Identifying exactly what is going to inspire someone to come up with the next great idea is clearly an inexact science. There are stories about how the simplest of observations spurred such great inventors as Leonardo da Vinci, Nikola Tesla and Thomas Edison. But when it comes to one consistent way of new ideas being formed, perhaps the adage from Plato “necessity is the mother of invention” best fits the bill.

If that adage is true, then there’s no better time than now for new methods of supplying energy to the world to emerge. We at ED+C have kept an eye out for alternative sources of energy and have found a few worth sharing.

Energy-Generating Revolving Door

This little gem came our way during Greenbuild and had us buzzing. Royal Boon Edam Group Holding has developed an energy generating revolving door for the Driebergen-Zeist railway station in the Netherlands. The TQM revolving door was designed not only to save energy, but also generate energy with every person passing through the door.

The revolving door is equipped with a special generator that is driven by the human energy applied to the door, while the generator controls the rotating speed of the door and makes it safer—no doubt to prevent some juvenile editors from trying to see how much energy they can generate and injuring themselves in the process.

The ceiling of the revolving door is made of safety glass and gives a clear view of the technology. A set of super capacitors stores the generated energy as a buffer and provides a consistent supply for the low-energy LED lights in the ceiling of the door. In case the LED lights have used up all the stored energy, the control unit will switch to the mains supply of the building. This ensures that the door is illuminated at all times, even when passenger flow is minimal.

LED scales inside the door indicate the amount of energy that is generated. When passing through the door at a slow speed, the scale will end up in the red or orange zone, whereas a normal or fast pace pushes the scale into the green zone, indicating that significant electric energy is generated. Another LED indicator at the control unit shows when the illumination of the revolving door is powered by human energy or by the mains supply. “Human Powered Energy” stickers were applied to the revolving door to make users aware of their contribution. The total amount of energy that is generated by the revolving door is accumulated and shown on a large display inside the building.

Barring removal of the speed safety feature and having someone stand near the door cracking a whip to get patrons to move faster, a door like this isn’t going to provide energy for the entire building—just the lights for the door. However, it will help offset energy usage more than not having it would, and every little bit of energy savings counts. A calculation was made for this particular situation that indicated an energy savings of around 4,600 kWh per year—not because of the energy generated, but because the door also minimizes the transfer of heated/cooled air with the outside. Visit www.boonedam.us for more information.

Gas Giant

The Shimuzu Mega-City Pyramid is a proposed project designed to help alleviate Tokyo’s ever-growing problem with population. This project aims to place an entire city in one 3,000-foot-high structure smack in the middle of Tokyo Bay, complete with express transportation systems and everything. However, one of the many hurdles facing this project is how to power it. The answer, right now, is hydrogen fuel cells.

You’re more than likely familiar with the notion of fuel cells. But did you know that scientists are dealing with the issue of where to get the hydrogen?

While hydrogen is the universe’s most abundant element, most of the hydrogen on earth is tied up with another element—like forming water with oxygen—and separating hydrogen from its bonds with other elements isn’t easy…or cheap.

Scientists are currently looking at using pond scum (more commonly known as algae) to naturally generate hydrogen. Certain types of algae emit an enzyme called hydrogenase that can create small amounts of hydrogen gas. The trick is to introduce this enzyme into the process of photosynthesis so as to generate as much, or almost as much, hydrogen as oxygen. Right now it’s something that can be done in laboratories on a small scale, but scientists hope the process will be able to be reproduced on a massive scale.

 Algae can grow in even the harshest conditions, like deserts and in areas where there’s a lot of waste. This makes researchers hopeful that if they can get algae to produce hydrogen, that it can be used for waste remediation while also producing energy for human use.

Of course, the big problem with this is that the process itself hasn’t even been refined yet. Even if and when the process is refined, there’s still the issue of storage and transportation. Hydrogen in its natural state is combustible—very much so. As the possibility of using hydrogen as a common energy source comes closer to being a reality, we’ll still need to address the issue of human safety.

Riding the Waves

As witnessed by the 2004 Indian Ocean tsunami tragedy, enormous amounts of energy can be stored in waves. Under normal circumstances, waves are fairly consistent and regular—thereby giving them the potential as a source of energy.

Scientists and inventors have been developing devices to harness this energy for years. It was only recently, in fall 2008, that the first fully functioning commercial wave farm went online off the coast of Portugal at Aguçadoura.

Designed and built by Pelamis Wave Power for Enersis, three 465-foot-long P-1 A wave energy converters, weighing about 700 tons a piece, produce a total of 2.25 MW of electricity for about 1,500 homes during peak hours. Each wave converter consists of four articulated sections. When the waves move up and down, these four sections move too. At the hinges between sections, hydraulic rams utilize the wave motion to drive generators, producing power. This energy is transported by underwater electrical cable to the Aguçadoura substation and fed into the Portuguese national grid.

The station at Aguçadoura plans on installing an additional 25 of the carbon steel-constructed converters to bring the total power production to 21 MW.

Other wave energy converter models continue to be developed and refined by Pelamis and others.

The most glaring drawback to wave energy is what impact, if any, there will be on marine life with the installation of these systems. As of right now, there are more questions than answers and studies are being conducted by a number of organizations in the search for answers.

What is already known is that the world’s oceans can be brutal. A major hurdle in designing and constructing a wave energy converter is ensuring its longevity against the power it’s supposed to harness. Furthermore, installing and repairing systems is made costly due to the difficulty of working in coastal areas.

Persistence Pays

While necessity is the mother of invention, great ideas don’t always “just happen.” As Edison once said, “I never did anything by accident, nor did any of my inventions come by accident; they came by work.”

We hope that everyone keeps working toward a greener future.