Hannah Herbst's $12 Ocean-Current Energy Prototype

Hannah Herbst's Ocean-Energy Prototype and Its Promise

Photo: Business Insider

In October 2015, Hannah Herbst, a 15-year-old ninth-grader from Boca Raton, Florida, won the Discovery Education 3M Young Scientist Challenge with a simple device she called BEACON. Built largely from recycled parts for around $12, it used a propeller turned by ocean currents to drive a small generator. In its first test it lit LEDs; her goal was a cheap, open design that could one day bring steady power to communities with unreliable electricity.

Her prototype was not a power plant, and she never claimed it was. What it did show was how a curious student can test a serious idea with very little money. Here is how the device worked, what it achieved, what it could and could not prove, and what Hannah went on to do.

The pen pal who inspired the project

Hannah's idea started with a personal connection. She had a nine-year-old pen pal in Ethiopia whose family had only limited, unreliable access to electricity. She wanted to find a power source that could run things like water purification and basic medical equipment for families in that situation. In an interview with Business Insider she said: “I can't even imagine a day without electricity.”

Living near the coast gave her the second piece of the puzzle. She had noticed how strongly the current pushed her family's boat, and she began to wonder whether that steady movement of water could be turned into usable energy.

How the BEACON prototype worked

Photo: FastCo.Exist

Hannah with an early version of her probe: a length of white PVC pipe with a propeller at one end, in front of her science-fair board.

The design is easy to picture. A 3D-printed propeller sits at the end of a plastic PVC pipe. When moving water spins the propeller, a pulley system inside the pipe transfers that motion to a small hydroelectric generator, which converts the mechanical rotation into electricity. Most of the materials were recycled, which kept the cost of the parts to about $12.

She tested it in the Intracoastal Waterway at Boca Raton, where tidal water flows in from the Atlantic. The probe produced enough power to light a small set of LEDs. Based on her measurements, she calculated that a scaled-up version could charge three car batteries in under an hour, enough, she suggested, to run devices such as saltwater desalination pumps, blood centrifuges for clinics or navigation beacons along a coast.

During the competition, each finalist was paired with a 3M scientist for a summer mentorship. Hannah worked with Jeffrey Emslander, a 3M corporate scientist, and over roughly three months took the idea from a design to a working prototype.

Winning America's Top Young Scientist

Photo: The Plaid Zebra

Hannah holds the Young Scientist Challenge trophy with a fellow finalist at the 2015 final in St. Paul, Minnesota.

The Discovery Education 3M Young Scientist Challenge is a US competition for students in grades five to eight. A small group of finalists present their projects at 3M's Innovation Center in St. Paul. Hannah, one of the 2015 finalists, won the title of “America's Top Young Scientist” and a $25,000 prize.

Photo: Business Insider

Celebrating with the $25,000 winner's cheque; the original report identified the man beside her as her 3M mentor, Jeffrey Emslander.

She said she planned to give part of the money to her pen pal in Ethiopia, put some toward her school and save the rest for college. She also said she would make the finished design open source, sharing the parts list and her data so that anyone could build it.

What a $12 prototype can and cannot prove

Stories about this project often went viral with headlines suggesting a teenager had solved energy poverty for $12. That overstates it. The $12 figure covered the materials for a small test probe, not the cost of a complete, durable installation, and lighting LEDs in a sheltered waterway is very different from running a village's water supply.

Any device left in moving seawater has to deal with corrosion, the growth of algae and shellfish on moving parts, storms, debris, anchoring and safe connection to batteries or a local grid. Professional ocean energy projects spend years and large budgets solving exactly these problems. The scaled-up figures Hannah gave were her own estimates, and no independent field data on a larger BEACON has been published.

None of this takes away from her achievement. Her project did what good science projects should: it asked a clear question, built a cheap test, measured the result and pointed to the next steps. That is how many larger technologies begin.

Is energy from ocean currents realistic?

The basic idea behind BEACON is sound and widely studied under the name marine current power. Ocean and tidal currents carry enormous amounts of energy, and unlike wind, their speed and direction are fairly steady and predictable. The Florida Current, which flows past Hannah's home region as part of the Gulf Stream system, is one of the most closely studied resources. One estimate quoted in research is that capturing just a thousandth of the Gulf Stream's energy could supply about a third of Florida's electricity.

Engineers use designs similar to underwater wind turbines, as well as underwater kites and cross-flow rotors, mounted on the seabed or floating on moorings. Tidal stream turbines placed in channels with strong tides work on the same principle. The challenges are cost, maintenance at sea, and possible effects on marine life, which is why commercial current power is still small compared with solar or wind.

For small, remote communities, compact river and tidal turbines remain an active area of work, and simple designs like Hannah's are useful for teaching and early testing.

What Hannah Herbst did next

The 2015 win was the start of a busy scientific career. Hannah went on to win awards at the Intel International Science and Engineering Fair in several years, studied at Florida Atlantic University's high school and university at the same time, and earned a bachelor's degree in management information systems from FAU, graduating magna cum laude. As a student she researched the properties of shark skin in FAU's biomechanics laboratory and developed an antibacterial reusable bandage, an idea prompted by a relative's hospital-acquired infection.

She was named to a Forbes 30 Under 30 list in the energy category, founded a startup, Tiburon Technologies, that won first place in the Florida Venture Forum's statewide collegiate startup competition, and later became founder and CEO of Golden Hour Medical, which develops emergency medical devices designed for use by non-specialists.

Students inspired by her story can find similar paths through science fairs, school engineering clubs and competitions like the Young Scientist Challenge. The site has also covered Angelo Casimiro's shoe-powered electricity project, another example of a teenager testing a small energy idea.

Sources: SlashGear: 10 years ago, this teen invented a $12 generator that draws energy from the ocean; Florida Atlantic University: FAU grad, entrepreneur passionate about helping people; Wikipedia: Marine current power. Interviews: Business Insider and Fast Company (2015). Photos: Business Insider, FastCo.Exist, The Plaid Zebra.

Related: