“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Monday, March 21, 2016

arpa-e 2016 notes part 1

Having spent six days traveling to, attending, and returning from arpa-e 2016, it's time to start chronicling some of my thoughts. At the broadest level, the summit was very well attended, much better than last year. As is typical, the demographic was predominately male, predominately Caucasian with a significant sprinkling of Indian (subcontinent type) as well as Asian attendees. There were extremely few African Americans and other "people of color" and a relatively small population of women.

It was stated by Katie Fehrenbacher, a senior writer at Fortune Magazine who focuses on energy and technology, that, at her first arpa-e summit attendance in 2010, there were many VCs (venture capitalists) whereas, in 2016, "not so much." The decline in funding for clean energy startup ventures that her comment implies has been well documented elsewhere.
Chart courtesy of: PwC.com

I'm not an expert investor but, as I implied in one of my posts on LightSail Energy and stated in my post regarding Bell Laboratories, today's investors' demands for quick returns on their investment are anathema to ventures that develop over periods of many years and require huge capital investments. Further there have been well-publicized failures of some large cleantech startups, e.g., Solyndra, Range Fuels, KiOR, A123, etc. Cleantech is HARD!

While at the opening session, I drew a little diagram on my Samsung Galaxy Note 4, a phone on which one can legitimately take handwritten notes and make such sketches. Here's the sketch I made: 

I'll concede that it's cryptic and hard to read but the idea is that the U.S. funds entrepreneurial innovations that lead to development in such a way that private equity of one sort or another sees the potential and ponies up sufficient funding to take the innovation to market. To date, arpa-e funded ventures have attracted $1.25B in private funding. To do so, it has provided $1.3B to some 475 projects. I'm unable, however, to find an arpa-e funded venture that has individually gone to market, though at least four have been purchased by large companies as of FY 2014.

I'll provide further input over the next few posts (perhaps interspersed with other topics) but I want to say that that $350M per year funding level for something as important as the goals of arpa-e is a pittance, especially in comparison to the scale of the problem. There are those who say government should stay out of such ventures and ask "what good has government investment ever done?" I'd point out Boulder (now Hoover) dam, Tennessee Valley Authority, Rural Electrification Administration, ARPANET, etc.

Sunday, February 28, 2016

Off to arpe-a 2016

Image credit: arpe-e
I'm rather shocked to find that this is the sixth (!) arpa-e energy innovation summit that I've attended. I intend to blog about my adventures here and, in particular, about some of the energy storage sessions as it's my considered opinion that storage breakthroughs are key to a sustainable energy future.

But for this post, I'm going to discuss getting to Washington, DC. I used three modes of transportation: my (new) Jeep SRT Grand Cherokee (with apologies to commenters who had suggestions for my avoidance of such a joule hog) to KSNA, i.e., John Wayne Airport; two legs of air carrier transport (KORD, O'Hare Airport was a layover); and a SuperShuttle van from DCA, i.e., Reagan National Airport to the Gaylord National Harbor Resort.

The trip to KSNA was about 18 miles, the Jeep is currently displaying an average mileage of about 15.5 m.p.g. (as stated in my previous post, I'm not driving for economy) so I burned about 1.16 gallons of premium fuel, thereby converting something like 137,000,000 joules of chemical energy to thermal energy to turn the wheels, move air out of the way, heat the atmosphere, etc. Therefore, I my rate of energy use in "joules/(passenger*meter) was about 4,730.

The leg from KSNA to KORD was in a United Airlines Boeing 737-724 aircraft featuring two CFM International CFM56 turbofan engines (of the "dash 7B24" variety). These engines are rated at 24,200 pounds thrust each. It's not easy to estimate the fuel burn for airline flights, I wish that I'd remembered to ask the Captain or First Officer, they're very cooperative to sharing such data. But, as best I can estimate, we burned around 18,000 pounds or 8,165 kilograms of fuel (fuel calculations for airplanes are typically done in pounds since aircraft weight enters into literally every aspect of every maneuver and operation) to take 118 passengers 1,818 statute miles. A kilogram of jet A fuel releases 43.5 megajoules of energy upon oxidation, and so we converted 3.55*10^11 joules of thermal energy. The plane carried its full complement of 118 passengers, and so the energy use in "joules/(passenger*meter) was about 1,040. Of the 3.55*10^11 joules converted, I was responsible for about 3 billion of 'em.

I'll spare my patient readers the detail of the KORD to KDCA leg on an Embraer 175 regional jet. I estimate that we converted 1.14*10^11 joules traveling 650 miles. This works out to about 1430 (joules/passenger*meter) for the 76 passengers on board. My allocation was about 1.5 billion of those joules.

Finally, I rode a SuperShuttle van for the approximately eight miles to complete the journey. I estimate that it burned about 0.5 gallons and converted 42,800,000 joules of chemical energy to thermal over the eight miles. My rate of energy use was thus about 3,320 joules/(passenger*meter).

My grand total of turning the energy in chemical bonds to thermal energy in the atmosphere
Image credit: PowersaveSchools.org
(and a very small amount in ground) was 4.68 billion joules. Of these, 4.5 billion or about 96% were in aircraft (I can't say "in the air" because we did taxi). But note that, of the 2,495 miles traveled, 99% were in the air. Thus, purely in terms of energy conversion, the air travel was quite efficient in comparison to ground transport. Of course, I was the solo passenger in my vehicle as I was (surprisingly) in the van, and having several passengers would change the joules/(passenger*mile) metric significantly. And, as some will no doubt point out, so would staying home.

And, so I understand (not having read enough to know why), hydrocarbons oxidized in the upper troposphere/lower stratosphere are much more damaging than those oxidized on the ground.

I'll be responsible for more joules and a greater rate of conversion when I return to Southern California on Thursday, since we'll be flying against the prevailing winds. For a round number, I'll add 20% to the eastbound total for 10.3 billion joules. It is to be hoped that I'll learn enough here to be able to participate in saving many times that number, at least, that is, from the burning of fossil fuels.

Addendum: Perhaps 10.3 billion joules has little meaning for some. This is about 2,860 kilowatt hours. The average US home uses about 2,733 kilowatt hours of electrical energy in three months.

Wednesday, February 17, 2016

The end of an era

In September of 2005, gas prices rose abruptly enough that I stopped driving as I had as a teenager in my Plymouth Roadrunner Detroit muscle car and started to do my best to squeeze every possible foot out of each gallon of gas. That was in a Jeep Grand Cherokee, which I followed up with a Land Rover and finally my current Lexus CT200h which I acquired in the summer of 2011. I've driven that vehicle in such a way that I've exceeded the EPA combined estimate of 42 m.p.g. by 8.5 m.p.g. I've done so using light touch on the pedals, attempting to maximize the vehicle's use of regenerative braking, maximizing time in traffic jams that the engine is off and motive power provided by the battery and electric motor, and a cruise controlled 55 m.p.h. maximum speed (except when converting potential energy to kinetic on long, steep downhill grades).

This blog started out as documentation of my efforts in that direction and has since grown to cover a variety of other energy related topics and even ventured into politics, economics, and philosophy at times.

But, notably, I've failed to save the world and I'm finished with this decade plus long experiment. I'll be going out this weekend to test drive and possibly drive away in a vehicle such as the Jeep SRT Grand Cherokee  or the Audi SQ5. And I have no intention of driving such a purchase so as to maximize fuel economy.

Now, was this change motivated by the steep decline in fuel prices? It was not. It's simply the case that I have had enough, the experiment has gone on long enough. I'm tired of having people run up on my rear bumper, honk, flash their high beams, etc. I'm tired of explaining to passengers why it takes me 27% longer to get anywhere. I'm tired of a car that, though it has a Lexus badge, is a Prius at heart (the passenger side seat has a pull bar to adjust position).


There you have it.

Now, does this mean that I'm also finished with blogging on energy and related topics? It most assuredly does not and I intend (though it has been said, in particular by my mother, that the road to hell is paved with good intentions) to post more regularly.

Saturday, January 09, 2016

Marco Rubio and what money can buy

bribery_bill.jpgIt should come as no surprise that Presidential candidate Marco Rubio is at the forefront of an effort to stymie local municipalities' efforts to prevent complete monopolization of broadband by Charter Cable, AT&T, and their ilk. I'm all for private enterprise but with monopoly comes a necessity for regulation.

(edited for clarity) What Rubio, et al, want to prevent is States that are beholden to carriers that currently enjoy, at worst, a near monopoly, being constrained by the FCC from legally shielding those companies from competition from local municipalities who deploy broadband networks. This sentiment is proffered under the guise of "private, competitive broadband marketplace" which, for all intents and purposes, does not exist. And, to the extent that it does, the would-be monopolists are doing all in their power (including the purchase of politicians) to stomp it out.

A further contention is the "States' rights" plea. Unpacked, what this means is Rubio, et al's insistence that States have the sovereign right to accept money from broadband monopolists who pay them to squelch local efforts to provide reliable and affordable broadband access. I hardly think that that's what the Federalist Founding Fathers had in mind.

'via Blog this'

Sunday, January 03, 2016

More green hype (though, apparently, well-intended)

Image credit: Wikipedia
It's been a while (and this isn't my first such apology) since I've posted an article. The long-awaited article (actually, articles) on the cost effectiveness of renewable energy with storage as base load and/or dispatchable electrical energy has taken a lot more time than I thought. And, of course, life intercedes. Nevertheless, lest I lose my faithful audience, I wanted to post.
Through a variety of feeds, I was led to a series of innovations by Manoj Bhargava, the founder of 5-Hour Energy (quite a few little bottles of which I've slugged down). He's committed to give away 99% (or 90%) of his (as of this writing) $4 billion dollar fortune. One venue for his philanthropy is his engineering and invention facility, called Stage 2 Innovations. Bhargava and his people have created a series of videos highlighting some of their innovations and concepts. The site is called "Billions in Change" and you can watch a 43 minute video on three of the concepts here or watch the shorter video that involves the subject of this post here
Image credit: video screen capture from "Billions in Change,"
Capture by Treehugger.com

He's encouraged his engineers to do big things, and one cited example is the "Free Electric hybrid bike." The idea is that a human peddles a mechanism (similarly to operating a recumbent bicycle) that turns a large flywheel. In turn the flywheel operates a generator which charges a battery bank. If you think that such a concept is unheard of, I invite you to look here or here or here or... well, Google is your friend. So what is special about this unit?

It certainly appears to be very well made and the large flywheel should ensure very smooth running. On the other hand, in comparison to the more standard versions linked above, it's sure to be dramatically more expensive to produce. But, if Bhargava is going to give them away, as they might say in Australia, good on him.

I do think that the claims are quite misleading though. Multiple times in multiple places, it's stated that a user can "pedal for an hour and have electricity for 24 hours." While this is, no doubt, true, it certainly won't be a lot of electricity. It's also true that much of the developing world is either completely without electricity or suffers extremely intermittent availability.

But let's think. A world class (as in, the very best in the world) cyclist can deliver about 400 watts for an hour. I strongly suspect that someone in a village in an underdeveloped country would be fortunate to deliver 150 watts for an hour. It's certainly the case that the cyclist to flywheel to generator to battery to load efficiency will be significantly less than 100%, I'll be optimistic and use 80%. So we'll have 120 watt hours available to do work. And we're going to use this energy over a 24 hour period and so our average load can be 6.25 watts. A single LED bulb with approximately the luminous intensity of a 60 watt incandescent bulb will use around 7 watts.

Now, we won't need the single bulb during the daytime or when sleeping, let's say we use it for five hours. That will use about 34 of our 120 watt hours, leaving us with 86 watt hours. We'll use some of them to charge a smart phone. A typical battery might have a capacity of 8 watt hours or so and let's assume a couple of people in the family have phones. We now have 70 watt hours remaining. Of course, it could be that we don't use our phone enough to need to charge it every day but, if we have kids and there's internet, we will.

We certainly can't use the energy for heat. While such a use is very efficient (approaching 100%) it's extremely power hungry. Let's figure that our family wants to use a Chromebook or some such to have internet access. The Samsung Chromebook battery features a 30 watt hour battery that lasts 7 hours. If we only use it for 3.5 hours per day we'll use 15 watt hours, leaving us 55 watt hours. We'll assume that the smart phone provides a wifi hotspot so that we don't need a router and some sort of IP service provider.

So, we have a single light on for five hours, two smart phones and a Chromebook and we've used over half of our stored power. We certainly won't be able to pump water, provide heat, charge a vehicle battery, etc. So, while there's no argument that 24 hours of electricity can be provided by pedaling for an hour, it's not the sort of electricity use that a denizen of a developed country thinks of. My family uses electricity at an average rate of about 2,000 watts (we're hogs though), a ratio of about 300:1.

Further, contrary to another Bhargava claim, this is not free. If we figure the human body
Image credit: unknown
operate at 20% efficiency in turning food chemical energy to mechanical energy (I think that this is high, others think that it's low) then these 150 watt hours or about 129 kilocalories (that is, food calories) will require ingesting about 650 kilocalories of food. My suspicion is that a family whose life will be changed by the ability to light a bulb for five hours, charge two phones, and use a Chromebook for 3.5 hours isn't sedentary and thus in need of exercise.

Might there be a use for the pedal powered generator/battery combination? I think that there could well be. But the idea is not original (though this application may be). Bhargava's heart would seem to be in the right place, I don't think he's charlatan. He also has innovations in health care, water purification, and to use graphene cables to draw heat from the Earth's mantle. He also funds and houses other innovators in an incubator fashion. You can't accuse him of not thinking big. In due time, I hope to look at some of his other innovations.

Update: Bhargava is interviewed about some of his innovations at CNBC. He says that the Free Electric hybrid bike can power "24 lightbulbs, a fan, a phone charger, and a tablet." He goes on to say that you can either use it all at once or store it in a battery. On the video linked in the second paragraph, someone working for him states that it can power "1050 equivalent watts of lighting." None of my physics books discusses the unit "equivalent watt" but the video shows 24 lit bulbs. A closeup reveals the labeling on the bulbs. Looking them up, they're 4 watt, 12 volt LED bulbs so we're talking about 96 watts. I'm sure that the "equivalent watt" is the conversion to the luminous intensity of incandescent bulbs. Also shown is a blowing small fan, a tablet with the display appearing to be on, and a smart phone in a charger. I'd estimate the total load of all that at something like 110 or 120 watts and so I'm confident that my discussion above does apply. They show a closeup of a digital meter that is displaying 274 but don't mention 274 of what. I assume that it's watts, and that the peddler was pushing himself at that moment.

Monday, October 26, 2015

LightSail yet again

Image courtesy of LighSail Energy
This will be a short one. LightSail Energy, a startup with innovations in compressed air energy storage, has already appeared in my writing twice, the most recent being after co-founder Danielle Fong was generous enough with her time to take me on a tour of their facility in Berkeley. In the first article I mentioned that I'd delve deeper into the thermodynamics of their process. After the second Ms. Fong mentioned that, in general, she felt that I'd been fair and accurate but that my skepticism regarding LightSail's ability to manufacture systems in the facility I visited was unfounded. Hmm... "uncalled for" is the actual quote. I'd like to take a look at both, but first the manufacturing capacity.
Image courtesy of LightSail Energy

As it happened, it turned out that I hadn't seen the whole facility. Further conversation with Ms. Fong revealed that LightSail's existing Berkeley facility does have some manufacturing capabilities and, in fact, has production runs of tanks in particular. It should be noted (and I've seen Fong tout this publicly in some of the amazingly large number of video presentations in which she's featured) that LightSail states that they have designed, prototyped, tested, and produced tanks with unprecedentedly high merit indices. These tanks can be sold for uses other than compressed air energy storage.

Further, LightSail is able to assemble, commission, and sell their compressor expanders out of their R&D facility. Thus, while LightSail is unlikely to be able to meet full scale production of their storage units at the Berkeley facility in the event that their compressed air energy storage technology takes off at the scale that the Company envisions, it's clear that they do, in fact, have significant manufacturing capabilities there. I stand corrected.

Sunday, September 27, 2015

How much storage is needed, part 4

Image credit: Unknown
My previous post in this series related some of the drawbacks of my simplistic analysis, the objectives I want to achieve, and a sketch of the methodology I've employed. Briefly, I've used a Monte Carlo simulation (yes, I linked to something other than Wikipedia, you're welcome Doctor Steve) to determine a likely outcome for generation of energy by a single hypothetical wind turbine in Dalhart, TX.

I ran 1000 simulations of 8760 data points of wind speed from what turned out to be a mixture distribution combining a normal and a Gamma distribution. This generated a total of 8,760,000 wind speeds. Each was delivered to an interpolating function generated from a digitized power curve of a 3MW nameplate capacity wind turbine. This resulted in 8,760,000 data points, each representing the average power delivered by the turbine for a hypothetical hour.

From there, finding the average power delivered was a simple process, and the result of this simulation was a mean power of 788 kW. This equates to a capacity factor of ~788*100/3000=26.3\%~. This is a surprisingly low number for the location and turbine chosen, given published figures at sites such as this that yield an implied capacity factor of 33.1%.  Further, the model estimate has no allowance for planned and unplanned maintenance outages. And, of course, the 33.1% number is ostensibly from measured data, so, as Dr. Steve might say, "who ya gonna believe, me or your lyin' eyes?"

All that said, perhaps Dalhart isn't the ideal location, perhaps the wind gradient is steeper than the model I used, perhaps they've used more highly optimized equipment, perhaps the measured year had, for some reason, particularly strong (but not too strong) winds. I'm going to proceed with my analysis based on the model data.

So, the next step is to determine the storage required for the ability to deliver a given power at, say, 99.99% reliability. That is, the system should be able to supply the specified power for all but ~8760/10000=0.876~ hours/year. This is actually less than the SAIDI*SAIFI (system average interruption duration index, measured as the average duration of outages*system average interruption frequency index, measured as the average number of outages per customer per year) and so sounds quite reasonable if not overly conservative.

One assumption will be that, when the turbine is delivering more than the power under consideration and the storage facility is "topped off," we can send the power to the grid. Another will be that, for the level of power being considered, the storage system is capable of delivering power at that level. As I've discussed in previous posts, there are two primary characteristics of an energy storage installation: the quantity of energy that the system can store; and the rate at which it can deliver that energy.

Of note, approximately 4.0% of the time, the wind is below the cut in speed of the turbine and thus all energy delivered by the system must come from storage. The modeled wind exceeded the cut out speed of the turbine a negligibly small 0.0004% of the time. But there are no black swan events in the distribution (think tornadoes).

It took me a little time to decide on an effective way to proceed, but ultimately I decided to start with a guess of storage and loop through each increment (i.e., each hour's worth) of power (since the power is in kilowatts and the increments are hours, no conversion is necessary). If the storage plus the increment minus the steady use exceeded the maximum available storage, the excess was discarded and the maximum was kept for the next iteration. If the sum was less, that was kept for the next iteration. Upon completion, determine the number of iterations at which storage was zero or less, adjust maximum storage if and as necessary and try again. Using the mean power from all of the trials, no amount of storage sufficed, but reducing it to 725kW gave me what I wanted.

And finally, the result: If our 3MW turbine plus storage system is committed to delivering 725 kilowatts and we can provide 40MWh* of storage, there's effectively zero chance of not having the committed power available. Of course, the system can deliver greater power than that when the wind blows and/or when plenty of energy is stored but committing to greater power than 725kW or installing less storage than 40MWh means that there will be times when the system cannot deliver. Obviously, installing it in an integrated grid system can offset this, but the goal here was to determine what storage will enable what level of reliable base load power for a single turbine so the result is likely to be conservative. This is a virtue in the world of engineering. Below is a chart showing the first 100,000 increments with increment number on the x-axis and energy stored on the y-axis.

One widely discussed concept in energy generation is "capacity value," a very different concept (and number) than capacity factor. Basically, this number represents how much other generating capacity can be avoided with the installation of a generator and, for wind in particular, it is typically much lower than the capacity factor. Since there are times when no wind is blowing and demand does not abate, for an unaided turbine, sufficient generating capacity must be available to meet the demand, even though it may only be used sporadically. The goal of adding storage in this analysis is to bring the capacity value of the wind turbine close to the capacity factor.

As I noted in my previous post (on another topic), most utilities are not looking for days of storage (my analysis above determined that 48 hours of storage at 24.2% of the turbine's nameplate capacity would provide that power continuously and reliably), they're looking for a few hours. And, of course, the myriad complexities of transmission constraints, demand side variability, planned and unplanned generator outages, etc. have not been considered. Others have taken some of these into account using a similar methodology (i.e., Monte Carlo simulation). None that I've found, however, incorporate storage into the analysis. If I were a professor at a research institution or an NREL researcher or, perhaps, if I worked for a turbine manufacturer or a storage technology firm, I'd implement a much more sophisticated model incorporating the above factors as well as a wind farm as opposed to a single turbine.

Next in this series (which, as readers may have noted, may be interrupted by posts on other topics) will be an analysis of the economics of such a system, or at least the beginning of such an analysis. I anticipate that the cost will be prohibitive without pricing the externalities of fossil fuel generation (i.e., without implementing a carbon tax).

*In several trials, 35MW would have sufficed with no increments less than 0, but this run had a particularly calm stretch and, even with 40MW, had 0.0088% of the increments less than 0. However, this met the criteria of 99.99% reliability at 99.9912%.