Risks of Going Solar

On February 22, 2016, Catherine Wolfram posted the blog Risks of Going Solar on the Energy Institute at Haas blog, part of the University of California Berkeley.  I posted the following, which I am adding to my blog.

Of the various regulatory Risks of Going Solar, Catherine Wolfram identifies two biggies, reducing the size of the net metering interval and shifting the rate design to include a smaller energy charge and a greater fixed charge.  But the risk of these two can be much larger than Dr. Wolfram suggests.  Reducing the size of the net metering interval exposes rooftop solar customers to the possibility of negative prices, while cost re-classification could result in (greater) demand charges instead of greater monthly customer charges.

In “Renewable Electric Power—Too Much of a Good Thing: Looking At ERCOT,” Dialogue, United States Association for Energy Economics, 2009 August,[1] I point out that a surplus of wind in West Texas forced the wholesale price for electricity below zero for about 25% of the pricing periods during that April, at least in West Texas.

Transmission constraints generally kept these negative prices from spreading to the rest of Texas.  Negative prices did spread to other parts of the state for just less than 1% of the rating periods.  As Dr. Wolfram well pointed out, these pricing periods are sometimes as short as 15 minutes (as they were in West Texas at the time), though are often one hour.

Many ISO do not seem to allow prices to go negative.  In West Texas, the combination of transmission constraints and the various credits[2] given to wind led to negative prices.  I believe that similar combinations elsewhere will force ISOs to allow negative prices in their dispatch programs.

I have long seen the need for utilities outside the footprint of an ISO to implement real time “value of solar” prices that are similarly negative.  Hawaii seems to be ripe for such negative solar prices.  Utilities outside the footprint of an ISO can implement “value of solar” prices using a Walrasian auction, as is discussed in many of my articles.

I actually disagree with the concept of a separate price for “value of solar.”  If we are to use prices to influence generation, there shouldn’t be a separate price for solar versus other spot generation imbalances.  A different price for unscheduled versus scheduled generation, yes, but not a separate price for just solar.

There will often be many prices during any pricing interval.  For instance, a single 15 minute period may be part of a 24×7 contracted delivery of power with one price and part of a 16×5 contracted deliveries with another price.  A third price might be applicable to variances.  Variances would include both solar that is dumped into the system and hiccups in the 24×7 or 16×5 deliveries, whether the hiccup is positive or negative.

Utility rate making often includes the concept of cost classification, where costs are identified as energy related, customer related, and demand related.  In the context of Risks of Going Solar, customer related and demand related are combined into the concept of a fixed charge.

The discussed increase in the monthly charge is only one way to reduce the energy charge.  The other way, and I believe a better way, to decrease the energy charge is to increase the demand charge, or to implement a demand charge when there is not a demand charge in place.

Customer charges impose greater burdens on small, often lower income, residential customers, while demand charges tend to protect these smaller customers, as is discussed in

  • “Curing the Death Spiral,” with Lori Cifuentes (Tampa Electric Company), Public Utilities Fortnightly, 2014 August;[3]
  • “Demand a Better Utility Charge During Era of Renewables: Getting Renewable Incentives Correct With Residential Demand Charges,” Dialogue, United States Association for Energy Economics, 2015 January;[4] and,
  • “Fairly Pricing Net Intervals While Keeping The Utility Financially Healthy,” 48th Annual Frontiers of Power Conference, cosponsored by The Engineering Energy Laboratory and The School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma, 2015 October 26-27.[5]

Thus, as we see a continued growth in solar, I see a growing need for finer pricing intervals and a growing need for demand charges.  Fortunately, the huge growth in interval meters allow these better rate designs.  We just need to political will to implement something other than a monthly charge for energy.

[1] http://livelyutility.com/documents/USAEE-ERCOT%20Aug%2009.pdf

[2] such as production tax credits and renewable energy credits

[3] https://www.fortnightly.com/fortnightly/2014/08/curing-death-spiral?authkey=54d8da5efd3f76661023d122f3e538b4b3db8c8d5bf97a65bc58a3dd55bb8672

[4] http://dialog.usaee.org/index.php/volume-23-number-1-2015/271-lively

[5] A copy is available on my website, www.LivelyUtility.com.

Electric Demand Charges: A Lesson from the Telephone Industry

The only ad with prices that I remember from 50 years ago was AT&T’s offering of a three minute coast to coast telephone call for $1.00.  With the inflation that we have seen over the last 50 years, one would expect that a coast to coast call would now be at least $10.00 for three minutes.  Instead, most telephone bills show a monthly service fee and no itemization for individual calls.  Automation has allowed the telephone companies to do away with most telephone operators, which was a significant portion of the variable cost of making long distance telephone calls.  The principal cost is now the investment in the wires, which doesn’t change with the number of calls that are carried.  So, most carriers now charge a monthly fee and little or no charge per call.  Perhaps it is time for the electric industry to go that way?

 

The restructuring of the electric industry has generally separated the distribution wires function from the generation[1] and transmission[2] function for most customers of investor owned electric utilities.  This restructuring puts such electricity customers into the same position as their counterpart customers of municipally and cooperatively owned utilities.  Municipally and cooperative owned utilities have generally been distribution only utilities, buying generation and transmission services from others, instead of being vertically integrated like most investor owned electric utilities.

 

The restructuring of the electric industry has resulted in most customers being served by a distribution company which has very little variable cost, much like the telephone companies.   A significant distinction is that telephone lines handle one call at a time.  The telephone line is either in use or is not in use.  In contrast, electric utilities provide a continuously variable service.  The customer may be taking 10 watts (a small light bulb) or 10 kilowatts (running the A/C, water heater, and stove at the same time), or any amount in between.  The telephone company has the wires to serve the customer’s demand, whenever that call occurs[3].  The electric distribution company similarly has the wires to serve the customer’s demand, whenever that demand occurs.  While the telephone company will have customers on a binary basis (they are either a customer or are not a customer), the electric distribution customer serves its customers on a continuous basis (they might be very small customers who never use more than 10 watts or a very large customer that might use up to 100 MW.)

 

The binary basis of telephony customers allows the telephone companies to charge their customers a specific amount on a monthly.  The continuous nature of the size of electric services suggests that electric distribution companies charge their customers a price based on the size of the electric service used by the customer.  For commercial and industrial customers, electric utilities have long included in their tariffs a demand charge that depends on the maximum power that the customer used during the billing period[4].  Typically such demand charges will be based on the average consumption for some 15 minute period.

 

Cost has been a significant factor that limited the use of demand charges to commercial and industrial customers.  Demand meters are more costly to manufacture, in that they do more than just accumulate the amount of energy that goes through the meter.  Demand meters are more expensive to read, in that the meter reader has to note two quantities and has to manually reset the demand register.  These two cost factors are lesser issues in regard to determining residential demand now that the industry has moved significantly to Advanced Meter Reading (AMR) and to Advanced Meter Infrastructure (AMI[5]), both of which automatically collect consumption data, including for 15 minute intervals.

 

Historically residential demand charges was thought to produce an insignificant shift of revenue among residential customers.  The reasoning was that, though residential customers are different in size, they have a similar load pattern.  A customer using 1,000 KWH a month would have ten times the demand as a customer using 100 KWH a month.  Implementing a demand charge that collected an amount equal to 20% of the energy revenue collected from the larger customer would also collect an amount equal to 20% of the energy revenue collected from the smaller customer.  There would be no revenue shift among these residential customer, at least for consumption.  However, the utility would have had to install more expensive meters, which would have increased the monthly customer charge of both customers without providing a significant benefit to the utility or to the customers.

 

The move to AMR and AMI has reduced the cost of determining the demand for residential customers.  Now the cost of determining metered demand is not an issue in differentiating between customers with different consumption patterns.  Customers who should be paying a demand charge equal to 30% of their energy payments can be distinguished from customers who should be paying a demand charge that is only 10% of their energy payments.  Further, on site generation has changed the paradigm that residential customers have similar load patterns, so that now the industry knows that there are the 30% customers versus the 10% customers and can bill them appropriately.  Indeed, for houses with sufficient on-site generation, the revenue from the demand charge could be several times the revenue from the energy charge, especially when the energy charge vanishes for a net zero home.

The growth in AMR and AMI along with the growth in residential on-site generation makes this an appropriate time for restructuring residential tariffs to include a demand charge to collect the cost of the distribution utility owning the power lines.  The energy charge should continue to collect the cost of generation and transmission, though the energy charge should be time differentiated to reflect the real time value of generation and transmission, as well as the associated energy losses.



[1] The creation of Independent System Operators (ISOs) is alleged to have brought competition to the generation sector of the electric industry.  However, many distributed generators, such as roof top solar, do not experience the real time market prices set by their local ISO.  This distorts the market for distributed generation.

[2] The creation of ISOs is also alleged to have brought competition to the transmission market.  But ISOs compensate many transmission lines on a cost of service basis, through a monthly fee, though they charge geographically differentiated prices based on line losses and line congestion and generally don’t compensate for loop flow or parallel path flows, such as PJM imposes on TVA and on the Southern Company, both of which have lines in parallel to PJM>

[3] Telephone customers occasionally receive a business signal, indicating that the called party is using his/her phone.  More rarely, customers will receive a circuits business signal, indicating that intermediate wires are in full use, not that the called party is using his/her phone.

[4] Demand charges come in a variety of forms including contract demand, thermal demand, and ratcheted demands, a distinction beyond the scope of this discussion.

[5] AMI is generally distinguished from AMR in that AMI generally includes the ability to communicate both ways, from the meter to the utility and from the utility to the meter/customer location.  The ability to communicate from the utility to the meter allows the utility to control devices that the customer has opted to put under the utility’s control such as electric water heaters, air conditioning compressors, and swimming pool pumps and heaters.

Utility 2.0 or Just Utility 1.X

On Tuesday, 2013 October 29, I attended a discussion of the report “Utility 2.0: Building the Next-Gen Electric Grid through Innovation.”  I left feeling that the innovations discussed are just more of the same, just as I have often described the smartgrid as SCADA[1] on steroids.  The innovations are not creating Utility 2.0 as much as making slow changes to the existing utility structure, just varying the X in Utility 1.X.

Electric utilities began automating the electric system as soon as Edison started his first microgrid, the Pearl Street Station.  At one time, an operator would read a frequency meter to determine the balance between supply and demand.  In the earliest days, Edison had a panel of light bulbs that would be switched on and off to maintain that balance, which was a strange form of load management.  The operator would also be able to vary the generation by change the water flow to a hydro-turbine, the steam from the boiler, and the fuel into the boiler.  Edison invented control mechanisms that were cheaper than the labor costs of the operator, control mechanisms that his companies also sold to other utilities.  These control mechanisms can be considered to be some of the first SCADA systems.  As the control mechanisms and telephony got cheaper and labor become more expensive, more labor saving devices could be installed.  The policy of having an operator at every substation was replaced by remote devices, lowering the cost of utility service.  The smartgrid concept is just more of the same, as computers become cheaper and faster, remote metering less expensive, and remote control easier to accomplish.

The true quantum change in utility operations occurred in federal law.  PUHCA[2] effectively prohibited private individuals from selling electricity to a utility, by defining the seller to be a utility, subject to utility type regulation and to prohibitions on non-utility operations.  Because of PUHCA, Dow Chemical operated its chemical plants as the ultimate microgrid, running asynchronously and unconnected to local utilities.  Dupont installed disconnect switches that would separate its microgrid chemical plant from the local utility if power began to flow out of the plant.  International Power and Paper became International Paper.  Exxon intentionally underinvested in its steam plants, limiting its ability to produce low cost electricity.  PURPA[3] provided exemptions from PUHCA for cogeneration plants such as those mentioned here and for qualifying small producers using renewable resources.  The latter exemption was almost in anticipation to the growth of roof top solar photovoltaics (PV).  These facilities needed utility markets into which to sell their surplus, which generally resulted in individually negotiated contracts.  The creation of the ISO[4] concept could be considered to be an outgrowth of the desire by these large independent power producers (IPPs) for a broader, more competitive market, instead of the monopsony into which they had been selling.  ISOs now have a footprint covering about 2/3 of the lower US, excluding Alaska and Hawaii.

ISOs generally deal only with larger blocks of power, some requiring participants to aggregate at least 25 MW of generation or load.  ISO control generally does not reach down into the distribution system.  The continued growth of labor costs and the continued decline of automation costs has allowed the SCADA concept to be economic on the distribution grid, including down to the customer level.  This expansion of SCADA to the distribution system will soon require changes in the way the distribution system is priced, both for purposes of equity and for Edison’s purpose of controlling the system.

  • The growth in rooftop PV is dramatically reducing the energy that utilities transport across their distribution system.  This energy reduction generally reduces utility revenue and utility income.  Under conventional utility rate making, the result is an increase in the unit price charged by the utility for that service.  Some pundits point out that the owners of the rooftop PV panels are generally richer than the rest of the population served by the utility.  These solar customers are cutting the energy they consumer, though not necessarily their requirements on the utility to provide some service through the same wires.  The rate making dynamics thus result in other, poorer customers seemingly subsidizing the richer customers who have made the choice for rooftop solar.  This seems inequitable to some.
  • The growth in rooftop PV has outstripped the loads on some distribution feeders, with reports that the generation capacity has sometimes reached three times the load on the feeder.  These loading levels cause operating problems in the form of high voltages and excessive line losses.  During periods of high voltage and excessive line loss, prices can provide an incentive for consumers to modify their behavior.  The genie seems to be out of the bottle in regard to allowing the utility to exert direct physical control over PV solar, but real time prices could provide some economic control in place of the tradition utility command and control approach.

I have discussed the need for real time pricing of the use of the distribution grid in “Net Metering:  Identifying The Hidden Costs;  Then Paying For Them,” Energy Central, 2013September 20.[5] I have described a method in “Dynamic ‘Distribution’ Grid Pricing.”[6]

Changes in state regulations have also impacted this balance between labor costs and automation costs.  Some states now have performance incentives based on the number of outages and the typical restoration times.  The cost associated with the time of sending a line crew to close a circuit breaker now competes with the incentives to get that closure faster, through the use of automation.

In conclusion, the increase in utility automation is not so much innovation as it is a continuation of the historic utility practice of the economic substitution of lower cost technology for the ever increasing cost of labor.  The 1978 change in federal law led to the growth of ISOs and bulk power markets, but did not reach down to the distribution level, perhaps of the lack of non-utility industrial support.  The growth in rooftop PV will provide the incentives for expanding the real time markets down the distribution grid to retail consumers.  Though computers indeed have gone from 1.0 (vacuum tubes), to 2.0 (transistors), to 3.0 (integrated circuits), I don’t see the current changes proposed for utilities to be much more than following the competition between labor costs and automation costs.  We are still Utility 1.X, not Utility 2.0.



[1] Supervisory Control And Data Acquisition.

[2] Public Utility Holding Company Act of 1935

[3] Public Utility Regulatory Policies Act of 1978

[4] Independent System Operator

[6] A draft of this paper is available for free download on my web page, www.LivelyUtility.com

Load Profiles and Unscheduled Flows of Electricity

In response to my earlier comments about a Fox News article equating decoupling with socialism, I received a question about time of use rate making and how my comments regarding unscheduled flows of electricity picked on small utilities. My response follows.

Most utilities group customers by their consumption patterns. You are grouped with McMansions and with hovels. Not because you have the same consumption, but the same pattern. Let’s say that a McMansion uses 10 times the energy that you use each month. Then, if you look at the consumption for the period defined as “on peak”, the McMansion will use about 10 times the amount of electricity that you use “on peak”. Similarly during any other well defined period. TOU pricing will not differentiate your average price from his average price, or at least not much.

Not much unless you or the utility invest in devices that control your consumption patterns. Thirty five years ago I worked for American Electric Power (AEP) in its New York City office. I helped investigate ceramic storage, a concept then in use in England. Turn on electricity to these “hot rocks” at night and then during the day just blow a fan across them to get heat into the room. Conversely, there is ice storage. Connect your A/C unit to a tank that looks like a water heater. At night dump refrigerant through the Ice Bear (a commercial brand I have heard of) and create ice. During the day, put the refrigerant through the Ice Bear instead of running your compressor. This creates huge swings in the multiplier between you and McMansion. During the night the multiplier might be down to 5 or less. During the day, the multiplier might be up to 20. The result is that you pay a lower average rate using TOU if you manage your load.

Dynamic pricing means to me a moment by moment change in the price of electricity. During the hottest day of the year, the price might soar by a factor of 100. Avoid 7 hours at that high rate and you have reduced your average price by 1% (730 hours on average in the month) or more, at least if I have done the math correctly. Many utilities have equipment that they attach to your AC compressor to allow them to turn it off during such periods. The standard pricing approach is to pay you $5/month. They save money by avoiding some of the energy at the 100 times multiple.

Pricing is considered by many to be a form of rationing. Economists say that pricing is the best way to ration a commodity. It gets people to give up lower valued uses when there is a scarcity. I like to think of it as a way to soak those who can afford it so I can put in my controllers that allow me to store energy thermally. In some jargons, my thermal storage can be considered to be a form of supply side, though most just look at it as demand side.

As to whether the small utility gets the free ride or the large utility, it depends on the circumstance. My employer AEP, one of the largest in the country, may have been getting a free ride by building fewer very large generators. That lowered their average cost but they got reliability by interconnecting with other utilities that had many, though smaller, generators. Even the transmission example is not clear cut either way, especially when the high voltage line fails and the low voltage line experiences huge electrical line losses.

Socializing the Grid

A friend sent me a message overnight that asked me, since my friend says I have an understanding of utility issues, to identify the misstatements in a 2009 January 15 article “Browner: Redder than Obama Knows” by Steven Milloy. http://www.foxnews.com/story/0,2933,480025,00.html   My response is below.  Now, as I am posting this to my blog, I realize that the article is over two years old.  When I began writing my response, I had focused on the January 15 and thought that I was only 11 days behind the time instead of two years.  Oh, well.  The interest in the article is current even if the article isn’t.

Before I talk about the Fox article, “Browner: Redder than Obama Knows”, let me talk a little about the socializing of the electric system, an issue I have been trying to correct for over twenty years.

Electric systems improve reliability by increasing the number of generators connected to the grid.  More generators with enough capacity and we are more likely to have enough electricity for everyone.  Electric generators have great economies of scale.  Larger units mean less steel and concrete per KW or KWH.  Perhaps more importantly, fewer power plant employees.  Manning an operating room 24×7 for a 2,000 MW plant takes not many more people than for a 300 MW plant.

So, eighty years ago electric systems were in a quandary.  To maintain high reliability, electric systems needed more units.  To keep costs low and improve profit margins relative to a fixed price, electric systems needed larger units.  So the trade off was between more, therefore smaller, units versus larger, therefore fewer, units.  The solution was to interconnect with one’s competitors which increased the number of units connected to the grid and allowed utilities to build larger, less costly, units.  In the summer of 1969 and from 1971 to 1976 I worked for American Electric Power (AEP).  In perhaps ten years times, AEP went from building 280 MW generators, to 800 MW, to 1300 MW, being able to achieve those economies of scale by having more interconnections with its neighbors than almost any other utility in the US.

Those interconnections created a form of socialism.  The utilities did not figure out how to charge each other for the increased reliability provided by the interconnection.  Reliability came to be considered to be a public good, not to be charged for.  Reliability regions created rules for their interconnected utilities, such as having a 20% reserve margin for each utility or having spinning reserves equal to the size of the largest unit.  If we assume only the 20% reserves, then a very small utility could build one large unit to enjoy the economies of scale and rely on the large number of interconnected units for reliability.  If an industrial facility builds and operates a cogeneration plant (whose per KWH fuel costs because of the steam usage is half of the per KWH cost of a conventional plant), then the industrial facility will not want to have a spinning reserve requirement that reduces the generation by on the cheapest unit on the system.

Over twenty years ago I wrote “Tie Riding Freeloaders–The True Impediment to Transmission Access,” Public Utilities Fortnightly, 1989 December 21 arguing for a de-socialization of the electric system, both of the generation component discussed above and of the transmission component.  I say that we need a system to pay for unscheduled flows of electricity on very small time increments.  That way the small utility with the single large unit would pay the current value of electricity whenever the unit went down.  If the unit always failed during the summer peak, then the prices would be very high.  If the utility did sloppy maintenance and the unit was out more than the average for the rest of the grid, then the utility would be making frequent payments.  The reliability regions were not able to devise a reserve rule to penalize the sloppy maintenance practices or the bad timing issues.  I say that pricing the unscheduled flows achieves the appropriate grid discipline, or at least better grid discipline.  India put into place such a pricing mechanism and improved its grid discipline.

The physical interconnection created a form of socialism of the generating system.  Real time pricing of the imbalances would remove some of that socialism.

For the transmission system, socialism comes in the form of loop flow.  Engineers often use the short hand of saying electricity flows through the path of least resistance.  But, when there are several paths of relatively low resistance, the electricity divides among those paths such that the marginal line losses on each path are the same.  Thus, two parallel identical lines will split the load equally between them.  Attach something to one of the lines and the load will split in some slightly different way, but not all going to the one line with the least resistance despite the short hand.

Higher voltage lines have lower resistance than do lower voltage lines.  Higher voltage lines are more expensive per mile of wire but less expensive per KW-mile, with much lower line losses.  Consider this another example of economies of scale.

Consider a small utility that has a low voltage transmission line connecting its customers over a long corridor.  Consider a large utility serving roughly the same corridor that builds a high voltage transmission line parallel to the other line.  If the lines are connected to each other at each end, total line losses are reduced when some of the power from the small utility travels on the wires of the large utility.  If there is a scheduled transaction for the flow, the small utility will pay a wheeling fee to the large utility.  Generally there is no scheduled transaction and the small utility gets a free ride, a form of socialism.  Some describe the claim by the large utility for a wheeling fee to be “vampire wheeling.”  My article says that the network needs to price this unscheduled flow by differentiating the price geographically in addition to the temporal differentiation discussed above.

In regard to the Fox article, the aiding and abetting has taken the form of support for carbon taxes that would impact utilities differently.  A utility with a large nuclear fleet would see its competitors costs go up.  That would competitively advantage the nuclear fleet owner and in restructured markets, such as those operated by ISOs, the price of energy from the nuclear fleet would go up by the carbon tax without the cost of the nuclear fleet going up.

In regard to decoupling, some utilities will weatherize my home, with little or no charge to me.  That will lower the amount of electricity that I consume for HVAC.  The utility will treat the cost it incurred to weatherize my home as a legitimate rate case expense.  This raises the price that everyone, including me, pays.  If the utility has 100 customers, then I end up paying in higher rates less than 1% of the cost that the utility incurred to pay for weatherizing my home.  With a thousand customers, I pay less than 0.1%.  But I will pay for weatherize other peoples’ homes.  Except, that my new, green and economy minded, wife and I already spent a fortune on new double paned windows and other weatherizing features.  So my costs will not get socialized but I would pay the cost incurred by the utility for weatherizing others.

The Fox article presents three ways for decoupling, different ways for the utility commission to treat the weatherization costs as a legitimate rate case expense.  Or the government could use stimulus money for the same purpose, a different form of socialization.

My comments above don’t actually identify and explain misstatements, just explain some of the statements.