Did ERCOT’s shift from zonal to nodal market design reduce electric power prices?

Jay Zarnikau, C.K. Woo, and Ross Baldick have examined whether the shift from a zonal to nodal market design in the ERCOT power market had a noticeable effect on electric energy prices. The resulting article, published in the Journal of Regulatory Economics, and this post may be a bit geekier than we usually get around here. I’ll try to tone it down and explain the ERCOT change and the effect on prices as clearly as I can.

The topic is important because the shift from zonal to nodal market structure was controversial, complicated, expensive, and took longer than expected. Problems had emerged shortly after launch of the initial zonal-based market and the nodal approach was offered as a solution. Some market participants had their doubts, but rather quickly ERCOT began the move to a nodal design. Note that phrasing: “rather quickly ERCOT began the move.” It took several years for ERCOT to actually complete the process.

In part the shift was promoted as a more efficient way to run the market. Zarnikau, Woo, and Baldick looked at the effect on prices as one way to assess whether or not the resulting market has worked more efficiently. They conclude energy prices are about 2 percent lower because of the nodal market design.

Don’t get hung up on the 2 percent number itself, but think of the shift as having a modest downward pressure on prices.

The result is consistent with an understanding one would gain from the study of power systems engineering as well as with what power system simulations showed. The point of the Zarnikau et al. study was to investigate whether data analysis after the fact supported expectations offered by theory and simulation. Because there is no better empirical study (so far as I am aware) and because their results are consistent with well-founded expectations, I have no reason to doubt their result. I will contest one interpretation they offer concerning the current resource adequacy debate in Texas.

Some background (which beginners should read and others can skip).

The delivery of electric energy to consumers is a joint effort between the generators that create the power and the wires that bring it to the consumer. The wires part of the system are not simple links between generators and consumers, but rather complicated network of wires in which consumers and generators are connected in multiple ways. The added flexibility that comes with networking helps the system work more reliably and at lower cost.

The network also comes with a big coordination problem, too. Power flows on the network are not individually controllable. With many generators producing power for many consumers, parts of the power grid may become overloaded. One key job of the power system operator is to watch the power flows on the electric grid and intervene as needed to prevent a transmission line from being overloaded. The intervention generally takes the form of directing a generator (or generators) contributing to the potential overload to reduce output and directing other generators to increase output. In areas outside of regional system operators, this function is done on a piecemeal basis as problems arise. A significant benefit coming from full-scale regional power markets integrated with system operations (such as ERCOT in Texas after the switch to a nodal market and in other similar ISO/RTO markets) is that such coordination can be done in advance, with more information, mostly automatically, and more efficiently than piecemeal adjustments.

Described in simpler terms, the regional power system operator helps generators and consumers coordinate use of the power grid in the effort to efficiently satisfy consumer demands for electric energy. A zonal market design, like ERCOT started with, did minimal advance coordination. The nodal market design and related changes implemented by ERCOT allowed the market to do more sophisticated and efficient coordination of grid use.

About data challenges.

In order to assess the effects on prices, the authors couldn’t simply average prices before and after the December 1, 2010 change in the market. The power system is a dynamic thing, and many other factors known to affect electric power prices changed between the two periods. Most significantly, natural gas prices were much lower on average after the market change than during the years before. Other changes include growing consumer load, higher offer caps, and increasing amounts of wind energy capacity. In addition, the prices are generated by the system has been changed, making simple before and after comparisons insufficient. For example, rather than four zonal prices produced every 15 minutes, the nodal market yields thousands of prices every 5 minutes.

One potentially significant data-related decision was a choice to omit “outliers,” prices that were substantially higher or lower than usual. The authors explain that extreme price spikes were much more frequent in 2011, after the change, but largely due to the summer of 2011 being among the hottest on record. At the same time the offer caps had been increased, so that prices spiked higher than they could have before, but not because of the zonal-to-nodal market shift. Omitting outliers reduces the impact of these otherwise confounding changes and should produce a better sense of the effect of the market change during more normal conditions.

Their conclusion and a mistaken interpretation.

Zarnikau, Woo, and Baldick conducted their price analysis on four ERCOT sub-regions separately so as to see if the change had differing impacts resulting from the changeover. The West zone stood out in the analysis, largely because that zone has seen the most significant other changes in the power system. The two main changes: continued sizable wind energy capacity additions in the zone, and more substantially, dramatic electrical load growth in the region due to the recent oil and gas drilling boom in west Texas. Because the West results were a bit flaky, they based their conclusions on results from the other three zones. Across a number of minor variations in specifications, the authors found a price suppression effect ranging from 1.3 and 3.3 percent, the load-weighted average of which is right around 2 percent.

So far, so good.

But next they offered what is surely a misinterpretation of their results. They wrote:

[T]he reduction in wholesale prices from the implementation of the nodal market might be viewed by some as a concern. In recent years, low natural gas prices and increased wind farm generation have also reduced electricity prices in ERCOT which has, in turn, impaired the economics of power plant construction. … It appears as though the nodal market’s design may have contributed to the drop in prices that the PUCT has now sought to reverse.

Strictly speaking, the goal of the Public Utility Commission of Texas hasn’t been to reverse the drop in prices, but to ensure sufficient investment in supply resources to reliably meet projected future demand. Lower prices appear to be offer smaller investment incentives than higher prices, but there is a subtle factor in play.

The real incentive to investment isn’t higher prices, it is higher profits. Remember, one of the most important reasons to make the switch from a zonal to a nodal market is that the nodal market is supposed to operate more efficiently. Zarnikau, Woo, and Baldick notice that marginal heat rates declined after the shift, evidence consistent with more efficient operations. The efficiency gain suggests generators are operating at an overall lower cost, which means even with lower prices generator profits could be higher now than they would have been. It all depends on whether the drop in cost was larger or smaller than the drop in prices.

The cost and profit changes will be somewhat different for generators depending on where they are located, what fuel they use, and how they typically operated. I’ll hazard the guess that relatively efficient natural gas plants have seen their profits increased a bit whereas less efficient gas plants, nuclear plants, and coal plants have likely seen profits fall a little.

FULL CITE: Zarnikau, J., C. K. Woo, and R. Baldick. “Did the introduction of a nodal market structure impact wholesale electricity prices in the Texas (ERCOT) market?.”Journal of Regulatory Economics 45.2 (2014): 194-208.

Here is a link to a non-gated preliminary version if you don’t have direct access to the Journal of Regulatory Economics.

AN ASIDE: One modest irony out of Texas–the multi-billion dollar CREZ transmission line expansion, mostly intended to support delivery of wind energy from West Texas into the rest of the state, has turned out to be used more to support the import of power from elsewhere in the state to meet the demands of a rapidly growing Permian Basin-based oil and gas industry.

Court says no to FERC’s negawatt payment rule

Jeremy Jacobs and Hannah Northey at Greenwire report “Appeals court throws out FERC’s demand-response order“:

A federal appeals court today threw out a high-profile Federal Energy Regulatory Commission order that provided incentives for electricity users to consume less power, a practice dubbed demand response.

In a divided ruling, the U.S. Court of Appeals for the District of Columbia Circuit struck a blow to the Obama administration’s energy efficiency efforts, vacating a 2011 FERC order requiring grid operators to pay customers and demand-response providers the market value of unused electricity.

Among environmentalists this demand-response enabled “unused electricity” is sometimes described as negawatts. FERC’s rule required FERC-regulated wholesale electric power markets to pay demand-response providers the full market price of electricity. It is, of course, economic nonsense pursued in the effort to boost demand response programs in FERC-regulated markets.

The court held that FERC significantly overstepped the commission’s authority under the Federal Power Act.

The Federal Power Act assigns most regulatory authority over retail electricity prices to the states, and the court said FERC’s demand response pricing rule interfered with state regulators’ authority.

Personally, I would have dinged FERC’s rule for economic stupidity, but maybe that isn’t the court’s job. Actually, I did ding the FERC’s rule for its economic stupidity. I was one of twenty economists joining in a amicus brief in the case arguing that the FERC pricing rule didn’t make sense. The court’s decision gave our brief a nod:

Although we need not delve now into the dispute among experts, see, e.g., Br. of Leading Economists as Amicus Curiae in Support of Pet’rs, the potential windfall  to demand response resources seems troubling, and the Commissioner’s concerns are certainly valid.  Indeed, “overcompensation cannot be just and reasonable,” Order 745-A, 2011 WL 6523756, at *38 (Moeller, dissenting), and the Commission has not adequately explained how their system results in just compensation.

But if this negawatt-market price idea survives the appeals court rejection and takes off in the energy policy area, I have the following idea: I’d really like a Tesla automobile, but the current price indicates that Teslas are in high demand so I’m going to not buy one today. Okay, now who is going to pay me $90,000 for the nega-Tesla I just made?



The case for allowing negative electricity prices – Benedettini and Stagnaro

Simona Benedettini and Carlo Stagnaro make the case for allowing negative prices in electric power markets in Europe. A few of the larger power markets in Europe allow prices to go negative, but others retain a zero price lower limit. Benedettini and Stagnaro explain both why it is reasonable, economically speaking, to allow electricity prices to go negative and the hazards of retaining a zero-price minimum in a market which is interconnected to markets allowing the more efficient negative prices.

It is all good, but I can’t resist quoting this part:

Negative prices are not just the result of some abstruse algorithm underlying the power exchange and the functioning of the power system. They are also, and more fundamentally, the way in which the market conveys the decentralized information that is distributed among all market participants, and that cannot be centralized in one single brain, as Nobel-prize winner Friederich Hayek would say. That information is translated into two major market signals, which are embodied in negative prices.

In the short run, negative prices show that there is a local condition of oversupply under which electricity is not an economic good which society is willing to pay for, but an economic bad for which consumers should be compensated. Therefore, negative prices create an economic incentive for consumers to shift their consumption patterns so as to capture the opportunity of being paid, instead of paying, to receive energy….

However, in the long run, negative prices talk to energy producers, not to energy consumers. The emergence of negative prices, although strongly conditioned by demand-side constraints, shows that the generating fleet encompasses too much “rigid” capacity (i.e. too much nuclear and coal-fuelled plants) and too little “flexible” capacity (for example CCGTs or turbo-gas power plants); or that grid interconnections are insufficient to properly exploit the spare, flexible capacity available within a market area.

So far as I know, all of the regional power markets in the United States now allow prices to go negative. The connections between wind power policy and negative prices have politicized the issue a bit in the United States. Benedettini and Stagnaro explain in a straightforward manner why, no matter what you think of renewable energy policies, you ought to favor allowing wholesale power market prices to go negative.

Texas wind power, the ERCOT power market, the Public Utility Commission

From SNL Energy, “Texas utility regulators expect to open investigation on wind ‘cost apportionment’“:

Having seen record wind output of more than 10,000 MW in March, ERCOT in the report also noted that Texas has gone well beyond its 10,000-MW capacity goal and far earlier than the 2025 target established in the state’s Public Utility Regulatory Act. …

And while wind energy continues to boom in Texas, the PUCT has been working with ERCOT on ensuring a reliable power grid amid wholesale prices that are not encouraging new fossil-fuel plant construction.

Perhaps, just perhaps, there is a connection between the “wind energy … boom” and the “wholesale prices that are not encouraging new fossil-fuel plant construction”?

The SNL Energy report noted the PUCT was beginning an investigation into cost apportionment issues surrounding wind energy and the recently completed CREZ transmission line additions.

AWEA brags about wind energy’s mediocre performance

On May 2 The Hill published a column by AWEA data spinner Michael Goggin, “Wind energy protects consumers,” in which the reader is regaled by tales of great service and low, low prices provided by the wind energy industry.

Sorting through the claims led me back to the AWEA blog, where among other things Goggin applauds the industry that pays his salary for its grand performance in trying times this past January in New York. Goggin exclaimed the New York grid operator “received very high wind output when it needed it most during the last cold snap, while other forms of generation experienced a variety [of] problems.”

Following the link provided to the NYISO press release I find the claim, “On Tuesday, the NYISO had the benefit of more than 1,000 MW of wind power throughout much of the day.” The New York grid operator reported peak demand during the day (January 7, 2014) at 25,738 MW, so wind energy’s contribution was in the 4 percent range. Another way to say that is that other forms of generation, despite experiencing a variety of problems, provided about 96 percent of the energy New York consumers received when they “needed it most.”

The AWEA website indicates that New York has an installed capacity of 1,722 MW of wind power. Doing the math reveals that about 40 percent of the wind energy industry’s generating capability failed to show when New York electric power consumers “needed it most.”

Impressive? Not really.

To more fully consider the situation, we’d have to ask just how much non-wind electric generating capacity has been driven from the New York market by subsidized wind power. It is part of the AWEA storyline that clean, low-cost wind energy “displace[s] output from the most expensive and least efficient power plants,” and obviously over time frequently displaced units are driven from the market. One may reasonably wonder how much generation capacity was driven from the market before that cold January day when New York electric power consumers “needed it most.”

In related news, the National Renewable Energy Lab just produced an exploration of the wind energy industry’s future with and without the Production Tax Credit. In brief, if the PTC is not revived once again, the industry will likely shrink by about half over the next several years, kept in business mostly by state renewable energy purchase requirements. Indirectly the study concedes that NREL doesn’t think wind power is cost competitive with alternative electric energy supplies, but under the best possible wind resource and grid access conditions.

Please note my occasional wind energy disclaimer: I am not against wind energy (a technology which can contribute real value in the right places), just against bad policy (which takes real value created by other people and shovels it in the direction of investors in wind energy assets and people who happen to own windy plots of land with good grid access).

Easy to dream big when you can spend other people’s money, and really, why else would you build solar power in Michigan?

Crain’s Detroit Business reports:

A solar power work group in Michigan is making progress discussing the possibility of expanding the current utility-sponsored solar incentive program ….

But the real question is whether DTE and Consumers will voluntarily expand their programs — as environmentalists, manufacturers and solar installers have been asking the state to require for job creation and public health reasons — before the programs expire in 2015.

Involved in the solar power work group discussion are state regulators, solar PV installers, solar PV manufacturers, environmental groups, and the state’s two large regulated utilities, DTE and Consumers Energy Co., who collect a regulator-approved renewable energy surcharge from their customers.

Not mentioned in the article are the views of retail electric power consumers, whose money is up for grabs, nor anyone thinking of federal taxpayers’ stake in the matter.

There is a respectable answer to the question “why else would you build solar energy in Michigan?” If you have strong pro-solar commitments, for ethical or other reasons, the you may well feel strongly enough about it to be willing to spend your own money on a system. Or, if you are off-grid or want to be, solar is one way to stay powered.

But the answer most prevalent in the work group, at least if the Crain’s article is a guide, is much less respectable: they are mostly people who feel strongly enough about solar power–or the money they might make from it–that they want to force their unwilling neighbors to pay.

Background on the Michigan solar power work group can be found at the pro-solar-policy Michigan Land Use Institute.

Decarbonization Now? (No, not yet.)

Paul Krugman’s recent opinion column in the New York Times ran under the headline, “Salvation Gets Cheap.” At first I though Krugman was making a snarky comment on ex-Mayor Michael Bloomberg’s claim that the ex-mayor’s work on restricting access to guns, and efforts on obesity and smoking would ensure a place in heaven. But no, Krugman is opining that technology is providing an easy way forward on climate change:

The climate change panel, in its usual deadpan prose, notes that “many RE [renewable energy] technologies have demonstrated substantial performance improvements and cost reductions” since it released its last assessment, back in 2007. The Department of Energy is willing to display a bit more open enthusiasm; it titled a report on clean energy released last year “Revolution Now.” That sounds like hyperbole, but you realize that it isn’t when you learn that the price of solar panels has fallen more than 75 percent just since 2008.

Thanks to this technological leap forward, the climate panel can talk about “decarbonizing” electricity generation as a realistic goal — and since coal-fired power plants are a very large part of the climate problem, that’s a big part of the solution right there.

It’s even possible that decarbonizing will take place without special encouragement, but we can’t and shouldn’t count on that. The point, instead, is that drastic cuts in greenhouse gas emissions are now within fairly easy reach.

The “Revolution Now” report, which was linked in Krugman’s column online, is surprisingly weak sauce. The U.S. Department of Energy report (your tax dollars at work) purports to describe “four technology revolutions that are here today” and “have achieved dramatic reductions in cost” and “a surge in consumer, industrial and commercial deployment” in the last five years. The four “revolutions” are onshore wind power, polysilicon photovoltaic modules, LED lighting, and electric vehicles.

Each “revolution” gets a two-page summary and a colorful chart showing declining costs and rising use. The summaries are footnoted, just like real research, and studded with more factoids than the front page of USA Today. Here’s a fun fact: the ratio of empirical claims to footnotes in the article’s two pages on wind power is 4-to-1.

You can get a sense of the quality of the report by considering the claims strung together on electric vehicles: First it is reported “more and more drivers are abandoning the gas pump for the affordability and convenience of in-home electric charging,” then that 50,000 EVs were purchased in 2012 and the rate of purchase doubled in early 2013. Next we are told “to maintain this momentum the most critical area for cost reduction is batteries.” A paragraph later the report said, “In many senses, EVs are already competitive with traditional cars.” In the final paragraph, however, a sober note: it will take “further progress on reducing the cost of EV batteries” to make “these benefits available to a larger audience.”

The sober note referenced a DOE battery cost target of $125/kwh by 2022, at which point the DOE expects ownership costs for a EV will be similar to a standard vehicle. A glance back at the chart suggests current battery costs nearer five times that level, leaving at least this reader wondering in which sense “EVs are already competitive with traditional cars” and part of the “technology revolutions that are here today.”

The revolution is here today! Or maybe in 2022!! Or maybe whenever “further progress” is made!!!

Overall the report is more enthusiasm than analysis, and not sufficient to justify changing beliefs on the cost of decarbonizing energy supplies.