In his bid for re-election, Dalton McGuinty has cancelled the development of a 280 MW gas-fired generator, called Greenfield South, near Sherway Mall in south eastern Mississauga. The key power system reliability justification Mr. McGuinty has provided for this decision is incorrect and he has omitted any comment on a key implication of his decision.

The Greenfield South facility was planned to start commercial operations a few months before the deadline for closure of the last of Ontario’s coal-fired generation, a key element of Mr. McGuinty’s electricity policies.

In the first video in this post from Mike Miner at TVO, hear Mr.  McGuinty defend his decision to cancel the generator development at that location with the claim, “The IESO tells us we have some breathing space now.” In the clip, Mr. McGuinty is responding to questions from Rob Ferguson of the Toronto Star. Notice Mr. Ferguson at the end of the clip asking whether Mr. McGuinty knew that the power plant was unneeded a month ago.

The IESO is the agency responsible for power system reliability in Ontario.

Every 6 months the IESO issues a fresh forecast of conditions the power system is expected to experience over the next 18 months. The last complete edition of this report was issued August 24, 2011. The analysis discussed in this most recent report was developed taking into account the cancellation of the 900 MW Oakville generator in 2010.  The IESO’s 18 month report makes quite clear that while the overall demand/supply balance in Ontario has breathing space, in south west GTA the local situation does not have breathing space with respect to reliability concerns.

Here is the key statement from the report:

Over the last few years the southwest GTA demand experienced moderate growth, compared to the higher growth seen in the previous decade, resulting in adequate supply margins still being available under normal conditions. However, to maintain reliability of supply under extreme conditions in the area, transmission solutions are now being considered. Until a transmission solution is in place some mitigating measures may be required under extreme conditions if local transmission elements become unavailable.

In this context, “extreme conditions” refers to events like hotter than normal weather and “mitigating measures” refers to IESO control actions that can include dispatching off some large consumers of power or a wide range of other actions.

The IESO is not alone in its assessment that south west GTA lacks breathing space. In 2009, prior to the cancellation of the much larger gas-fired generation facility in Oakville, the Ontario Power Authority issued this summary of its analysis of the the available breathing room in the south west GTA. In particular, note this statement:

A new natural gas generation plant is essential in the southwest GTA. It is critical for supporting the elimination of coal-fired generation by 2014 and to meet the electricity needs of a region whose peak load has grown more than twice as quickly as the provincial average.

The Greenfield South generator in south east Mississauga was a large part of the plan to cover the needs that would have been met by the Oakville generator.

In the absence of both generators, very significant changes will now be required to the transmission systems serving the south west GTA. Mr. McGuinty has not yet acknowledged these requirements, their costs or their implications for communities in the path of these developments.

Regarding the cost of cancellation of Greenfield South, note that as of June 30th, the Ontario Power Authority reported that “Major equipment has been ordered and several powerhouse column footings are complete.”