Skilancer Solar - Automated Solar Panel Cleaning

AUTOMATED SOLAR PANEL CLEANING ROBOTS SKILANCER SOLAR PRIVATE LIMITED PHONE: +91-9971045274 PHONE: +91-9711625784 EMAIL: CONTACT@SKILANCER.COM HTTPS://WWW.SKILANCERSOLAR.COM

BA C K G ROU N D The solar module in order to produce power requires direct irradiance (meaning that this light is directly coming from the sun).However, other than internal

factors (such as refractive index of glass, refractive index of EVA, composition of glass, etc.) there are various external factors as well which affect the amount of irradiance entering the solar module. One such factor is soiling and the loss of power associated with such factor is known as soiling loss. Soiling refers to accumulation of soil, dust particles, etc. on the solar module. This soil

accumulation hampers the solar irradiance to pass into the solar module. This

primarily leads to reduction of power output from the solar module. This reduced power output may remain till the module is cleaned which may not be soon enough. The result of soiling is that it leads to loss of money if not tackled

properly. The effect on plant owner would be they would lose money due to reduced energy generation. Hence it is important to understand the factors effecting soiling, the factors that necessitate cleaning cycle.

Proper cleaning of solar panels require, water, manpower and sometimes

chemicals, The chemicals can cause environmental damages in the long term,

whereas usage of water adds to the cost and wastage of resources for the solar panels. That is where we come in, to help you save costs and resources by saving manpower, water and energy loss in the long term.

A BOU T U S

OUR STOR Y

Skilancer Solar was established in 2017 and is the brainchild of IIT

Jodhpur alumni Neeraj Kumar with 3 years of work experience in the

solar industry & Manish Kumar Das, an instrumentation engineer with 10 years of experience. The company specializes in providing

permanent professional cleaning services [MCS] of solar panels of commercial parks and establishments.

Skilancer Solar is backed by Venture Catalyst and Alfa Ventures. We have been selected for incubation in 2018 under LIncubator, which is under IIM Lucknow.

OUR TEAM

Neeraj Kumar Co-Founder, Director-Technology Manish Das Co-Founder, Director-Business

M ENT O R S

Dhianu Das Afla Ventures Dr. Apoorva Sharma Venture Catalyst S.K. Jain Indo-Autotech Ltd Rishabh Jain

Indo-Autotech Ltd

SOIL IN G & POW E R L OSS The solar module in order to produce power requires direct irradiance (meaning that this light is directly coming from the sun).However, other than internal factors (such as refractive index of glass, refractive index of EVA, composition of glass, etc.) there are various external factors as well which affect the amount of irradiance entering the solar module. One such factor is soiling and the loss of power associated with such factor is known as soiling loss. Soiling refers to accumulation of soil, dust particles, etc. on the solar module. This soil accumulation hampers the solar

irradiance to pass into the solar module. This primarily leads to reduction of power

output from the solar module. This reduced power output may remain till the module is cleaned which may not be soon enough. The result of soiling is that it leads to loss

of money if not tackled properly. The effect on plant owner would be they would lose money due to reduced energy generation. Hence it is important to understand the factors effecting soiling, the factors that necessitate cleaning cycle The factors affecting soiling and the power loss are as follows:

• Climatic conditions: The local climatic condition in conjunction with the geographical location of the solar power plant can have significant effect on soiling. The local

conditions may be extremely dry/humid or a combination of extreme dry and humid weather (in few cases). This in addition with the continuous flowing wind would deliver soil and dust particles on the solar module.

• Tilt angle of modules: The tilt angle of modules is known to affect the production of

a PV power plant. It is known that the optimum tilt angle is the latitude of a particular location. However due to increased shadow length at such higher angles and/or

space constraints, the tilt angle is usually kept at lower angles. However, it is a lesser

known fact that such lower tilt angles (as low as 5° in few cases) causes an increased deposition of dust. A factor of energy loss due to soiling (generally between 3 to 5%) is considered while designing the power plant. However, power loss as high as 1012% may be observed and are reported due to decrease of such tilt angle.

SOIL IN G & POW E R L OSS Additionally it is also important to understand how often the cleaning cycle is

required and would such regular cleaning offset its cost. The energy gain vs the no. of cleaning cycle is shown in Figure below, it is clear that there would be more than

25% of energy lost if no cleaning cycle is undertaken for a month. For one biweekly, one weekly and twice weekly cycle the energy output increases accordingly. For a

country like Abu Dhabi where the local climatic conditions are dry and dusty, it makes sense to clean the solar panel once or twice in a week however for country like India, once in a week or two week cleaning cycle is fine.

• Effect on module components (primarily Glass, EVA): While the above two points

could be physically visualized and easily monitored, effect on module components

cannot be seen. This is because once the dust starts settling over the glass, it would

decorate the quality of glass. Additionally, with the dust longer settling on the glass,

there are chances that it, along with moisture could seep-in to the module. This seep in addition to module power loss (in short term) leads to deterioration of module

quality in long term and finally rendering the module useless. Such module (if not

changed immediately) could have a significant effect on power output of the entire module array.

SOIL IN G & POW E R L OSS • Type of liquid used for cleaning: This factor can be directly attributed to the

chemical composition of the liquid and its direct effect on the glass surface. Few droplets of the cleaning liquid always tend to stick to the solar glass when the

module is cleaned. This liquid while evaporates may leave behind few of its deposits which usually vary in thickness. This would result in decrease in transmittance from

the glass (as shown in figure below) which directly leads to loss of power output from module. Additionally, the varying chemical composition primarily reacts with the

glass surface (and its ARC) which may either causes the dust to stick and settle on the glass.

While the above mentioned parameters are important as they give information on

how soiling loss occur and the factors which affect them. With soiling in place on the module, it is important to clean such modules to regain its power output. However

there are few crucial factors which affect cleaning cycle. These factors are as follows: • Power gain vs frequency of cleaning: It is a known fact that cleaning of solar module is important. But it is necessary to understand what exactly should be the cycle time

as cleaning cycle is usually associated with a cost. The outcome of the cleaning cycle is that the energy output of the cleaned array (and/or the power plant)increases which would lead to increase in revenue. However it is important to understand whether such increase in revenue would offset the cost of cleaning.

SOIL IN G & POW E R L OSS We can safely say that soiling has adequate impacts both at plant and module level.

Thus it is important to keep the plant clean. However for number of cycles per

week/month, one may keep it after a thorough evaluation of performance, cost and availability of resources. It is also suggested that the cleaning of power plants are carried out only by distilled water and/or suggested liquid by the module

manufacturer/EPC provider. Additionally, we have seen many cases where

performance of plant is gauged by its Performance Ratio (PR) (a ratio of how

efficiently the plant is performing to the expected value). In few of those plants, we have seen that there is dust settlement on the irradiance meter (pyranometer) as

well. Many a cases, these meter are located at such places where cleaning them may either be difficult or forgotten as it is unnoticeable. This decrease offsets the

decrease of energy output of plant and the PR of the plants almost remains constant.

Thus it is suggested that proper cleaning cycle is undertaken of such meters as well.

The underestimation of soiling losses is due to a particularly stealthy effect. In most

cases, the irradiance sensor suffers from the same amount of dirt that is covering the solar PV panels. Consequently, the measured irradiance level decreases, despite the actual irradiance

remaining the same. The decrease in measured irradiance balances out the decrease

in electricity generation of the panels, thus the PR does not change, effectively hiding the losses.

Focus on dry cleaning:

Fully‐automated cleaning devices are installed on each row of a PV system and are stored at a parking station at one side of each row. They are programmed to move

along a single module row only. Most of the devices have an error detection system and take weather conditions in consideration before they operate. All fully‐

automated products operate with an on-board battery, although some devices may be additionally

charged by their own PV modules. Fully automated devices may have an additional rail system installed; obstructions between tables (space, steps and tilt) must be

taken into account. As the name implies, fully automated devices do not require any manual labour for the cleaning process or for the positioning of the devices. Fully‐ auto‐ mated devices can also operate during the night.

SOL A R PA N E L C L E A N IN G ROBOTS Design The design of the device was a rolling brush that traverses along an array of solar panels.

The device would attach to the array using rollers that grip the frame of the panels and use them as rails to roll along the panel. The system cleans the panel using a spinning brush to clear any dust or debris. Ideally, the device would not use water and would not need to be connected to any source of water.

Functional Analysis We devised a system that moves along the length of an array of panels, cleaning the entire array. This design was selected primarily for its simplicity. Its component subsystems have been observed to function well in other applications. The device moves across a row of panels and cleans using a spinning array of brushes. The system will move using soft rubber wheels driven by an electric motor. The rotating brush system will be mounted on a rotating axle which is also spun by the main drive motor. Using a single motor is advantageous for both cost and simplicity. However, the drive motor will need to deliver high torque in order to function effectively. To reduce the stress on both the system and the panel surface, a series of lighter cleaning cycles will be used rather than a single more intense cleaning. This device will run across a row of panels and back to its original position. The device will be powered by an internal battery. At the end of each cleaning cycle, the system will return to a docking station at the end of the panel where it will recharge the battery. The dock system will act as an extended platform next to the panels to allow the system to move off the panel surface, so it does not obstruct sunlight from any part of the panel. The system uses a motorized brush to clean the surface of the panel array. The system is moved along the panel by two sets of motorized wheels, with one set located at either end of the device. The entire system is driven by a compact hightorque DC motor. The entire system is controlled by an onboard microcontroller which is paired with a dedicated motor controller. This control system is able to fully automate the system’s cleaning process with the ability to schedule cleanings at any given time.

SOL A R PA N E L C L E A N IN G ROBOTS Our Solar Cleaning Robot is a water-free cleaning system, meaning that your site not only avoids the cost of water, but also the infrastructure that supports it, be it tanker trucks, storage containers, hoses and piping. It removes 99% of soiling on a daily basis using a combination of three factors A special microfiber that gently wipes soiling away, controlled airflow over the panel surface, and gravity to ensure soiling is moved downwards and off panel rows Can be installed anywhere The system runs directly on the array frame structure Fewest possible moving components Only four direct drive motors on the entire assembly The tilt angle gives cleaning benefits No misalignment issues

BE N E FITS & FE A TU RE S Autonomous

Safe & Reliable

Energy Independent Operation

Internet Connected

Remote Monitoring

Daily Cleaning of PV Modules

No Water Required

No Chemicals Required

Reduced Manpower cost

Less Energy Loss due to dust

Approx. 18 months payback period

Reduced Operational Costs & Increased Revenues

Artificial Intelligence Enabled

ROBOT SPE C IFIC A TION S Cleaning frequency

Twice a day

Weight

25-30 Kg

Length x Width

6m x 0.56m

Operation

Centralized computer controlled

Sensors included

Dust Detection System (DDS). Weather monitoring System, Sun Radiance meter.

Controller

Arduino based Micro-controller

Signal Transmission

Wireless (RF) based Arduino controller to operate robots with high precision from remote location.

Cleaning Speed

20m/minute or 1 Table per minute

Motor type

D.C Servo Motors

Cleaning Fiber

Poly Nano-fiber

Maximum Angle of elevation

44 degrees

Power Input

21Ah Li-ion Battery which will be charged by a solar panel installed on Robot

Cleaning of Robot

Once in two months using air blower

Battery running capacity

4200 meters on fully charged

Load Distribution

Robot's weight is 25Kg which is divided onto six wheels resulting in 4.2 Kg weight on each wheel. The load is distributed evenly due to the symmetric design of the robot.

Wind Load Analysi

Upto Wind speed of 15m/s or 54Km/h

TE C H N IC A L SPE C IFIC A TION S Dimensions

Command/Control Characteristics

Length

1-6 mtr

Logic

Height

400 mm

Comms 1 LoRa wireless

Width

500 mm

Comms 2 SCADA integration

Weight

25-30 Kg

Program Fully programmable cycle

Independent operation

Power Characteristics

Mounting System Characteristics

Supply

Retrofit

Bracket mounted rail

Storage 20Ah/14.8V Li-ion battery

Integrated

Rail/Support integrated

Control

Panel Overhang < 600 mm

10-20W solar panel Charge controller

Operating Characteristics

Cleaning Methodologies

Clean rate

0.3-0.6 m/s

Full Automatic

Row length

> 1 Km

Semi-Automatic 2 operators per schedule

Row facewidth

1-6 mtr

Daily cleaning/On demand

RU N N IN G SPE C IFIC A TION S Stoppers at each end of row Solar panel for auxiliary power

Docking Station

Self-cleaning of roller brush

Poly Nano-fiber roller brush

MON ITORIN G Our internet connected cleaning robots can be monitored remotely. Our analytics platform allows our clients to view overall, plant level and robot level running data. The data is later used to help automate the cleaning services by the robot itself.

C L E A N IN G C OM PA RISON Manual Vs. Skilancer Robot cleaning comparison: 1: Plant Size: 5 MW 2: Type of solar panels: Poly-crystalline 3: Site location: Jaisalmer, Rajasthan Out of 5 MW plant capacity, we were given 1 MW for the test deployment of our robot.

Testing was done for a period of 30 days in the month of May 2017. The power output was measured during the time 11 AM to 1 PM every day.

Condition 1: Soiling loss in %, if the panels were not cleaned for a period of 30 days if the panels were not cleaned for a period of 30 days

C L E A N IN G C OM PA RISON Condition 2: Power output from 2 different sets of solar panel arrays which were physically similar in all aspect , on 1st panel array robot was installed where the cleaning was done daily while on the 2nd panel array, manual cleaning was done at a frequency of 15 days.

C L E A N IN G C OM PA RISON

L OSS A N A L YSIS LOSS ANALYSIS FOR 1 MW PLANT WITH 3 DAY MANUAL CLEANING CYCLE Power Loss Analysis

Avg. Loss due to dust deposition

4%

Power Loss

40 kWh

Total Loss per day (assuming 5 hour of sunlight) 200 kWh Daily monetary loss @ INR 4.00 /kWh

INR 800.00

Monetary loss annual

INR 2,88,000.00

Monetary loss per month

Water Loss Analysis

INR 24,000.00

No. of modules (@ 320 watt per panel) Water required for cleaning 1 module Total water required for the plant Frequency of Cleaning Number of cleaning per month Net monthly water consumption Monthly water consumption cost @0.175/Litre Annual water consumption cost @0.175/Litre

Manpower Analysis

Cleaning time for 1 module Number of modules Cleaning time for all modules Total monthly man hours Daily working hours per person Manpower required for cleaning Labor cost @ INR 400/day Monthly labor cost Annual labor cost

Net Monthly Loss INR 54,969.00

3134 2 Litres 6,268 Litres 3 days 10 62,680 Litres INR 10,969.00 INR 1,31,628.00

30 seconds 3134 26 hours 260 hours 6 hours 5 INR 2,000.00 INR 20,000.00 INR 2,40,000.00

Net Annual Loss INR 6,59,628.00

BU D G E T, TIME L IN E , A N D D E L IVE RA BL E S The budget varies according the installations. The key factors in determining are: Number of panels to be covered Number of robots to be installed Installation spares required Labor charges

Delivery, Installation & Services: Robots are usually delivered within 10 days of ordering.

Our engineers can install 5 robots per day One year warranty is provided for each robot from the day of installation Post warranty date, AMC can be signed for upto 15 years

OU R C L IE N TS