XYLENE POWER LTD.

TRANSMISSION PLANNING

By C. Rhodes

INTRODUCTION:
For many years the cost of operating and maintaining the transmission/distribution system has been comparable to the cost of operating and maintaining the generation. However, due the increasing fraction of renewable generation on the grid we are gradually entering a new era where the cost of operating and maintaining the transmission/distribution system will be two to three times greater than the cost of operating and maintaining generation.

the reasons for this change are that the sources of renewable energy are much further from the load than the sources of fossil fuel and nuclear energy and that renewable energy is two to three times less efficient in use of transmission than is nuclear energy. Some improvement in the efficiency if transmission utilization can be realized through the use of energy storage, but such energy storage also has a cost.

This web page addresses long term transmission planning issues relating to southern Ontario.

ENERGY TRANSMISSION CORRIDORS:
A major problem with the Ontario Power Authority (OPA) draft business plan as of September 14, 2009 is lack of long term perspective, particularly with respect to acquisition of energy transmission corridors.

If Ontario is to continue to reduce CO2 emissions the law of conservation of energy demands the following:
1. The ability to bring large amounts of additional non-fossil electricity into the Greater Toronto Area (GTA) from the north.
2. The ability to efficiently store surplus energy during times and seasons of energy surplus and to efficiently recover and use that energy during times and seasons of energy deficiency.
3. In the long term meeting point #1 will require at least two new north-south 500 kV dual circuit transmission lines each of which must pass either west or east of Lake Simcoe.
4. For reliability the north-south energy transmission corridors will need to be tied together, probably via an east-west energy transmission corridor routed through the north edge of East Gwillimbury and on past Bradford. This east-west energy transmission corridor will likely have to accommodate both electricity and natural gas transmission, as well as a roadway interconnecting Hwy 400 and Hwy 404.
5. In the long term meeting point #2 will require two new 500 kV dual circuit transmission lines between the GTA and Niagara Falls to access pumped hydraulic energy storage between Lake Erie and Lake Ontario.
6. In the long term displacing fossil fuels in the transportation and heating sectors will require additional high voltage transmission between the perimeter of Toronto and the core of Toronto.
7. The acquisition of these energy transmission corridors will be one of the major challenges facing the OPA in the years to come. The more this issue is delayed for political reasons the more difficult it will become due to on-going property development on the required energy transmission corridors and on neighboring lands.
8. A high priority for the OPA is to firmly identify these energy transmission corridors and to get Ontario legislation passed that:
a) Prevents further new development along these corridors in a manner similar to the existing Greenbelt legislation.
b) Provides a long term mechanism for Hydro One or the OPA to purchase existing developed properties along and bordering these corridors at fair market price as these properties come on the market.
9. By exercising this purchase mechanism, over a period of about 20 years most of the properties substantially affected by the contemplated new energy transmission corridors could be acquired at fair market price without dispute or political conflict.
10. The OPA should also consider use of the same corridors for future highway, natural gas and commuter rail services. The main issue with commuter rail services is the requirement for large parking areas adjacent to each rail station. For example, it might be prudent for Hydro One or the OPA to purchase Buttonville Airport as a future commuter rail station. In the interim this property could continue to be used as an airport. Similar areas of land should be purchased near Aurora, Newmarket, Sharon, Queensville and Keswick to allow for a 500 kV power line and a commuter rail line parallel to Hwy 404.
11. The OPA should purchase an east-west energy transmission corridor through the north edge of East Gwillimbury and on through Bradford while this land is still readily available. The present East Gwillimbury and Bradford town plans do not provide for this corridor. In the future this corridor will be essential to provide east-west energy transmission and east-west vehicle transit north of the GTA.
12. In summary, lack of long term planning, particularly with respect to acquisition of energy transmission corridors into the GTA and acquisition of energy transmission corridors necessary to access Lake Erie-Lake Ontario seasonal energy storage is the most glaring deficiency of the OPA's 2010-2012 Business Plan.

ENERGY TRANSMISSION CORRIDOR DETAILS:
The past political difficulties related to acquiring right-of-way for 500 kV power lines has led to development of combined energy transmission and surface transportation corridors. Such corridors, such as Hwy 407, are typically 400 m wide with a large diameter high pressure natural gas transmission pipeline running down the center of the corridor. The 200 m corridor width on one side of the natural gas transmission pipeline is sufficient to accommodate two rows of 500 kV dual circuit transmission towers and a railway. These electricity transmission towers can collectively move about 6000 MW of electricity. The 200 m corridor width on the other side of the natural gas pipeline is sufficient to accommodate a large divided highway.

From a land use planning and zoning perspective it is a good idea to make the zoned energy transmission corridor 800 m wide and restrict the land use in the range 200 m to 400 m from the large diameter high pressure gas pipeline axis to agricultural uses. This planning concept accomplishes the dual objective of increasing the safety setback from the large diameter high pressure natural gas pipeline and reducing the impacts of highway noise, railway noise and electricity transmission line proximity on nearby populations.

LARGE DIAMETER HIGH PRESSURE NATURAL GAS PIPELINE RUPTURES:
A major problem with routing large diameter high pressure natural gas pipelines through urban areas is that these pipelines are subject to long term spontaneous rupture failure. Each such rupture failure causes an initial rupture explosion, a huge roaring noise, a deafening delayed ignition explosion and a tremendous ongoing fire. The explosions and fire usually destroy nearby electricity and water services. In practice the natural gas fire can only be extinguished by valving off the pipeline both upstream and downstream from the rupture. The radiant energy from the natural gas fire can directly ignite buildings up to 400 m from the pipe rupture location. The initial rupture explosion throws rocks and other debris high into the air. This falling debris can damage building roofs hundreds of metres away. The pressure pulse from the delayed ignition explosion can blow out windows as far as 1.6 km from the rupture location.

With respect to the radiant thermal energy released by the natural gas flame from a ruptured large diameter high pressure natural gas pipeline, it is possible to calculate a safety setback distance Rs that is a function of the natural gas pipeline's diameter and operating pressure. This calculation is contained on an adjacent web page titled Natural Gas Pipeline Safety Setback.

This web page last updated January 4, 2012.