Note: Solar Choice has no incentive to promote one VPP program over another. This review is designed to provide homeowners with a clear, unbiased overview of Diamond Energy’s Virtual Power Plant program.
New to Virtual Power Plants (VPPs)? See our comprehensive guide to VPPs.
Looking to compare? See the best VPPs compared in Australia.
VPP Overview
Diamond Energy is a long-standing Australian electricity retailer known for supporting renewable generation projects. Its Virtual Power Plant (VPP) is called WATTBANK®, an add-on to your standard electricity plan.
- Company: Diamond Energy (Australian-owned retailer).
- Program name: WATTBANK® VPP.
- Availability: Residential customers in SA, VIC, NSW, and QLD (Energex region only).
- Eligibility: Minimum 5 kWh usable battery capacity, 5 kW PV system, and 3 kW inverter. Must not be part of another VPP.
- Partners: Works with a set of compatible inverter/battery brands such as Sungrow, GoodWe and LG.
Financial Benefits Offered
Diamond Energy’s WATTBANK® rewards you in two main ways:
- WATTBANK® Credit: A fixed ongoing credit for giving Diamond Energy access and control of your battery. This is typically worth $250–$450 per year, depending on your system size.
- Battery Usage Credit: If Diamond uses your stored energy between 6 pm and 8 am, you earn 30c/kWh for electricity exported to the grid.
- Establishment Fee: A one-off $68 fee applies, unless waived when installing a new solar-battery system financed through Plenti.
Example with a 15 kWh battery
- Access credit: ≈ $350/year (mid-range figure).
- Battery usage: exporting 5 kWh on 4 nights each month earns about $72/year.
- Total potential ≈ $420/year, less the $68 sign-up fee if applicable.
Electricity Tariff / Rates
The WATTBANK® program is an add-on to Diamond Energy’s normal market offers. You stay on Diamond’s standard retail plan, with your normal usage charges and feed-in tariff. The VPP then adds credits and export bonuses on top. Rates vary by postcode; see Diamond’s market offers or use our Battery Price Guide to check potential payback.
Battery and System Requirements
To participate, you need:
- Battery: At least 5 kWh usable capacity.
- Solar PV: At least 5 kW DC capacity.
- Inverter: At least 3 kW and on Diamond’s compatible list (includes Sungrow, GoodWe, LG).
- Connectivity: Smart meter and continuous broadband internet.
- Other: You must allow Diamond ongoing access to manage your battery, and no one in your home can rely on life support equipment.
Contract Length and Exit Terms
- No lock-in: Agreements are ongoing with no exit fees.
- Cancel anytime: You can leave by notifying Diamond Energy or by switching electricity retailers.
This makes the program more flexible than many other VPPs that require fixed multi-year contracts.
Technical Operations
- Control: Diamond Energy can remotely charge or discharge your battery when the grid needs support.
- Export rewards: Only exports between 6 pm and 8 am qualify for the 30c/kWh Battery Usage Credit.
- Event frequency: Diamond suggests VPP events may occur 3–4 times per month, but this will depend on grid conditions.
- Impact on you: Some battery capacity may be used for VPP events instead of household use, though operation should remain within manufacturer limits.
Pros & Cons
Pros
- Up to $450/year in credits, plus extra export payments.
- No lock-in contract and no exit fees.
- Available across multiple states with common battery brands supported.
Cons
- $68 establishment fee (unless waived).
- Only night-time exports earn the higher credit.
- Diamond Energy gains control of part of your battery operation.
- Diamond Energy WATTBANK® VPP: An Independent Review - 15 September, 2025
- Discover Energy VPP: An Independent Review - 15 September, 2025
- Commercial Energy Audits in Australia: A Business Owner’s Guide - 10 September, 2025
