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Natural Gas and Electricity Are Parting Ways – Part 2

In our last article, Natural Gas and Electricity Are Parting Ways – Part 1, we explored the weakening correlation between wholesale natural gas prices and electricity prices in the Mid-Atlantic.  While natural gas prices have fallen dramatically over the past seven years, and electricity prices have fallen as well, electricity prices have not fallen as far.  We discussed how this weakening relationship is, in part, a result of natural gas-fired generating units more and more often being dispatched before coal-fired units.  In this article, we look at the influence of capacity prices.


The cost of energy delivered by a competitive supplier consists of several elements—generation, capacity, transmission, and ancillary services.  Costs to suppliers resulting from PJM’s energy auctions are reflected in competitive suppliers’ generation charges.  Competitive suppliers are also required to own or to reserve generation capacity.  PJM runs separate capacity auctions to place a price on this capacity.  These auctions establish capacity prices for each of the three consecutive future planning years.

Polar Vortex 

During the depths of the Polar Vortex of January 2014 (see What Does Volatility Look Like?), there were times when more than 20% of generation capacity in PJM was unable to respond when dispatched by the grid operator.  The grid operator then had to call upon non-economic (meaning more costly) resources to fill in, some of which also were unable to respond.  The grid came within a few thousand megawatts of brownouts, and prices soared to more than $2,600 per megawatt hour during some hours.

Capacity Performance

Clearly more reliable generation capacity was required.  PJM proposed, and the Federal Energy Regulatory Commission (FERC) approved, a change in regulation creating a new Capacity Performance product.  With Capacity Performance, PJM established new, more stringent requirements for generation regardless of weather conditions and system conditions, and also established onerous penalties in the event that generation does not respond when called.  Most generators bid their capacity again during two Transitional Auctions, for the planning years 2016/2017 and 2017/2018. As a result, due to this change in regulation, capacity prices have been reset higher for each of these two planning year periods.

The table above presents, for the 2016/2017 and 2017/2018 planning years, capacity prices that were originally established as part of Base Residual Auctions (BRA) and the new prices established as part of Capacity Performance (CP) Transition Auctions.

Additional investment was clearly needed in order to improve system reliability.  PJM’s strategy with Capacity Performance is, on the one hand, to provide generators “resources to invest in improvements in such areas as dual-fuel capability, securing firmer natural gas supplies and upgrading plant equipment,” while, on the other hand, imposing substantial penalties for non-performance.

These increased costs associated with Capacity Performance, which will be reflected in electricity prices, are unassociated with changes in natural gas prices and are another driver of the decline in correlation between electricity prices and natural gas prices.


– Evelyn Teel contributed to this article

– Capacity prices and quote from PJM website

The Avalon Advantage – Visit our website at www.AvalonEnergy.US, call us at 888-484-8096, or email us at  Please feel free to share this article.  If you do, please email or post the web link.  Unauthorized copying, retransmission, or republication is prohibited.  Copyright 2015 by Avalon Energy® Services LLC

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Natural Gas and Electricity Are Parting Ways – Part 1

In recent articles, we have explored the dramatic decline in natural gas prices over the past seven years.  See These Are Days To Remember and 10,000 Maniacs Were Right.

In the US Mid-Atlantic, natural gas and electricity prices have, over time, tended to move together.  While there has by no means been a perfect correlation between the two, the relationship has been strong.

Over the past 15 years, the coefficient of determination (R2) has averaged about 67% (see yellow line).  In other words, over this time period, 2/3 of the change in electricity prices can be explained by changes in natural gas prices.  More recently, however, the strength of this relationship has weakened and continues to weaken further (see red line).  Electricity prices have declined but not as precipitously as those of natural gas.

Why has this relationship weakened?  Two significant drivers relate to (i) dispatch order and (ii) capacity prices.

Dispatch Order

In scheduling energy to serve electricity users, the grid operator, PJM, utilizes a least-cost dispatch model.  PJM develops an expectation of projected system load on an hourly basis and then seeks bids from generators to supply energy to serve this load.  After bids have been submitted, for each hour, PJM accepts the lowest cost offers first and then works their way through higher price offers until sufficient supply has been cleared to match the projected load.  (There are a number of system constraints and complications that must be incorporated into the process, but this pretty much captures it.)  For each hour, the price at which the last megawatt-hour (MWh) clears sets the price for all the supply offers that clear in that hour.

For many years, the last generating units cleared were generally natural gas-fired units.  As a result, it has been these natural gas units that have set the price for electricity, leading to the strong link between natural gas prices and electricity prices.  A common understanding was that “as natural gas prices go, so go electricity prices.”

But now, low natural gas prices are leading to lower and lower supply bids by natural gas-fired generators, causing them to more frequently fall down the dispatch order and clear before coal-fired units.  Because of this, coal fired units are now more often becoming the marginal, or price-setting, units.  And, as a result, falling natural gas prices have not driven down electricity prices to the extent they once would have.

In addition to procuring energy, electricity wholesale suppliers must also own or procure capacity.  In our next article, we will look at how capacity costs influence electricity prices.

Evelyn Teel contributed to this article.

The Avalon Advantage – Visit our website at www.AvalonEnergy.US, call us at 888-484-8096, or email us at  Please feel free to share this article.  If you do, please email or post the web link.  Unauthorized copying, retransmission, or republication is prohibited.  Copyright 2015 by Avalon Energy® Services LLC

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Best Friends? – Natural Gas and Electricity Prices – An Update

By David White

In a post from January 2012, the declining correlation between the price of natural gas and the price of electricity was explored (click here).  At that time, the correlation between the two was declining as a result of the greater recovery in electricity prices relative to those of natural gas.  The graphs from that post are presented below.

The graph on the left shows monthly average electricity and natural gas prices spanning January 1, 2001 through November 2011.  The graph on the right shows the correlation between the two.  This correlation peaked at 97.2% during May 2010, then declined to 45.4% during November 2011.

Since this post, both electricity prices and natural gas prices have generally moved upwards.  While they both have recovered, the difference between them has increased.  In other words,   Electricity prices have increased more than natural gas prices.  Plotted below is the continuation of electricity and natural gas prices through September 2012, displaying this recent rise in prices.

Despite the increased gap between electricity and natural gas prices, the correlation between them has increased significantly since the last posting.  This correlation is plotted below.

On the graph, the blue line represents the data presented in the January 2012 post, and the red line is the newly acquired data.  Since the last posting, the correlation between the prices peaked at 79.9% in April 2012 and, as of September 2012, is 71.9%.  This is a significant increase from the correlation value of 45.4% that was observed in November 2011.  Through last November, the correlation had an 11-year historical average of roughly 71% and is represented by the orange line on the graph.  While the correlation of electricity and natural gas prices has fluctuated significantly over the years and this pattern is sure to continue in the future, at the moment the correlation between electricity and natural gas prices is regressing to the historical mean.

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Copyright 2012 by Avalon Energy® Services LLC