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Cloud Shadow Speed Sensor

The Future of Solar Forecast Technology

Ed Chen, National Tsing Hua University, TaiwanRicardo Vidrio: UC LEADS/UCSD STARS

Mentor: Dr. Juan Luis BoschPI: Dr. Jan Kleissl

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Opening Question Think about this

If we cover 30% of the Nevada area with solar power plant, can we power the whole US?

Copper Mountain Solar 1• Solar photovoltaic power plant in Nevada• Area: 468 acres = 1.894 km2

• Annual Production: ~124,000 MWh/year

• Electrical Power Production in the US in 2012 = 4.048 x 109 MWh/year

• Nevada area: 286,367 km²

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IntroductionOur way of life is not greenSolar Energy Engineering’s Challenge

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We all want renewable energy, but there are some pros and cons.• Pros• Environmental friendly• Avoid using fossil fuel

• Cons• Generally more expensive than

unrenewable energy.• Unstable dynamic output.

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We all want renewable energy, butIt’s usually more expensive.Levelized Costs Of Energy

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We all want renewable energy, butOutput of renewable energy is usually unstable.Output vs. time graph

SolarWind

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• Cons•Generally more expensive than

unrenewable energy.Fossil fuel will be more expensive in the long runSolar forecasting technology

•Unstable dynamic output.Solar forecasting technology

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Why can’t we power the whole US with only Solar Energy?• Output Variation• Day & Night• Sunny & Cloudy

• Loss in Long Distance Transmission• Cable Resistance• Transformer Efficiency

• Energy Storage• Store energy at day time for night time usage.• Battery efficiency.

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Solar Energy Engineering’s Challenge

Changing cloud cover is a major source of solar radiation variability, and pose challenges for the integration of solar energy.

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1010 kw Solar Panel Output in different situation

id10t naïve sunny cloudy

kW

hours

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Possible Solutions for Dynamic Output of Solar Power

A. Build more solar power plant, so that we can still have high output in cloudy day.expensive, occupy spaces. Not practical at all.

B. Construct energy storage system, so that we can store energy when it’s sunny, and release the energy when it’s cloudy.a little expensive, energy loss. Not very practical.

C. Predict the solar output in the next few hours, so that we can use other energy source to compensate the drop off.need solar energy forecasting technology, can intergrade with current electric grid. Practical.

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How toPredict the solar output in the next few hours?A. Ask someone to monitor the cloud all day.

Not precise, tiring. Not practical at all.

B. Use Doppler radar to measure the velocity of clouds. Too expensive($200,000), cloud speed and direction doesn’t totally represent cloud shadow. Not practical at all.

C. Build a cheap system to gather the data of sky image and cloud shadow speed.Acceptable.

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Solar Forecast TechnologyGoal:Predict the solar output in the next few minutes or hours in order to compensate the incoming drop off with other adjustable energy sources and keep the electric grid stable.

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USI

CSS

CSSCSS

CSS

CSSCSS

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CSSCloud Shadow Speed Sensor

• Cheap feasible way to predict short term cloud speeds and direction• Estimated cost ~ $400

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The layout of the CSS

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The Cross Correlation Method

We need this to find our highest correlated time lag between all nine sensors

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USIUC San Diego Sky Imager

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Flood of Data• Three persons team assigned to complete

spreadsheets such as this oneDate Multiple Cloud Layers Cloud Changed? Cloud Cover Cloud Direction

12/1/2013 no/no/no no 75/45/25 SW/SSW/SW

12/2/2013 no/no/no no 85/90/95 WSW/SW/WSW12/3/2013 yes/no/no no 95/95/90 SSW/SSW/SSW

12/4/2013 no/yes/no no 35/65/55 WSW/WSW/SW12/5/2013 no/no/no no 60/65/0 SW/SSE/NA12/6/2013 no/no/no no 30/65/10 S/S/SSE12/7/2013 no/no/yes no 95/100/85 W/WSW/W12/8/2013 yes/yes/yes yes 95/40/85 WSW/S/W12/9/2013 no/no/no no 40/75/65 W/WSW/WSW

12/10/2013 no/no/no yes 45/35/53 SSE/S/S12/11/2013 yes/yes/no yes 30/55/85 NNE/SSE/SE12/12/2013 no/no/no no 15/0/0 N/NA/NA12/13/2013 no/no/no no 25/25/20 SW/SW/WSW12/14/2013 no/no/no no 0/0/0 NA/NA/NA

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Was watching the videos worth it?

• How far we were from one another

Month (Morn) Person 1 Person 2 SimilarityDEC 217.1 219.6 98.50%JAN 223 219 98.20%FEB 223 219 98.20%MARCH 224.1 216.3 96.60%APRIL 221 202.5 91.70%MAY 168.8 172.5 97.80%JUNE 176.9 189.6 93.30%JULY 221.5 183.2 82.70%

Month (Evening) Person 1 Person 2 SimilarityDEC 0.13 0.13 100%JAN 0.25 0.21 83.30%FEB 0.26 0.35 75%MARCH 0.3 0.37 81.80%APRIL N/A N/A N/AMAY 0.065 0.16 40%JUNE 0.069 0.21 33.30%JULY 0.4 0.53 75%

Cloud Direction Multiple Layer of Clouds

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The CSS Data

Comparing the CSS and USI

• Some of our results are illogical. This makes sense, and will take time to analyze

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1/2/2014 Morn

CD (CSS) CD (USI) #1 CD (USI) #2 Cloud Cover #1 Cloud Cover #2

No Cloud No Cloud 337.5/NNW 0% 5%

1/2/2014 Afternoon

CD (CSS) CD (USI) #1 CD (USI) #2 Cloud Cover #1 Cloud Cover #2

No Cloud No Cloud 292.5/WNW 0% 10%

1/2/2014 Evening

CD (CSS) CD (USI) #1 CD (USI) #2 Cloud Cover #1 Cloud Cover #2

No Cloud 292.5/WNW 292.5/WNW 20% 10%

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References(1/2)• Fung, Victor, Juan Luis Bosch, and Jan Kleissl. "Cloud Shadow Speed Sensor."

Atmospheric Measurement Techniques, 2014: 1693 - 1700.• Bosch, Juan Luis, and Jan Kleissl. "Cloud Motion Vectors from a network of

ground sensors in a solar power plant." Center for Renewable Resources and Integration, 2013.

• Kent. Kent Solar Panels. 2011. http://uk-solarpanels.blogspot.com/ (accessed August 11, 2014).

• Wile, Rob. Business Insider. May 29, 2012. http://www.businessinsider.com/chart-heres-why-renewable-energy-has-miles-to-go-before-it-leaps-into-mainstream-2012-5 (accessed August 9, 2014).

• Levelized Cost of New Electricity Generating Technologies. n.d. http://instituteforenergyresearch.org/wp-content/uploads/2011/02/Levelized-Cost-of-New-Electricity-Generating-Technologie11.pdf (accessed August 8, 2014).

• Zyga, Lisa. PHYS ORG. April 9, 2011. http://phys.org/news/2011-04-energy_1.html (accessed August 8, 2014).

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References(2/2)• US energy use chart shows we waste more than half of our energy

http://phys.org/news/2011-04-energy_1.html• http://www.caiso.com/outlook/systemstatus.html• Why Expanded Alternative Energy Increases the Need for Natural Gas

http://theenergycollective.com/jemillerep/178096/expanded-wind-and-solar-power-increase-need-natural-gas

• Why is The Peak Output of Solar Panels So Low? Why do my solar panels generate less than their rating?http://uk-solarpanels.blogspot.com/2012/05/solar-panels-low-peak-output.html

• CHART: Here's Why Renewable Energy Has Miles To Go Before It Leaps Into Mainstreamhttp://www.businessinsider.com/chart-heres-why-renewable-energy-has-miles-to-go-before-it-leaps-into-mainstream-2012-5

• Levelized Cost of New Electricity Generating Technologieshttp://instituteforenergyresearch.org/wp-content/uploads/2011/02/Levelized-Cost-of-New-Electricity-Generating-Technologie11.pdf RE

Acknowledgements• UC LEADS• UCSD STARS• University System of Taiwan• National Tsing Hua University• Summer Research International Undergraduates• Victor Fung (Creator of CSS)• Prof. Jan Kleissl• Dr. Juan Luis Bosch• Dominic Fong• Joel Zahnd

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Questions

Thank You