How Much of the Grid Must Be Upgraded?

Guest Essay by Kip Hansen  —   12 April 2022

Have you ever seen a transformer mounted on a power-pole explode?  Marvelous fireworks. Why do they explode?   One energy company exec quipped “My experience and understanding of the way utilities do things is they just wait until the neighborhood is overloaded and then the transformer blows up.” [ source

And what overloads power-pole transformers?  Lots of things:  lighting strikes to poles or transmission wires, shorts caused by trees falling on wires, or, more simply, too much electricity being draw through the transformer by homes and businesses.

What would cause a home to draw too much power? Well, on  a neighborhood level, summer or winter. When every home in the neighborhood turns their air conditioners up to maximum on a hot muggy summer afternoon or in winter, when too many all-electric homes kick their electric heating up to fight the cold on a freezing winter’s  night. 

Or when too many neighborhood homes install electric vehicle fast-chargers.   What?  Say again….

“Currently available DC fast chargers require inputs of 480+ volts and 100+ amps (50-60 kW) and can produce a full charge for an EV with a 100-mile range battery in slightly more than 30 minutes (178 miles of electric drive per hour of charging).”  The more usual and affordable overnight chargers need 240v/50ampstimes two means you will need 100 amps available for car charging at night.

So, if your family were to have two EVs and wanted two overnight chargers – and who wants to argue with their spouse over who gets first dibs on the  charger – your home would probably have to have a new electrical service panel and a new 200 amp service drop installed by your local utility  — that is the wires that run from the nearest power pole to your home.

Pictured here is electrical service drop to a typical American home.  Suburban homes in the United States usually have 100 amp service.  My current home only had 60 amp service when we moved in in the 1980s which meant the lights dimmed whenever the water heater kicked in or the water-well pump motor started up.    Newer homes here usually have 200 amp service,  though a larger all-electric home – as in electric heating, air conditioning, electric water heater, electric sauna, electric hot tub, electric stove top and two electric ovens, electric clothes dryer plus the entertainment systems – may require 250, 300 even 400 amps service depending on the overall size of the home and number of electricity gobbling appliances.

“If you’re running large appliances frequently (central air, heating) or have items with large electric demands (in-home saunas, hot tubs), you could benefit from installing a 300- or 400- amp service instead.” [source ]

Large appliances include in the modern kitchen two electric ovens and electric stovetop, refrigerator, chest freeze, dishwasher and elsewhere in the home a washing machine, clothes dryer, heat-pump heating, whole-house air conditioning, window air-conditioner, hot tub, sauna, or pool heaters, electric water heaters (many larger homes have more than one).  Look around your home, you may be able to add to the list.

And now, EV chargers.  Repeating the data from above, almost all EV owners will want one overnight-charger for each vehicle. Each requires a 240v/50amp circuit breaker in the panel box. In a modern home with normal electrical appliances, it is unlikely that  local electrical codes will allow you to add two 240v/50amp circuits if you have only 100 amp service.

Note that this is not because 50 + 50 = 100. That’s not how you determine circuits in your panel box, it is more complicated.

In the end, you may be looking at the rather expensive job of replacing your electrical system from the pole to the main panel (see illustration far above) —  New service drop, service point, service entrance wires, service meter (usually supplied by your power company), probably a new service disconnect, and a new service panel.  Cost?  Up to $5,000.

What if you live in suburbia and everyone in your neighborhood wants two overnight chargers? 

The items in the red boxes may need to be upgraded or duplicated – base load generating stations, substations, and local distribution lines including pole mounted transformers.

Let’s look at a real example:  Palo Alto, California , one of the principal cities of Silicon Valley.  In this report:

City of Palo Alto Utilities Advisory Commission Staff Report (ID # 11639) 4 November 2020.  [ .pdf ]

Highlights of Study Results: Impact to the Electric Utility

The study shows that electricity demand for all-electric homes peaks on winter mornings due to heating, and averages around 3.62 kW per home, or 264% of a mixed-fuel home’s peak demand. EV charging can add an additional 1.216 kW to the average peak demand of an all-electric home. Assuming each distribution transformer serves 8 houses, the load on each transformer under the all-electric SFRs scenario is calculated at 2.64 times the current transformer load plus 9.74 kW for EV charging.

As shown in Table 1 below, the additional load will trigger the need to upgrade some of the distribution transformers, secondary distribution lines (which connect the distribution transformer to the homes served by the transformer), and feeder lines (which connects the substation to the distribution points).

The total cost to upgrade the distribution system grid is estimated to range between $30 million and $75 million. Around 40% of this cost is equipment cost, and 60% is labor cost. This covers the cost to upgrade 95% of the distribution transformers, 20% of the secondary distribution lines, and 25% of the feeder lines. The cost estimate does not include additional undergrounding of feeder lines or secondary distribution lines.”

How much is that going to cost?

Between $2,000 and $5,000 per home or in total for Palo Alto, somewhere between 30 and 75 million dollars

Those costs don’t include the costs to homeowners, who must pay for the service upgrade, service entrance wires, and circuit breaker panel box. And, of course, does not include the purchase new appliances or the installation of EV chargers.

To go all-electric in every single family residence (SFR) in California also means replacing all the natural gas usage with electrical appliances – heating, cooking, domestic water heating, and for many homes, pool heating.

The cost?

The cost of disconnecting the natural gas lines is estimated between $1,114 to $3,578 per home. That does not include the cost to the homeowner of replacing the appliances with electric models.  All told, for this piece of going electric will cost from $11 million  to $53 million – for Palo Alto’s single family homes alone.  This does not include businesses, apartment houses, retail shops and any other type of building. 

Palo Alto’s has about 15,000 homes….but there are approximately 7.5 million single family residences in California.  That means that the numbers given in the Palo Alto report will have to be multiplied by 500 to get an estimate for the state of California. 

For pole mounted transformers, that will require up to  335,000 pole mounted transformers alone. Also, millions of new electric stove tops, millions of electric ovens, millions of electric water heaters.  Not all of the 7.5 million homes in California use natural gas, but the California Public Utilities Commission tells us there are 11 million gas meters in California.    That’s a lot of natural gas customers.

A gold star for the first reader to give the probable cost to the individual California home owner to upgrade home to all-electric with two EV over-night chargers.  Give a list of what you are including.

For other readers, try to give an estimate of the materials needed to accomplish going all-electric just in California.  Components needed for the grid upgrade, new appliances in homes, EV charges, 200 amp  service entrance wire (currently costs about $20 per foot), new circuit panels, . . . . .  [this is a long list].  Give your opinion on whether or not you think that the manufacturing  and supply chain is adequate to the task in today’s world. 

Please be aware that there are about 140 million homes in the United States.  Anyone care to try the estimates for cost and time to convert all those homes all-electric?

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Author’s Comment:

Personally, I don’t think there is the political will to carry-out the all-electric-cars-and-homes demand, not even in California.  I don’t think there is enough electrical generation to supply the U.S. grid with enough electricity to meet average demand for a nation made up of all-electric homes and all electric vehicles.  I’m not sure we can even supply the components for the transformation.

And then there is the task of replacing the 276 million cars and light duty trucks that currently exist in US households, even over time.    Can we manufacture enough batteries to replace those ICE vehicles? 

I hate to be a pessimist, but I don’t think it is doable.

What’s your opinion?

Thanks for reading.

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via Watts Up With That?

April 12, 2022 at 12:06AM

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