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Xcel and NREL Unveil Wind2H2 Project

Wind2h2
The Wind2H2 project. Click to enlarge.

Xcel Energy and the US Department of Energy’s National Renewable Energy Laboratory (NREL) unveiled a pilot facility that uses electricity from wind turbines to power electrolyzers to produce hydrogen, which is then compressed and stored at 3,500 psi.

The Wind2H2 project is designed to examine the system integration issues with wind-hydrogen production, compression, storage, and use. The project integrates wind turbines directly to the electrolyzers testing both AC and DC connections. The hydrogen is used to power a Hydrogen Engine Center (HEC) genset. (Earlier post.) A hydrogen fueling station for vehicles is planned for the future.

Today we begin using our cleanest source of electricity—wind power—to create the perfect fuel: hydrogen. Converting wind energy to hydrogen means that it doesn’t matter when the wind blows since its energy can be stored on-site in the form of hydrogen.

By marrying wind turbines to hydrogen production, we create a synergy that systematically reduces the drawbacks of each. Intermittent wind power is converted to a stored fuel that can be used anytime, while at the same time offering a totally climate-friendly way to retrieve hydrogen, to power our homes and possibly cars in the future.

—Richard Kelly, Xcel Energy chairman, president and CEO

Currently, there are limitations to both wind power and hydrogen. Wind farms only generate electricity when the wind is blowing, which is about one-third of the time in the United States. This creates the need for backup generation, which is usually fossil-fueled. Hydrogen production currently relies on the reforming of natural gas, or on electrolysis of water—energy-intensive processes that result in greenhouse gas emissions (depending on the source of the electricity).

NREL assessed the economics of wind-powered hydrogen production and concluded that while the near-term cost is around $4.03 per kg of hydrogen, long-term costs could drop down to $2.33/kg hydrogen.

NREL also concluded that it would be feasible to produce 154 billion kg of hydrogen per year from Class 4 and higher wind in the United States. Current transportation fuel usage is around 140 billion gallons per year.

The project allows our researchers to compare different types of electrolyzers and work on increasing the efficiency of a wind to hydrogen system. And, it has the potential to point the way to a completely emissions-free system of making, storing and using energy.

—Dan Arvizu, NREL director

NREL and Xcel Energy expect to offer a public update on the operation of the project around the middle of 2007. Results will also be shared with the Hydrogen Utility Group, made up of Xcel Energy and nine other utility companies interested in hydrogen’s future role in the utility industry.

The Xcel-NREL Wind2H2 project is one of several projects in the US sponsored by the DOE to investigate the combination of wind power and hydrogen production. (Earlier post.)

Resources:

Comments

SJC

Some would say the best use for wind or solar electric is to put it on the grid. However, time shifting the energy can be done with pumped hydro, flywheels, batteries or other methods. This should quantify the electrolyzer efficiencies. It is my understanding that they can be efficient, if run at an optimum level.

Thomas Pedersen

I am all for using wind power to produce hydrogen for industrial purposes. Let's replace all the natural gas we can.

However, I do not see hydrogen as the miracle that solves the problem of intermittency of renewable resources. The efficiency is just too low (google Ulf Bossel if you want more info). Furthermore, from the schematic it appears that power above the capacity of the electrolyzers is fed to the grid. If that is true, they have only increased the variability of wind power on the grid, which is exactly the opposite from what they set out to do. I have heard from other sources that electrolyzers do not work well with strong variations in power. From a peak-smoothing point of view, the electrolyzers should only run when there is surplus power on the grid, irrespective of wind output.

I still maintain that it is much better to organize power consumption such that non-essential consumers switch of when the price is high. By non-essential I mean PHEVs, freezers that are cold enough, air-conditioning (cold enough), water heaters, etc. All it takes is minute-by-minute metering and prices of electricity and appliances that switch of automatically would become price competitive.

t

Yes. Feed all the electricity that is available from wind into the grid first. If there is power available but no call from the grid, then backup the power. However, wind is providing a very small proportion of the power that the grid requires. Therefore, could someone please explain why backup is needed. Backup might be needed if wind became a high percentage of the grid. But I don't see this happening in the U.S. for decades, if ever.

SJC

NREL assessed the economics of wind-powered hydrogen production and concluded that while the near-term cost is around $4.03 per kg of hydrogen, long-term costs could drop down to $2.33/kg hydrogen.

NREL also concluded that it would be feasible to produce 154 billion kg of hydrogen per year from Class 4 and higher wind in the United States. Current transportation fuel usage is around 140 billion gallons per year.

What they seem to be implying is that the hydrogen highway would be lined with windmills. I do not see that likely to happen.

DS

Hydrogen is still the "Darling Child" of Greenwashing.
Flywheel storage can address this issue today.

http://www.greencarcongress.com/2006/11/beacon_power_re.html

SJC

I wonder if the price per kg includes selling the oxygen. It would have been good if they had used a fuel cell or better yet, a reversible PEM.

netscrooge

Vanadium redox flow batteries already provide about 75% round trip efficiency (much better than flywheels that idle for any length of time). I doubt any hydrogen electrolyzer /compressor / fuel cell can get anywhere near that.

http://en.wikipedia.org/wiki/Vanadium_redox_battery

SJC

I think you are right. Even if the hydrogen can be created and compressed with 80% efficiency and the electricity can be generated with an SOFC and turbine at 60% efficiency, that would be .8 x .6 = .48
I look at this as between batteries and pumped hydro. Even though pumped hydro is more than 70% efficient, it is hard to find suitable terrain and can not scaled down easily. Batteries may be more efficient, but can not be scaled up for cost and replacement reasons. As far as the hydrogen highway, we will see.

allen_z

Rise of the humongo battery...or capacitor. Alternatively, ther could be a large number of battery sites to go with all the wind farms.

allen_z

The only upside to H2 production is for chemicals.

Roger Pham

Most economical usage of wind electricity is to provide backup power generation by means of diesel (or H2-ICE)generators for local heat and electricity co-generation.
Many smaller units of diesel (or Hydrogen-ICE) generators can be turned on or off rapidly in response to varying in wind electrical output without shortening durability unlike gas turbine power plants that will experience shortened life span with frequent shut-down or power down.
Diesel with efficiency 42% or higher with turbocompounding, and H2-ICE with efficiency of 45-50% can compete with even combine-cycle gas-steam turbine power plants because the smaller distributed generation genset provide 110-220 volts directly at the site of consumption. This can avoid the 8-10% loss from the use of power transformers to step up and step down the voltage for long-distance power transmission, with some line losses as well.

Now then, if you wanna make transportation-grade fuel (H2) from wind, nothing can beat high-temp electrolysis with electrical efficiency of 140-150%. The high-temp heat greatly reduce the electrical power input, thus making electrical efficiency greater than unity. The source of heat can come from the free heat of stand-alone gas turbine power plants.
Thus, 1.5 x .6 (from SOFC) = .9, or 90% efficiency wind electricity to H2 and then electricity again. No other energy storage device can beat that!

SJC

How about high grade concentrated solar thermal heat. A dish than can generate 1000C along with an SOFC electrolyzer should make that hydrogen highway real smooth :)

netscrooge

Roger, I'm having trouble understanding "1.5 x .6 (from SOFC) = .9, or 90% efficiency..." Could you elaborate? Maybe you could provide some references too? It sounds like you're assuming "free" heat from some other source. If so, that's not a fair comparison.

I still think the flow battery is currently the best solution for leveling the power flow from solar and wind. Allen has a good point, though. It might make sense to produce H2 if there is a goal other than generating electricity.

steve g

You are all missing the boat here. The real use for wind h2 is in to the Fischer-Tropisch process. Wind h2 in conjunction with co2 from coal fired production plants can be combined to make affordable high quality fuel. The bonus is that it is a 100% co2 neutral process. It consumes the same amount of co2 as it produces. No need for fuel cells, transmission lines, new engines or fuel transportation systems. F-T fuels will run in any diesel or jet engine made today. When co2 credits are used the fuel can be produced for under $2 a gallon
http://www.greencarcongress.com/2006/03/a_proposal_for_.html

SJC

If you are using CO2 from coal, it is not CO2 neutral, you are just using the CO2 twice. If you used the CO2 from ethanol fermentation, it would be CO2 neutral, because the plant absorbed the CO2 as it grew.

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