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Solar Projects & Education

Our Weekly Solar Update

Follow us along as we bring you weekly updates on the solar panels we track on the top of our Lake Elsinore, CA home.

We started this weekly series after the back to back rain storms we had in October 2018. After the storms we began tracking the dirt, dust, pollen and other contaminants that started to accumulate on our panels. Every 3 or 4 weeks we clean the panels and have left a row of 3 panels untouched since the October rain storms. 

See how fast build up can occur and what kind of an impact it has on your solar investment.

Renogy 50 Watt Solar Panel Experiment

We started this project with the intention of actually comparing apples to apples how the accumulation of dirt, dust, pollen and pollution can directly affect your solar panels from producing the energy they are capable of.

Follow this series a long as we purchase, set up and monitor 2 Renogy 50 watt solar panels. Leaving one panel untouched and the other cleaned with a routine cleaning schedule. We find out with live readings how much of an impact panels that are not maintained are costing you!

Info our solar customers how quickly environmental contaminants build up on your solar investment. 

They might not look bad from the street but when you get up close you can see the build up first hand.

We are doing this to show what the rain can do if it is heavy enough.

Also to show without the agitation of a brush to get the stuck on contaminants off how quickly the dirt, dust, pollen and pollution can build back up versus the panels that are maintained.

Since the back to back rainstorms we saw our panels get rinsed off pretty well.

What we didn’t expect was how fast the environmental pollutants would return to our panels. 

Cleaning the panels in week 3 we saw first hand how much accumulation of dirt, dust and pollen had built up on the panels.

More to come………..

2 x Renogy 50 watt solar panels

1 x Digital Multi-meter

Deionized water

Soft bristle brush

Making sure both panels are reading the same out put out of the box.

Set both up in same location. (same amount of sun and pollutants).

Clean one panel every 4 weeks.

Leave the other panel dirty only gets washed when it rains.

This step is currently in process.

What we hope to see:

To confirm that dirty panels have a significant impact on energy production.

How many kw is my solar system and what can it power?

How to calculate your solar systems output.

This will be based on a 20 panel solar array. With each panel in the array rated at 250 watts.

Items that use the most electricity in your home.

To achieve a "credit" on your energy bill you need to offset these energy consumers.

  • 20 panels x 250 watts a panel = 5000 watts of potential energy production in a hour.
  • Converting watts to kilowatts 1000 watts = 1 kw
  • This system could produce 5 kWh
  • Can power 83 light bulbs rated at 60 watts in that hour.
  • During the year the average peak sunlight period is 5.38 hours in southern California. By multiplying 5.38 hours by 4000 watts you produce on average 26,900 watts or 26.9 kWh. This is dependent on cloud cover or inclement weather. Click the button below for the website referenced for peak sunlight periods.
  • Central A/C unit 3 ton (3000 watts or 3 kw) an hour
  • 1 1/2 HP Pool Pump (2,000 watts or 2 kw) an hour
  • Ceiling Fan (75 watts or .075 kw) an hour multiplied by the number of fans used.
  • Portable Heater (1500 or 1.5 kW) a hour
  • Energy Star Refrigerator 17 Cu/Ft (100 watts or 0.10 kw) a hour.
  • To find out more commonly used items and there energy consumption. Click the button below for the website referenced for above information .

What It Costs!

Average Solar lease over 20 years broken down to what it costs a day. Then broken down to peak Summer hours and peak Winter hours.

Average 5 kw solar system cost $20,000. Financed over a 20 year period.

$20,000 / 20 years = $1000 a year

$1,000 / 12 months = $83 a month 

$83 / 30 days in a month = $2.76 a day

Summer Months

Average hours of peak sunlight is 6.19 hours.

$2.76 a day / 6.19 peak hours = .45 cents an hour what your solar loan costs you during peak hours.

5 kWh x 6.19 hours of peak = 30.95 kWh net production during a peak summer day.

If your average price per kWh is .47 cents from So Cal Edison during your summer peak hours. You would be saving $14.55 a day.

.47 cents x 5 kWh = $2.35 a hour savings.

$2.35 a hour x 6.19 hours of peak = $14.55 a day.

93 days in summer x $14.55 a day = $1,353.15 of solar potential savings!

.45 cents solar loan cost x 6.19 peak hours = $2.78 a day.

93 days in summer x $2.78 a day solar loan = $258.54.

$1,353.15 solar potential savings – $258.54 solar loan payback = $1,094.61 potential net offset amount towards your energy bill. 

If your energy consumption during the summer months is less than $1,094.61.  You should see a credit on your energy bill.

If the above factors are based on Southern California Edison TOU-D-A rate plan I used as a reference.

Winter Months

Average hours of peak sunlight is 3.42 hours.

$2.76 / 3.42 hours = .81 cents an hour

Your loan costs you .81 cents an hour and you are producing 17.1 kWh during peak hours.

If your average price per kWh is .35 cents from So Cal Edison during your winter peak hours. You would be saving $5.99 a day.

.35 x 5 kw = $1.75 a hour savings

$1.75 a hour x 3.42 hours of peak = $5.99 a day

89 days in winter x $5.99 a day = $533.11 of solar potential savings!

.81 cents solar loan cost x 3.42 peak hours = $2.77 a day.

89 days in winter x $2.77 a day solar loan = $246.53

$533.11 solar potential savings – $246.53 solar loan payback = $286.58 potential net offset amount towards your energy bill.

If your energy consumption during the winter months is less than $286.58. You should see a credit on your energy bill.

If the above factors are based on Southern California Edison TOU-D-A rate plan I used as a reference.

How Much Are These Items Costing Me?

An average central air conditioning unit will use 3000 to 5000 watts of power every hour or 3 kWh to 5 kWh. During the hotter months your ac unit can run approximately 9 hours a day. For our example below we will us a 4000 watt or 4 kw ac unit.

So Cal Edison peak hours cost per kWh is .47 cents.

.47 x 4 kw = $1.88 an hour

$1.88 x 9 hours of run time = $16.9

When Can I Bank The Most Net Energy?

During the winter/spring time when the temperatures in Southern California are mild and we don’t have the need to use the Air Conditioner.

At this time of the year is when most solar customers see a credit on their monthly electric bill. This helps offset the energy bill in the summer time when the use of air conditioning is needed.

Hopefully your solar system is rated to produce more energy than you consume during the summer months. If this is true with your solar system then you should see an annual net energy bill with a credit on it. Ways to help ensure your solar system is going to produce the most efficient net energy for you is to have them routinely cleaned and maintained.

What Are Soiled Panels Costing Me?

Basing this off of routine panel cleaning our customers report a 20-30% increase in net production. 

Going back to the 5 kw solar system. We are going to take 30% away from 5 kw.

5,000 watts x 30% = 1,500 watts of potential net loss.

This takes our solar system from a 5 kWh net production during peak hours to a 3.5 kWh during peak hours.

Going with what we did in the column to the left. If we do the same calculations with the 3.5 kWh system these are the results:

3.5 kWh x 6.19 hours of peak = 21.66 kWh net production during a peak summer day.

.47 cent So Cal Edison rate a hour x 3.5 kWh = $1.65 a hour in savings. This is a reduction of .70 cents an hour with soiled panels.

$1.65 a hour x 6.19 hours of peak = $10.21 a day. This is a reduction of $4.34 a day with soiled panels.

Lets continue with the total summer days calculation.

93 days in summer x $10.21 = $949.53 a solar potential savings.

unsoiled panels = $1353.15

soiled panels = $949.53

That’s a potential net loss from dirty panels of $403.62 during the peak summer hours.

With our cleaning services on a 20 panel system it would cost your $100 for use to clean them one-time and for a bi-annual cleaning it would cost $170. 

If you went with a one time cleaning your potential savings could be $303.62 or if you wanted to ensure maximum performance from your panels insuring peak efficiency going with the bi-annual you have a potential savings of $233.62. 

It makes sense to have your panels cleaned. If there are any questions please contact us.

We hope this comparison is clear and can help our potential customers maximize their solar investments potential and allow us to return their solar investment to operating at peak efficiency for them.

Note: Every individual solar customer is different when it comes to energy consumption. The above information is an example based on a 5 kw system. It is based solely on what the potential net output could be vs potential net loss with soiled panels.