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The Grid is Essential for America’s Well Being

July 10, 2015

A number of my articles have pointed out that the grid is essential and worth saving.

For example, wind energy cannot transmit electricity without the grid. There also isn’t enough rooftop space in cities for PV rooftop installations to provide city residents with the electricity they need.

Now, with information from Energy Matters, by Roger Andrews, it’s clear that the U.S. grid is absolutely essential, and everything must be done to save it from the actions of extreme environmentalists.

Mr. Andrews analyses demonstrate that PV rooftop solar will not allow, with any reasonable assumptions regarding cost, homeowners to go off grid, except in the Southern states.

In other words, we MUST keep the grid.

In examining his analyses, I found the logic and assumptions, except as noted, to be sound.

His analyses [See note below for link] examined PV rooftop solar using batteries, and, alternatively, he examined using oversized PV rooftop systems without batteries to allow the homeowners to go off the grid.

Here is how Mr. Andrews describes the oversized system: “Over design the system so that it’s large enough to fill demand in winter when solar output is at a minimum and simply curtail the excess power generated in summer.”

The analyses covered latitudes 20, 40 and 50 degrees north latitude, which includes all of Cuba, all of the United States and Southern Canada. He assumed annual consumption of 5,000 kWh, while actual annual average consumption by homeowners in the United States is 10,908 kWh. or twice the amount used by Mr. Andrews in his analyses.

So as not to distort any of Mr. Andrews’ conclusions or calculations, all of the following data is taken from his analyses. It should be noted, however, that the areas required for installing PV rooftop systems and the weight of batteries has been doubled to reflect the larger average consumption in the United States.

His analysis of an oversized system without battery backup includes a natural gas generator as backup, as there will be times when the rooftop system cannot provide the needed electricity.

U.S. Map with Latitudes Courtesy of Enchanted Learning

U.S. Map with Latitudes Courtesy of Enchanted Learning

Alternative 1: Using Batteries:

It’s immediately clear that installing batteries to achieve grid independence is irrational.

The cost is prohibitive and the weights involved are too great for any normal residential house to accommodate. Even if Powerwall batteries can become twice as efficient, which isn’y likely in the near future, batteries will continue to be unsuitable for allowing homeowners to go off the grid.

Table 1

Battery Backup

Degrees North Latitude

Cost

Battery weight in tons (1)

20

$117,000

6

40

$253,000

14

50

$550,000

30

(1)  Weight adjusted for actual annual usage by average US home

 

Alternative 2: Using oversized installations:

By building oversized PV rooftop installations, it may be possible for homeowners to become grid independent in the Southern states.

It should be noted that above 40 degrees north latitude, the area required for an oversized PV rooftop system may be too great for the average home size. A typical 2,000-sq.-foot ranch style home will only have half the rooftop area available for the PV system, or 1,000-sq.-feet of roof area, with the other half facing in the wrong direction. A large, 3,000-sq.-foot two story home will have a roof area of 750 sq. feet available for installing a PV rooftop system.

Table 2

Oversized system

Degrees North Latitude

Cost

Percentage curtailed

Area required in sq ft (1)

20

$24,000

10%

536

40

$32,000

33%

802

50

$58,000

57%

1,738

(1)  Area adjusted to reflect actual annual usage by average U.S. home

 

Note that the roof must face due south or it will not generate the anticipated amount of electricity. If the PV rooftop system faces east or west, the amount generated can be cut by as much as 25%. (Alternatively, the PV rooftop system size and area must be increased by 25%.)

Table 2 shows that large amounts of electricity are wasted.

  • One-third of the electricity generated in homes located at 40 degrees north latitude will be curtailed, or dumped.

While it may be possible for some people living in the southern tier of states from Florida to Arizona, to install oversized PV rooftop systems to become grid independent, it’s not likely many would spend the money to do so.

There are two, possibly three, conclusions that can be drawn from these analyses:

  1. Only a fraction of the population of the United States can become grid independent, which confirms that the grid is essential to the functioning of the United States. Policies that undermine the grid, such as subsidies for solar installations and renewable portfolio standards, are destructive to the well being of Americans.
  2. The glib pronouncements by EIon Musk that the Powerwall battery can allow people to become grid independent are unrealistic. In essence, he was grandstanding for the sake of publicity.

And possibly a third:

3. Europe, most of which lies above 40 degrees north latitude, is wasting billions of dollars in their efforts to cut CO2 emissions.

 

 

Link to analysis: at http://bit.ly/1T4UGqK

 

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4 Comments leave one →
  1. Don Shaw permalink
    July 10, 2015 9:33 am

    Donn,
    Great article with lots of good analysis, data and sensible conclusion. Shame the EPA and DOE can’t make these calculations and honestly inform the populace instead of relying on subsidies from taxpayer dollars.
    My principal residence in NJ is on a lot with lots of trees eating up all that CO 2. In the summer no sunlight strikes the roof and we can keep comfortable with modest AC use. Given the low electricity bills and all the CO 2 consumers on the property, think I could sell carbon credits to the Washington folks who fly all around the country and world consuming massive amounts of fossil fuels with no obvious benefit to the country.
    Sounds foolish? But no more so than the claims coming out of their mouth regarding the benefits and viability of green energy.

  2. donb permalink
    July 10, 2015 1:10 pm

    To follow up on Don Shaw’s comment above, here in the South we are most concerned with summer cooling and that Sun is a major source of heat into a home. So, people often plant large trees to shade their roof. So the choice becomes have shade trees but no PV system, or cut the trees for a PV system but increase the need for air conditioning operated by the PV just installed.

    Donn on your article, I have read several excellent reports on Energy Matters about storage of renewable energy by batteries, pumped hydro, and making hydrogen. For much of the US going off grid it is currently impossible, no matter how much people are willing to spend. I would respect much more the argument given by our government and by green advocates if they would discuss a middle ground, namely how much wind and solar can be introduced into the grid before fossil fuel plant output is significantly disturbed, and how can the problem that produces be worked. But I hear none of that. An all or none approach is self-defeating.

    • July 10, 2015 2:07 pm

      Thanks. Great comment.
      It’s all or none because it’s the ideology of stopping climate change by stopping CO2 emissions.

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