JAMAICANS considering a switch to solar energy are being advised to conduct proper load assessments to ensure their investment is worthwhile.

The concern was raised by Errington Case, grid manager at the Jamaica Public Service Company [JPS], during an investment conference recently.

“If you don’t know what percentage of your load you’re using during the day as opposed to the night, you cannot make a safe investment in solar — you’ll be literally shooting in the dark,” said Case.

According to Case, a JPS bill showing total monthly consumption is insufficient to determine whether solar energy is a suitable investment. He explained that a detailed load profile must be conducted over a 24-hour period to analyse energy usage patterns. This evaluation, which may span three days, seven days, or even an entire month, provides a breakdown of how energy is consumed during the day versus the night.

Using a hypothetical example, Case pointed out that 40 per cent of energy might be consumed during the day, while 60 per cent is used at night. Based on such an analysis, a solar project without battery storage would only target the daytime usage, limiting potential savings to 40 per cent of the total bill.

“Let the person presenting the project say to you, ‘This is what we are targeting; this is what the opportunity is,’ so now we’re managing expectations,” Case advised.

A load assessment helps to assess potential cost reductions, determine whether the investment is worthwhile based on payback time, and calculate the savings from reduced JPS bills. Additionally, for those on the net billing programme, understanding the load profile allows for accurate projections of earnings from selling excess energy back to JPS. Under the net billing programme, customers use solar energy during the day and sell any excess power to JPS, receiving payment for it. The overall benefits include both the energy offset and the income generated from the excess sold.

“When these two benefits are calculated and amortised over the system’s lifetime, customers should see a net positive return, at the end of the day,” he said.

He further emphasised the need for accurate load assessments to ensure the system’s design matches energy consumption patterns. For instance, customers using air conditioning during the day — whose energy consumption follows a bell curve similar to solar generation — can offset 80 to 90 per cent of their daytime consumption on a sunny day. Conversely, households that primarily use energy at night may find solar systems less beneficial without battery storage.

Case addressed common misconceptions, such as claims that solar installations can eliminate JPS bills, which he says would be impossible because once the sun goes down, around 5 or 6 pm, all energy needs will still be supplied by JPS. He also cautioned that poor weather conditions, including overcast skies and tropical depressions, can significantly impact solar efficiency. Batteries may deplete earlier than expected during such conditions, further emphasising the importance of realistic expectations.

“On good years when we have no hurricanes, no tropical depression and no cloud cover, it’s good. 2024, not good,” he said.

To maximise the benefits of solar energy, Case recommended designing systems with slightly higher capacity than actual needs and ensuring that all appliances are energy-efficient. He also urged Jamaicans to adopt energy-saving habits and avoid adding unnecessary daytime loads.