out of solar at that point? And that is the high demand use during that time. Of course, wind would be better in the winter/year round…. any thoughts?

            Can you consult or refer me to someone for this area for larger projects?

          • Bob_Wallace

            That’s a tremendous amount of electricity to use if you want to go off the grid. Panels won’t be the cost issue, but storage. You’ll need a lot of of batteries.

            I’m off the grid, my daily consumption is less than 3 kWh in the winter and my batteries cost about $2,000. That’s for a set of batteries that should last ten years.

            I minimize my cloudy day power needs by doing laundry and pumping water on sunny days. I’m sure I have fewer cloudy days than you.

            Heating with electricity is very power demanding. Wood an option?

            On a cloudy day I get enough from my panels to power radio/computer/refrigerator while the Sun is up. Not enough to charge the batteries. After a couple of days of clouds I have to use my generator.

            How about a wind turbine? Or a combination of wind and solar?

            If you’ve got hydro potential that that would be golden.

            I don’t know anyone in your area.

            What I would suggest is getting familiar with Home Power Magazine. They are on line and your library might have a subscription (our does). If you can get your hands on a bunch of copies look through for people who are off the grid and living in areas like you.

          • cool – ty – will check the library – I would want to do wind and solar and yes I was running an electric heater in a leaky old trailer. I will do better in the cob house i have planned as well as using a rocket wood stove with that. The 30kwh was my max use in winter with electric heater.

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