Why robotic dairy farms have the perfect consumption for solar power
Cows are normally milked twice per day, in the early morning and the evening. However, this creates limitations for commercial solar power in the dairy industry: plant consumption is high at times of the day when solar energy production is low or zero, and in turn solar energy generation is high when the dairy plant is using little power.
One option for dairy farmers with solar PV systems is to export surplus production to the power network, but energy retailers in Australia have relatively low feed-in tariffs: the rate paid for surplus generation is around one-third of the retail price of electricity. In other words, solar energy is more valuable when it can be consumed as soon as it is generated. Cows are normally milked during brief periods to save time and human labor, but robotic dairy farms can milk cows as an ongoing process throughout the day, and thus they can rely more on solar power.
In the case of large plants subject to capacity charges, these charges can also be reduced by spreading energy consumption evenly throughout the day, instead of concentrating it in short periods. As a side note, capacity charges apply for utility clients consuming more than 160,000 kWh per year, and are based on the highest 30-minute demand for a 12-month period.
Benefits in increasing daytime energy use in dairy plants:
As previously mentioned, consuming solar energy provides higher electricity bill savings than exporting it to the power network. When dairy plants use automated milking technology to milk cows throughout the day, this is precisely what they accomplish. Milking equipment cannot rely on solar power early in the morning or late in the afternoon, but automated machines can be powered fully by the sun when they operate during daytime hours. By using automated milking, dairy plants can also justify a larger solar array, for the simple reason that more energy is used during daytime.
Dairy plants can follow two approaches to benefit from solar power: they can purchase their own photovoltaic array, or they can sign a Power Purchase Agreement (PPA). In a solar PPA, the system supplier remains the owner and is responsible for financing, operation, maintenance and component replacements. The dairy farmer can simply pay for the energy used, at a price lower than the utility rate.
Regardless of how solar energy is obtained, and assuming the same plant capacity, an automated dairy plant can achieve greater savings than another facility with conventional milking equipment that is used for short periods. Don’t forget a basic rule of solar power: using the energy generated is more valuable than exporting it to the power network, unless the local utility offers an incentive for exporting it.
Large dairy farms get an additional benefit from robotic milking equipment: peaks in energy consumption are eliminated, which results in a lower capacity charge. These charges can be eliminated completely if solar power brings net consumption below 160 MWh, but if this is not possible, at least the charge can be minimised with automated milking technology throughout the day.