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We carefully monitor emissions from our thermal generating stations and use ambient air monitoring stations to keep track of how those emissions affect the quality of the air we breathe.

Emissions Limits

Nova Scotia Power operates its thermal generating stations in compliance with provincial government limits on emissions from our thermal (coal, oil and natural gas-fired) generating stations.

Greenhouse Gases

In August 2009 the province enacted limits on Nova Scotia Power’s greenhouse gas emissions that began in 2010. The intention is to limit Nova Scotia Power's greenhouse gas emissions through a series of staged emission caps from an average of 9.6 million tonnes over 2010 and 2011 to 7.5 million tonnes by 2020.

The provincial and federal governments have announced they are working to ensure Nova Scotia’s regulations take precedent over proposed federal regulations on greenhouse gas emissions so long as they have an equivalent environmental result.

Sulphur Dioxide

  • Caps on sulphur dioxide (SO2) emissions first came into effect in the mid-1990s. Nova Scotia Power’s original cap on SO2 emissions was 145,000 tonnes.
  • In 2010, the cap was reduced to 72,500 tonnes, a 50%reduction from the original cap.
  • In August 2009 the Nova Scotia Department of Environment enacted a further cap reduction in 2015, down to 60,900 tonnes - a 58% reduction from the original cap. These changes also included an additional reduction for 2020, down to 36,250 - a 75% reduction from the original cap.

Nitrogen Oxides

  • The year 2000 was used as a baseline for recording emissions for nitrogen oxides (NOx) caps. In 2000, Nova Scotia Power generating plants emitted 26,706 tonnes of NOx.
  • The current cap began in 2009. It limits Nova Scotia Power’s NOx emissions to 21,365 tonnes, a 20% reduction from the baseline year.
  • The August 2009 changes include an additional reduction of the NOx cap in 2015 to 19,228 tonnes, a 10% reduction from 2009 and 28% below the baseline year. As well a further reduction in 2020 to 14,955 tonnes was enacted.


A mercury cap has been in place since 2005. In 2010, the cap on Mercury emissions was reduced to 110 kg and will continue to be reduced in stages toward a cap of 35 kg in 2020.

Air Quality

Nova Scotia Power monitors ambient air quality to monitor the levels of emissions that come out of the stacks of our generating stations. We monitor the air using networks of equipment located in nearby communities around each of our generating stations province-wide. This equipment operates 24-hours-a-day, 365-days-a-year so that our operations don’t affect the local air quality or cause air quality limits to be exceeded. Our air monitoring equipment also records emissions from sources other than our thermal generating stations, including pulp and paper plants, cars and agricultural dust.

One way we’re working to reduce emissions and improve air quality is by installing new technology at our power plants. Over the last several years we have installed:
  • ‘Low-NOx’ combustion systems which prevent the creation of nitrogen oxides at all of our generating units except for Tufts Cove and Trenton Generating Station unit 5.
  • A ‘baghouse’ at our Trenton Generating Station, unit 5. This technology basically acts as a large particulate matter filter for the plant’s emissions.
  • Activated carbon capture systems for mercury control.
We’re also working to reduce our emissions by improving our infrastructure overall. Learn more about the new ways we’re generating electricity, including wind, biomass, hydro and making use of more cleaner burning natural gas in the How We Make Electricity Section.

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