## Genuine optimism

I wasn’t going to post the video of Elon Musk announcing Tesla’s new batteries, but having watched it on Rachel’s blog, I thought I would. I was more impressed than I expected to be. I think my slightly cynical, initial response had been that it might just be too good to be true. That may still be the case, but what I really liked about the video was the sense of genuine optimism: there is a potential problem, but we have a solution. Of course, I’d also forgotten that Elon Musk was born in South Africa, which clearly means that he’s brilliant and – obviously – right 😀

It was a nice change from the Ridleyesque form of optimism, which is essentially “don’t worry, everything will be fine, carry on as usual”. It’s one thing to be optimistic that we can address the problems we might face; it’s another to assume that the problems don’t exist, or aren’t anything to concern ourselves about. What was also impressive was that Elon Musk presented his vision without even the slightest hint that those who might disagree with him were effectively advocating for the death of millions in the developing world. Maybe some people could learn from this?

The final thing that I found impressive was that Elon Musk claimed that it would need more than just Tesla to develop these technologies, and claimed that all the patents would be open source. This seems like a risky business strategy, but if you really do want your technology to make a significant contribution to solving what might be a major problem, this does seem like the right way to do so.

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### 57 Responses to Genuine optimism

1. Richard says:

I loved the talk too. Of course, the naysayers will tell us that the costs are still too high (for payback on batteries etc), but every new transition starts with costs that that progressively improve as volumes and competition kick in. Without the Munk’s of this world in actually start to make things happen, that journey never starts. It makes a great change to those who tell us that only nuclear fill the gap. All that GWs will take time to switch over but as Munk says, it is about the same as changing all the trucks and cars on the planet and that turns over every 20-30 years. The great thing about solar is it is scalable – from a small house on the prairie to a manufacturing facility.

2. Richard says:

Excuse the typos. That Reserva Alhambra beer is stronger than I realised!

3. Richard,
Yes, I initially thought “billions, that’s a lot”, but as Munk pointed out, we turnover a huge number of vehicles every year, and – as you say – almost all on a 20-30 year timescale, so it’s not insurmountable at all. I shall have to try some of that beer 🙂

4. Todd De Ryck says:

Would be good to know the “cradle to grave” energy requirements eg mining, manufacturing, etc, but promising nonetheless http://theness.com/neurologicablog/index.php/tesla-introduces-the-home-battery/

5. The picture Musk paints is very attractive, however there are questions that need answering regarding supplies of raw materials. At this moment it seems to be lithium, but presumably other storage battery types will be developed.

The great thing about what Musk is doing is showing the way forward and will it demonstrate the difference workable distributed storage can make to the way we run our energy system. Apart from anything else, if enough people install these and start importing cheap off-peak electricity at night it could drastically reduce the peak grid capacity requirement.

Once Musk’s ideas start to change things I can’t help thinking there will be many companies with a vested interest in fossil fuels who will do their utmost to ‘discourage’ this new technology. Call me a conspiracy theorist, but I’m suspicious the current overproduction which has driven down oil prices is an attempt to stifle competitive technologies and renewables.

The other issue I can see arising will be when sufficient numbers of people start buying Powerwalls or equivalent to add to their PV installation (I’ll certainly now start looking into this myself). As adding storage will have the effect of reducing feeding power back into the grid, I’m pretty certain it’s breaking the terms of one’s FIT agreement—in spirit if not in fact. I can imagine the Government turning a blind eye while this remains a fringe development, but I will expect them to look at ways to reduce payments if and when when storage takes off.

6. John Mashey says:

Well, with all due respect to S.A. … Musk has been in Silicon Valley for quite a while, and optimism (sometimes over-) is normal around here. Also, people understand issues of creating new markets with products whose early costs are high, but can be sold to early adopters, and if successful, trechno9logy + cost/volume improvements bring them down.
There is also the intertangle of a) related technologies b) distribution/installation costs and c) government rules that either impede or assist new tech. Sometimes one has to be aggressive to push a missing piece to induce the others to happen. For instance, people didn’t worry too much about permitting and Balance of System costs when PV panels were much more expensive, but now that they’ve gotten cheaper, permitting, BoS, installation, etc get much more attention.

Consider cellphones: when they first came out, they were big boxes in cars, only available in a few cities, because one needed the infrastructure also. Cellphones would not exist without a vast array of components that mostly grew from earlier products, and then with bigger market, shrank and got cost-reduced, and also made it worthwhile to build infrastructure fo higher bandwidth and better coverage.
This is like electric cars, which don’t work everywhere, but in some places, there are already lots of public charging stations.

CA law says:
By 2020,all new houses will be zero-net-energy.
Some construction firms (like Lennar), include PV solar as a standard feature in new houses in some areas. One would guess that companies like that would start wiring houses so that home batteries could be easily installed.

Germany has done OK with PV and Passivhaus, in an unlikely climate, so it isn’t just mild CA climate.

Ridley seems: “forward to the 1800s, relieve the heights of the British Empire, coal is king.”

7. BBD says:

Does anybody know what the average US citizen’s daily electricity consumption is in kWh/day? Or that of the average UK citizen?

8. semyorka says:

Around the end of last year I started telling people that I thought that the next big paradigm shift in the global economy would be a “flight to the sun”, or the steady movement of energy intense industries to the 30th parallel. As the cost of solar comes down and starts dropping below fossil fuel electricity, then it will become an economic pull to run your factory for much of the daylight on reduced to zero grid electricity. The 30th parallel is (roughly) where you get a lot of sun light and the air tends to be sinking thus cloud free and dry (and many of the worlds great deserts are around this mark).

For the past 20 years renewables have been sort of life style enhancements for the global well off (EU\G7 type states). But as you start hitting grid parity and below the next two decades will be driven by the pull of economic imperative. In many ways industrialisation will come full circle. It began in the dales of Pennines and the glens around the Clyde valley because this is where the fast moving water was to power the early mills. Luck and canals brought the coals of Yorkshire, Ayrshire, Lancashire and Lanarkshire to the new town and cities to take over from water and thus began the trend of industry following cheap skilled labour rather than energy.

Musk’s batteries opens the possibility of this being a 24 hour renewable world and not just a 12 hour one. (On shore wind is also closer to grid parity than is commonly assumed).

This looks like the beginning of a classic disruptive technology, an innovation that suddenly destroys the previous paradigm. As people have been saying, solar pv is not a resource but a technology so does not follow the classic remorse cost curve of being cheap when relatively new and bountiful but becomes cheaper as it is more widely adopted.

9. BBD says:

Musk’s batteries opens the possibility of this being a 24 hour renewable world and not just a 12 hour one.

Well, that very much depends on how much electricity the average US home uses in the period when SPV is not generating.

10. BBD says:

I should not be so lazy.

Here, from the EIA:

In 2013, the average annual electricity consumption for a U.S. residential utility customer was 10,908 kilowatthours (kWh), an average of 909 kWh per month. Louisiana had the highest annual consumption at 15,270 kWh, and Hawaii had the lowest at 6,176 kWh.

11. johnrussel,
Yes, you’re right, there are still questions to be answered, but it is an interesting development.

JohnM,
Good point about Silicon Valley. Although, that’s what we probably need: people who are optimistic and are willing to take risks, rather than people who think we should just plod along as we have and hope that somehow someone develops something that will help us when we need it.

BBD,
So about 30kWh per day. So, the battery is a reasonable fraction of a day’s use.

12. BBD says:

@ johnrussell

The picture Musk paints is very attractive, however there are questions that need answering regarding supplies of raw materials. At this moment it seems to be lithium, but presumably other storage battery types will be developed.

This article paints a fairly optimistic picture re: lithium, which is both relatively plentiful and perhaps equally importantly, can be recovered and recycled. The recycling process requires freezing the batteries to a very low temperature which process alone will make it extremely energy-intensive.

13. BBD says:

ATTP, yes, thanks. I didn’t really finish working through the numbers in my previous comment did I? Just ****ing bone idle.

🙂

14. David Young says:

Lomborg triumphant. This is a solution people can do themselves. And we should welcome those of an activist bent stepping forward and helping to make this a success. I might even do it myself.

15. DY,

Lomborg triumphant.

I really fail to see how this has anything to do with Lomborg. Also, if you think that those critical of Lomborg were critical of technology development, you weren’t really concentrating. It’s quite possible to criticise someone without your position being the exact opposite of what that person is suggesting. In fact, Lomborg’s general suggestion (low/negligible carbon tax) would not really aid these kind of developments.

This is a solution people can do themselves. And we should welcome those of an activist bent stepping forward and helping to make this a success. I might even do it myself.

I’m not quite sure I’m following you, but if you’re suggesting that this is a good thing and that we should embrace it and try and make it a success, then I agree.

16. BBD says:

Climate change mitigation is Lomborg triumphant?

Eh?

17. Eli Rabett says:

Oooo goodie, Bjorn Lomborg and the coal powered Stanley Steamer

18. For the UK…
Typical electricity use is 9kWh/day per medium-sized dwelling.
A 4kW PV installation (the largest that will attract the full tariff) will produce an average of 16.5 kWh per day in summer and 4 kWh per day during winter months (figures based on my system in SW UK).

One can see therefore that a 10kW storage system would enable a PV-equipped household to operate for free over the summer months—when demand is less than 25kWh/day—but be of little value during the winter months when demand is higher that 9kWh/day and PV production is low.

Incidentally, in examining my PV production logger I’ve just realised that the UK’s sunshine in the SW has been remarkable during March and April this year. In fact April, at 510 kWh, is higher than last June’s 500kWh!

One thing we shouldn’t forget is that the 9kWh daily electricity consumption is typically only used for lighting and operating equipment. Heating is typically fossil-fuel-powered and averages 45kWh /day.

19. BBD says:

john

20. Pleasure, @BBD.

I just noticed that the reference to “25kWh/day” in 2nd para should be “9kWh/day”.

Just to show what an exceptional month April was, here’s my data logger for last 12 mths:

21. anoilman says:

johnrussell40: I wanna know all about your solar system. How many kw installed? Do you adjust it for seasonal variance? (Most panels in the north are adjusted for optimum output in summer, and are expected to draw back in winter.) What is your average consumption? Are you using electric heat or other heat?

The typical household in Alberta uses 600kwh, but we use natural gas for heating. Panels are making more and more sense to me since (for sociological reasons beyond the scope of this discussion) I use air conditioning. Even a small system would just plain get 100% used. (I also have a few 100 watts in electronics running all the time.)

Oh and yes. This winter has been very very very very unusually sunny in the UK. It may be a factor in lower carbon emissions from this winter.

22. Brandon Gates says:

Anders,

I have an OT question for you and/or the other literati. Here we have two formulations for calculating spectral radiance by way of the Planck distribution for a given temperature in K:

… which takes wavenumber as an input and …

For 300 K as the temperature parameter, the first formula using wavenumber puts the radiance peak around 17 microns whereas the second formula using wavelength puts the peak at 10 microns. Raising wavelength to the third, instead of fifth, power in the latter formula brings them into agreement. I’m stymied because I see the same formulations elsewhere from reputable sources. It really doesn’t help matters that this plot from SoD’s blog …

… puts the peak at 10 microns whilst (my plot adapted from) Grant W. Petty (2006) rather unarguably puts it at 17 microns:

I’m inclined stick with the way which conforms to observation, but any help getting me sorted on the confusing theoretical aspect would be most appreciated.

23. Brandon,
It’s a bit late, so I hope I don’t mess this up, but the subtlety is those two functions are really W/m^2/Hz, or W/m^2/m (i.e., energy per second per square metre per unit frequency interval, or energy per second per square metre per unit wavelength interval). So, the equivalence is

$B(\nu) d\nu = B(\lambda) d\lambda.$

However,

$c = \nu \lambda \Rightarrow \lambda = \dfrac{c}{\nu} \Rightarrow d \lambda = -\dfrac{c}{\nu^2} d\nu.$

So, if you want to convert $B(\lambda) d\lambda$ to $B(\nu) d\nu$ you have to do

$B(\lambda) d\lambda = -B(\nu(\lambda)) \dfrac{c}{\nu^2} d\nu,$

which then puts the peak of the function in what appears to be a different place, but really isn’t because you need to consider the relationship between $d \nu$ and $d \lambda$.

At least, I think that’s right.

24. Brandon Gates says:

Anders, I thought it might be a units issue but I couldn’t figure out the appropriate conversion factor. I’ll plug those in and see if it works, will ping back with my results. Appreciating that it’s late for you, I appreciate you taking the time to answer — I have a retired PhD physicist on the line insisting that I’m wrong, Petty is wrong, and therefore AGW is wrong. Yes, one of those. Cheers.

25. Marlowe Johnson says:

the real market for storage will be utility scale and developing countries where grid infrastructure is nonexistent or unreliable. will certainly help with peak shaving in developed countries but I think it would be a mistake to put too much emphasis on the ‘grid defection’ scenarios, RMI’s work notwithstanding.

in any case, musk is certainly doing his best to disrupt established industries with Tesla (automotive), SpaceX (aerospace) and power gen/distro (solar city & Tesla) and it’s exactly this kind of high *personal* risk/high *societal* reward capitalism that’s needed right now and it should be applauded across the political spectrum.

won’t happen of course but then I still don’t have a pony either.

26. BBD says:

Marlowe Johnson

That’s certainly how I see it, so it is encouraging to learn that you feel the same way. Also agreed that Musk is apparently trailblazing for capitalism 2.0. Let’s just hope there aren’t any skeletons in the corporate cupboard.

27. Marlowe Johnson says:

well google ‘justine musk’ and ‘starter wife’ if you want to see his skeletons on display. doesn’t seem to have hurt his ability to attract investors, but it might make his appearances on ‘the view’ a little awkward ;).

28. Magma says:

I think my slightly cynical, initial response had been that it might just be too good to be true

I’m not sure why that would be. The Powerwall is essentially ~800 high-quality 18650 Li-ion cylindrical batteries in series and parallel (probably 100×8) with an elegant charger and cooling . Tesla’s breakthrough is (or will be) to get the unit price down to where it’s increasingly competitive with other power generation/distribution methods.

And current Li-ion batteries may turn out to be a relatively short-lived technology for such applications. While being quite prepared to doubt the hype around the recent Al-graphite battery developed by Stanford researchers, I was very impressed with the care they had paid to carrying out basic prototyping when I read their article in Nature. It was certainly more than just a theoretical discussion of the chemistry of possible battery materials of the future.

The defenders of fossil fuels are always eager to play up the (locally) intermittent nature of wind and solar power while rarely displaying much understanding of how complex the North American and European power grids are today. Considering a disproportionate number of (educated) climate change deniers are engineers, the lack of appreciation for simple technological breakthroughs in power generation and storage on their part has always struck me as odd.

You’d think the fact that an increasingly decentralized power generation, storage and distribution network that would be robust to disruptions, outages and natural disasters is now technically and economically feasible, or on the verge of being so, would be a matter of celebration.

29. BBD says:

MJ

Well, yes, but I did say corporate cupboard 😉 Money, accounting, ducks-in-a-row; boring stuff.

30. Ken Fabian says:

For the pv fitted home, this will be a winner. For bringing electricity to people without access to a grid, this will be a winner. The consequences of this technology becoming widespread will be profound, and the comparison to the ubiquity of vehicles is one that has occurred to me before – the cost of a small car per household is only a few percent of that of a (European/North American/Australian) home and most can already afford several. Even better that the stated prices are actually much lower than I was expecting so soon. Even with some inflation of prices for those outside the US the Powerwall will not lack for ready customers! I want one! I suspect demand will exceed supply for a while.

Periodically and intermittently solar and wind can already be the cheapest and the problem for incumbents isn’t that of supplanting their existing fossil fuel generation in one hit, but the incremental forcing of it into ever greater periods of intermittency, which has serious implications for their profitability.

With the loss of premium prices for sunny daytime power already occurring here in Australia, the prospect of even relatively small amount of storage in solar homes across the grid, eating into the still lucrative evening peak and further reducing profitability must be on the incumbent’s radar – even if fixing the climate probably still barely rates. I think the market consequences can and should be managed to become a kind of defacto carbon price, incentivising renewables and storage whilst forcing FF energy costs higher.

Watch for lot’s of lobbying for hostile regulatory/fee arrangements that diminish or exclude that advantage to renewables from an open energy market on the basis that “we are essential” – even as we head towards them being replaceable or optional. They need to recognise that the core business of power companies of the future will be storage and distribution.

Of course what is needed is the kind of planning and forethought that puts much existing FF plant into it’s proper place in a transitioning energy market – as transitionary backup supply – and accommodate it with clear incentives for leaving it turned off as much as possible and replaced at the earliest.

31. anoilman says:

Magma: “Considering a disproportionate number of (educated) climate change deniers are engineers, the lack of appreciation for simple technological breakthroughs in power generation and storage on their part has always struck me as odd.”

Got any stats on that? I really haven’t run into many that appear educated in anything technical at all. 1 or 2 around here…

Most of what I come across are technicians (2 year diplomas) and arts (4 year BA) educated.

Incidentally, even among engineers I’ve met very few who are actually smart and get what is going on in the base science. Most are just ‘lunch boxes’ doing their time and doing what they are told.

32. Brandon Gates says:

Anders,

On review, if I understand you properly I see that it’s not just unit conversions which are the issue but the fact that the intervals used to take the derivatives are not equivalent when using wavenumber vs. wavelength. This hurts my brain, but it may be starting to gel for me.

33. Magma says:

@ anoilman: you’ll notice I qualified that group with ‘(educated)’. I’d like to have some numbers, but like many other interesting political and sociological aspects of the denier phenomenon that’s not my field of expertise. I know that among the minority who are not completely clueless about science or technology and who state or leave clues as to their background quite a few seem to be involved in oil & gas (engineers and the occasional geologist) with a few electrical, chemical and computer engineers chiming in. The occasional physicist falls prey to their stereotyped arrogance with respect to the ‘lesser’ sciences, but they seem to be uncommon.

For some reason the individuals in question seem to feel that whatever expertise they have in their own field can be extrapolated to different fields like climate science and trump researchers in those fields. You can imagine their contempt if Michael Mann or Gavin Schmidt were to share their opinions on the best design for cracking and distillation units in an oil refinery.

34. @anoilman
How many kw installed? = 3.8kW (to be legal for the FIT in the UK it must not exceed 4kW per phase.)
Do you adjust it for seasonal variance? = They’re mounted on a south-facing roof at 35 degrees from the horizontal, which is the pitch of the roof. I’d love to have a sun-tracking system but it would need to be ground level and would be rather expensive.
What is your average consumption? = 9300 kWh per year*
Are you using electric heat or other heat? = All electric. I run a ground source heat pump and I also have 11 sq metres of solar thermal for hot water.
*As well as the main house, two adjoining holiday cottages share all these systems. As you can guess I spent a lot of time building in insulation and, most importantly, heat-recovery ventilation.

35. anoilman says:

johnrussell40: Thanks. I’m keen to see about adjusting angles on roof panels. Most panels are oriented so they are optimum for summer only. Yet its winter which is frequently an issue for solar.

36. Brandon Gates, it might be easier if you did not think of the density functions analytically, but pretend to solve them numerically. If you take regular intervals in wavelength space, you would get gradually changing intervals in frequency space. And the other way around. The total amount of solar energy within such an interval will thus depend on whether you compute it in frequency or wavelength space.

😦 Not sure if this really made it easier, but just in case…

37. Brandon Gates says:

Victor,

I AM ultimately attempting to integrate numerically since that’s pretty much the only choice with observational data … and I just got it, though I had to multiply by pi to get there. I was looking for the absorption band at 15 microns to be 9.66% of the total area under the theoretical curve at 295 K, and my (new) answer is dead-nuts on, with the peak of the curve at 10 microns instead of 17 as expected.

I think I almost understand the maths behind what you are saying, it is helpful, thanks. A good night’s rest, some strong coffee tomorrow morning and I stand a good chance of actually understanding how I just got the correct answer. Cheers.

38. not a grossly efficient house hold here – 2 people (now) electric cooking, washing, dishwashing, lighting and electronics. most energy is for tv/computers

lead acid should not be forgotten – fully recyclable
Rolls 5000 Series 24v 20kW Battery Bank
24v (4 x 6v cells) Rolls 5000 battery bank, rated at 28kW at C100 and 20kW at C20. 3200 cycles at 50% DoD.
.Excl. Tax: £3,279.00
Incl. Tax: £3,902.01
Weight (KG) 576 (not easily stolen!)

39. Anyone interested in reviewing a paper on characterizing charging-discharging regimes of Li-ion batteries? I am shopping this around for submission somewhere, and is more in my academic wheelhouse than the climate science I am dabbling around with.

40. I’ve been trying to figure out how expensive it would be to go off-grid, both for the reduced carbon footprint and increased resiliency to climate change. Tesla’s Powerwall seems like a bargain at $3500 for 10kWh of lithium-ion batteries, but it’s difficult to make a fair comparison because most solar installations use cheaper lead-acid batteries. For example, I’m sizing my hypothetical system by deciding that I can live on 3.1 kWh per day, which is equivalent to running 131 Watts continuously. Note that this is much less than the average American household (*). Since even deep-cycle lead-acid batteries have longer lifespans if they’re not actually deep-cycled, I chose a (fairly common) maximum discharge percentage of 20% and decided that I wanted this to get me through 1 day without sunlight. (For instance, if a blizzard covers the panels.) That requires a ~16kWh battery bank. All large systems should use the highest practical voltage to minimize current losses in wires and to use more efficient inverters, and 48V seems like the highest voltage that’s widely available. At 48V, that requires a 341 amp-hour battery bank. All lead-acid battery banks should be configured in series, not parallel, because batteries in parallel have much shorter lifespans due to the fact that they don’t all have the same current flowing through them. For similar reasons, batteries of different ages (or different usage cycles) can’t be easily combined together in the same system. I also read that most people destroy their first battery banks, because knowing when and how to equalize them takes practice. For this reason, many websites suggest buying a slightly cheaper battery array at first. Blue Pacific Solar sells 8 Trojan T-105RE 6V 225Ah batteries for$1200 plus shipping, which is 10.8 kWh.

This battery bank is cheaper than Tesla’s Powerwall, but it only has a 2 year warranty whereas the Powerwall has a 10 year warranty. With experienced care and regular (distilled) watering, this T-105RE battery bank might last 5 years. The more expensive Powerwall (hopefully) wouldn’t require this maintenance, so its total cost of ownership over 10 years probably wouldn’t be too much higher than a lead-acid battery bank. Ultimately, this depends on how many more cycles one can squeeze out of the Powerwall compared to a more conventional lead-acid battery bank.

But the Powerwall has another advantage. As a rule of thumb, lead-acid batteries shouldn’t be charged faster than their capacity (in amp-hours) divided by 10. So that 225Ah T-105RE battery bank shouldn’t be charged with more than 22.5 amps. This wouldn’t be a problem in Arizona which has lots of sunlight in the winter, but it would be a problem in Portland, Oregon which only gets 1.24 full “sunlight hours” on average in December according to pvwatts.nrel.gov.

So in Portland this system would need to produce 3.1 kWh each day during only 1.24 full sunlight hours. After accounting for a 66% MPPT charge controller efficiency, this requires a fixed solar panel array of 3.8kW, or 16 240W panels. At noon on a sunny day, the charge controller would be sending ~53 amps to the battery bank. That would fry the batteries, or at least severely limit their lifespan.

At this point, many solar enthusiasts suggest buying more expensive Absorbent Glass Mat (AGM) batteries which can handle higher currents. But I think these are even more expensive than the Powerwall, and lithium-ion batteries seem to accept even higher currents than AGM batteries.

Another alternative is a one (or two) axis tracking system, which would allow one to buy fewer solar panels and decrease peak current by maximizing electricity production during morning and evening.

Yet another alternative is a “virtual tracker” configuration which splits the solar array into two pieces which face SE and SW (in the northern hemisphere). The virtual tracker produces two peaks in the morning and evening, which can produce more average power while keeping the peak current lower than the standard fixed configuration, at the cost of buying more solar panels. (However, it has no moving parts, and solar panels are rapidly getting cheaper.)

The fact that the Powerwall can accept higher currents than lead-acid batteries could make solar power more feasible in places with very little winter sunlight.

(*) I only got as low as 131 Watts by assuming that I’m living in an earth-sheltered home using John Hait’s “Passive Annual Heat Storage” (PAHS) design based around a Formworks construction shotcrete shell. By storing summer heat in earth around the house under a cheap subterranean “umbrella”, heating and cooling costs could be virtually eliminated. This configuration has the added advantages of being nearly invulnerable to earthquakes, severe weather, forest fires, and requires much less maintenance (because there’s no roof and only one exterior wall), and more secure (which could be useful during another another PETM or end-Permian).

One concern is warm summer air condensing on the cool walls, which could cause property damage and maybe even health problems by promoting mold growth. Unfortunately, running a dehumidifier would largely defeat the purpose because they draw so much power. Maybe the condensation problem could be fixed with the right configuration of earth tubes and a small amount of insulation between the house and the earth “storage zone” (but not enough to defeat the purpose of the PAHS design). If only I had time to run a finite element analysis using Elmer FEM to find out if that would work.

Even after “designing away” the need for heating and cooling power, it was still difficult to get the minimum required power down to 131W.

Instead of an upright fridge which loses its cold air every time it’s opened, I decided to buy two (manual defrost) chest freezers and convert one to a fridge using an external thermostat. This reportedly uses only ~10% the energy of an upright fridge. Based on SunDanzer’s data, I think the freezer would use 30W and the fridge would use 10W. Again, condensation could be a long term problem because freezers aren’t supposed to be warm enough for liquid condensation. It would be great if more companies would sell high-efficiency chest fridges.

Cooking during the summer would be done using an ECO-WORTHY Portable Parabolic Solar Cooker Water Cooking Oven and an All Season Solar Cooker, along with a few Sun Rocket solar kettles. The All Season Solar Cooker could still cook during the winter, but would probably have to be supplemented by a wood stove like a “rocket stove” made out of a 55 gallon drum.

Hot water would be supplied using a $2K solar water heater. Any modern well-sealed home requires a good ventilation system. At first I wanted to supplement the earth tubes and their intended natural convection with an HRV/ERV, but it required too much power. Instead, a simple exhaust-only system would only use an average of ~6W and would simply draw air in through the earth tubes anyway. A Friendly Aquaponics Micro System 64 would use 40W for water pumps and aerators to supply enough vegetables (and a little fish) for ~1 person. Another 15W should suffice to run a Raspberry Pi monitoring system and automation to make sure the aquaponics system doesn’t silently fail. Again, this could be very useful during another another PETM or end-Permian. For entertainment, I’ve budgeted a continuous 30 W, which is enough for 16 hours/day of: a 15W LED bulb, a 10W netbook, and a 20W Dell G2410 24″ green monitor. Note that this 131W is just the absolute minimum required power which would need to be maintained during a severe blizzard in December. Dishwashers and clothes washing machines could still be used with care during sunny winter afternoons when the battery bank is already charged but the solar array is still producing excess power. However, clothes dryers would probably still require too much power, so an Amish-style pulley clothesline seems necessary. 41. Richard says: @johnrussell I have an old friend in Yorks UK who runs an alt energy business (PV, heat pumps, …) and doing very well. I sent him the Munk link and he said he was tracking progress on batteries but felt the current price point made it a tough sell in UK where everyone is on a reliable grid, and everyone frames the decisions in terms of payback/ROI). Of course the price will come down through scale, competition and innovation – and there are other factors (the grid is not 100% reliable). But, would you buy it today (from a purely economic POV rather than what you know about AGW)? Btw – the Solar + heat pump combo is gaining popularity amongst his clients. 42. entropicman says: Webhubtelescope The military are using lithium ion cells a lot in small drones and other man-portable equipment. I use them in model aircraft, an area in which the hobbyists are always interested in high discharge rates, maximum current from minimum battery weight. Fast recharge is also welcome, since you need fewer packs. If all else fails try contacting a model aircraft or model helicopter magazine to see if they would be interested in intendedan intermediate level article. 43. @anoilman The cheapest way to fit panels is flat against the roof. Once you start varying the panel compared with the roof angle you run into engineering problems relating to wind loads and the strength of a typical roof to support the required structure (which is closely policed to meet FIT requirements). There are also aesthetic problems which are a big deal for many people. Ground arrays are of course unhindered by such considerations. My own idea, if I ever do this, is to mount the panels vertically and then lie some sheets of mirror-like material on the ground in front of them. This would mean the inclination of the sun would no longer be a factor in the output. Then, you could argue, it might be better to consider a tracking system. 44. GSR says: This report from Renew Economy http://reneweconomy.com.au/2015/solar-grid-parity-world-2017 Investment bank Deutsche Bank is predicting that solar systems will be at grid parity in up to 80 per cent of the global market within 2 years, and says the collapse in the oil price will do little to slow down the solar juggernaut. In his 2015 solar outlook, leading analyst Vishal Shah says solar will be at grid parity in most of the world by the end of 2017. That’s because grid-based electricity prices are rising across the world, and solar costs are still falling. Shah predicts solar module costs will fall another 40 per cent over the next four to five years. Even if electricity prices remain stable – two thirds of the world will find solar to be cheaper than their current conventional energy supply. If electricity costs rise by around 3 per cent a year, then Deutsche’s “Blue sky” scenario is for 80 per cent of countries to be at grid parity for solar. “We believe the trend is clear: grid parity without subsidies is already here, increasing parity will occur, and solar penetration rates are set to ramp worldwide,” Shah notes. Deutsche Bank says unsubsidised rooftop solar electricity costs anywhere between$US0.13 and $US0.23/kWh today, which is well below retail price of electricity in many markets globally. “The economics of solar have improved significantly due to the reduction in solar panel costs, financing costs and balance of system costs,” it notes. And further cost falls over coming years will come from improved panel efficiencies, and falls in balance of system costs due to scale and competition.” 45. anoilman says: Dumb Scientist (@DumbSci): There are more complications to all this talk about solar. American houses are huge (and therefore have bigger roofs) compared to the rest of the world. (FYI, Canadian houses are 2/3 the size of an American one, and Brits are 2/3 the size of Canadian.) Getting efficient energy conversion is also apparently difficult if you have more variation in shade, and panel orientation. Micro Grid Tie Inverters ease all those issues; http://www.wholesalesolar.com/enphase-energy.html I think the 10 year warranty is a big deal too. It means you can plan and design around this without any concerns about surprise bills. A 10 year loan for$3500 is $33.80 per month. The cost per kwh used is therefore pretty low, and can be readily understood in relation to your current electricity bill. johnrussell40: Interestingly my wife mentioned aesthetics to me as well. It suggests that designers need a solar roof color pallet in order to paint your house so it looks nice. I’m more concerned about winter solar output than summer since BBD mentioned that to me. The UK, like Canada has smaller roofs. The argument that you can just add more panels may not make as much sense with small houses in a northern climate. Adjusting the angle of panels causes shade to panels behind reducing any efficiency gained, but this is not an issue with a single line of panels. If you want to go off grid, you need way more (5X?) panels for winter. However, a single axis adjustment would greatly improve seasonal (and in particular winter) efficiency. I’m cognizant of the wind sheer and engineering issues. (What if a branch gets stuck in there… and by the way its got to last at least 10 years, and work reliably for that time.) I suspect that is why no one is doing this. I like your idea about vertical mounting but I suspect it will have aesthetic issues as well. 46. anoilman says: GSR: There is one cost associated with solar PV that is not improving at all. Installation. It requires a lot of work to install, integrate with electrical in the house and or grid. Never the less, much of how good solar is now has been achieved with little market share. If it hits 10% market share globally it will be dirt cheap. 47. Gingerbaker says: I’m not sure if the PowerWall is the best idea since sliced bread, or the worst idea since school vouchers or private medical insurance. You all have been discussing the merits of the product, I would like to point out the negatives. The PowerWall (PW) is a product which will further the new corporate privatization of our (U.S.) national electrical utility system, which has been the most non-profit, publicly-owned, and consumer-protected segment of our economy. This is a boutique product geared for the rich, so they can sequester themselves into their own electrical gated community. And like school vouchers and private medical insurance, once you’ve taken care of number one – yourself and your family, you are very much less inclined, ideologically and financially, to support spending more for public programs. We need is a huge public investment in our national energy infrastructure, on the order of$6 – 10 trillion, to build us a carbon-free energy system. Rooftop solar will play a rather small (see Jacobson and Delucchi) part in that investment, and is unfortunately a hugely expensive and inefficient way to go solar compared to ideally-sited and scaled large installations. And, right now, the economic burden of rooftop solar is being borne by individuals, not shared in an egalitarian fashion.

The last time I checked, electric utilities were a service provided to us by our tax dollars and public investment, and our energy future is rightfully part of our National security calculus. Citizens being responsible for their own energy procurement sounds like Somalia, a libertarian nightmare, not the civilized world.

The PW is a symptom of us not getting the governmental services we pay for, not a viable investment for everone’s real energy future. It is part of the attempted conversion of our public and semi-public electric utility system into a for-profit, deregulated corporate entity. We can watch that happen, or encourage it, but it may be at our own peril.

48. entropicman said:

If all else fails try contacting a model aircraft or model helicopter magazine to see if they would be interested in intendedan intermediate level article.

I kind of doubt that a hobbyist magazine will be interested in an article that works out the statistical mechanics of the ion diffusion process.

That’s the level of the discussion in my paper. Like I offered, if anyone is interested in material science and solid state physics characterization just ask.

Designing a battery with constant discharge characteristics is more dependent on the material than anything else. Diffusion has the effect of leveling and stabilizing the drain for longer periods. Behavior like this is good for batteries but is not so good when CO2 enters the environment and only drains away slowly 😦 Uh oh.

49. GSR says:

Gingerbaker, there are issues of maintaining the grid. Currently your utility’s power bill covers grid rental and PV users (on or off grid) will still have to contribute to supporting transmission in some way.

50. anoilman says:

GingerBaker: You do understand that all markets get started with relatively wealthy early adopters and keeners, right? And you do understand that this tech easily rolls out in any relatively rural areas because the utilities don’t subsidize that? (In Alberta we charge \$3000 per pole for a grid tie to a farm. When you have acres, that solar starts to look mighty cheap.)

No. Utilities are not a service provided by us for our tax dollars. It varies from place to place. Here, I have deregulated power, and private companies are allowed to compete with a public service. (Wind power is all private here.)

Since you haven’t actually worked in an industry like a utility you may not know what its like. Tech is never adopted by utilities. Ever. It takes decades just to prove it out. They like things that last a long long time. Locally, our utilities (this is probably the same everywhere) own their own private wireless data network. This is because they can’t replace the entire grid every few years like Cell phone users. What was wireless data like 5 years ago? 10? 15? 20?

To my eyes, this tech is essentially being proven by early adopters, and will later be adopted by utilities as it proves it self.

51. Brandon Gates says:

I note with interest that Anthony Watts favourably reviewed Musk’s announcement. The first 5 or so comments on the thread echoed his enthusiasm. The rough balance of the comments were an exercise in racing to the bottom of pessimism and outright hostility. What a monster the man has unwittingly created.

52. Eli Rabett says:

Brandon, the advantage of using inverse wavenumbers is that they are directly proportional to energy so that when you integrate over an interval to find the power/energy you get the answer directly (ok, you technically have to multiply wavenumber by hc to get energy, but it what is a constant amongst friends.).

Doing the same with wavelength to find energy requires an integrating factor of 1/wavelength (or c/wavelength or hc/wavelength, but it is still all the same)

53. Eli Rabett says:

Web, send it to one of these

http://www.scimagojr.com/journalrank.php?category=1603

You probably want to start high and work your way down till you get a review.

Eli

54. Brandon Gates says:

Victor,

Brandon Gates, it might be easier if you did not think of the density functions analytically, but pretend to solve them numerically.

It’s rapidly becoming clear to me what a steep learning curve I’m on. In an effort to not be so ad hoc about this, I’ve begun going at it from first principles like I should. I finally broke down and purchased a 1-month license for SpectralCalc because I’m sunk if I can’t plot things. Nifty thing about them is that they describe what goes on under the bonnet. To anyone else looking for concise, domain-specific references, I am finding these documents indispensable:

A good general overview: http://spectralcalc.com/info/CalculatingSpectra.pdf

Blackbody calcs alternatively using wavenumber, wavelength or frequency: http://spectralcalc.com/blackbody/CalculatingBlackbodyRadianceV2.pdf

I also think better in code than pure maths, so this Appendix from the above document is solid gold for me: http://spectralcalc.com/blackbody/appendixA.php

55. Brandon Gates says:

Eli,

I am rapidly becoming a wavenumber convert for the very reason that I can integrate using a constant. My brain is still screaming at me that it must be wrong for the peak of the Planck distribution to end up in a different spot than when using wavelength instead. I totally get it now that I just didn’t take enough physics because quite obviously the results of the integrations are exactly the same, which is what really matters here.

56. Brandon Gates says:

PS: IOW, I have seen the light …

57. Michael 2 says:

John Mashey says:”CA law says: By 2020,all new houses will be zero-net-energy.”

Ah so, the LED illuminates! All residential buildings must have on site storage. Tesla batteries are compact and relatively lightweight, meaning you can put them on upper floors of a multi-story building. At any rate, California has pioneered many flops, “New math” for instance, and they can certainly revoke this mandate when they realize a 400 unit residential complex with 200 pounds of lithium in every residence is an arsonist’s wet dream, and that’s just for the 10 KWh battery.

But yes, I’d love to have one of those batteries. Some of the details might shock you, they come in 350 volt and 450 volt output. The inverter is actually going to have to step down to typical U.S. residential voltage (120).

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