Thermal Electricity

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Thermal Electricity

Coal

For many years, coal has supplied most of Nova Scotia’s electricity and been the main reason for rising electricity prices over the past decade. Coal is traded on the world market and prices have climbed, especially for the low-sulphur, low-mercury coal required to meet environmental regulations. While all coal is dirty, some grades contain fewer pollutants and NS Power purchases some of the cleanest coal available. Until 1999, our plants were supplied with coal mined in Nova Scotia, utilizing what was a local and economical resource. Today, government-run coal mining operations in the province are closed and most of the coal we use is sourced from international markets.

In 2012, coal accounted for 59% of the electricity used by Nova Scotians, down from as much as 80% in 2006 and the lowest amount since 1983, when the reliance on the fuel was increasing.

We operate four coal-fired power plants in Nova Scotia: Lingan, Point Aconi, Point Tupper and Trenton that use a mixture of coal and petroleum coke to improve efficiency.

 

Natural Gas

Natural gas is considered cleaner than other fossil fuels like coal and oil because it produces fewer air emissions. Around the world, it is found in reservoirs under the earth while in Nova Scotia, it's found under the ocean floor and supplied through a pipeline that leads to our Tufts Cove Generating Station in Dartmouth. The plant can burn oil or natural gas to generate electricity, but economical prices in recent years have led to it being run primarily with gas.

Because we’re producing so much electricity using natural gas at Tufts Cove – 21% of the province’s needs in 2012, up from 3% in 2006 – we’re making less power using coal at our plants, resulting in lower emissions and electricity costs.

Waste Heat Recovery

The Tufts Cove Waste Heat Recovery project added a sixth generator to the plant in 2011 that produces up to 50 MW of electricity, enough to power up to 35,000 homes.

The new equipment captures waste heat from the exhaust streams of the two natural gas combustion turbines and uses it to power a new steam turbine and generator set, generating 25 MW of electricity without any additional fuel or emissions. A second 25 MW is generated by burning gas added directly into the waste heat stream from the turbines to increase energy output even further.

Oil

Until the 1970s, most of Nova Scotia’s electricity was generated by burning oil. In the wake of the OPEC oil crisis, the government decided to switch from imported oil to Cape Breton coal as Nova Scotia’s primary source of electricity.

Today, oil supplies only a small amount of Nova Scotia’s electicity. The Tufts Cove Generating Station in Dartmouth is designed to burn either oil or natural gas, but due to low prices in recent years has run primarily on gas.

We also operate three oil-fired combustion turbine units, located in Victoria Junction (66 MW), Tusket (24 MW) and Burnside, Dartmouth (132 MW). Because they burn expensive light fuel oil and tend to be less efficient than other thermal generating units, the turbines typically serve as a secondary source of generation and are not commonly used. Oil supplied 0.1% of Nova Scotia’s electricity in 2012.