Farmers are now able to harness solar radiation to potentially reduce their overall power bills.
Electricity is used in multiple ways in on-farm agricultural production. Take field crop producers for example. These types of farm use electricity to pump water for irrigation, grain drying and storage ventilation.
Greenhouse crop farmers use energy for heating, air circulation, irrigation and ventilation fans.
Dairy and livestock farms use electricity for cooling their milk supply, vacuum pumping, ventilation, water heating, feeding equipment, and lighting appliances.
As you can see, even for farmers, there is no escaping those utility bills.
Or is there?
In this article, we will address whether this solar energy for farm use is efficient and economic, and whether it would be able to offset your electricity consumption.
Using Solar Energy in a Dairy Farm
In addition, the average-sized dairy farm in the U.S. ranges between 1000 to 5000 cows.
Around 50% of the electricity used on a dairy farm goes towards milk-production equipment. Such as vacuum pumps, water heating, and milk cooling. Additionally, ventilation and heating also make up a large proportion of energy expenditure.
Small Dairy Farm in California
|Monthly electricity consumption:||83,000 kWh|
|Monthly water consumption:||1,350,000|
|Monthly peak sun hours:||156 hours|
|Annual Rainfall:||21.44 inches|
|Cost per kWh:||$0.1844|
Let's begin by establishing the rough solar system size you will need to offset your electricity consumption.
Solar system size
First, we will divide the monthly kWh consumption by the area's monthly peak sun hours. This will give us a rough solar system size.
83,000/156 = 532 kW
A small dairy farm located in California with around 1000 cows will require a 532 kW solar system to offset their electricity consumption.
Now that we have the solar system size required, we can work out how much this will cost to build.
Based on the NREL's bottom-up modeling, a 532 kW ground-mount solar system will cost a dairy farm $915,040 at $1.72/W.
The current cost of electricity in California sits at $0.1844 per kWh making your monthly electric bill $15,305.
Therefore, your total ROI would be approximately 5 years. From there on out you will be saving $15,305 every month or $183,660 per year on your electricity bill.
So, assuming your farm's solar system lasted 25 years. You would see a total savings of $3,673,200.
Land space required
Assuming that your system is made up of 400-watt solar panels, the land space required would be around 2656m2.
However, we will need to include an extra 20% to allow for movement around and in between your solar structures.
Therefore the required space for a 532 kW ground-mount solar plant would be 3187m2.
Rain collection potential
A 532 kW solar plant would be made up of approximately 1330 solar panels. If each one of these solar panels measured 21.5 ft2 the total catchment area would amount to 28,595 ft2.
Using the formula we mentioned at the beginning of the article, we can estimate the total rain collection potential.
28,595 ft2 x 21.44 inches x 0.623 = 381,946 gallons per year.
A 532 kW solar farm located in California would have the potential to collect 381,946 gallons (1,736,360 liters) of water per year.
In contrast, the average American household uses approximately 300 gallons of water per day, or 109,500 gallons per year.
While using your dairy farm's solar system to collect rainwater won't offset your consumption entirely, it will amount to moderate water savings.
Keep in mind, this example was based on a farm located in California, and while this location is optimum for solar production, it is also one of the driest states in the U.S.
|Solar-system size:||532 kW|
|Land space required:||3187m2|
|Rain collection potential:||381,946 gal per year.|
|Return on investment:||5 years|
|Total 20-year savings:||
As you can see, solar is most certainly a viable solution for farms located in a sunny location willing to invest the capital needed to offset their operation.
Please note, all the estimates produced in this article are only rough and as such should not be taken as financial advice.