A raft of measures have been put in place to reduce the amount of ethane Shell is being forced to flare while the Mossmorran plant in Fife is shut.
Shell has been left with a surplus of ethane since its customer Exxonmobil temporarily closed the plant in August.
Now Shell said it had switched from powering its furnaces with propane to using ethane and reduced the amount of North Sea gas it receives.
Residents said they had not noticed much change in flaring.
However, Shell said it had managed to reduce flaring of ethane “significantly” as a result of the new measures, which also include adding ethane into household’s supply of methane.
Exxonmobil’s plant at the site will be closed until mid December for work to be carried out to make the plant more “reliable”.
Since the Fife Ethylene Plant was temporarily closed down Shell said it “did not have the storage capacity for the significant quantities of ethane produced from North Sea gas”.
Shell separates methane, which is used in homes across the country to power cookers, boilers and fires, from North Sea gas at the St Fergus plant in Aberdeenshire.
The rest of the mixture of North Sea gas, ethane, propane and butane is then piped to Shell’s Fife Natural Gas Liquids plant in Mossmorran.
It then processes propane and butane for onward distribution and it sells the remaining ethane to the neighbouring Exxonmobil plant at Mossmorran, which turns it into ethylene.
However, Exxonmobil is Shell’s only ethane customer so while it has been shut down Shell has been burning it off by flaring.
Now Shell said it has found a way to mitigate the problem by adding some ethane into the methane used in homes as well as switching the fuel supply to its furnaces and lowering the amount of gas it receives from North Sea fields.
Andy Adam, 55, who lives in Cowdenbeath which is near the Mossmorran site, told BBC Scotland: “I welcome Shell trying to make changes but I haven’t seen much of a reduction in the ground flares since Exxon shut in August.”
A Shell spokesman said it was “very unusual” for them to have to take such measures.
“Since mid-August Shell has been temporarily reducing the overall amount of gas it receives from North Sea fields, to lower the amount of ethane brought to shore. This is being done in close coordination with the national grid.
“At the St Fergus plant we have adjusted operations to temporarily add a large portion of the ethane which comes ashore to the mix that we use to supply the national grid – as much as is permitted within the specifications of home appliances such as gas hobs and boilers. Normally, this ethane would go to Mossmorran.
“At Mossmorran to further minimise the amount of flaring we have also temporarily switched the fuel supply we use for the furnaces of the Shell plant in Mossmorran to ethane instead of its usual source.”
James Glen, chairman of Mossmorran Action Group said: “Ground flaring has been a permanent fixture at Shell for the last three months, prompting continuous complaints from nearby residents about light pollution, vibration and health impacts.
“While ground flaring is less intrusive than elevated flaring, Shell’s prolonged continuous ground flaring has created new and increased problems for local communities.”
Ian Buchanan, chief officer at the Scottish Environment Protection Agency (Sepa), said: “It’s right that both businesses work together to both continue to minimise impacts of the current shutdown and address the root causes of flaring.”