Hawai`i Energy Storage 3: Energy experts review the future of storage

A small group of highly educated geeks got together recently to talk about the current state of research in utility-scale energy storage systems.

This was a small conference of about 50 people, mainly chemical and mechanical engineers, but also physicists, and others. A handful were students. Twenty percent were women. The nationality list was enormous: Australia, China, Czech Republic, Germany, Holland, India, Japan, South Africa, Spain, Sweden, Thailand, and, of course, the U.S. 

 The June conference, “Massive Energy Storage for the Broader Use of Renewable Energy Sources,” was chaired by Sudhakar Neti of Lehigh University. and Trung Van Nguyen of University of Kansas. Convener Engineering Conferences International ’s technical co-sponsor was MEMC/SunEdison.

The world of energy storage is amazingly complex. The conference dealt mainly with chemical storage systems and heat storage systems, but also pumped hydroelectric power, and issues like converting solar heat into liquid fuels.

Why is storage important? Eighty-five percent of the world’s energy still comes from fossil fuels, 6 percent from hydro, 5 percent from nuclear and only 1.9 percent from renewables.

But renewables are the fastest growing category at 7 percent annually, and a lot of renewables are intermittent. Thus they need storage to be able to play a significantly larger role.

Hawai`i is on the radar for these energy folks. They know about the Hawai`i Clean Energy Initiative. They recognize that Hawai`i’s high electricity costs and dependence on oil create a special demand for renewable energy storage.

Babu Chalamala of Sun Edison, a major national solar contracting firm, said grid-scale storage was not likely to be a big player on the U.S. Mainland. Rather, it would be more likely to play a role in places with smaller, unreliable grids, and in high-cost places like Alaska, California and Hawai`i.

It’s not just Islanders who are aware of the high cost of power here. Hawai`i’s costs were mentioned more than once by the Massive Energy Storage researchers.

I would guess that when most folks think storage, they think battery, and most of those batteries are chemical batteries.  Perhaps the most common example of a standard chemical battery is lead acid—the battery in your car, and the battery most folks use who have off-grid home power systems. Or lithium-ion, the battery that's in your phone and your laptop/

But these kinds of chemical batteries aren’t the only kind of energy storage. Not by a long shot.

Another class of chemical battery is the flow battery, which differs from familiar batteries in that a liquid electrolyte doesn't just sit there like in your car battery, but is pumped through the battery. It is also different in that the energy is stored in the electrolyte, while in a standard battery the charge is stored on the electrodes.

At this conference, there was also discussion of capacitors, an energy storage device that takes a charge very quickly and discharges very quickly. These cannot normally be used to deliver energy over time like a lead-acid battery.

But there is work on hybrid capacitor systems, which use capacitors to charge an electrolyte, which then can be used for long term energy delivery. The title of a talk on this was “The Electrochemical Flow Capacitor: Grid Scale Capacitive Energy Storage.” They’re being studied at Drexel University.

And, of course, there are many kinds of energy storage that have nothing to do with chemical batteries, like compressed air, pumped hydro, solar thermal, flywheels and lots more.

The Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) grants cash to researchers that are developing entirely new ways to generate, store, and use energy.”

ARPA-E doesn’t just fund anything—it’s not a vehicle for pure basic research. Its projects are designed to have ready application. The projects need to have a “road to market.”

ARPA-E is looking for projects that develop storage at $100 per kilowatt hour, can charge and discharge at least 5,000 times, have an 80 percent roundtrip energy efficiency, are made of abundant raw materials and are recyclable.  (http://arpa-e.energy.gov)

There's nothing out there right now that meets all those requirements, but there's lots of work underway on the subject.

As this series progresses, we will doubtless be called out for not listing one or another kind of storage. We’ll plead guilty right here. The list of energy storage research areas is pages long and we won't get to all of them.

In our next section, we’ll look at a few of prominent ones that came up at the Massive Energy Storage conference.

© Jan TenBruggencate 2013

Hawai`i Energy Storage 2: Time travel and stacked services

The numbers generally don’t add up for a homeowner with a solar array to put in a big battery system and go off-grid—it’s too costly.

But it CAN make sense for utilities—largely because they can make those batteries perform far more tasks, each of which has a payback value. Stacking those services a battery performs can make a compelling argument for them.

For this second piece in a series on Hawai`i energy storage , we are relying primarily on a new industry/government report, the DOE/EPRI/NRECA Electricity Storage Handbook for 2013, which was released earlier this summer. It is available without cost here. 

The report makes the point that one of the most critical functions of a battery system is to make energy travel through time. That is, they let you collect energy at one time, and hold it for delivery at another time.

That is particularly valuable if there are times when you don’t have enough generating capacity to meet the load, or if (think solar, wind) there are energy sources whose production doesn’t coincide with when you need the power.

We won’t go into lots of detail here. You can find a much broader discussion in the 340-page report. But briefly, some of the services include:

TIME SHIFTING, LOAD SHIFTING. The energy time-travel service discussed above.

COST CONTROL. A good storage system may not only be able to shift energy from periods of periods of excess to periods of shortage, but may also be able to shift energy from periods when it’s cheap to periods when it’s expensive. (Often, these may be the same.)

COST DEFERRAL. Meeting peaks in demand with stored energy may allow you to hold off on spending new money for generation to meet those peaks. The construction of transmission and distribution equipment can also be deferred through energy storage.

CUTTING GENERATOR WEAR AND TEAR. Since many generators wear more quickly if their output needs to vary, a storage option can reduce wear by taking up the variable load while the generator operates at stable output.

SPINNING RESERVE, SUPPLEMENTAL RESERVE. This refers to using a battery as a source for quick power delivery in case of a generator failure or transmission problem. Spinning reserve is defined as that which can be delivered within 10 minutes, while supplemental reserve is electricity that can be available within an hour. Utilities often meet this need now by burning oil to keep generators hot and running without load—so they can be quickly called into service.

BLACK START. This is a term for starting up a system that has shut down entirely. Many generators need power (think pumps, blowers, etc.) to start up. You can fire up a diesel generator to power the startup of a big steam generator, or you can use stored energy to deliver that power immediately.

VOLTAGE SUPPORT, FREQUENCY RESPONSE. In being able to respond quickly to add power or remove power from the grid, some kinds of storage can provide reliability, stability and better power quality.

As discussed earlier, it might not make sense to pay for a storage system for just one of these things, but it might if you consider all the potential uses. Example: having a massive battery just to provide black start capacity might be cost prohibitive, but if that battery also allows you to shift energy through time, reduce generator wear and create spinning reserve—then it might make economic sense.

It is clear that not every storage technology is appropriate for every one of these energy services. Example: pumped hydro and compressed air energy storage are great for bulk power management, but may not be much use for frequency response. And while high-energy supercapacitors might be wonderful for maintaining power quality, they’re not so good for load shifting.

In our next segments, we’ll begin looking at some of the energy storage options that are available now, or may soon be ready.

© Jan TenBruggencate 2013

Hawai`i Energy Storage: Many storage technologies compete to back up intermittent renewables

You can’t run a 24/7 power system on intermittent renewables like wind and solar.

They won’t keep the lights on.

But the Islands are building intermittent renewables like mad, and leaving legacy fossil fuel plants to back them up. Ultimately, that’s neither sustainable nor in line with state policy.

The next few RaisingIslands posts will review how the paradigm is changing. The key to the change is the fast-moving new world of energy storage.

With appropriate storage, intermittent power becomes firm power. Oil and coal plants can go away.

Our primary sources for this series are a four-day conference on utility-scale energy storage research and a new industry/government report, the DOE/EPRI/NRECAElectricity Storage Handbook for 2013, which was released earlier this summer.

If you’re interested, you should read the report, as we’re only going to summarize pieces of it here.

As little as 10 years ago, there was very little choice available in terms of energy storage—most folks were getting by with lead-acid batteries, although there was a lot of “potential” out there for different storage technologies.

That has changed.

“Storage for frequency regulation has become fully commercial and facilities are being built to explore renewable integration, PV smoothing, peak shifting, load following and the use of storage for emergency preparedness,” wrote Imre Gyuk, of the U.S. Department of Energy’s Energy Storage Program, in the foreword to the report.

The Hawai`i Clean Energy Initiative plays a role in the story, and is cited in the report.

What quickly becomes clear when you pay attention to energy storage is that this field is dense, complex and difficult to summarize, other than to say there’s a lot going on.

Most folks think about storage and think batteries, and indeed, batteries are a key piece—perhaps the biggest piece. But they’re certainly not all of it. There is also, flywheel energy storage, compressed air energy storage (CAES), pumped hydropower, thermal storage, and hydrogen.

Each of these technologies has strengths and most also have significant weaknesses. Some are appropriate for certain applications but not for others. Balancing those features is both difficult and necessary to move forward.

There are many issues in deciding whether a new system is ready for prime time. Here are some of them, which I drew from my participation in a June conference in Newport Beach, “Massive Energy Storage for the Broader Use of Renewable Energy Sources.”

This list is largely designed to rank battery storage systems, but much of it can be applied to any storage technology.

The dream energy storage system of the future needs to be:

Made of cheap materials;

Efficient, in that you get nearly as much energy out as you put in—preferably 80 percent round-trip efficiency or better;

Safe, in that it won’t explode, leak, or otherwise endanger those in the immediate vicinity;

Have charge-discharge capacities of approaching 10,000 times;

Energy dense, so it is compact (although this is more important for mobile systems like electric car batteries than stationary utility-scale storage, it can't take up too much acreage);

Made of non-toxic compounds;

Recyclable at the end of its useful life;

Able to operate at ambient temperatures.

Oh, and it needs to be far cheaper than anything available today. The U.S. Department of Energy’s ARPA-E program is looking for batteries in the $100 per kilowatt-hour range. Most of the cheapest technologies available today are in the range of 5 to 10 times that...or more.

Can we get there? In this series we’ll take a look.

(ARPA-E stands for Advanced Research Projects Agency-Energy. It is a Department of Energy program modeled on the Department of Defense's DARPA, the Defense Advanced Research Projects Agency.)

© Jan TenBruggencate 2013

Hawai`i research: Climate change with us for seven generations, or more

University of Hawai`i researchers, after studying previous climate cycles, conclude that climate change will be with us a long, long time.

And it’s because of our persistent use of carbon-based fuels, said University of Hawaiʻi at Mānoa oceanographer Richard Zeebe in a paper in the Proceedings of the National Academy of Sciences. A press releaseon the paper is here.

(Image: Earth, from space. Credit: NASA.)

That carbon use has driven the atmospheric carbon-dioxide  index from 280 to 400 parts per million since the start of the industrial age. And that in turn will drive further warming, whose impacts will include continued melting of large ice sheets and resulting sea level rise.

Zeebe looked at the feedback in the climate system caused by such warming. There are faster feedback mechanisms like snow cover and clouds (as snow and cloud cover change, the amount of solar radiation reflected away from the planet also changes.) But there are slower feedback mechanisms as well, including impacts from changing vegetation patterns. And some of those changes could extend for centuries, he calculated

“The calculations showed that man-made climate change could be more severe and take even longer than we thought before… We need to put the impact that humans have on this planet into a historic and geologic context.” Zeebe said.

“By continuing to put these huge amounts of carbon dioxide in the atmosphere, we’re gambling with climate and the outcome is still uncertain.  The legacy of our fossil fuel burning today is a hangover that could last for tens of thousands of years, if not hundreds of thousands of years to come.”

© Jan TenBruggencate 2013

Citation: Zeebe, R. E., Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions, Proceedings of the National Academy of Sciences, 110, doi:10.1073/pnas.1222843110, Aug 05, 2013.

The story about GMO-fed pigs with stomach ailments? Not exactly what they're claiming.

Lots has been made of a report that GMO feed causes stomach inflammation in pigs.

As usual, popular accounts of the science don’t tell the whole story. If you read the study, and we did, you’ll find it doesn’t say exactly what they’re saying it says.

The study, published in the Journal of Organic Systems, is entitled “A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet.” Researcher authors are American and Australian, and include organic farming advocates, although they assert that they have no conflicts. The journal, which is Australian, is supported in part by the Organic Federation of Australia, the Australian government, and a New Zealand sustainable agriculture organization, CSAFE.

You can read the study yourself here. 

They separated 168 pigs into two equal groups, feeding some organic corn and soy, and others corn and soy that had been genetically modified for insect and/or herbicide resistance. (A few young pigs in both groups died during the 23-week trial, at rates that the authors say are standard for commercial hog production.)

The study admits that the GM-fed pigs were fed somewhat moldy feed, while the non-GM pigs received feed with less significant levels of mold. “Mycotoxin analyses (Midwest Laboratories Inc, Omaha, Nebraska, US) showed 2.08 ppb total aflatoxins and 3.0 ppm total fumonisins in a pooled sample of the GM feed and no aflatoxins and 1.2 ppm total fumonisins in a pooled sample of the non-GM feed.”

But the authors insist that this had no impact on their results: “The concentration of mycotoxins in the feed was insignificant.”

In virtually every test the researchers recount, there was no statistical difference between the two groups of pigs. They were inspected and blood was taken when they were alive, and they were autopsied once they were slaughtered.

“There were no differences between pigs fed the GM and non-GM diets for feed intake, weight gain, mortality, and routine blood biochemistry measurements,” they wrote.

The only significant difference was stomach inflammation, and even that is not nearly as clear as you’d expect, given the way the popular press has told the story.

Most of the pigs in both groups had some level of stomach inflammation, although it was not equally distributed. And in fact, 11 percent of GM-fed pigs had no stomach inflammation whatsoever, while only 5 percent of non-GM-fed pigs had no stomach inflammation at all.

Of 73 non-GM pigs, 69 had some level of stomach inflation. Of 72 GM-fed pigs, 64 had some level of stomach inflammation. The difference: in the pigs with severe inflammation of the stomachs, more tended to be GM-fed.

If you’re appalled at the presence of any stomach inflammation in pigs, know that it’s a common occurrence due to feed preparation: “The pig industry uses finely-ground feed to maximise feed efficiency which can increase inflammation and ulceration of the stomach,” the authors note.

The researchers wisely say—as researchers commonly do—that their results demand more study. What are the odds that the results would be different if you did the same study again?

But just to be clear, while their results show statistically that severe inflammation of the stomach was more common in the GM-fed pigs, it is also true that inflammation as a whole was more common in the non-GM pigs.

And it would be technically accurate, though also misleading, to write a headline that said: “Stomach inflammation in pigs higher when fed organic diet.”

© Jan TenBruggencate 2013