Friday, January 14, 2011


Blowhole Energy

by Henry Curtis

Some wave systems operate underwater. Others wiggle on the surface. Some use toxic substances. Many have broken down in the water. Get all of that out of your mind. Let us talk blowhole energy.

A traditional blowhole is a cave along the ocean with a hole in its roof. When a wave reaches the shore its fills the cave with water and a water column is shot out of the hole. This is, in non-legalese, a land-based water-shooting blowhole.

By contrast, if the cave does not fill with water, an air column can shoot out of the hole. This could be called a land-based air-shooting blowhole.

Offshore ocean-based platforms have similar phenomena.

Picture any partially submerged container with the open end facing the oncoming waves. It could be a paper bag, a box, a container. As a swell arrives the water level in the container rises, as the swell recedes the water level falls.

Picture a small hole in the roof of the container, at the end away from the incoming swell. With each swell an air or water column is pushed out and then sucked back into the hole in the roof. A propeller is placed just above the opening. As the air or water races by the propeller the propeller spins creating electricity.

These could be called ocean-based air-shooting blowholes and ocean-based water-shooting blowholes.

An Australian mathematician figured out how to spin the propeller in the same direction regardless of which way the air column is moving (in or out). This increases the efficiency of the unit. This is also simple. The center of the propeller is solid and there are small spokes or toggles on the side. They move as wind hits them. So the center always spins in the same direction and the paddles on the edge move back and forth to allow wind pushing on them to pass by.

A fancy name for a variable height water column is an oscillating water column. An oscillating water column energy conversion system has only a single moving part. For air-shooting blowholes the moving part is above the water line. For water-shooting blowholes the moving part is sometimes above the water line. There are no oils, no toxics, and no contaminants.

The system has been commercially tested off Australia, and will be built off Maui. The Maui system will be a single small unit since the utility can accept small but not large proposals outside of the new Public Utilities Commission approved competitive bidding process.

Dr. Tom Denniss and his company Oceanlinx (formerly Energetech) has won numerous awards. It was a Top Ten finisher in 2006 for the International Academy of Science's Outstanding Technology of the Year. European Venture Capitalists has found that it is the most cost effective wave energy system in the world. The Electric Power Research Institute (EPRI) found that O`ahu-based wave energy conversion systems could provide 100% of O`ahu’s energy needs.

The blowhole energy systems can produce net power (after accounting for the power to run the system) with a six inch ocean swell.

The physical structure rises about 30 feet above sea level.

Each unit can produce 2MW of power. A field of several units located 3 miles off the coast could be tied to the grid with a single undersea transmission line. The use of horizontal directional drilling would allow the line to be built below the beach and coral reefs, and then to rest on the bottom of the ocean the rest of the way to the wave energy system.

The system can be built in Hawai`i rather than imported, thus increasing the number of local jobs.

The location of the proposed unit is about half a mile offshore from and east of Pauwela Point Lighthouse. The transmission line would come ashore at Kuiaha Bay (Shark Bay).

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Henry Curtis



Sounds interesting. I will take that into consideration for our community of Waimanalo to discuss.

RKawehi Kanui

Hi - I have never looked into energy workings before, but tonight on the news, there was a discussion about wind turbines killing 80 bald eagles a yr, which in cost of fines for killing them, come out to $10,000 a bird/ $800,000 a yr. It never came to my mind that of course wind turbines would smack and kill bird as they would try to fly near the turbine -- anyways, so I've been looking online for innovative energy makers and came across your site. My actual search in google was "blowhole energy"! Right now California is looking for some ideas in how to fix the wind turbine problem, and I think you have a beautiful solution. Obviously, if it can be set up in a beautiful place like hawaii and not take away too much from the aestethics, then California can undergo the same thing. There are natural blowholes all over, but I wonder if making more of them to provide more energy makers would hurt the environment at all? :) I hope the use of blowhole energy and other natural every day occuring energy resources and be explored and used, it really makes a whole lot more sense then the ecologically damaging energy makers we have wordwide right now.

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