Archive for Hydrogen

Transport Fuels and Solar Technologies: Bird’s Eye View

For my last couple AltEnergyStocks Columns, I’ve been taking a step back and looking at how we can get an understanding of the broad trends of energy technologies. Last week, I added to the Visual comparison of Electricity Generation Technologies I did last spring with a new Visual Comparison of Transport Fuels.

Following up, today I published a look at the varius solar technologies through the lens of their applications.

Before we go back to looking at trees, I hope you enjoy this look at the forest.

(and don’t miss the National Tour of Solar Homes next Saturday)

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Canadian RE picks

There’s a good rundown of public Candian Renewable energy companies in the Globe and Mail today by Richard Blackwell.  They mention all of my favorite Canadian companies, and even one I had not yet heard about.logo

One note, there are several Canadian Income Trusts listed.  These are currently very volatile because of changes in thier tax status.  The extra volatility will undoubtedly lead to some excellent buying opportunities, but they are much more volatile than your standard income investor is probably ready for.  Where once I might have bought them for my more conservative clients, now I’m looking at them for my more aggressive clients.

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The Gust Ceiling: How much wind is too much?

On Dec 13, the Midwest Wind Integration Study, (see article) which was required by the Minnesota legislature in 2005 to evaluate reliability and other impacts of higher levels of wind generation and carried out independently by EnerNex Corporation and WindLogics, found that the total integration cost for up to 25% wind energy delivered to all Minnesota customers is less than one-half cent ($0.0045 cents) per kWh of wind generation.  Great news, but it’s a little bit anticlimactic (as well as “anti-climatic change”) compared to the announcement on Dec 5 that Denmark plans to increase wind powerfrom 20% today to over 50% by 2025.  (All penetration rates are given as percentage of power supplied, as opposed to nameplate capacity, a measure which would make wind penetration rates seem even higher.)

That’s not to say this report is a total yawn.  First, Europe has a much more robust electric grid than the US (as the Northeast found out in 2003), and the fact that the study was sanctioned by a government body, rather than a renewable energy or environmental group gives it added weight.  Finally, by using extensive simulation, they came up with some relatively hard numbers on what it would cost to reach various levels of penetration.

 The study concludes that the total integration operating cost for up to 25%wind energy delivered to Minnesota customers is less than $4.50 per MWh of wind generation, or less than 1/2 of 1 cent per kWh.  Put another way, this is less than 10% of the average cost per kWh of wind energy.

As I alluded to before, when talking about Europe, we need to be careful when we generalize from one utility grid to another as to the costs of integration: Europe’s grid is not the same as America’s, and Colorado’s grid is not the same as Minnesota’s.  Costs for integrating wind into Colorado’s grid are likely to be higher than in Minnesota, because we are behind the rest of the country in terms of how robust and well integrated our grid is to the rest of the country.  Because of the limitations of out grid, all of the major wind farms now in Colorado or under construction have had to be scaled back.

 Nevertheless, the study is great ground for hope.  Colorado desperately needs to upgrade our transmission anyway, and the Minnesota study only takes advantage of one of the many possibile strategies that helps firm up the capacity factor of wind: geographical diversification: “the wind is always blowing somewhere.”

Other strategies not considered:

  • Time of use pricing, which can be used to shift demand to times when the wind is blowing.
  • Plug in Hybrids, which can be programmed to be charged when power is cheap, or even supply peaking capacity to the grid.
  • Energy storage, such as the Wind-to-Hydrogen project recently unveiled at NREL’s Wind Technology Center (in partnership with Xcel Energy.)  One interesting aspect of this project that did not make most of the articles on the center is that they are experimenting with directly connecting the wind turbine to the electrolyzer, without the intermediate step of a transformer which has to be used to convert the wild AC power from a wind turbine the regulated AC power used by the grid. 

In short, I see 25% as a good start, but given that wind power has already shown itself to be cheap, safe for the environment (despite claims to the contrary, wind kills far fewer birds than coal; just ask the Audobon society), and is proving much easier to integrate into the grid than skeptics imagine, we need to start thinking like Denmark, and aim for numbers much higher than 25%.  It will take creative thinking, and serious investment not only in wind farms, but also in our grid, and even behavioral changes on the part of consumers. 

The small sacrifices we will need to make in terms of our behavior to get large penetrations of wind onto the grid, such as checking our time of use meter before we start the dishwasher or dryer, are much smaller, in my mind, than the giant sacrifices we are currently making to coal fired generation in terms of the effects of pollution and global warming on ourselves and our children.  We just don’t see the current sacrifices, because we have become used to the death from a thousand cuts in the form of mercury and other pollutants, and the incremental year on year warming of our planet, lost in the noise of large local and seasonal variations.

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Large Scale Electricity Storage.

One of the biggest barriers to the adoption of wind and solar electricity generation is the lack of storage technology with the capacity to handle the hundreds or megawatt hours necessary.    

Large scale electricity storage technology also allows utilities to flatten their demand, and defer construction of expensive new generation. 

Here’s a quick rundown of some of the technologies vying to meet this need.  Most of this is information is drawn from the Electricity Storage Association website.

Technology

Description

Comments

$/kWh; efficiency

Investment opportunities?

Pumped Hydro: Reservoir to Reservoir

Energy is stored by pumping water from a low reservoir to a higher one, and recovered by running the water back out through a turbine.  This system can be easily retrofitted into existing reservoirs, but has limitations due to water regulations.  First used in 1890.

The cheapest and most developed technology, pumped hydro is nevertheless limited by the availability of suitable sites.

$3-$50 per kWh;

70% to 85%

The major supplier in the business is private.  Could look for opportunities in utilities that have good potential projects.

Compressed Air Storage (CAES)

Energy stored by compressing air into large underground caverns.  Air combined with natural gas on exit and burned in turbine.  The gas compensates for the cooling as air decompresses. 

Gas used is about 40% of the amount used in comparable peaking turbine.  First built in 1978.

70% to 80% efficient; $30-$100 per kWh

 

Underground Pumped Hydro

As above, but water is pumped between an aquifer and an above ground reservoir.

More sites available, developing application.  Might have some water quality issues.

Costs Low

75% to 85% expected efficiency.

Small turbine/pump makers.

Polysulfide Bromide battery

A regenerative fuel cell based battery technology (aka “Flow Battery.)  Seems have run into difficulties due to the toxicity of the chemicals involved.  

15 MW demonstration project in 2003; more recent projects canceled.

75%, unknown cost;

Regenysis, the owner of this technology, was a subsidiary of
Germany’s RWE.  No recent activity; the program may have been wound down.

Molten Sodium-Sulfur (NaS) Battery

Molten battery technology.  “Safety concerns addressed in

30 sites in
Japan, mostly for peak shaving.  Largest is 6 MW for
Tokyo electric

Cost “High” compares to BrS and hydro/ CAES.

NGK, Japanese power equipment supplier focused.  Can be bought by US investors on the Pink Sheets NGKIF.PK

Regenerative Fuel Cell (Hydrogen)

Fuel cells can be run in reverse for electrolysis, with the hydrogen stored in large tanks.

First pilot project 2004

“much less” than 80%

Fuel cell manufactures: Ballard, FCEL, and others.

All these technologies except hydrogen are dealt with very well on the Electricity Storage Association site.  They have some great technology comparison graphs which deal with a lot more variables than I have here in their technology comparison section.

Cost Comparisions

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Efficiency/Quality Comparisons:

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Of these technologies, Pumped Hydro and CAES are the only ones ready for near term, large scale deployment (with NaS and Flow Batteries applicable in some markets highly constrained markets.)

The major downside for pumped hydro is siting, part of which problem can be solved with the smaller scale reservoir to aquifer option.   For CAES, the downside is the need to use gas to run the turbine, albeit a very efficient one.  One option might be to substitute for the natural gas used in CAES with hydrogen from electrolysis, allowing the system to work at locations remote from natural gas supply, and, for wind energy storage systems, be 100% renewable.

 10/20/06- Article about a flow battery from VRB power systems for an Irish wind farm.

8/5/07: Here’s an article I just wrote about two potential investments in utility scale electricity storage.

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John Turner’s Renewable Energy Future; renewable technologies compared.

When you want an informed, but unbiased opinion, it’s usually best to ask someone John A Turnerwhose livelihood does not depend on coming back with the “right” answer.  When it comes to comparing different renewable energy technologies, one of the best experts I’ve heard from is John Turner.   Dr. Turner is a principal scientist for the Center for Electric & Hydrogen Technologies & Systems at the National Renewable Energy Laboratory (NREL), in Golden, Colorado.

The Hydrogen economy is that long hoped for world in which one day our cars will fill up at the corner hydrogen station, and combine that fuel with oxygen in the air, a process which will create electricity for the car’s motor, and with the only emissions being water.  It all sounds wonderful, but to reach that nirvana of zero emissions, the hydrogen itself needs to be produced with non-emitting technology.  That is because, contrary to oversimplified hype from politicians, hydrogen is not an energy source, but rather an energy carrier.  Like a battery, it has to be produced (charged) before it can be used.

Dr. Turner’s goal is to guide us to the hydrogen economy with as few missteps as possible, with missteps in his mind being the used of unsustainable technologies to get there.  Since he wrote his visionary 1999 article in Science, outlining a path to a “Renewable Energy Future” in which hydrogen serves as portable energy storage for an economy fueled solely by renewable sources of power.  The weak link in this chain is fuel cell technology.  Fuel cells are used to efficiently convert hydrogen and oxygen to electricity and water.  They have been around for well over a century, but are still too expensive for use in cars, although they are practical in some military and larger scale civilian operations.  A similar problem exists for hydrogen storage.

In contrast, hydrogen as a storage medium for electricity from intermittent power sources such as wind is a technology whose time has come. Norsk Hydro is currently doing a trial run of a wind/hydrogen combination system on a small Norwegian island, powering 10 homes.

What is most interesting to me about his presentation, is his unbiased comparison of different renewable technologies, along with nuclear, and Internal Gasification Coal Combustion (IGCC) with carbon sequestration.

He compares these technologies for robustness: the ability to meet our future energy needs; for expense, and for Energy Payback.  Energy payback and the related measure EREOI (Energy Return on Energy Invested) give us an idea of how much of our energy will have to be devoted to making more energy.

Here’s the run-down (with some additions of my own):

Technology

Energy Payback/ EROEI Robust? Price per kWh (approximate 2003 prices) Long term?
Wind

3-4 months; 20-30x

Yes

5-8 cents

Yes

Solar PV

3-4 years; 8x

Very

21-24 cents

Yes

Concentrating Solar

5 months; 40x

Very

8 cents

Yes

Biomass

varies

No

7 cents

Yes

Geothermal

varies by source

No

4-7 cents

Yes

Nuclear

1 year, not counting waste disposal. <20x

Yes

13-18 cents

?

Coal (w/ carbon sequestration)

16% of energy required for sequestration.

For now

5-6 cents

70 yrs, at current growth rates.

Energy efficiency

months; 50x +

Can never get all energy from efficiency

1-2 cents

Yes

(Items with links are from linked sources)

We’ll need all these energy sources, but Wind and concentrating Solar (CSP) stand out as near-term, robust, economical solutions, while Energy Efficiency and Geothermal will give us the most bang for our buck as we try to get started down the road.

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