Tuesday, May 25, 2021

Tesla Hates Battery Swap for No Good Reason

 I have to defend NIO battery swap:

1. Elon sold himself on battery swap in 2013. (Since Elon has arguably the best foresight in the industry, we know the idea makes sense) The conventional wisdom is that Model S battery swap failed because of low consumer demand. Yes, Tesla soon abandoned the idea, but THE TESLA BATTERY SWAP PILOT WAS COMPLETELY INVALID. Think it through:
a. In 2013-2015 Tesla Model S was sold only to rich people with home charging available. Therefore, there was zero demand for quick battery swap. Local supercharging was only for emergencies, and most people charged while sleeping, which always be the most time efficient method.
b. Battery swap was not tested for long trips. If they had tested a cross-country network, they would have uncovered real demand for battery swap.

2. Teslas are still too expensive for apartment dwellers. This will change, and these lower income EV owners will desire faster charging than 20 minutes. Nobody wants to waste 10-20 minutes EVERY DAY. (This is one reason NIO swap is successful in China, where single family homes and garages are relatively rare.)

3. Battery swap is criticized because it ties up more physical batteries than supercharging, and there is currently a battery shortage.
This argument will be moot as rapid automated battery production is ramped up, raw material supply is increased, and more abundant raw materials are used.

4. The conventional wisdom is that structural batteries cannot be swapped. This is wrong. There is no reason that a structural sandwich cannot be attached to the bottom of a car with removable fasteners. Given large enough bolts, location pins, and smart engineering, the strength of a removable structural battery sandwich can transfer to the entire car.

5. The conventional wisdom is that supercharging stations are more space efficient than swap stations. This is wrong. Supercharging is initially more cost efficient, but not more space efficient. In dense population centers, space efficiency and consumer demand for faster charging will win. The current cost efficiency advantage that superchargers currently enjoy is mostly at the expense of the consumer wait times.

6. So Tesla, because of an incomplete and misguided pilot test project, and false assumptions about cost efficiency, fooled themselves into forgetting about battery swap.

Saturday, May 1, 2021

Travel Trailers and RVs as ADUs?

 As one of the founders of Denver's Friends of Granny Flats, this article really caught my eye:


Even as a temporary solution while apartment construction catches up with demand, this is a great idea.

Although they aren't very energy efficient, they are certainly very space efficient, and using them for affordable housing during their 20 year lifespan is infinitely greener than using them for camping only a few weeks a year.

Tuesday, November 12, 2019

Amazing Deals on LED Bulbs Thanks to Xcel

Prices as low as $0.24 per bulb

The Bulb Finder app from Xcel: 

There is a large selection at the Habitat Re-Store at 70 Rio Grande Blvd.

Note there isn't anything at Home Depot, you'll have to swing by Costco, Sam's Club, or Ace Hardware.  Inventory is changing all the time.

Saturday, July 15, 2017

Super Quick Payback Now Possible with LED light bulbs

In a previous article, we showed that an average LED bulb will save $10.69/yr.

I just bought dimmable A19 bulbs at ACE Hardware for $0.99 each.   Even if I use this lighting half as much as the estimate, the payback period is under 3 months.

Here's a link to finding those 99 cent bulbs

Thursday, August 18, 2016

Solar Power Now Worth up to Triple the Cost of Grid Power in CO

This is big news for photovoltaic solar customers in Colorado.

I first proposed this in 2007.  Xcel then tried Smart Grid City which they bungled.

Xcel is finally letting us benefit from the advantages of:

"Net Metering Time of Use (TOU)
COSEIA and other solar parties scored a win with the agreement that  extra energy generated by solar systems in a given month can be rolled over as a monetary credit that recognizes the value of the energy at the time it was generated. The credit will be used to offset the bill for consumption the next month and can continually roll over. Those who have elected to cash out extra production will still have that option. "

(From a COSEIA email announcement of the settlement)

Time Periods:
On Peak:       2 PM through 6 PM (weekday, non-holiday)
Off Peak:       9 PM through 9 AM
Shoulder:      All Other Hours

Price per kilowatt-hour (kwh): 
                                Summer                     Winter
On Peak:                  $0.13814                   $0.08880
Shoulder:                 $0.08420                   $0.05413
Off Peak:                  $0.04440                   $0.04440

For example, if your PV system generates 10 kwh between 2 pm and 6 pm, Xcel must give you a credit of $1.38.
But if you can use the same 10 kwh during off peak hours, it will only cost you $0.44.

Some of the takeaways:

1.  Solar systems will earn more money if they face to the southwest instead of due south.
2.  Homes in Colorado can now benefit from smart timers and products like the Tesla Powerwall.
3.  The demand peak for power occurs at 4pm, which doesn't align with peak solar production. Battery storage is the key to solving this problem, hence the Gigafactory and V2G.

Note that there are a bunch of fees and charges on your utility bill that make it difficult to see your actual cost per kwh.  This issue killed TOU rates the first and second time around.

Thursday, June 16, 2016

Now You Can Affordably Tell if the Air in Your House is Healthy

Nate Adams has tested some of the affordable consumer grade indoor air quality (IAQ) monitors:

UDATE:  I bought the Foobot, and it will go into our new homes to see if the initial air quality is acceptable. 

With all the new materials and paint, etc., the initial air quality can be suspect.

Monday, June 6, 2016

Low Energy Carriage House Under Construction

After a painfully long permitting process, GBID's "Tandem House" at 2268 S Acoma (off the alley) is under construction.

Design Highlights:

1.  Double stud "Shirley Wall" construction to meet superinsulation goals.

2.  Insulated forms for stem walls.

3.  No natural gas needed for the house.

4.  Heated and cooled with one ductless minisplit heat pump.

5.  Passivhaus air tightness goal, (0.6 ACH 50)

6.  Fluid-applied Vapor Permeable Air Barrier.

7.  Grid tied PV system for net zero yearly energy usage.

8.  Induction range for cooking.

9.  Ductless heat recovery ventilator.

10. Ventless heat pump clothes dryer.

11. Complies with Denver's new Tandem House zoning form.  The home can be legally sold seperately from the home in front.