Natural gas vs. district heating

It is generally conceded by most energy analysts that natural gas production peaked in North America soon after 2000. Consumption, on the other hand, has continued to climb. One of the reasons for the seemingly sudden interest in liquefied natural gas (LNG) is the fact that the shortfall between production and consumption must be met by suppliers off the North American continent. Demand exceeding supply and competition for international supplies are the principal reasons for rising natural gas prices.

In light of this, it may seem strange that the provincial Minister of Energy, Cecil Clarke, continues to call for the expansion of natural gas into parts of Nova Scotia. In late August, the minister was praising the proposed natural gas cogeneration facility intended to supply heat to Saint Mary's University, Dalhousie University, and the hospital complex on the Halifax peninsula, calling it a "crucial part" of his yet-to-be-revealed green energy strategy.

For a moment, it looked as if the minister had finally learned the importance and benefits of district heating (the supply of "waste" heat from cogenerating power stations to homes, offices, and other buildings). Sadly, this was not the case, as he then went on to explain that the planned cogeneration facility would be the "anchor" bring natural gas to the peninsula. With this statement he was simply parroting those parts of the Electricity Marketplace Governance Committee's final report dealing with cogeneration (notably Recommendation 62, which states that a cogeneration facility "will anchor a natural gas transmission line to an area or region of the Province of Nova Scotia not then served by gas transportation infrastructure").

The minister's slavish devotion to natural gas, as called for in his party's now outdated Energy Strategy, is being done at the expense of other viable alternatives. For example, peninsula Halifax and downtown Dartmouth are of sufficiently high density to allow for the installation of a district heating system to supply the area with heat and hot water. Furthermore, the Tufts Cove power station has sufficient "waste" heat to meet this demand.

Using natural gas, a high-grade fuel, for an application such as space heating that requires only low-grade heat, is both inefficient and wasteful. The "waste" heat from power stations is an ideal low-grade heat source that can be supplied to buildings through a district heating systems' network of insulated, underground pipes. Since the district heating system can use any fuel source (including coal, oil, natural gas, biodiesel, and biomass), customers are not held hostage to a single supplier or fuel, thereby improving the community's energy security.

District heating is not a new idea; it has been used for over one hundred years in many parts of Scandinavia. Interestingly, when natural gas was discovered in Denmark's sector of the North Sea, it was used in district heating plants to generate heat and power, rather than burned directly to heat buildings.

There are significant environmental benefits associated with district heating: as Stockholm's district heating system was installed, particulate matter and sulphur dioxide levels fell. Since district heating reduces the amount of energy required for heat and power, greenhouse gas emissions can also be lowered.

The minister of energy is advocating that the streets of Halifax be dug up to install natural gas pipelines. In a few years, as natural gas prices continue to climb, we may well need to dig the streets up again to install district heating pipe. Let's do it right and dig them up once, rather than twice, because of a misguided and outdated energy policy.

Submitted to Chronicle-Herald 24 August 2005 - unpublished