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?

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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.

Texans should pay higher taxes

From Breitbart, “Drumbeat to raise gas tax extends to conservative event“:

Texans should pay higher gasoline taxes, a Texas Tech University professor advocated at a policy conference organized by the conservative Texas Public Policy Foundation in Austin on April 16. He acknowledged that how transportation dollars are spent must also be carefully considered.

Generally, I’m a “starve the beast” proponent, but I endorse the view expressed above. In fact, I said it.

“Fuel taxes serve as a road ‘user fee’,” said Michael Giberson, who serves on the faculty at Texas Tech’s College of Business. “Those who use the roads, pay for them.”

Giberson told the TPPF conference attendees that the tax should be increased to a level that brings in the same revenues as in 1991–when the tax was last increased.

Texans currently pay 20 cents per gallon, but to meet the 1991 spending power Giberson said the rate would need to be 33.7 percent. He also recommended tying the gas tax to inflation, so that it would increase automatically.

Giberson acknowledged that more fuel efficient engines and electric-powered cars mean the gas tax will continue to be a declining revenue source. He said other options, such as charging Texans on the basis of their miles-driven, should be considered even as he acknowledged concerns about privacy and practical implementation.

I’d quibble just a bit with the characterization of my presentation. I didn’t recommend a 33.7 cents/per gallon tax, but rather was illustrating the toll that inflation had taken since the state gasoline tax was last raised. I did suggest tying the tax to inflation, but commented that the current method allows the tax to diminish over time and forces the legislature into direct action to raise it. I like that latter idea better the more I think about it.

In Texas two things stand between the fuel taxes and the user fee concept. First, about half of the gasoline tax is federal, 18.4 cents/gallon for gasoline, and Texas gets only about 80 percent of the Texas-sourced federally-collected fuel taxes back from Washington DC. The money comes back with some federal strings attached and some of the money is diverted from projects that benefit fuel taxpayers. Second, the feds 20 percent cut off the top is actually better for Texas fuel taxpayers than the state’s cut. By law, 25 percent of fuel taxes collected in Texas go to state government educational funding, so Texas road users only get about 75 percent of the Texas-sourced state-collected fuel taxes back from Austin. The 25 percent cut of fuel taxes for education is enshrined in the state’s constitution (a holdover, I suspect, when fuel taxes were paid primarily by the wealthy).

In response I favored proposals circulating in Congress to radically cut the federal fuel tax and related spending, and shift the responsibility for revenue collection and spending to the states. Congress has a duty to protect interstate commerce, but that need not involve a massive federal overhead to manage. I’d like to claw back the 25 percent fuel tax take from state educational funding, too. We amend the state constitution in Texas just about every other year, so that is no big deal, but because the amendment would appear anti-education I see it as a hard sell.

I also urged more use of toll roads, which have become much more efficient these days, and congestion-based tolls on roads where congestion is a frequent issue. (Nothing annoys me more than some denizen of east coast metropolitan areas saying federal gasoline taxes ought to be higher because it will reduce congestion. For example. No amount of taxing my cross-Texas drives is going to speed your east coast metropolitan commute.)

In the Breitbart article TPPF Vice President Chuck DeVore pushed back against my tax-raising views. He hasn’t changed his views, but recently in response to President Obama’s transportation spending proposal, DeVore’s views and mine seem pretty close: cut the federal role dramatically and let the states decide the mix of taxes and tolls needed to fund transportation infrastructure for themselves.

The Texas Public Policy Foundation put together a great event, with a program organized largely by TPPF staff economist and recent Texas Tech econ PhD Vance Ginn. Happy to be part of it.

Links to video from the conference and presentations are posted, along with links to other media coverage of the event (mostly focused on the Dallas Fed chairman’s lunchtime remarks, not the “gasoline tax controversy”, but I tried). My presentation is second in the panel 1 video.

ADDED: After my presentation I had two promising suggestions from conference attendees. One is that, given that almost all of the actual wear and tear on the roads in Texas come from heavy trucks rather than cars and light trucks, we should tax large commercial vehicles more–probably on a vehicle-miles traveled basis–and the “user fee” for personal vehicles likely falls to something reflecting the modest consequences of driving relatively lightweight vehicles. Trucking companies would complain, and the political prospects of the idea are probably not good. Otherwise makes a lot of sense to me. The other suggestion was to employ certain oil and gas drilling fees currently in surplus for road work, at least for the road improvements needed in the parts of the state experiencing significant increases in commercial traffic due to the oil and gas drilling boom. The suggestion seems a bit kludge-y to me, but comes with enough symmetry between the payers and the beneficiaries to be plausible. Good enough for government work, as is said.

Looking for renewable policy certainty in all the wrong places

From EnergyWire comes the headline, “In Missouri, industry wants off the ‘solar coaster’.” (link here via Midwest Energy News).

A utility rebate program authorized by voters in 2008 is making Missouri into a solar leader in the Midwest. But $175 million set aside to subsidize solar installations is [nearly] fully subscribed … and the same small businesses that scrambled to add workers last year to help meet surging demand are facing layoffs….

Heidi Schoen, executive director of the Missouri Solar Energy Industries Association, said the industry, which has generated thousands of jobs and millions of dollars in new taxes for the state, is just looking for certainty.

“We want off the solar coaster,” she said. “We don’t want to be in this boom-and-bust situation.”

It is a patently false claim.

If they wanted off of the boom-and-bust policy ‘solar coaster,’ they’d get off. They could go do unsubsidized solar installations for example, or if (when?) that proves unprofitable get work doing something else. By their actions they signal that they prefer the booms-and-busts that come with reliance on politicians for favors.

Better red than dead, but not red yet (on solar power)

In her New York Times Economix column Nancy Folbre recently said (“The Red Faces of the Solar Skeptics,” March 10, 2014):

If the faces of renewable energy critics are not red yet, they soon will be. For years, these critics — of solar photovoltaics in particular — have called renewable energy a boutique fantasy. A recent Wall Street Journal blog post continues the trend, asserting that solar subsidies take money from the poor to benefit the rich.

But solar-generated electricity is turning into a powerful environmental and economic success story. It’s also threatening the balance sheets of electric utility companies that continue to rely heavily on fossil fuels and nuclear energy.

I don’t count myself a renewable energy critic, but I do find myself as a critic of most renewable energy policies and so feel a bit like Folbre is addressing her points to me. In response I’ll say my face isn’t red yet, and I’m not expecting it to turn red anytime soon.

Folbre is a distinguished economist at the Univ. of Massachusetts, but she isn’t a specialist in environmental or energy economics, and I think her thinking here is a little muddled. (In this muddling through she has similarly distinguished company–consider this response to a Nobel prize winner.)

So a sample of my complaints: She trumpets the fast declining price of solar panels by picking a factoid out of a story in ComputerWorld: “declined an estimated 60 percent since the beginning of 2011!” ComputerWorld? Maybe the work of the U.S. Department of Energy or other more traditional information sources wasn’t sensational enough (claiming as it does, merely that “U.S. solar industry is more than 60 percent of the way to achieving cost-competitive utility-scale solar photovoltaic electricity”).

An investment company would have to acknowledge that cherry-picked past results are no guarantee of future performance, but it isn’t even clear that she is firm on the idea of “cost.” Folbre declares that generous subsidies and feed-in tariffs have “allowed solar photovoltaics to achieve vastly lower unit costs.” Really? Well maybe if we subsidize it a little harder, it will become free for everyone!

C’mon professor, get serious! Perhaps it is true that generous subsidies and feed-in tariffs have allowed owners of solar PV systems to experience lower out-of-pocket expenses, but it is a little embarrassing to see a distinguished economist make this mistake about costs. Should we conclude congressional junkets overseas don’t cost anything because the government foots the bill?

Not until the penultimate paragraph does Folbre get back on firm ground, talking about renewable energy policy rather than technology:

Subsidies are not the ideal public policy for promoting clean energy. As a recent analysis by the Carbon Tax Center points out, a carbon tax devised to protect low-income households from bearing a disproportionate share of higher energy prices would yield more efficient overall results, as well as encouraging solar power.

But in our subsidy-encrusted energy economy, some subsidies are better than others. As farmers say, make hay while the sun shines.

Yes, as any economist ought to say, “subsidies are not the ideal public policy for promoting clean energy.” In fact, it’s been said here a time or two.

[HT to Environmental Economics.]