Tuesday, September 15, 2009

The Hydrogen Challenger

A couple days ago I was cruising the internet and stumbled across something interesting: the Hydrogen Challenger.

The Hydrogen Challenger is a tanker ship that has been refitted with wind turbines and an electrolyzer to make hydrogen. The ship cruises out to the open sea where the wind blows the hardest, anchors for awhile and fills up with hydrogen, then cruises back to port and unloads the hydrogen.

At first I thought this was a weird idea cooked up by someone with too much money, or maybe another Rainbow Warrior. But at a second glance, I think it may be an idea ahead of its time. Compared to the most similar alternative, offshore wind turbines, it has several advantages.

Higher wind speeds: The best wind resources on land are about 9 m/s. A mile or two offshore, where offshore wind turbines are located, the wind blows at about 13 m/s. The Hydrogen Challenger can go further from the coast than offshore turbines, where wind speeds approach 20 m/s. The power delivered from a wind turbine increases by the wind speed cubed, so the same turbine could deliver almost four times the power if its on the Hydrogen Challenger instead of stationed offshore.

Higher Capacity Factor: A wind turbine only generates electricity when the wind blows, and when people want to buy its electricity. A lot of times, turbines generate power when it isn’t needed, such as at night, so the power is wasted. The Hydrogen Challenger stores energy in hydrogen, so the generated power is never wasted.

Storage and Markets: Unlike electricity, hydrogen can be stored in large quantities and for long periods of time. Storing energy in hydrogen allows the generator to sell power only when and where the price is highest. This means that every kWh of hydrogen energy is much more valuable than a kWh of electricity.

Transmission: Although it seems impractical to retrofit barges with wind turbines, I bet it is cheaper than running undersea electric lines to offshore power turbines. Undersea electric lines are very expensive, ranging from $20,000 - $80,000 /MW-km. Sources say transmission costs are 10% - 20% of total cost for offshore wind farms.

I think the Hydrogen Challenger is a good idea that we’ll see more of in the future, but there are some problems that will need to be addressed:

Electrolyzer cost / efficiency: Electrolyzers are expensive and inefficient (~70%).

Storage: To generate as much power as possible, the barge should stay at sea generating power as much as possible and minimize unloading trips. A barge may not have enough volume to store the amounts of hydrogen generated.

Wind Speed: Curiously, no commercial wind turbines today can handle the 20 m/s winds hydrogen barges would see…most max at 13 m/s.

Shipwreck!: The top heavy barge can't capsize in a storm.

An interesting concept. What do you think…will we see fleets of pirate turbine-barges trolling the open seas in the future?


  1. I'm now imagining Don Quixote riding a jetski

  2. I think one solution to the storage could be to make a permanent wind turbine barge and then use LNG-type tankers to bring loads of hydrogen to shore. That way you keep the turbines going all the time. But then you deprive people of the view of a giant barge of wind turbines coming to shore every once and a while.

  3. There are no transmission losses from a pipe, just pipe the gas to shore.

  4. As for "shipwreck":
    If you have enough spinning blades (and make the blades such that 1/2 spin in the opposite direction...) you get angular momentum to keep the ship very stable.

    That said, on a ship, you really can't fit too many, and the closer you pack them, the less efficient they are. (The wind blows around them all.)

    So, the far-off-shore BARGE does seem more compelling, with a smaller ship (or later, pipeline) taking the hydrogen periodically.