Wed 20 Jul 2016 - Tech

Run Silent, Run Deep: The Case for a Subsea Hyperloop

Blake Cole

Marine Engineer

Think of it.
On the surface there is hunger and fear.
Men still exercise unjust laws.
They fight, tear one another to pieces.
A mere few feet beneath the waves their reign ceases, their evil drowns.
Here on the ocean floor is the only independence.
Here I am free!
-Captain Nemo, Twenty Thousand Leagues Under The Sea

For most of the past century, the tunneling industry has been grounded in, well, the ground. Most of us have seen photos of giant boring machines gouging throughways out of the rock, sand, and gravel dozens of yards beneath the surface. The prospect of building tunnels through water was often viewed as fringe. It was seen as needless, expensive, dangerous, and complex. But in the last decade or so, advances in engineering, materials, and design have allowed us to build underwater tunnels at an unprecedented rate, at increasing depths, far faster, and at a lower cost than ever before. The most prestigious engineering firms in the world are allocating more time and resources into underwater tunneling, a move likely to kick in further gains in cost, safety, and reduced complexity.

Hyperloop One has had subsea aspirations almost since our inception in November 2014. We’ve alluded to it in press releases, and hinted at routes that would take passengers or cargo under the sea at the speed of sound. It’s no secret any more. Our partners at FS Links recently unveiled a 500-kilometer Nordic route that gets people from Helsinki to Stockholm in under 30 minutes. Part of that journey includes a 200-kilometer stretch dipping above and below the Åland archipelago in the Baltic Sea between Finland and Sweden. This international stretch would incorporate one of the world’s longest water tunnels ever built, estimated to cost $6 billion out of the $21 billion total capital budget for the project. As the company’s first and, for now, only marine engineer, one of my jobs is to help figure out how to safely and affordably construct a Hyperloop under water.

The big question is: Do we tunnel under the sea floor (traditional approach) or do we go through the water (not so usual)? For a rider, the trip would feel no different than one over (or through) land; the transition from land to water will be so smooth as to be imperceptible, and the duration of the subsea segment will be so brief, at least initially, that the entire experience will last only seconds or minutes. The rider will happily emerge from his or her pod at the end of their journey, having traveled faster beneath the waves than any living creature in Earth’s history.

In many ways, designing the Hyperloop to operate in an underwater environment is no more complex than adapting the system to function within bored-rock tunnels. Most of the pod levitation and propulsion systems will be directly transferrable, and a great deal of the vacuum technology will be adaptable to the subsea environment, with some relatively minor alterations. Both systems require intricately planned ventilation systems and egress protocols; both systems must contend with extremely high-pressure external environments; both systems must preclude water leakage and collapse, at all costs.

The big challenge to underwater tunneling is the industry’s collective lack of experience. Many tens of thousands of earthen tunnels have been constructed worldwide. Engineers are comfortable with established bored-tunnel construction techniques, but these techniques were hard learned over decades and even centuries. Underwater tunneling has yet to experience the same coming of age.

Subsea tunnels fall into three distinct categories. The oldest, and most conventional variety are called subsea bored rock tunnels, a methodology more or less identical to terrestrial bored-rock tunneling—although highly-saturated soils present a few additional challenges. A notable application of this technique was the construction of the Channel Tunnel from the United Kingdom to France. Its construction began in 1988 and it opened for traffic in 1994.

A section of an immersed tunnel before its installation under the Bosphorus Strait in Turkey. Credit: Wikipedia.

The second variety of underwater tunnel, and by far the most prevalent as of late, is called an immersed tunnel. Only around 200 immersed tunnels have been completed in past hundred years, according to engineering firm Ramboll. This type of tube employs precast steel or concrete segments resting on the benthos, or sea floor. In most shallow waters, immersed tunnels are cheaper and faster to construct than bored rock tunnels. And, because submerged tunnels are going into shallower waters they typically require shorter transitional tunnels from the land mass on either side. Famous examples include the TransBay Tube in San Francisco and the Oresund Bridge Tunnel between Denmark and Sweden. Here’s a great animation showing how the giant Fehmarnbelt immersed tunnel will be assembled and installed between Denmark and Germany.

The complexity and cost of immersed tunnels depends largely on two items: tunnel length and bathymetry. Bathymetry is an oceanographic term meaning “underwater topography.” If the seafloor is smooth, the maximum water depth is less than, say, 100 meters, and the required tunnel length is on the order of kilometers to tens of kilometers, an immersed tunnel will probably suffice. The deal-breaker with immersed tunnels is depth. For every 10 meters' increase in depth you increase the amount of hydrostatic pressure on a submerged tube by the weight of one full atmosphere (~12 km of air). At a certain point no hollow structure can hold up to this staggering compressive force, which is why no immersed tunnels have been built at depths below 70 meters. Immersed tunnel ‘best-practice’ is constantly evolving, and great leaps in cost-reduction and efficiency are made with each subsequent innovation. We plan to be part of that evolution.

The only solution we’ve seen for crossing waters deeper than 70 meters and over distances of 100 kilometers or more is the submerged floating tunnel (SFT). Also called an Archimedes’ Bridge, this tunnel employs the buoyancy of the tube itself, in conjunction with stabilizing tension cables, to traverse the underwater environment at a fixed distance below the surface. Some anchorless systems have been considered, though not in great detail. Because the SFT hovers off the bottom, the system is largely unaffected by undulations and obstacles on the sea floor. And because it is anchored at least 20 meters down, it avoids the highly turbulent surface layer of the sea. Of course, the advantages are met with many engineering challenges. An SFT, unlike an immersed tunnel, still has to deal with waves and currents, changes in water density and local variations in buoyancy, not to mention the possibility of a collision with ships, macrofauna, and submarines. Corrosion is also a big issue.

A rendering of an automotive submerged floating tunnel. The photo at top shows a rendering of an SFT from the surface. Credit: Vegvesen

Add all these challenges up and it’s no wonder that no SFT has ever been constructed. But academic studies on the topic have blossomed in the past decade. Since 2010, Statens Vegvesen, the Norwegian Roadway Authority, has invested extensively in various SFT prefeasibility studies. Given its multitude of narrow fjords too wide to bridge and too deep to tunnel underneath (some bottom out at 1,300 meters below sea level), it is no surprise that Norway is particularly enticed by the SFT concept. South Korea and China have also expressed interest in the idea as of late.

We can most easily deliver a subsea Hyperloop via a bored-rock tunnel (the approach we will likely take across the Baltic Sea) or an immersed tunnel in the right environmental conditions. But that would be too easy! Successfully building an underwater Hyperloop using a submerged floating tunnel will score us double entries in the history books: a novel form of transportation through a novel conduit of traffic.

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  • Q. What is Virgin Hyperloop?

    We're a privately-held company on a mission to create fast, effortless journeys that expand possibilities and eliminate the barriers of distance and time.

  • Q. Why are you building a hyperloop?

    There are too many people caught bumper-to-bumper in traffic, who have to make a hard choice with their family on where to live and work, and who are limited in their access to experiences and opportunities. We're building a system that will give back time and deliver the travel experience of the future.

  • Q. Why do we need hyperloop now?

    The number of cars is set to double worldwide by 2040, same with air and trucking. We are already dealing with the effects of pollution, lack of access, and congestion. If we only invest in the same technologies we’ve had for more than a century, tomorrow will look like today, only much worse. It’s been over a century since the Wright Brothers first showed us human flight was possible. It’s time for a new era in transportation capable of carrying us forward for the next 100 years.

  • Q. How much funding has Virgin Hyperloop received?

    To date, we have received over $400 million.

  • Q. Who are the key investors in Virgin Hyperloop?

    A major investor of ours is DP World, a leading enabler of global trade who sees the potential of sustainable hyperloop-enabled cargo systems. Additionally, we are backed by the Virgin Group, an industry leader across rail, aviation, ships, and even spacecrafts. For more on our investors, visit the company page.

  • Q. Does Virgin Hyperloop have any partners?

    Virgin Hyperloop One is the only hyperloop company that has a strategic partnership with a mass transportation company, the Virgin Group, an industry leader across rail, aviation, ships, and even spacecrafts. Another key partner of ours is DP World, a leading enabler of global trade who sees the potential of sustainable hyperloop-enabled cargo systems. Other industry-leading partners include KPMG, Foster + Partners, Systra, BIG, SNCF, GE, Deutsche Bahn, Black & Veatch, McKinsey, Deloitte, Jacobs, Turner & Townsend, ARUP, and Steer, among others.

  • Q. Is Elon Musk an investor or affiliated with Virgin Hyperloop?

    No, there’s no connection with Elon Musk.

  • Q. How do you plan to scale up operations around the world?

    We aren't just building a hyperloop; we're building a network of public and private partners to scale an integrated supply chain ecosystem. Our business model is based on partnerships that create local jobs and opportunities for those who choose to invest in this technology. We are working at the highest level of governments around the globe to put in place commercial agreements to make hyperloop a reality.

  • Q. What is hyperloop?

    Hyperloop is a new mode of transportation designed to eliminate the barriers of distance and time for both people and freight. It can travel at speeds approaching 700mph, connecting cities like metro stops - and it has zero direct emissions. The journeys can be booked on demand so there’s no wait time or delays.

  • Q. How does hyperloop work?

    With hyperloop, vehicles, called pods, accelerate gradually via electric propulsion through a low-pressure tube. The pod floats along the track using magnetic levitation and glides at airline speeds for long distances due to ultra-low aerodynamic drag.

  • Q. Has hyperloop technology been proven?

    On May 12th, 2017, we made history two minutes after midnight when we successfully launched our vehicle using electromagnetic propulsion and levitation under near-vacuum conditions at our full-scale test site in the Nevada Desert. We've since run hundreds of tests, acquiring validated knowledge that only comes from real-world testing. For more info on DevLoop, our 500 m test track, visit our progress page.

  • Q. How fast can hyperloop go?

    We estimate that the top speed for a passenger vehicle or light cargo will be 670 miles per hour or 1080 kilometers per hour. That is about 3 times faster than high-speed rail and 10-15 times faster than traditional rail. The average speed vehicles travel will vary based on the route and customer requirements.

  • Q. Why keep the tube at low-pressure and not at a perfect vacuum?

    A perfect vacuum would decrease the drag on the vehicle even more, but not significantly. We have already gotten rid of 99.9% of the air in the tube. Lower levels of vacuum than this are important if you are performing scientific experiments, but the cost would not be worthwhile.

  • Q. How is hyperloop different from high-speed trains?

    Hyperloop is an entirely new mode - think the best of trains, planes, and the metro. Hyperloop is on-demand, offering flexible travel schedules with no stops, no transfers, and no weather delays – all at speeds about 3 times faster than high-speed-rail and less cost. Hyperloop is highly efficient, with a smaller environmental impact than high-speed rail because the closed system can be tunneled below or elevated above ground, avoiding dangerous at-grade crossings. The VHO system is 100% electric and can reach higher speeds than high-speed rail for less energy due to our proprietary electric motor and low-drag environment.

  • Q. Is hyperloop safe?

    Fast, effortless journeys go hand-in-hand with journeys where everything works reliably without interference, and where all passengers feel comfortable and safe. The Virgin Hyperloop is designed to be inherently safer than other modes, with multiple redundancies in place. Our system operates autonomously in an enclosed tube and is not susceptible to weather delays, accidents from at-grade crossings, human error, or power outages. Our proprietary high-speed switching architecture eliminates unsafe track configurations and moving trackside parts, a failure point of traditional rail with mechanical switches.

  • Q. How do you plan to get hyperloop certified?

    As new mode, we have to prove our safety case to regulators and work with them to develop a regulatory framework, so passengers can ride the hyperloop in years not decades. We are encouraged by the support we are seeing at the local and federal level around the world to support hyperloop certification based on the fundamentals of safe operating that are already standard practice. In March 2019, the U.S. Secretary of Transportation, Elaine Chao, created the Non-Traditional and Emerging Transportation Technology (NETT) Council to explore the regulation and permitting of hyperloop technology to bring this new form of mass transportation to the United States. This Council is an important step forward in recognizing hyperloop is a new transportation mode and that we need to shift our mindset and acknowledge that this technology does not fit into a regulatory structure that is over 100 years old. The European Commission’s Directorate-General for Mobility and Transport (DGMOVE) has also been leading discussions with hyperloop companies to advance regulatory standards and, in India, the Principal Scientific Advisor (PSA), Prof. Vijayraghavan, has set up an independent committee called the Consultative Group on Future of Transportation (CGFT) to explore the regulatory path for hyperloop. For more, visit our regulatory progress pages.

  • Q. What will it feel like to ride hyperloop?

    While flying through a tube at more than 1000km/h might seem like a thrill ride, the truth is we are able to mitigate any uncomfortable acceleration forces within our controlled environment. The journey will be so smooth, you could sip a coffee the whole time without spilling a single drop. Normal acceleration and deceleration of 0.20 Gs will feel similar to a train. As a comparison, flooring a typical sedan gives between 0.4-0.5 Gs and commercial airplanes see 0.3-0.5Gs depending on the plane and load.

  • Q. What happens if there's a sudden breach in the tube?

    Pods will continue to travel safely to the next portal even with a large breach. Our response to a breach would be to intentionally repressurize the tube with small valves places along the route length while engaging pod brakes to safely bringing all pods to rest before it is deemed safe to continue to the next portal. A sustained leak could impact performance (speed) but would not pose a safety issue due to vehicle and system architectural design choices. This assessment is based in solid understanding and analysis of the complex vehicle load behaviors during such an event.

  • Q. Is hyperloop sustainable?

    Without a massive leap forward, pollution from the transportation industry is expected to almost double by 2050 - well above the carbon budget. By combining an ultra-efficient electric motor, magnetic levitation, and a low-drag environment, the VHO system can reach airline speeds for 5-10x less energy (depends on route length) and can go faster than high-speed rail using less energy. In regions like the Middle East, we could power the system completely by solar panels which cover the tube. As fighting against climate change becomes an existential issue for cities across the globe, hyperloop will create a new, shared, electric mobility model for helping to permanently reform an industry with some of the world’s highest carbon emissions.

  • Q. How much energy does hyperloop use?

    We are designing Virgin Hyperloop to be more efficient than other modes of transportation. Modern jetliners use up to 10 times the energy we use per passenger-mile over the entire journey. We can cruise at 500 miles per hour for less energy (per passenger) than an electric car doing 60 miles per hour. At peak speed, the VHO system consumes approximately 75 watt hours per passenger kilometer (Wh/pax-km). To put this in perspective, the fastest conventional maglev train travels at about half our speed and consumes 33% more energy.

  • Q. Where will hyperloop get its power?

    Our system is 100% electric with zero direct emissions. We're energy-agnostic. Our system can draw power from whichever energy sources are available along the route and support a transition to a renewable energy-powered future. In regions like the Middle East, we can completely power the system with solar panels which cover the tube.

  • Q. How much noise does hyperloop make?

    It’s similar those new electric vehicles that are so quiet they need to create noise to indicate movement. With hyperloop, we eliminate sources of mechanical noise, like wheels on track, and we actually have a sound barrier inherent in our tube design

  • Q. Can hyperloop be used for cargo?

    DP World Cargospeed is a global brand for hyperloop-enabled cargo systems operated by DP World and enabled by Virgin Hyperloop technology. These systems will deliver freight at the speed of flight and closer to the cost of trucking for fast, sustainable, and efficient delivery of palletized cargo.

  • Q. What type of cargo would a hyperloop system transport?

    The focus would be on high-priority, on-demand goods – fresh food, medical supplies, electronics, and more.

  • Q. How can hyperloop help transform logistics?

    With DP World Cargospeed, deliveries can be completed in hours versus days with greater reliability and fewer delays. It will expand freight transportation capacity by connecting with existing modes of road, rail, ports, and air transport, and will provide greater connectivity with manufacturing parks, economic zones, distribution centers, and regional urban centers. This can shrink inventory lead times, help reduce finished goods inventory, and cut required warehouse space and cost by 25%. DP World Cargospeed networks can also enable just-in-time, agile manufacturing practices.

  • Q. Will the first hyperloops be passenger or cargo systems?

    The Virgin Hyperloop is unique in that it doesn’t need to be passenger-only or cargo-only. We are designing a mixed-use system that fully utilizes system capacity while maximizing economic and social benefits. However, it is possible to run cargo commercial operations while certification and regulation are still ongoing for passenger use.

  • Q. When will hyperloop systems be ready for cargo and passengers?

    We are working with the most visionary governments around the world to make sure you can ride the hyperloop in years, not decades. Our goal is to have operational systems in the late 2020s. Our ability to meet that goal will depend on how fast the regulatory and statutory processes move.

  • Q. Where will the first hyperloop get built?

    We are working with visionary governments and partners around the world to make hyperloop a reality today. To learn more about our projects around the world, visit our progress page.

  • Q. How much will hyperloop cost to build and operate?

    Capital and operating costs will range widely based on the route. We recently released a study that showed our linear costs are 60-70% that of high-speed rail projects. In addition, we expect the operational costs to be significantly lower than existing forms of transportation.

  • Q. How much will hyperloop cost to ride?

    It’s simple – if it’s not affordable, people won't use it. We are looking to build something that will expand opportunities for the masses, so they can live in one city with their family and work in another. Currently, that kind of high-speed transport is not feasible for most people. The exact ticket price will vary for each route, but a recent study showed that riding a hyperloop in Missouri could cost less than the gas needed to drive.

  • Q. How are hyperloop routes selected?

    We are in the business of serving local needs, not the other way around. Public and private support is key. In some cases, we will respond to solicited bids with partners when we feel the technology matches the project’s objectives. In other cases, we will make an unsolicited bid for a project when we see that hyperloop could offer a unique solution to market needs.

  • Q. What is the process for getting a passenger route up and running?

    While the technology is different, the process for building a hyperloop is similar to that of building a highway, railway, or any other type of linear infrastructure. The first stage is project development. This phase includes feasibility studies, and then more detailed engineering reports and environmental impact studies. Once a project is approved to move forward, a consortium is formed to finance and deliver on the project.

  • Q. How much land does hyperloop require?

    Many infrastructure projects succeed or fail based on right-of-way issues. We are designing a system that requires only about half the right-of-way as high-speed rail and can more easily adapt to existing right-of-ways. At high speeds, the VHO system has a 4.5 times tighter turn radius compared to high-speed rail and can climb grades that are 6 times steeper, reducing the disturbance at crossings. Portals will be purposely integrated into and support existing communities and landscapes. Low noise levels will expand opportunities to build hyperloops closer to the city center.

  • Q. With the focus on connecting cities, how will hyperloop support rural communities?

    Hyperloop also holds enormous promise for rural communities. Virgin Hyperloop systems can be built below or above ground, which means no one’s farm needs to be cut in half. Our system enables rural areas to retain residents, who can now have more access to urban job centers, educational opportunities, and health care facilities. Additionally, hyperloop could enable freight distribution centers to be placed in rural areas, leading to job growth and industrial clusters. After a system is built, there is the opportunity to add additional on and off-ramps, supporting a greater number of people along the route.

  • Q. How will hyperloop projects be financed?

    Transportation infrastructure has traditionally relied on extensive government funding. This is because the benefits of clean, safe, and efficient transportation are enjoyed by the entire community, not just the user buying a ticket. However, most existing mass transportation modes are unprofitable and hindered by existing infrastructure built in the past century or by legacy systems. We want to change that and are focused on public-private partnerships. By developing a new mode of transportation from scratch, we're able to leverage technological developments that have occurred in the last century, especially the IT revolution. We're able to keep maintenance costs low, energy efficiency high, and transport tens of thousands of passengers per hour. This keeps margins and accessibility high, contributing to more financially attractive returns than if the corridor was served by existing modes. These benefits aren’t just hypothetical. While this is an exceptional case due to high demand, a third-party evaluation found that our Mumbai-Pune Hyperloop Project could be funded 100% by private capital. In the U.S. we see enormous potential to attract investment from the private sector, leveraging public investments. Involving government stakeholders as well as potential private investors early in the project development process is critical.

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