Emissions from power plant sources increased by 25.3 per cent last year over 2016, official data issued on Monday by the National Statistics Office shows.
Emissions dropped by half in 2015 when the Marsa power station was closed, compared to 2014. That was the year when the interconnector was commissioned.
They dropped even further in 2016, the first full year without the Marsa power station.
But the CO2 equivalent emissions then rose again in 2017, the year when the new gas power station was inaugurated.
Asked for an explanation, the National Statistics Office said: "In 2017, D3 Power Generation (the BWSC plant converted to gas) and D4 Electrogas Malta started operation when compared to 2016 when the only power station in Malta was the one in Delimara. Besides in 2016, a higher percentage of the electricity generated was through the interconnector.
"Thus there was a significant increase in indigenous electricity generation in Malta, reflected in the increase in local consumption of fossil fuels for the generation of such electricity, between 2016 and 2017. On the other hand, it is also worth noting the substantial increase in efficiency, in terms of the emissions intensity of local electricity generation, i.e. a decrease in emissions per unit electricity generated. It should be noted that in 2017, natural gas-powered generation plant started operations in combination with HFO and gas/diesel oil fired plant (In 2016, only Heavy Fuel Oil and gas/diesel oil fired plant was operating)."
The NSO also reported that in 2017, 6.5 per cent of electricity generation was derived from renewable sources.
During 2017, electricity generation from power plants and the interconnector increased by 5.8 per cent compared to the previous year.
The highest power generation was recorded in 2017 with 2,376,786 megawatt-hours (MWh), followed by 2008 with 2,275,892 MWh.
August featured the highest increase (16.1 per cent) in electricity generation compared to the previous year. Approximately 31 per cent of the electricity generated in 2017 was between July and September.
During 2017, a total of 0.9 million MWh, or 37.7 per cent of generation was imported through the interconnector. In 2016, 68 per cent of power came through the interconnector.
Energy harvesting from renewable sources registered an increase of 21.8 per cent, reaching 165,109 MWh in 2017. Most renewable energy (94.1 per cent) was produced from photovoltaic cells.