Since early 2024, the rules for installing solar panels on rooftops have changed significantly. Through Minister of Energy and Mineral Resources Regulation Number 2 of 2024, the net metering scheme for rooftop solar power plants (PLTS) has been eliminated. Excess production from panels flowing into the PLN grid is no longer counted as a deduction from the bill.
This change may sound technical, but its impact is real for homeowners and office owners. Previously, installing a large on-grid system made sense because daytime surplus could be "stored" with PLN and drawn back at night. Now, electricity that is not used immediately and has been exported practically loses its value.
At this point, an old question becomes relevant again: what type of system is actually most suitable for a home or office, on-grid, off-grid, or a combination of both?
On-Grid, Off-Grid, and Why the Choice is Different Now
An on-grid system is connected to the PLN grid and generally does not have batteries. It is the cheapest and simplest option, but it also goes down when PLN electricity is out. Off-grid systems operate independently with batteries for storage, suitable for locations without a grid or those needing backup power, with the consequence of significant battery costs. Between the two is a hybrid system that remains connected to PLN while also storing energy in batteries.
After the elimination of net metering, the design logic has shifted. The capacity of on-grid systems should now ideally be calculated to match daytime consumption, rather than simply being as large as possible. Unused power is no longer beneficial. For some users, adding batteries to store daytime surplus for use at night is starting to make sense.
Sizing is Not Guesswork
Determining the right capacity requires calculations, not rough estimates. For on-grid systems, the starting point is the PLN contract power and daily usage patterns. For off-grid systems, additional variables come into play: daily consumption in kWh, Days of Autonomy or how many days the system must last without sunlight, and Depth of Discharge of the battery which affects its lifespan.
Miscalculations lead to two classic losses. An oversized system means wasted capital. An undersized system leaves the owner fully dependent on PLN or generators. Local irradiation data from sources like PVGIS, NASA, or BMKG serves as a basis to ensure production estimates are not far from reality on the ground.
Simulations and Viability Numbers that Matter
Before a single panel is installed, the system's behavior throughout the year can actually be predicted using software like PVSyst. This simulation accounts for losses due to shading, temperature, and dirt on the panels, then produces indicators like Performance Ratio and Specific Yield that describe how effectively the system operates.
These technical figures only become meaningful when translated into monetary terms. Levelized Cost of Electricity compares the cost of solar electricity with PLN rates or generator costs. Indicators like payback period, IRR, and NPV answer the most common questions from homeowners and business operators: how long until the capital is recovered, and is the investment worthwhile? Without these calculations, the decision to install a PLTS resembles guessing the wind direction.
Engineering and Financial Decision
The elimination of net metering is not the end of residential PLTS, but a reminder that installing solar panels is both an engineering and a financial decision. A system designed with careful calculations, from sizing to economic analysis, will be much more resilient to regulatory changes than a system installed haphazardly. Amidst the national rooftop PLTS capacity reaching nearly 773 megawatts by November 2025, the ability to design the right system becomes increasingly valuable.
If the choice falls to a system with batteries, the storage size is determined by how many kWh of daytime surplus are actually used at night, not by the panel capacity. Capacity estimates and viability can be calculated using the solar battery size calculator.
References:
- Ministry of Energy and Mineral Resources – Revised Ministerial Regulation on Rooftop Solar Power, Electricity Trading Scheme Eliminated → esdm.go.id
- Katadata – New Rooftop Solar Regulations Officially Issued, Electricity Export Import Eliminated → katadata.co.id
- IESR – Ministerial Regulation No. 2/2024 Limits Public Participation to Support Energy Transition through Rooftop Solar → iesr.or.id
- Tempo – Net Metering for Rooftop Solar Eliminated, ESDM Prepares Other Incentives for Household Installers → tempo.co