Battery & Solar Glossary

Essential terms and acronyms explained for WA homeowners. Search or browse to understand battery jargon.

CEC Approval

Clean Energy Council approval required for batteries to be eligible for federal rebates (STCs). All batteries must appear on the CEC Approved Products List.

DEBS

Distributed Energy Buyback Scheme - Synergy's export tariff that pays 10c/kWh during peak hours (3-9pm) and 2-3c/kWh off-peak for the first 50kWh exported per day.

Depth of Discharge (DoD)

Percentage of battery capacity that can be safely used. Most modern batteries have 90-100% DoD, meaning you can use nearly all the stored energy.

Round Trip Efficiency

Percentage of energy that can be retrieved from a battery compared to what was stored. Modern batteries typically have 92-98% efficiency, meaning small losses during charge/discharge.

STC (Small-scale Technology Certificate)

Federal rebate certificates created for small-scale renewable energy installations. Batteries earn STCs based on capacity and deeming period (years until 2030). Reduces upfront cost by $2,000-$4,000.

VPP (Virtual Power Plant)

Network of home batteries controlled by an aggregator to provide grid services. Synergy Battery Rewards is WA's main VPP, required for the state battery rebate.

AC-Coupled

Battery connected to AC side of system via its own inverter. Works with any existing solar inverter and allows battery to charge from grid. More flexible but slightly less efficient.

DC-Coupled

Battery connected directly to DC side of solar system through a hybrid inverter. More efficient (one less conversion) but requires compatible hybrid inverter. Best for new installations.

Western Power

WA's electricity distribution network operator. All battery installations require Western Power approval. ESM (Emergency Solar Management) is mandatory for systems ≤5kVA.

A1 Tariff

Synergy's standard residential tariff. Currently ~32.37c/kWh import rate (as of July 2025). Most common tariff for Perth homes.

Deeming Period

Years remaining until STC program ends (Dec 31, 2030). Determines STC multiplier. 2025 = 5 years = 9.3 STCs/kWh. 2026 = 4 years = 8.4 STCs/kWh. Reduces annually.

ESM (Emergency Solar Management)

Western Power requirement for systems ≤5kVA on Western Power network. Allows remote curtailment of solar export during emergencies. Mandatory for grid stability.

LFP (Lithium Iron Phosphate)

Battery chemistry known for safety, longevity, and stability. Most common in home batteries. Safer than NMC but slightly lower energy density. Excellent for Australian climate.

Synergy SSL

Synergy Supported Solutions List - batteries approved for Battery Rewards VPP program. Check DER-Storage section before purchasing if VPP participation is required.

Degradation

Gradual loss of battery capacity over time. Quality batteries degrade 1-3% per year. After 10 years, expect 70-90% of original capacity depending on usage and conditions.

Can't find a term?

If there's a battery or solar term you'd like us to add to this glossary, let us know through our contact page. We regularly update this list based on common questions from Perth homeowners.