Green Tech

CAMBRIDGE, Mass.--The fledgling ocean energy industry is awash in ideas for making electricity from moving water but it is still reaching for a toehold in the commercial world.

Greentech Media last week released a summary of an ocean energy report that forecasts great potential for wave and tidal energy.

Click on the image to see a photo gallery of different wave and tidal energy machines.

(Credit: Ocean Power Delivery)

Ocean power--a resource often located near large population centers--could ultimately generate 25 percent of today's total electricity usage, said report co-author Travis Bradford, president of the Prometheus Institute for Sustainable Development.

In the next six years, electricity production from the ocean could swell from just 10 megawatts now to 1 gigawatt a year, a $500 million market.

Before ocean power becomes an economic reality, however, there are huge hurdles to overcome, including too many competing turbine designs, lengthy environmental permitting, costly installation, and, in many cases, a harsh working environment at sea.

Research in ocean energy is active, with most of it done in the U.K. There are a number of pilot projects in the works which, if completed, would total 650 megawatts of electricity production. That's roughly the size of one coal or natural gas power plant.

But charting the course from prototype to grid-connected generator has proven tricky, according to a number of speakers at an event last week hosted by the UK Trade and Investment initiative, Flagship Ventures, and Greentech Media.

"The challenges have been greater and the timelines have all slipped. It hasn't been an easy ride so far," said Andrew Mill, CEO of the U.K.'s New and Renewable Energy Center (NaREC). "Most of the devices to date haven't actually reached the water."

Many wave power machines are designed to capture the energy of the wave's motions through a bobbing buoy-like device. Another approach is a Pelamis wave generator, now being tested in Scotland and in Portugal, which transfers the motion of surface waves to a hydraulic pump connected to a generator.

Tidal power typically uses underwater spinning blades to turn a generator, similar to how a wind turbine works. Because water is far more dense than air, spinning blades can potentially be more productive than off-shore wind turbines for the same amount of space.

In addition to being renewable, another key advantage of ocean power is that it's reliable and predictable, said Daniel Englander, an analyst at Greentech Media.

Although they can't generate power on-demand like a coal-fired plant, the tides and wave movements are well understood, giving planners a good idea of energy production over the course of year.

Because it's an immature industry, ocean power is more expensive than other renewables. In the coming years, the costs are projected to go down to about the range of wind and solar today, according to Greentech Media. "But the fact that you know when the generator is going to spin gives you a lot more value," Englander said.

Wind circa 1980?
Many people consider ocean energy to be roughly at the same stage that wind power was at in early 1980s: there were a number of competing turbine and blade designs, and the cost of wind power was far higher than it is now.

As the number of ocean generator types consolidates and components become standardized--as has happened in wind power--the costs of ocean power devices should go down.

The visible portion of an underwater turbine that captures tidal energy in Port MacKenzie Inlet in Alaska.

(Credit: Ocean Renewable Power)

There has been about $500 million invested in ocean power since 2001, mostly in the form of government research and some venture capital, according to Greentech Media. That's tiny compared to wind or solar; several solar start-ups have individually raised more than that in the past year.

The report's authors predict that venture capitalists will be investing in ocean power as they seek new green-technology areas.

Big energy companies have dabbled in ocean power as well. General Electric purchased a stake in Pelamis Wave Power, while Chevron and Shell have invested in ocean companies through their venture capital arms, Englander said.

One positive sign is that ocean power appears to be developing quicker than wind, said John Cote, a vice president at General Electric's financial services arm.

"The wind industry, their Valley of Death (from product prototype to commercialization) was much longer," Cote said. "The development of standards is happening much quicker in the marine industry."

Tough sailing
But despite the optimism, life on the water is tough, according to executives at ocean power companies.

With almost no infrastructure around the industry, companies need to build a lot of their own equipment. To install and test devices, they have to hire expensive vessels, typically used for offshore drilling.

Ocean Renewable Power is testing two of its horizontal turbine design tidal machines in Maine and Alaska. It's working on a new design that uses composite materials instead of steel, which it hopes to finish by the end of year and test extensively next year.

While working in freezing temperatures and 30-mile-per-hour winds in the Bay of Fundy off the Maine coast, it found that "everything that can go wrong, will go wrong," said Ocean Renewable Power CEO Chris Sauer.

Most of the failures were related to weather and marine conditions and equipment problems. "As a start-up, we have to make our own instrumentation systems put together on the cheap," he said.

Wavebob's wave-power machine. Bobbing devices that convert wave motion to electricity are one of the most common designs.

(Credit: Wavebob)

New York City's East River, meanwhile, is the test site for another tidal power installation being led Verdant Power, which makes underwater turbines that get energy from changing currents.

In the space of three weeks, all six turbines being tested failed the same way--a mechanical problem in the connections point between the blade and hubs, said Ronald Smith, Verdant Power's CEO.

But the biggest hurdles with the project has been environmental concerns, he said

Regulators want to make sure that fish, or other marine life, will not be killed in the blades. The company has equipped its devices with acoustic and other sonar devices to gather data for regulators, Smith said.

Another big potential cost for ocean power devices is operations and maintenance. Simply getting vessels--and staff--to service machines can be expensive, making the "survivability" of ocean energy gear a top priority.

Executives at the panel predicted that ocean power installations in the future will be several units, rather than one large device. For example, Ocean Renewable Power's 250-kilowatt modules can be stacked on top of them other, so if one machine fails, the entire operation isn't taken offline.

Even relatively successful companies--like Wavebob, which is set to build a 250-megawatt ocean power installation in Ireland--are doing software simulations, environmental reviews, and additional engineering to increase the odds of success.

"We're stopping on the edge of commercialization and taking two steps backward," Derek Robertson, the general manager of the company's North American business. "We're investing in detailed operations and systems engineering process to retire risk."

Google sees the future of computing at sea.

The search giant has filed a patent for a "floating data center" that uses wave motion to power on-board computers and the ocean's water to cool them.

The patent was submitted in February last year but was spotted in the U.S. Patent & Trademark office's electronic filings and posted at Slashdot on Saturday.

The system Google engineers sketch out is a self-powered data center placed three to seven miles offshore, potentially operating off the grid. Standard shipping containers would house racks of computers that could be transported by truck and placed onto a boat by crane.

Full steam ahead! An image from Google's patent application for a floating data center that uses wave and tidal power generators.

(Credit: Google)

A wave-power generator would be the primary source of electricity. But wind turbines could be used to, for example, run water pumps and a tidal power generator could be used in rivers.

The patent specifies the use of a so-called Pelamis machine, which uses pontoons with pumps to convert wave motion into electricity. A British company, Pelamis Wave Power, is operating a prototype in Scotland and intends to install one off Portugal.

Google engineers calculate that an array of pontoons spread over a square kilometer (a bit more than a half mile) could produce 30 megawatts of electricity, enough to operate a single system.

Also envisioned is equipment to use the direct current electricity to run DC-capable computers, which some people consider more energy-efficient than using alternating current.

Server makers and data center operators are already circulating water to cool computing gear. Google's patent application envisions using the ocean to act as a giant heat sink, cooling computers through seawater-freshwater heat exchangers.

For the crew and operating staff, there could be living quarters and, potentially, a helipad to get there.

Seeking fortunes at sea
With the rising cost of electricity and concerns over the environment, getting cheaper and cleaner forms of electricity is a big concern for data center operators.

Google argues that floating data centers offer other advantages, such as placing computing closer to consumers, cutting down on transmission distances.

"Also, transient needs for computing power may arise in a particular area. For example, a military presence may be needed in an area, a natural disaster may bring a need for computing or telecommunication presence in an area until the natural infrastructure can be repaired or rebuilt," according to the patent application.

Google is not the only company to envision modular, container-based data centers or even floating data centers.

A San Francisco company, International Data Security (IDS), plans to pack discarded cargo ships with computing equipment.

The company intends to have its data center ships placed near urban centers and have one operating by the third quarter of this year.

According an IDS company blog, the primary motivation for IDS's floating data center is the higher cost of building a land-based facility, the resistance to earthquakes and other natural disasters, and the potential to tap water cooling.

"It seems (Google's) plan is slightly different than IDS; IDS floating data centers will be anchored in port the majority of the time, whereas Google's will be positioned out at sea," according to a company blog post on Saturday.

The financial model of operating a data center at sea may be the most clever aspect to the patent application, argues Larry Dignan, editor-in-chief at ZDNet. In theory, a floating data center would not have to pay any property taxes, he said.

Rich Miller at Data Center Knowledge said the Google plan could invoke different legal definitions of territory boundaries.

"The offshore location also raises interesting questions about jurisdiction, and which laws would govern the handling of any consumer data managed from the floating data centers. U.S. territorial waters typically extend 12 nautical miles, but other nations' claims range from 3 miles (Singapore) to 200 miles," he wrote.

There are a growing number of designs being floated to make electricity from the sea. But the Seadog Pump may get the prize for the simplest.

Wave- or tidal-power devices use underwater turbines or buoys to convert the motion of the ocean's water into electricity.

A source of electricity? Click on the image to see installation of the Seadog Pump in the Gulf of Mexico last year.

(Credit: Independent Natural Resources)

The Seadog Pump from Independent Natural Resources in Minnesota just focuses on pumping water.

A floating station uses wave motion to drive a piston that pumps water through an exhaust pipe. That water is collected and then passed through standard turbines to make electricity when needed, returning the water to its source.

A schematic of how the Seadog Pump works to pump water, which is stored and then passed through a turbine to make electricity.

(Credit: Independent Natural Resources)

The company last week said that Texas A&M University at Galveston's Marine Engineering Technology Department had evaluated a demonstration machine in the Gulf of Mexico. The university found that the Seadog Pump was able to convert 22 percent of ocean wave energy into usable energy.

Independent Natural Resources is looking to test the system for generating power for electrical utilities or for desalination. Water treatment and pumping are very energy-intensive.

The company says the simplicity of design will make it cheaper to scale up.

It uses readily available parts and no electronics, making it more durable in salt water.

"We are planning our first commercial demonstration facility by year-end 2008 or first-quarter 2009, and have already applied for permitting through the required regulatory agencies," said Doug Sandberg, a company vice president.

Independent Natural Resources plans to have an 18-pump field in the Gulf of Mexico used to desalinate seawater.

Ocean power is, for the most part, experimental technology. One company called Marine Current Technologies is expecting to commission a 1.2-megawatt installation in Ireland in the coming months.

There are a number of other tests taking place. But there's a great deal of potential: experts estimate that wave and tidal power could generate gigawatts of electricity within 10 years, enough to power millions of U.S. homes.

Hydro Green Energy, which wants to plumb America's waterways for electricity, has received $2.6 million in funding.

The company wants to create somewhat small, modular turbines and then set them down in arrays in waterways. Each turbine would be capable of harvesting 250 kilowatts of power. The size of the array would then depend on the size and power of the waterway.

It hopes to plant these arrays in Minnesota, Louisiana, Mississippi, and other states.

Many other companies, such as Ireland's OpenHydro, are building large machines that look like oil derricks for harvesting power. These larger machines go in the ocean.

Tidal power has a number of advantages over other renewables. For one thing, it's predictable. Computer simulations can calculate the amount of electricity that can be generated from tides decades in advance. Besides being predictable, tides are also constant, unlike wind or solar.

The bad part? It's still experimental. Most companies haven't even tested out full-scale prototypes yet. These machines will also have to survive in harsh, unpredictable environments. The impact on fishing fleets and marine life is also unknown. Commercial tidal power, however, should begin to start in a few years and will likely hit before commercial wave power, according to some experts.

Here's one interesting tidbit: The Quercus Trust was the lead investor. Quercus is also an investor in LiveFuels, which wants to make fuel out of algae, and some unusual lighting projects. It's one of those investment outfits that swings for the fences.