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Five Energy Companies Disrupting the Status Quo

The views expressed are those of the author and are not necessarily those of Scientific American.

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This month, five energy companies joined CNBC’s “Disruptor 50″ list. Their inclusion illuminates an interesting trend in the energy sector – a push for Negawatts before Megawatts. Overall, four of the five companies included in CNBC’s list of energy disruptors focus a significant portion of their work on energy efficiency. They also reveal how companies (big and small) are increasingly able to use modern data resources to increase energy system efficiency.

Included in the list were LightSail Energy, MicroSeismic, Nest Labs (of the Nest thermostat), Opower, and Picarro. According to CNBC, “in a battle between wildcatters in the shale boom and renewable energy dreamers, [these] five companies are uniquely positioned to influence the future of the energy market and climate policy.”

1. LightSail Energy – This company’s technology stores heat energy using compressed air, which can improve energy system efficiency and increase the economic integration of renewable power generation with system optimization. LightSail Energy was founded in 2009 by Forbes 30-under-30 Danielle Fong, Steve Crane, and Ed Berlin.

2. MicroSeismic – Targeting another vein in energy system operation optimization, this company is focuses on improving how the world identifies and accesses natural gas and oil resources. According to the company’s CEO and founder Peter Duncan “Before MicroSeismic’s PSET seismic imaging technology, no one believed it was possible to detect the energy release equivalent of a human heartbeat through 10,000 feet of rock. Not only does the technique work, it has opened new ways for operators to improve their oil recovery previously not possible.”***

3. Nest Labs: The “Nest Learning Thermostat” is designed to learn behavioral patterns, which allows it to personalize a home’s temperature control. The goal is to maximize energy efficiency while maintaining comfort. [Note: Plugged In's David Wogan has written a few posts about his personal experiences with the Nest thermostat]

4. Opower: Taking the saying “knowledge is power” to heart, this company links consumers with their energy consumption data through innovative software. Their platform allows for increased efficiency and demand response capabilities.  To date, this company reports that their work has resulted in more than 2.4 TWh of energy. Today the company has expanded to more than 350 employees and works with approximately 80 utilities to increase the energy efficiency of 15 million homes. Last year, Opower was featured on Earth Day in “Green at Google.”

5. Picarro: This company’s vehicle-mounted gas measurement systems allow for the measurement and tracking of fossil fuel emissions. The Picarro Surveyor is reported to be 1,000 times more sensitive than traditional methods for detecting natural gas leaks. Founded in 1998, this company has realized 115% five-year compound annual growth rate and is expected to reach profitability in 2013.

Photo Credit: Featured photo by tedytan and used under this Creative Commons license.

*** May 30, 2013 – this post was originally published with this video for MicroSeismic

Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. phalaris 12:57 am 05/27/2013

    These companies may be challenging the status quo, but whether they disrupt it will have to be seen.

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  2. 2. Carlyle 4:47 am 05/27/2013

    They all look interesting but LightSail Energy has the most difficult challenge I suspect. The vast quantities that have to be compressed & stored to be worthwhile, without losing the contained heat energy that they plan to capture & re infuse when discharging the compressed air, I think will be overwhelming. Perhaps cavernous underground reservoirs in hot ground but you don’t find those conditions everywhere.

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  3. 3. rkipling 11:18 am 05/27/2013


    LightSailEnergy claims to store and retrieve energy with only a 9% loss. I was going to try to look up motor and generator inefficiencies, but this is something you may already know. Is an overall efficiency of 91% realistic going from electrical power through a motor and compressor, then to storage, then back to power generation?

    Without looking into details this sounds like it will have high capital requirement compared to the potential return. Generating power from hot water sounds especially iffy to me from an efficiency standpoint. All I have experience with is steam to power.

    I’m not asking you to do research. Just wondered if you had some of this efficiency data in hand.

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  4. 4. rkipling 11:19 am 05/27/2013

    It is refreshing to read an environmental topic written by an engineer.

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  5. 5. rkipling 11:39 am 05/27/2013

    From reading LightSail Energy’s website, they have yet to ship a unit. They say it is designed to fit inside a shipping container. That seems very small scale for much energy storage. But they have raised over $50M in investment, so you could make the case that they have already made their fortune as Ms. Fong talks about in the video.

    It will be interesting to follow this company’s progress. I hope for Ms. Fong’s sake they are not just using her as an articulate, wunderkind, front person (who happens to be photogenic).

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  6. 6. rkipling 11:43 am 05/27/2013

    Ms. Lott,

    Have done a cursory feasibility study of LightSail Energy’s device? Can you point us to additional information beyond their website?

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  7. 7. Fanandala 4:45 pm 05/27/2013

    @ rkipling
    there are individual processes that could work at 91% efficiency, but to compress a gas and convert it back into electricity is a multistage process and I doubt very much that 91% is achievable.

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  8. 8. rkipling 4:58 pm 05/27/2013


    Yup,seems optimistic to me too. I wish them luck in their venture, but I wonder who would use a unit small enough to fit in a cargo container? If the customer is someone with a windmill or two, I wonder if they will have the maintenance crew to keep it running? I also wonder what the price for such a unit would be? It’s difficult for me to see a return on investment.

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  9. 9. N49th 4:59 pm 05/27/2013

    So now its methane, I swear there were americans selling ice boxes. Literaly, ice in a box and tried to call it refridgeration.
    Colourful pictures will only get you so far.

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  10. 10. Carlyle 10:05 pm 05/27/2013

    It certainly is NOT possible to recover 91% of the electrical energy input to electrical energy output. Electric motors have a fairly high efficiency, converting up to 90% of the electrical energy into mechanical energy. There are much greater loses compressing the air & converting compressed air to mechanical energy, governed by the Carnot cycle, then you have an additional loss from your turbine through the generator.
    I suspect that the 91% they are quoting is the percentage of the theoretically possible energy in to out of the compressed air but not the efficiency losses in compression machinery nor turbine & generator losses. Below is part of the story. Preventing heat loss is critical.
    As explained in the thermodynamics of gas storage section above, compressing air heats it and expanding it cools it. Therefore practical air engines require heat exchangers in order to avoid excessively high or low temperatures and even so don’t reach ideal constant temperature conditions, or ideal thermal insulation.
    Nevertheless, as stated above, it is useful to describe the maximum energy storable using the isothermal case, which works out to about 100 kJ/m3 [ ln(PA/PB)].
    Thus if 1.0 m3 of ambient air is very slowly compressed into a 5 L bottle at 20 MPa (200 bar), the potential energy stored is 530 kJ. A highly efficient air motor can transfer this into kinetic energy if it runs very slowly and manages to expand the air from its initial 20 MPa pressure down to 100 kPa (bottle completely “empty” at ambient pressure). Achieving high efficiency is a technical challenge both due to heat loss to the ambient and to unrecoverable internal gas heat.[22] If the bottle above is emptied to 1 MPa, the extractable energy is about 300 kJ at the motor shaft.
    A standard 20 MPa, 5 L steel bottle has a mass of 7.5 kg, a superior one 5 kg. High-tensile strength fibers such as carbon-fiber or Kevlar can weigh below 2 kg in this size, consistent with the legal safety codes. One cubic meter of air at 20 °C has a mass of 1.204 kg at standard temperature and pressure.[23] Thus, theoretical energy densities are from roughly 70 kJ/kg at the motor shaft for a plain steel bottle to 180 kJ/kg for an advanced fiber-wound one, whereas practical achievable energy densities for the same containers would be from 40 to 100 kJ/kg.

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  11. 11. rkipling 11:20 pm 05/27/2013

    Okay. I didn’t think so. It seems they misrepresent the value of their device if they don’t quote the actual energy output compared to the energy input. Somebody has some connections to collect $50M. I am impressed by their money raise.

    I didn’t follow your calculations, but thanks anyway. I understand about compressing gases. I used an air compressor to heat air for the drying cycle on a Rosenmund filter once.

    So, any guess what percentage of input energy they might be able to recover?

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  12. 12. eponsonby 1:05 pm 05/28/2013

    On the topic of the video for LightSail Energy- Michael Noer, quit interrupting her! Almost every time you ask her a question you interrupt her answer. Let the woman speak! Sheesh.

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  13. 13. Dr. Strangelove 9:49 pm 05/29/2013


    what percentage of input energy they might be able to recover? Less than 48%

    If you compress air, it will heat up. Assuming no heat loss, effect on temperature of isentropic compression of air: T2/T1 = (P2/P1)^X and X = 1 – Cv/Cp

    where: T2 = final temp., T1 = initial temp. (298K), P2 = final pressure (10 bars), P1 = initial pressure (1 bar), Cv = specific heat at constant volume (0.718 KJ/kg-K), Cp = specific heat at constant pressure (1.0 KJ/kg-K)

    Hence, compressing air to 10 bars will increase its temperature to 570K. The Carnot efficiency (Ec) of any heat engine operating between T1 and T2 is:
    Ec = 1 – T1/T2 = 48%

    Hence, the theoretical limit is 48% efficiency. Actual is lower because you have to subtract heat loss, friction and efficiencies of motor and generator.

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  14. 14. Dr. Strangelove 2:28 am 05/30/2013

    Ms. Danielle Fong,

    With due respect, your claimed 500+ operating hours at 94% thermal efficiency violates the 2nd law of thermodynamics. I suspect your calculation of thermal efficiency does not follow the standard in engineering thermodynamics. You can attain 94% efficiency if you further heat the compressed air. But this requires external energy input. I suspect you treat this energy input as “free” if coming from the sun or other renewable sources.

    Perhaps you only considered the electrical energy input that costs money in calculating the thermal efficiency. While it might make economic sense, that is not the correct way to compute thermal efficiency.

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  15. 15. Dr. Strangelove 4:58 am 05/30/2013

    To Fong et al

    IMO the flaw in your compressed air energy storage system is the use of heat exchanger. That will lower the temperature of both compressed air and water as heat is transferred from hot air to water at ambient temperature. Lower temperature means lower thermal efficiency. What you want is high temperature to increase efficiency but the downside is heat loss.

    The solution is increase the pressure and temperature, and keep the air hot by good insulation. The key is good insulation. Use vacuum to eliminate conductive and convective heat loss, and mirror to reflect back infrared (radiative heat loss).

    Technically the solution will work but economically I bet your car battery is cheaper. Heat is a highly disorganized form of energy because it is the random motion of molecules. Heat is difficult to convert to useful energy. Even with good insulation, you are limited by Carnot efficiency. Chemical energy is more well-organized because it is the bonding/disbonding of electrons. That’s why your car battery has 90% efficiency.

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  16. 16. Dr. Strangelove 3:49 am 05/31/2013

    I welcome rebuttals from LightSail if you see any error in my assessment. I will take no reply to mean you agree with me. There’s nothing controversial about what I said. It’s basic thermodynamics stuff found in engineering textbooks.

    For instance, for your compressed air engine to attain 94% thermal efficiency, you need a temperature of 5,000 C. That’s almost the temperature of the sun. Your engine would have melted.

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  17. 17. Danielle Fong 1:08 pm 06/22/2013

    Ok, I’ll bite.

    First of all if you’re actually looking for rebuttals, it’s usually easier if you post it to my email or some website I own (e.g. and have notifications for. We get an awful lot of media coverage and I don’t monitor everything.

    Second, the efficiency we’re targeting is 70%. Not 91%. I don’t know where people got that from. We include all of the practical losses that people have mentioned — motor inefficiency (at our scale, typically 5% loss, not 10%, as some people seem to believe — it depends upon scale), friction, heat loss through our insulated tanks, etc. We are not actually there yet. If our first product is between 60% – 70% efficient we’ll be pleased, but we’re determined to push that as high as we can.

    Third, it appears you are under some confusion about thermodynamics.

    It is a slippery field, and I don’t blame you: both Bill Gates and his advisors made similar mistakes the first time through.

    a) We’re not doing isentropic compression or expansion. The whole point of the water spray technique is to approximate an isothermal compression and expansion cycle — the water absorbs heat from the air rapidly. The correct first order approximation is that the heat capacity of the *mixture* is effectively added to the heat capacity of the air. Try deriving this from the 1st law, starting from T_water = T_air, and following the derivation of adiabatic compression without heat exchange to the outside that you see in any thermodynamics text.

    Actual results have our output ∆T < 20 C and maximum hotspot ∆T = 60 C. Water spray actually cools. It is surprising how controversial this has been in the 21st century…

    b) You're using Carnot efficiency in an erroneous way. Compression and expansion are only part of the cycle. While it's true using the generated heat alone in a heat cycle would grant you the efficiencies you describe, this is irrelevant, because we're not doing that. There's a whole other thermodynamic resource: *the compressed air* that this is wasting. So we're not doing that.

    Here's an illustrative exercise.

    A Carnot Cycle is perfectly reversible: run the cycle backwards, and 100% of the heat turns back into mechanical energy. How is this possible, one might ask, while at the same time being compatible with Carnot efficiency?

    Several reasons: as a heat pump, the Carnot cycle turn W units of work into 1/(1 – Tc/Th) units of Th heat! There's more heat, in joules, pumped than work put in.

    This might seem to violate intuitions, but you can purchase heat pumps at any hardware store. You will notice that there are heat pumps and refrigerators with a coefficient of performance much greater than 1 widely available. This really works.

    Now, draw a T-S diagram of a Carnot cycle for an ideal gas. It's a rectangle in T-S space, the isothermal compression and expansion processes are horizontal lines, and the adiabatic processes are vertical.

    Shrink the adiabatic processes to nothing, so that isothermal compression and isothermal expansion are at the same temperature. No heat is moved, and there is no net work. It is still a reversible Carnot cycle. But it doesn't seem to do anything.

    Why would you do a thermodynamic cycle if you get no net work energy out?

    Answer: if you get energy out at a *better time*!

    If you get 100% of the energy out that you put in, but at a different time, then this is an *IDEAL* energy storage cycle. You can't get more efficient than that!

    However, by your mathematics, you'll have a 0% efficient heat engine.

    The thermodynamic equations for a full heat cycle are *different* than for an energy storage cycle. You cannot just use them blindly. You have to go back to the first principles: the first and second law. (which, by the way, are never violated here — there is never entropy destruction in this or any other ideal reversible cycle).

    All this said, this is an idealization. In fact there are losses in the process. Friction, for example. Resistance in our motor coils. Air turbulence running through valves. All this goes to heat.

    What we do with this heat is that we collect it so that we expand air at as high a temperature as we can.

    We don't get as much energy out as if the energy never went to heat, but it is a small boost if we can get it. About 10% relative energy storage efficiency (E_out/E_in) for a 30 C heat increase if we've got it, nothing to sneeze at.

    But even if we lose 100% of the extra heat, and have to expand at ambient temperature, our efficiency only goes down by that same 10% relative efficiency. It is not bad.

    Also, it's not so hard to insulate a large tank.

    In general, while I applaud the efforts of people to work out things for themselves, you have to be extra careful that you're not deluding yourself. It is worse to take a well known equation, misapply it, and declare impossibility, than it is to say that you heard about something but haven't worked to complete understanding from the fundamentals yet.

    It's not actually working something from first principles if you get them wrong…


    Danielle Fong
    LightSail Energy

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  18. 18. Danielle Fong 1:14 pm 06/22/2013

    It may be more efficient to post any additional comments on my blog here:

    Link to this
  19. 19. Danielle Fong 1:17 pm 06/22/2013

    As for whether there is a market for container sized units,

    If you need more, just get more modules. It is really not very complex. And it’s good if they are container sized. Then you can actually transport them to the site.

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  20. 20. 1:30 pm 06/24/2013

    Danielle: Agreed, a battery is not an engine, and no work is done except, recreating a thermal mass in your case. But that’s minor. Engine efficiency analysis applies because, you still have to go from the retrieved thermodynamic mass (whose potential energy is a percentage of the input kinetic energy), back through mechanical conversion to “Q-out”. A lot of the brouhaha would go away, if you gave the most meaningful performance objective, ie Efficiency: given kWhs in, what percentage are output as kWhs? (not BTUs) Secondly, how does this efficiency decrease as a function of time? I have research in this area, lots of factories affecting duty cycle, and efficiency, plus a number of alternatives, improving in Moore’s law fashion.

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