Solar-Storage-Diesel Microgrid for Off-Grid and Weak-Grid Sites
Reliable, clean and cost-effective power where the grid is absent, weak or too expensive to extend. SiRay Energy integrates solar PV, battery storage and diesel generation into one architecture, dispatched in real time by our Energy Management System.
What Is a Solar-Storage-Diesel Microgrid?
A small-scale generation and distribution system that runs independently in island mode or in parallel with the utility. PV is the cheapest daytime source, the battery shifts that energy into the night, and the genset covers the gap. The EMS decides which one runs, every second.
- Island and grid-connected operation with seamless switching
- Black-start - restarts the site after a full blackout
- Multi-energy complementarity - PV, storage and diesel as one plant
- Containerized, modular, delivered ready to run
System Architecture - Four Components, One EMS
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Solar PV Array
Primary clean source, mono modules, multi-channel MPPT.
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Battery Energy Storage (BESS)
LFP cells, PCS integrated.
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Diesel Generator
Grid-forming anchor and fallback, fuel minimised by dispatch.
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EMS + PCS Control
Real-time dispatch, grid-forming control, cloud monitoring.
Three Operating Modes for an Off-Grid Battery System
Mode A - PV + Diesel
Diesel forms the grid, PV cuts fuel. Best for minimal storage investment.
Mode B - PV + Diesel + ESS
Diesel anchors the grid, the battery absorbs surplus PV and releases it at peak. Best for moderate renewable penetration.
Mode C - PV + ESS + Diesel
The battery forms the grid, the genset starts only below a state-of-charge threshold. Best for maximum fuel savings.
The EMS - Brain of the Microgrid
It monitors PV output, battery state of charge, genset status and load, then dispatches for minimum fuel and maximum stability. Remote access through vEMS 2.0.
What You Gain
- Fuel savings of 30-60% through PV-priority dispatch
- Seamless black-start
- Grid-forming stability
- Modular and scalable
- Remote monitoring and AI forecasting
- Lower emissions and less noise
Solar Storage EV Charging Station on the Same Plant
A 120 kW charger normally needs a transformer you do not have. Put a battery between the supply and the gun and the arithmetic changes: charge the battery at 40 kW all day, discharge at 120 kW for twenty minutes. The same EMS that dispatches PV and the genset now also dispenses the charger.
Mobile units - X7560 to X416240
75-416 kWh, 60-240 kW. Move it between sites.
Mobile EV ChargersGround-mounted permanent units - F200120 / EV208-120
200 or 208 kWh, 120 kW, optional solar input, card payment on the EV208-120.
Ground-Mounted EV ChargersContainerized - T1000480
1 MWh and 480 kW across four guns in a 20-ft container for sites that move many vehicles a day.
T1000480 Containerized Charger| Available supply | Without a battery | With a 208 kWh battery |
|---|---|---|
| 40 kW three-phase | 40 kW of charging | 120 kW at the gun; about five 80 kWh sessions per day |
Connectors and payment: GB/T, CCS1, CCS2 or CHAdeMO, 200-1000 V DC, OCPP 1.6J. The EV208-120 adds RFID, VPOS and bank card.
A Microgrid We Built
Southeast Asia island resort: 580 kW of PV, over 1 MWh of containerized BESS, diesel kept as backup. Diesel consumption fell 50-70%, and the site has run 24/7 without interruption since commissioning.
System Parameters at a Glance
| Parameter | Range |
|---|---|
| PV array | kW to MW, mono modules, multi-channel MPPT |
| BESS | 51.2 V to 768 V LFP, 5 kWh to 2.411 MWh |
| Diesel genset | Sized to the residual load, retained as fallback |
| Operating modes | Island, grid-tied, black-start |
| Communication | CANBUS, Modbus TCP/IP, RS485 / CAN |
| Deployment | Containerized, modular, factory-tested |
From Inquiry to Commissioning in 5 Steps
- Send load data and site conditions
- Sizing and simulation
- Quotation
- Containerized build and factory test
- Shipping, commissioning and training
Common Questions
What is a solar-storage-diesel microgrid?
A solar-storage-diesel microgrid is a small-scale generation and distribution system that combines photovoltaic arrays, battery energy storage and diesel generators under one Energy Management System. It runs independently in island mode or in parallel with the utility grid, switches between sources automatically and can black-start the site after a full blackout.
How much diesel can a microgrid save?
A SiRay solar-storage-diesel microgrid reduces diesel fuel consumption by 30-60% through PV-priority dispatch, where solar serves the load first and the genset runs only to cover the gap. In the tropical island resort project SiRay delivered in Southeast Asia, measured diesel consumption fell by 50-70% against the previous diesel-only setup.
What are the three operating modes of a SiRay microgrid?
Mode A is PV plus diesel, where the genset forms the grid and solar cuts fuel - best for minimal storage investment. Mode B is PV plus diesel plus storage, where the genset anchors the grid and the battery absorbs surplus PV - best for moderate renewable penetration. Mode C is PV plus storage plus diesel, where the battery forms the grid and the genset starts only below a state-of-charge threshold - best for maximum fuel savings and minimum emissions.
Can a microgrid run without any grid connection?
Yes. SiRay microgrids are designed for island mode, in which the system forms its own voltage and frequency through a grid-forming PCS or genset. They also provide black-start, restarting the site after a complete blackout without any external supply.
What does SiRay need to size a microgrid?
SiRay needs the site's load profile (what must run, at what power, for how long), the grid situation (no grid, weak grid or stable grid), the site location and solar resource, and any existing generation. From that data SiRay simulates PV yield, battery dispatch and fuel saved, then returns a quotation with a bill of materials.
What is a mobile EV charger?
A mobile EV charger is a battery pack, a DC charger and a wheeled chassis in one unit, so it can charge a vehicle at full DC power without a grid connection at the charging point. SiRay mobile chargers carry 75 to 416 kWh of LiFePO4 and deliver 60 to 240 kW DC at 200-1000 V through GB/T, CCS1, CCS2 or CHAdeMO connectors.
Does a mobile EV charger need a grid connection?
No. The battery inside the unit supplies the DC power, so the charging point needs no grid supply and no transformer. Ground preparation at the charging point depends on the site and the mounting. The unit itself recharges later from a standard three-phase AC supply or from another DC charger. The exception is the G2V-30160, a portable DC charger with no battery that requires a three-phase grid input.