The biggest misunderstanding about solar in Jamaica is what happens to the power you send back to the grid. A lot of people assume JPS credits you the same price you pay them, so a unit out cancels a unit in. It does not work that way. Jamaica runs on net billing, not net metering, and the difference changes how you should think about a system. Here is how the credit is actually calculated.
Two different prices
The thing to get your head around is that there are two separate prices in play, not one.
When you take power from the grid, you pay JPS the normal retail rate for your customer class, the same rate as any other bill, fuel charge and all. When your panels make more than your home is using and the surplus flows back to the grid, JPS buys that surplus from you at a different, lower rate called the avoided cost. So the unit you export is worth less than the unit you later import. That gap is the whole point of net billing, and it is what most people miss.
What the avoided cost rate actually is
The export rate is called the short-run avoided cost of generation. In plain terms, it is roughly what it would have cost JPS to make that unit itself, and that is driven mainly by fuel. It is worked out month by month: the total fuel cost for the month divided by the units generated across the system, giving a price per kilowatt-hour. The Office of Utilities Regulation, the OUR, sets and publishes this rate, and it moves up and down with fuel prices from one month to the next.
Because it is a wholesale, fuel-based number, the avoided cost is well below the retail rate you pay for the power you draw in. You can see the official explanation on the JPS net billing page.
Why this changes how you size a system
Here is the practical punchline, and it is the most useful thing to take away. A unit of solar you use the moment you make it is worth the full retail rate, because it is a unit you did not have to buy. A unit you export is worth only the lower avoided cost. So the most valuable solar is the solar you actually use during the day, while the panels are producing.
That flips the usual instinct. The goal is not to build the biggest system that dumps as much as possible onto the grid for credits. The goal is to cover your own daytime use first, then decide what to do with the surplus. Working a system out from your real usage rather than a sales pitch is the approach in how to size a solar system for your electricity bill.
Where a battery comes in
This is also why batteries matter more here than people expect. Without storage, any power you make and do not use right away goes to the grid for the low avoided-cost credit, and then you buy it back in the evening at the full retail rate. A battery lets you keep your own daytime surplus and use it at night, so it offsets power at the retail rate instead of being sold cheap and rebought dear. On top of that, it keeps you running through an outage. For the bigger picture on whether the whole thing pays, see is solar worth it in Jamaica right now? and the plain-language walkthrough in how JPS net billing actually works.
The honest takeaway
Net billing still makes solar worth it for a lot of homes and businesses in Jamaica. It just rewards a different design than people assume. You save the most by using your own power as you make it, sizing the system to your real usage, and using a battery to shift surplus into the evening rather than selling it cheaply. Understanding that the export credit is the lower avoided cost, not the retail rate, is what lets you plan a system that actually pays.
Related reading
- How JPS net billing actually works for the plain-language overview of the whole arrangement.
- How to size a solar system for your electricity bill for working a system out from your real usage.
- Is solar worth it in Jamaica right now? for whether the numbers stack up for you.
- Solar system planning for sizing a system around how you actually use power.
Does JPS pay me the same rate I pay them for power?
No. That is the most common misunderstanding. You pay the full retail rate for power you draw from the grid, but JPS buys your exported surplus at a lower rate called the avoided cost. A unit you send out is worth less than a unit you bring back in. Jamaica uses net billing, not one-for-one net metering.
What is the avoided cost rate?
It is the short-run avoided cost of generation, roughly what it would have cost JPS to produce that unit itself, driven mainly by fuel. It is worked out monthly as the total fuel cost divided by the units generated across the system, giving a price per kilowatt-hour. The OUR sets and publishes it, and it moves with fuel prices.
Why is the export credit lower than my normal rate?
Because the avoided cost is a wholesale, fuel-based number, while the retail rate you pay includes the full cost of delivering power to you. Selling at wholesale and buying at retail is how net billing works, so exported units are credited at the lower figure, not the price you pay for what you consume.
How does this change how I should size my solar?
It means the most valuable solar is the power you use as you make it, since that offsets the full retail rate. The aim is to cover your daytime use first rather than build a system to dump as much as possible to the grid for low credits. Sizing from your real usage is the sensible approach.
Does a battery help with net billing?
Yes. Without storage, surplus daytime power is sold to the grid at the low avoided cost, then bought back in the evening at the full retail rate. A battery lets you keep that surplus and use it at night, offsetting power at the retail rate instead, and it keeps you running through an outage too.
Is solar still worth it under net billing?
For many homes and businesses, yes. Net billing just rewards a different design: use your own power as you make it, size the system to your real usage, and use a battery to shift surplus into the evening. The savings are real, they simply come more from self-use than from selling power back to JPS.
The next step
Net billing pays best when a system is built around how you actually use power, not around selling as much as possible back to JPS. Get a free quote or message us with a recent bill, and we will size a system, with or without a battery, that makes the most of your own production.