Australia’s greenhouse gas emissions rose slightly in 2024.
The rise was driven in part by a rebound in fossil-fuel electricity generation and record diesel consumption, according to new government data.
The modest 0.05 per cent annual increase underscores the challenge of maintaining downward emissions momentum amid growing energy demand and changing weather conditions.
The electricity sector – responsible for 34 per cent of national emissions – saw a 1.5 per cent annual rise in emissions despite growth in renewables. High demand and a sharp drop in hydroelectric output, particularly in Tasmania, meant more reliance on coal and gas.
Emissions in the National Electricity Market (NEM) increased 1.8 per cent over the year, though coal’s contribution dropped below 50 per cent for the first time in the December quarter thanks to increases in rooftop solar (up 3.2 per cent), wind (up 4.8 per cent), and hydro (up 1.0 per cent) in that quarter alone.
For rooftop solar, the data reaffirms its critical role in emissions reductions.
Rooftop systems contributed significantly to curbing emissions in the final quarter of 2024, helping to push NEM emissions intensity down to 0.48 tCO2-e/MWh.
Without this contribution, fossil generation would have climbed further, particularly as overall electricity generation increased 3.8 per cent over the year.
But the gains were not enough to reverse the trend in annual electricity emissions, which rose as hydro generation fell 10.5 per cent and gas rose 14.8 per cent.
For installers and suppliers, the findings highlight a technical and policy imperative: increased integration of rooftop solar and storage is essential for mitigating fossil backsliding during low-renewables quarters.
The federal Safeguard Mechanism and the expansion of the Capacity Investment Scheme will need to work in tandem with reforms to grid access and rooftop PV export rules.
Transport emissions also hit a record high, rising 1.9 per cent, fuelled by surging domestic aviation and diesel use – up 4 per cent and 2.4 per cent respectively.
Diesel demand was driven by freight and growing SUV uptake, suggesting that electrification of heavy transport is lagging.
For engineers in renewable integration, the report offers both a challenge and an opportunity: as rooftop solar matures, greater system-level coordination, storage, and demand response will be crucial in reversing emissions growth, particularly during adverse weather periods.
The trend reinforces rooftop PV’s frontline role in decarbonisation – and the need to keep scaling it intelligently.