[writimov]

These guys have some good videos on Boring Company tunnels. https://www.youtube.com/watch?v=VGG1nWzP-Oc&list=PLDn5j59RTW...

The summary: the hard part of tunnels and people was what to do with exhaust gases. That's solved with electric cars. The tunnels will probably pay for themselves or at least break even.

In 5-10 years, its likely that most major freeway projects will have a very difficult time getting funding as tunnels will be cheaper to build and much much much cheaper to maintain than roadways. And existing investments in tollroads or bonds for roads will be selling for pennies on the dollar.

The cost per mile may even get as low as $100k/mile. At that price point, individuals could be drilling their own private tunnels.

As a comparison against tunnel prices now, when Google Fiber tried to lay fiber optic cable in San Francisco a few years ago using shallow trenches and not full tunnels, the full cost was estimated to be in the $100's of millions for the backbone and low billions including all house hookups. https://sfbos.org/sites/default/files/FileCenter/Documents/5...

And San Francisco is a tiny city: 7 miles by 7 miles. Once the Boring Company gets prices down to $1mil/mile, you could make the same Fiber backbone with 3 tunnels N-S and 3 tunnels E-W for 6x7 = $42million - a little more than 1/10th the quoted cost.

More comparisons: the Alaska Way Viaduct project (SR 99) in Washington State cost >$3billion and was only 2 miles long and took 12 years. The cost was $1bil/mile - so Boring Company will be 1000 times cheaper. https://www.wsdot.wa.gov/projects/viaduct/budget

The San Francisco BART extension cost $3bil/mile!! https://sf.curbed.com/2018/6/18/17464616/bay-area-subway-tra...

[writimov]

Overall point: There is a potential solution to the housing crisis for almost every city. It is too early to tell if it will work. But it looks promising.

Steps:

1) Build electric cars (exhaust gases in tunnels kill people). (Completed 2020 - Tesla)

2) Build tunnels that are 1/10th to 1/1000th cheaper than current technology. (In Progress - Boring Company)

3) Build tunnels that connect cities and the infrastructure to make city to city commutes through a tunnel but walking on foot using tunnel bus-like vehicles, easy, cheap and safe. (In Progress - Boring Company)

4) Build a test town of 1k-10k condos and connect to a major city with Boring Company tunnels. Initial cost of a test would be $500mil to $5bil. (Not started - ?)

5) Reduce the cost of building towns through 10X or better infrastructure improvements and develop a franchisable business model around towns.

6) Franchise the towns.

Result: Housing supply goes way up near where people want it right now. NIMBYs can't stop it. Investors may lose their shirts or make massive profits.

Advantages over other solutions: This only works if the business model works out. It leaves the politics of land-use within cities almost completely out of the picture.

Disadvantages: Its never been done before. It will cost a LOT of money to test it. The investors must be in it for the longish haul: 5-10 years at least.

[newyankee]

I understand how reducing tunnel diameter by half reduces cost by a factor of 4. I can even imagine that using electric motors, batteries and few other optimizations might give an energy efficiency of 2-3x compared to current TBMs. However i find it difficult to believe that tunneling costs will reach 1 million $/mile. The different types of strata, energy costs, use of advanced tech like lasers/supercapacitors in parts might help.

[writimov]

Q: How it can get so much better?

Ans: From the most recent full presentation (pretty dated at this point Dec 2018): https://www.youtube.com/watch?v=nSIzsMlwMUY

From 10:22mins in the video: * Increase speed: automated segment erection and logistics; simultaneous mining and installation of reinforcement segments; 3X increase in power for TBM; continuous dirt removal; modified cutter design. Probably leads to 10X faster.

* 13:12mins: Decrease costs: onsite integration, reduced diameter of tunnels, electric locomotive, sell bricks. 15% of costs is dirt removal. Selling bricks for $0.10ea pays for dirt removal. 15% savings right there. (Price comparison: bricks cost $0.25 retail at Home Depot)

So the test tunnel cost $10mil/mi but can only put through 1/4 the area. So to balance against existing tunnels at $1bil/mi lets round up to say equivalent throughput for mass is $50mi/mile - assumes people throughput happens at the same speed of current mass transit - 45mph. Hyperloop tunnels will go much faster than that. But even non-hyperloop electric cars can go 90mph with self-driving - so double speed = double mass transfer and half mass_transfer cost per mile per time unit.

So kinda apples to kinda apples comparison of the very first tunnel Boring Co made is $50mil/mi versus $1bil/mil in LA for same mass throughput at same speed. They are already 1/20th the cost. Even if I am way off, by a factor of 10, the Boring Co is already HALF the cost of existing tunnels with their very first attempt in Dec 2018. The next update will put them even further along.