Glossary of green terms

Don’t know your STC from your PHEV? Get confused by kW and kWh? Don’t worry, this no-nonsense green cheat sheet will have you sounding like an eco-expert in no time.

AC (alternating current) – is a type of electrical current where the flow of electrons switches back and forth. It is the type of current used by your household appliances when plugged into the sockets in your house.

Battery capacity – is usually listed in kilowatt hours (kWh) and tells you how much power a battery can store. The power rating, measured in kilowatts (kW), tells you how much power can flow into or out of the battery at any given instant. The depth of discharge (DoD) tells you what percentage of the battery’s power can be used before the battery will need recharging.

Battery management system (BMS) – is any electronic system that helps manage and monitor the flow of energy through a battery storage system.

Battery storage system – or battery energy storage system (BESS) – is a system that allows energy produced by a renewable source such as solar, hydro or wind to be stored in a battery for use later on.

BEVs – or battery electric vehicles – are cars that are 100% powered by electricity and use batteries to store that energy. BEVs need to be plugged in to recharge the batteries.

Carbon dioxide (CO2) – is a pollutant released when fossil fuels are burnt for energy. Excess CO2 acts like a blanket over the planet, trapping heat in our atmosphere and causing the temperature on Earth to rise.

Carbon footprint – the amount of carbon a person, household, business or entity contributes to the atmosphere. The aim is to make your footprint as small as possible.

Carbon neutral – a concept whereby you reduce the amount of carbon you produce to a minimum and offset what you can’t help producing, thereby adding no carbon to the atmosphere overall

Carbon offset – a way of offsetting the carbon you create by investing in a program that reduces carbon emissions by an equivalent amount. For example, you can offset the carbon incurred on a flight by paying a reforestation project the amount required to offset that carbon by planting trees

Carbon positive – this is when your activities help reduce the amount of carbon in the atmosphere. It’s a step beyond being carbon neutral (where you don’t add any more carbon). Being carbon positive means you are taking carbon out of the atmosphere, and your activities have a net positive effect on the environment.

Carbon target – a goal that states how much a country, state or council wants to reduce its carbon emissions by, and by when. For example, the federal government has committed to reducing carbon emissions to 43% below 2005 levels by 2030, and to net zero by 2050.

Charging stations – these are places where you can recharge your electric vehicle. They can be attached to your house or located within the community at public charging stations.

Climate change – the unnatural warming of our planet caused by human activity. Climate change is having significant and unsustainable impacts on our weather, the environment and our ability to sustain life on earth. In particular climate change is caused by the carbon dioxide (CO2) we release into atmosphere by burning fossil fuels.

Community batteries – large batteries (roughly the size of a large car) that allow multiple households to store and share any excess power generated by their individual solar panels for collective use later on.

CSG – coal seam gas – is gas extracted from coal deposits. To eject the gas, fluid is injected into rock in a process called fracking.

DC (direct current) – a type of electrical current that flows in one direction only. Solar panels use DC current because the flow of electrons created by the sun’s rays goes in one direction only. To connect solar panels to household power you need an inverter to change the DC current into AC current, which is the type of current your household appliances use.

Depth of discharge (DoD) – tells you how much of a battery’s power you can use before it will need recharging. Expressed as a percentage, it is usually stated by the manufacturer. Most lithium batteries designed for household solar systems or EVs have a DoD of between 10% and 20%. This means that in a 5 kWh battery with a recommended DoD of 20%, only 4 kWh of energy can be used before the battery will need recharging. For non-lithium batteries (e.g. the lead-acid batteries found in most cars), the DoD tends to be around 50–60% (i.e. you should only discharge them by about half).

ESG – stands for environmental, social and governance factors and is a way of measuring how well an organisation is performing in terms of its ethical, social and sustainability responsibilities. In particular, ESG measures help ensure accountability for an organisation’s carbon footprint.

EVs – electric vehicles. EVs are entirely powered by batteries and are recharged by plugging them into an electricity source. Think Tesla.

Feed-in tariff (FiT) – the amount of money your energy retailer pays you per kWh of energy you feed back into the grid from your solar panels and battery storage system. For example, at the time of writing, the minimum FiT in Victoria was 5.2 cents per kWh.

Greenhouse gas emissions – all the emissions, mainly CO2, that create a greenhouse effect by trapping the Earth’s heat under the atmosphere and contributing to global warning.

GreenPower – a government-certified renewable energy program. Paying extra for accredited GreenPower means your retailer sources renewable energy on your behalf.

Hybrid cars – these are petrol cars that have a battery as a supplementary power source. The battery adds power to the car, making it more energy efficient, and is charged through regenerative breaking. Hybrid cars, unlike EVs, do not need to be plugged into an electricity supply for recharging.

Internal combustion engine (ICE) – traditional type of engine that burns a fuel such as petrol or diesel to produce the energy needed to create motion.

Inverter – transforms a power supply from DC (direct current) to AC (alternating current) or vice versa. An inverter acts like a translator between different energy sources. It can also be used to measure how much energy is being produced or used.

Kilowatt (kW) – is a measure of power, i.e. the rate at which energy is used or transformed. For example, it’s the rate at which the solar panels on your roof transform energy from the sun into electricity, or the rate at which a light bulb transforms electricity into light. The appliances in your home consume electricity measured in watts or kilowatts (“kilo” means thousand, so 1 kW = 1000 W). A high-speed blender might use 1 kW at any given moment, while an electric heater might use 3 kW. Kilowatts (kW) are not to be confused with kilowatt hours (kWh) – see the next entry.

Kilowatt hour (kWh) – is a measure of energy consumed over time. It’s the power of an appliance multiplied by the hours you’ve used it for. So if you run a 1 kW appliance for 10 hours, you’ve used 10 kWh. If you run a 10 kWh appliance for 1 hour, you’ve also used 10 kWh. If you’re confused about the difference between kW and kWh, it might help to think of a water analogy. Think of kilowatts (kW) as being like the rate at which water is flowing into a bath. If you’ve turned the tap on full (high kW) water comes out at a fast rate and you can fill the bath quickly. If you’ve turned the tap only a little (low kW), there’s only a trickle of water and it will take longer to fill the bath. In contrast, kilowatt hours (kWh) are like the total amount of water in the bath. The bath contains the same amount of water (kWh) whether you turned the tap on full and filled it quickly, or just turned the tap on a trickle and filled it slowly.

Net zero – means achieving a balance between the amount of carbon emitted into the atmosphere and the amount removed from it. Net zero refers to a state of neutrality where the carbon humans produce is negated by the carbon we remove.

Off-peak period – the time of day when electricity is least in demand. This is often the cheapest time to use power from the grid (usually late at night).

Peak periods – the times of day when electricity is most in demand (mornings and evenings). Energy retailers often charge extra for electricity during peak periods.

PHEVs – plug-in hybrid electric vehicles. These cars use electricity to run but have a back-up petrol system for when the battery power runs out. To charge, they are plugged in just like fully battery-powered electric vehicles.

PPA – or power purchasing agreement. Under a PPA, a third party pays to install a solar system on your property and you pay them to use the power produced. It means you don’t have to pay upfront to install the solar panels and don’t have to maintain them, but you still get to benefit from the lower cost of the energy produced. You are locked into a contract with the provider, though, and the terms can be restrictive.

Range anxiety – the fear that an electric vehicle will run out of charge before reaching its destination, or fear about how far it will go before needing to be recharged.

Rebates – government-led financial incentives and programs designed to help offset the cost of transitioning to sustainable and renewable energy.

Shoulder period – the part of the day between when electricity is most in demand (peak period) and least in demand (off-peak period).

Solar panels – photovoltaic panels that absorb energy from the sun and transform it into electricity we can use to power our buildings and appliances.

Standby power mode – when an appliance is plugged in and drawing electricity but isn’t being used.

STC – or small-scale technology certificates. These are a form of rebate offered by the federal government to reduce the upfront cost of buying solar panels. Solar providers usually incorporate the value of the STC into the price they quote you.

Time of use tariffs – this means that the price of electricity changes throughout the day, rising in peak periods and becoming cheaper when demand on the grid is usually lower. Pricing periods are usually broken up into peak, shoulder and off-peak periods.

Virtual power plant (VPP) – this term refers to a cloud-based way of linking individual solar panel systems together so they can be used as a virtual power plant. A VPP is different from a physical community battery that is placed within a community.