Disclaimer. After nearly 40 years managing money for some of the largest life offices and investment managers in the world, I think I have something to offer. These days I'm retired, and I can't by law give you advice. While I do make mistakes, I try hard to do my analysis thoroughly, and to make sure my data are correct (old habits die hard!) Also, don't ask me why I called it "Volewica". It's too late, now.

BTW, clicking on most charts will produce the original-sized, i.e., bigger version.

Sunday, January 29, 2017

A solution for homelessness

Each night, tens of thousands of people sleep in tent cities crowding the palm-lined boulevards of Los Angeles, far more than any other city in the nation. The homeless population in the entertainment capital of the world has hit new record highs in each of the past few years.

But a 39-year-old struggling musician from South LA thought he had a creative fix. Elvis Summers, who went through stretches of homelessness himself in his 20s, raised over $100,000 through crowdfunding campaigns last spring. With the help of professional contractors and others in the community who sign up to volunteer through his nonprofit, Starting Human, he has built dozens of solar-powered, tiny houses to shelter the homeless since.

Summers says that the houses are meant to be a temporary solution that, unlike a tent, provides the secure foundation residents need to improve their lives. "The tiny houses provide immediate shelter," he explains. "People can lock their stuff up and know that when they come back from their drug treatment program or court or finding a job all day, their stuff is where they left it."

Each house features a solar power system, a steel-reinforced door, a camping toilet, a smoke detector, and even window alarms. The tiny structures cost Summers roughly $1,200 apiece to build.

LA city officials, however, had a different plan to address the crisis. A decade after the city's first 10-year plan to end homelessness withered in 2006, Mayor Eric Garcetti announced in February a $1.87 billion proposal to get all LA residents off the streets, once and for all. He and the City Council aim to build 10,000 units of permanent housing with supportive services over the next decade. In the interim, they are shifting funds away from temporary and emergency shelters.

Councilmember Curren Price, who represents the district where Summers's tiny houses were located, does not believe they are beneficial either to the community or to the homeless people housed in them. "I don't really want to call them houses. They're really just boxes," says Price. "They're not safe, and they impose real hazards for neighbors in the community."

Most of Summers's tiny houses are on private land that has been donated to the project. A handful had replaced the tents that have proliferated on freeway overpasses in the city. Summers put them there until he could secure a private lot to create a tiny house village similar to those that already exist in Portland, Seattle, Austin, and elsewhere. "My whole issue and cause is that something needs to be done right now," Summers emphasizes.

But the houses, nestled among dour tent shantytowns, became brightly colored targets early this year for frustrated residents who want the homeless out of their backyards. Councilmember Price was bombarded by complaints from angry constituents.

In February, the City Council responded by amending a sweeps ordinance to allow the tiny houses to be seized without prior notice. On the morning of the ninth, just as the mayor and council gathered at City Hall to announce their new plan to end homelessness, police and garbage trucks descended on the tiny homes, towing three of them to a Bureau of Sanitation lot for disposal. Summers managed to move eight of the threatened houses into storage before they were confiscated, but their residents were left back on the sidewalk.

If the city won't devote any resources to supporting novel solutions, Summers urges officials at least to make it easier for private organizations and individuals like him to pave the way forward. The city owns thousands of vacant lots, many of which have been abandoned for decades, that could provide sites for tiny house villages or other innovative housing concepts that can have an immediate impact.

"Everything that they have been doing doesn't work. It's just years of circles and bureaucratic holds and wait times," says Summers. "10, 20, 30, 40 years—where's all the housing?"

 Read more here

Solar has doubled every 2 years for 30 years

I read somewhere a while ago that solar capacity has doubled every two years for 30 years, but stupidly, I didn't keep the link, and I haven't been able to find it again.  But I stumbled across a different site which showed a slightly lower growth since 1975, namely 30% per year.  To double every 2 years the growth rate would have to be 41% per year.  So, in the early years, when solar was so expensive, obviously growth was lower, because we know that since 1990 it has doubled every 2 years.  Currently solar provides about 1.2% of global electricity, which means it is just 6 doublings (or 12 years) away from providing 80% of all electricity.

It's a nice chart, but it would be better on a log scale, which works much better for exponential growth, or exponential decline (in module price) for that matter.


Miami: adaptation.

The sea level in Miami is rising inexorably as a result of rising global temperatures (and no, the land isn't sinking)  So what are they doing to keep up?

Essentially, they're raising streets and sidewalks.  How much higher and how often will they have to do this?  Streets and sidewalks have been raised 3 feet.  What happens when the sea rises another 3 feet, and floods over the edge of the raised area into the shops and offices and homes which are now 3 feet below street level?

And Florida still votes Republican!

Read more here.

Friday, January 27, 2017

Not satire

At first, I thought this was satire.  But it appears to be true.  Donald Trump has declared his own inauguration day "National Day of Patriotic Devotion".  Good grief.




Thursday, January 26, 2017

Variability worries

The Australian government, ostensibly concerned about energy security, is running with a narrative that renewables are too variable for safety of the grid, and so we should have more coal.  Yes, really.

Some thoughts.

Australia has a RET (renewable energy target) of 23.5%.  Some politicians and commentators on the Right (misleadingly called "Liberals" in Australia) want to get rid of that.  Many of them are in the pocket with, or rather, fill their pockets with coal money.  They still believe that coal will save the world.  We know that is piffle: new coal is more expensive, in some places twice as expensive as renewables. But, we have to have some storage to cover the times "when the wind isn't blowing and the sun isn't shining."   How much?   The CSIRO estimates that we will need just half a day's storage to back up the grid if power sources are diversified (wind as well as solar)   Already utility-scale solar plus 10 hours of storage is cheaper than coal, according to Lazard.  Battery costs have plunged: halved just over the last year.  And they're likely to decline further (Tesla predicts "significant" price falls as the Gigafactory builds out) The technical solutions to renewables supply variability are at hand, right now, and will only get cheaper over time.

So let's look at an interesting segment of the supply and demand for electricity--the 25% of demand (and potentially supply) represented by households and small businesses.  Already the Tesla Powerwall 2 is close to providing one day's power for an average Ozzie house (13.5 kWh vs an average daily demand of 16kWh.  Over 10 years (and both battery and panels will last much longer than that), the cost of a Powerwall (A$10,500) plus 5 kW of panels ($4500) works out at about 30 cents/kWh, which is only a little above the cost to households of electricity from the grid. I pay, for example, 28 cents/kWh (including GST).  Another year and the battery/panels combo will be perhaps 30% cheaper, which takes the cost down to 21 cents/kWh.  And households will start to switch.

Will they remain on grid?  According to ConEd, 32% of generating assets are used for just 6% of the time.  This is costly: an extra 50% capacity just for a few occasions.  And it's even more expensive for an individual household or establishment to go off grid, because the grid is averaged out, which reduces the extremes.  So it would be tempting for utilities to say, nah, they'll never do it,   But that would be to underestimate our anger at the steady rise in electricity prices.   On the other hand, utilities would be wise to offer households with storage a good deal, because such prosumers could help mitigate extreme demand.  For example, the utilities could offer lower rates if they can reduce power to houses with batteries when demand spikes.  This would be substantially cheaper than the vast extra capacity needed for 1% or 2% or 5% events.

Widespread behind-the-meter batteries at households and small businesses will stabilise the grid, if the utilities are sensible (and less greedy). And that's before we even start talking about the power stored in electric cars--a week's worth. Within 10 or 15 years, 100% of car and lorry and bus sales will be electric.  Asking them to fill their batteries when demand is low and not to fill them when demand is high, for an appropriate fee reduction, would make the grid much more stable.  And, of course, it goes without saying that there will be utility scale batteries too.

Truly, there is no need to worry about the variability of renewables. By the time we get from 23% to 100% in 20 years time, the battery infrastructure will be in place. We don't need coal for energy security, whatever the Government says.

I decide what the truth is

Sunday, January 22, 2017

Clean disruption

This remarkable video by Tony Seba shows how dramatically the energy and transportation landscapes are going to shift over the next 5 to 10 years.  I don't usually post videos, because they take a lot of time to watch, more time than the equivalent text.  But I make an exception with this one.  Almost every minute of it is worth watching, and its conclusions are very significant for our society.  Watch the whole thing, then if you want to go back and see individual sections, refer to the notes below the video.

Some key projections and points, to whet your appetite, with my comments in square brackets:

  • The decline in battery storage costs is accelerating [this was before Tesla announced that costs of the Powerwall had halved in one year]
  • By 2020, one day's storage would cost $1 per day, less than a cup of coffee.
  • Large scale storage will completely displace gas peaking power plants, soon.  Already in some locales they are cost effective even at $350/kW storage, but by 2020 storage will be $200/kW and by 2024 $100/kW.
  • 32% of generating assets are used for just 6% of the time.  Batteries will be much cheaper [but we might need more because of weather related variability]
  • The plunge in battery prices means that by 2017 an "average" EV will cost $35,000, by 2020 $30,000, by 2022 $22,000.
  • EVs have only 18 moving parts compared to an ICE (internal combustion engine) vehicle with 2000+.  They are 5 times more efficient than an ICE and 10 times cheaper to run.
  • By 2025 100% of all new vehicle sales will be electric
  • By 2020 all EVs will have self-driving technology.  Already self-driving is feasible for 90% of the time.
  • At some point most people won't own a car but will share in a self-driving, automated EV fleet [like those robo-taxis SF authors used to talk about] 
  • Installed base of solar has doubled every 2 years since at least 1990.  We are just 7 doublings away from solar providing not just 100% of all electricity but of all energy.
  • The cost of rooftop solar will soon fall below the cost of transmission which means no alternative power source will be economically efficient, not nuclear, not fusion, not hydro, not coal nor gas.
  • But we will still need utility-scale power for factories, data centres, smelting metals [and blocks of flats and offices and EVs] 
  • Solar at 5.5 cents/kWh is the equivalent of oil at $10 barrel and gas at $5/MMBtu [recent solar contracts are now 40% to 50% below 5.5 cents/kWh]


At 2;35, how ATT which invented many of the key mobile phone technologies asked McKinsey and Co how many cell phones would there be in the US in 15 years (2000).  McKinsey's answer: 900,000.  Actual number 109 million.

At 4:10, how the internet was never going to be anything important.  "The internet will catastrophically collapse in 1996" (Robert Melcalfe 1995) "There is no reason anyone would want a computer in their home" (Ken Olsen, 1977)  "I do not believe the introduction of motor cars will ever affect the riding of horses" (Scott-Montague, 1903)  Seba points out that it is the experts or insiders who will deny that disruptive opportunities and risks.

At 4:44, why do smart people at smart organisations consistently fail to anticipate or lead market disruptions?

Exponential technologies.  At 6:56, Moore's Law: for the same dollar we get twice the  computing power every 2 years.  If you double every 2 years, over a decade that's a 1000 fold improvement, over 2 decades it's a 1 million fold improvement and over 3 decades a 1 billion fold improvement.  Kryder's Law: hard disk $ cost down 50% every 18 months.  Hendy's Law: digital imaging (pixels per $) down 59% every year.  Butter's Law of photonics (network capacity): the $ cost of transmitting one bit falls by 50% every 9 months,  The convergence of all 4 led to the smartphone and internet revolutions.

Key exponential technologies, at 8:56.  Sensors (9:52) market up 1000 times, costs down 1000 times, power down 1000 times, physical size down 1000 times in just 7 years.

Energy storage, at 11:38.  From 1995 to 2010, lithium-ion batteries fell by 14% per year.  Then 2 new industries came into lithium-ion: transportation and energy storage.  This accelerated the decline in the cost curve, from 2010 to 2014, cost declines accelerated to 16% per annum.  (Note that Seba's presentation was made in March 2016: since 2014 battery costs have halved)  At 16% by 2020 storage will cost $200/kW, by 2024 $100/kW.  Tesla's Powerwall 1 and Powerpack 1 battery costs were already (at the time of the presentation) below Seba's projected cost curve.  Now of course they are much lower than his curve.  Tesla got a billion dollars in orders on the announcement, and as a result the gigafactory, already planned to double world output of lithium-ion batteries, will be expanded in size by 48%.  at 15:58, Tesla isn't the only one doing this: BYD, Foxconn, LG Chem, Samsung SDI, TDK, Apple, Bosch, VW, etc.

Business model innovation, at 16:46.  Storage as a service 17:25.  By 2020, one day's storage (which by the way is more than we need) will cost about $1 (18:38) .  Half the cost of a coffee.  At 20:23, large scale storage likely to replace peaking power plants : billions of dollar in power plants used for just a few hours a year.  According to ConEd, 32% of generating assets used for just 6% of the time,

EVs, 22:10.  Tesla Model S: the best car ever made, not just the best EV.  The best selling large luxury car in America.   At 23:26, The EV is 5 times more efficient than the internal combustion engine (ICE), is 10 times cheaper to charge (24:08), has 2000+ moving parts compared to 18 in an EV (24:47), which makes EVs 10 to 100 times cheaper to maintain, and has much more torque (25:35).  When will EVs replace ICEs (26:56)?  $35,000 EV by 2017,  $30,000 by 2020, $22K by 2022.  By 2025 all new vehicles will be electric.  And note: it won't just be the incumbent companies who do it--Foxconn is to make an EV costing $15,000 (30:58)

Autonomous vehicles (32:52).  Tesla capable of self-driving 90% of the time (33:08).  What an autonomous car sees (34:02) Cost of LIDAR sensors has fallen  from $70,000 in 2012 to $10K in 2013 to $1K in 2014 to $250 in 2016 and a projected cost of $90 in a year or so (34:42)  World's first 1 teraflops computer in 2000 cost $46 million (36:13).  Would now cost $59 (36:43)  Is the market ready?  Yes, in Brazil, China, India, where traffic congestion is horrendous, self-driving cars are very desirable (37:25)  In San Francisco, 50% of Uber rides are car pools (38:43)  Cars are parked 96% of the time (39:09).  The convergence of EVs, self-driving, and shared cars will mean the end of individual car ownership (41:17)

The solar disruption (43:28) Installed base of solar has doubled every 2 years since at least 1990 (44:00)  7 more doublings, or 14 more years until solar can provide 100% of  total energy, not just electricity (44:25)  Grid Parity or God Parity (46:03)?  80% of global market will reach grid parity by 2017 (46:15)  Colour TV technology adoption curve (46:47) God Parity (48:18) where cost of rooftop solar is cheaper than costs of transmission, implying that no matter what alternative technology is used, even if it has zero cost, rooftop solar would be cheaper.  And that will happen by 2020 (49:16)  But we will still need utility scale solar, because blocks of flats, office blocks, aluminium/steel smelting (50:29)  Solar at 5.5 cents/kWh is the equivalent of oil at $10 barrel and gas at $5/MMBtu (51:00)

Tuesday, January 17, 2017

The Peaking Duck Curve

Ergon Energy, the state-owned  Queensland "gentailer" is responsible for supplying power to most of Queensland outside the densely populated south eastern corner.  This chart shows net residential electricity demand, i.e., net after electricity produced by rooftop solar.  Each year, the midday dip has got bigger, and the evening ramp up larger.  In 2015, net demand went negative for 90 minutes at midday.


I liked this chart because it gives you a very rough idea of how many hours of storage is needed.  Looking at it from the net demand side, you'd need storage from about 16:00 to about 1:30. The peak after midnight is prolly from water heaters, which were programmed to turn on after midnight in the days when all power was produced by baseload generators.  Those timers should be shifted to midday.  So that suggests (in the absence of wind) that we need 8 or 9 hours of storage.  Looking at it from the supply side, we'd need enough storage to store electricity from  6:30 to 16:00, which is 11 to 12 hours.

The new Tesla Powerwall will store 14 kWh.  Average annual electricity use by households in Queensland is 5793 kWh, or 16 kWh a day.  That means that one Powerwall battery should almost cover net demand from 16:00 to 6:00.    I keep on meaning to do a proper estimate of the Powerwall's LCOE, but a rough and ready guess would be AU 13.6 cents/kWh (=A$10,500 including GST and installation, divided by 14 kWh*365 days*15 years)   Now my electricity retailer, here in Victoria,  charges AU 28.5 cents per kWh., including GST.  I imagine costs in Queensland aren't that different.  Which means that it makes sense if you already have solar panels to install a Powerwall battery "behind the meter".  And as behind the meter storage becomes more common, the "peaking duck curve" will flatten.

Monday, January 16, 2017



When I wrestle with climate denialists and fossil fuel spruikers, they keep on saying that wind and solar only provide a small percentage of total electricity generated world wide.  And therefore (a) we might as well give up, and (b) we simply have to keep on using coal. Forever.  Never mind the rise in global temperatures.  Well, no. It's perfectly true that renewables still make up just a small percentage of global electricity generation.  But that completely misses the point.

From 2000 to 2015, the percentage of electricity generated from solar has doubled 7 times.  Over the same period, the percentage of electricity generated from wind has doubled 4 times. That means solar has risen 128 fold and wind 16 fold, over 15 years.  In fact, the percentage of solar in total global electricity supply has been doubling every two years for over 30 years, a growth rate of 41% per annum.  As costs have fallen, so more solar has been installed,  which has led to further cost falls.  A classic virtuous cycle, or learning curve.  The wind percentage, meanwhile, has doubled every 3 years, which is a growth rate of 26% per annum.

Together, wind and solar now produce about 5% of global electricity.  This means that together they are just 4 and a half doublings away from 100%.  Obviously as we get closer to 100%, growth rates will slow.  But over the next few years, as costs continue to decline, and the concern about global warming continues to grow, growth rates are likely to remain high.  At 25% growth, the percentage of electricity from wind and solar will reach 15% in 5 years, 45% in 10 years, and would exceed 100% within 15 years. In fact, all we need to reach 100% renewables over the next 20 years is a mere 16% growth per annum.  And that ignores nuclear and hydro.  Eminently doable.

A similar dynamic is happening with electric cars.  They make up just over 1% of the world car sales.  But sales are doubling every 18 months.  That means that in ten years 100% of car sales could be electric.

We doubt these forecasts because our brains think linearly.  Exponential growth at some deep level make no sense to us.  But you have to ask yourself, using the logical analytical parts of your brain: why would growth rates slow before we reach close to 100% saturation?  Prices keep on falling; awareness of these new technologies keeps on rising, the cost advantage keeps on improving.  And technology take up S-curves are extremely common.  Think mobile phones, DVDs, microwaves, the telephone, colour television, electricity itself, etc, etc, as this beaut graphic shows.


What could stop 100% renewable electricity?  Well, the only thing, now that cost is no longer a hindrance, is that renewables are intrinsically variable in output.  And as we get closer and closer to 100% renewables, we will need progressively more storage. That will add to the total all-inclusive costs of wind and solar, so their uptake will slow.  But a grid with mixed sources of supply might need one day's storage (the CSIRO in Australia estimates that only half a day's storage is needed to reach 100% renewables).   And in 15 years, batteries and perhaps other storage will be one tenth of current costs.  So I don't think that will be too big a factor.  I think growth in wind and solar will continue to barrel along for another decade or more.

The implications for fossil fuel producers--and for policy makers and governments-- are clear.  Beware the carbon bubble.  Change is happening faster than our linear-constrained brains realise or feel comfortable with.  And getting it seriously wrong could be disastrous, for everybody. We don't need more coal mines.  And oil companies should stop exploring for new oil, because we won't need it.

Moral Crisis


Sunday, January 15, 2017

Renewables just keep on getting cheaper

(Source; click to enlarge)

In Mexico:

Twice in 2016 Mexico held two renewable power auctions that raised significant investor participation. 
The most recent, in September, saw 23 winning bids out of a pool of 57 to build renewable projects worth $4 billion for 2,871 megawatts of new capacity. More important, the average price at the auctions was US$33.47 per megawatt hour, (MWh) 30 percent less than prices from a previous auction in March. In the September auction, 54 percent of the supply was awarded to solar projects and 43 percent to wind farms. 
The March auction drew 69 prequalified bidders and awarded 18 projects with a total of 1,691 megawatts for solar and 394 for wind. The a average contract price was $47.60/MWh


In Chile:

According to media reports, Mainstream Renewable Power Ltd. and Empresa Nacional de Electricidad/Chile SA won more than two-thirds of the electricity supply auction in Chile. 
Meanwhile, Solarpack set a new record-low solar bid at 2.91¢/kWh ($29.1/MWh). That beats the 2.99¢/kWh bid a Masdar Consortium provided for an 800 MW solar power project in Dubai earlier this year. 
Mainstream has won rights to supply 3.7 TWh of electricity every year (30% of the auctioned electricity), while Endesa, a subsidiary of Enel, will supply 4.9 TWh (40% of the auctioned electricity). There was a significant correction in tariff in this auction compared to previous one. The average tariff bid in the auction declined 40% to US$47.59 per MWh compared to the previous auction. 
To supply the contracted electricity Mainstream will develop 7 wind energy projects with a total capacity of 985 MW. To achieve this capacity, the company is expected to invest $1.65 billion over the next 5 years. Electricity generated from these projects will be sold at tariffs between $38.8 per MWh and $47.2 per MWh.


In Abu Dhabi:

The United Arab Emirates has seen yet another record-breaking solar power tariff bid. Abu Dhabi received the lowest-ever bid for a solar PV project at a shocking 2.42¢/kWh, taking back the title of cheapest solar power project from Chile. 
Abu Dhabi Electricity and Water Authority received a total of 6 bids for the proposed 350 MW solar PV project planned to be built in the town of Swaihan, Abu Dhabi. Out of 6 bids, the lowest ever bid of 2.42¢/kWh has been submitted by the JinkoSolar–Marubeni consortium. The results of the tender are not out yet, as authorities will now evaluate the proposals for technical and economic viability. 
The current bid of 2.42¢/kWh is the lowest so far globally, and by quite a bit — it is shockingly low. This bid is 20% lower than the previous record bid of 2.91¢/kWh submitted at an auction in Chile last month. 
The second-lowest bid in the Abu Dhabi tender was reportedly not much higher, at 2.53¢/kWh, and was submitted by a local firm. These bids also beat the 2.99¢/kWh bid (shocking at the time … and still to some extent) submitted by a Masdar-led consortium for an 800 MW solar PV project in Dubai. 
The Abu Dhabi solar park was initially planned for 350 MW. However, media reports state a possible increase in project size, as bidders were allowed to bid for larger capacities. The final capacity of the solar power park may well increase to 1 GW.


Some points:

  • These, like South Africa, are mid-ranking developing countries.  Their electricity demand, contrasting with the situation in developed countries, is still growing.
  • Solar costs have more than halved in two years.  More than halved.  In two years.
  • These prices are already irresistibly cheap.  And they're going to get cheaper.  If electricity demand is expanding, the new generators built are not going to be coal-fired.  They're going to be wind and solar.  In developed countries, it's harder.  Even though renewables are cheaper than new coal, often much cheaper, existing coal power stations look cheap, because they're fully depreciated.  So the switch to renewables is constrained, though it is happening, especially where generation is highly competitive, for example in the USA.  The good news is that most of the coal generating fleet in developed countries is past its design life, and major refurbishment is not worth it.  New capacity (as it already is in the US) will be renewables plus gas, and coal-fired power stations will be progressively retired.
  • This means that coal demand has peaked, and that emissions from burning coal have peaked too.  Coal is the biggest contributor to CO2 emissions.  It's very likely that within 20 years there will be no coal-fired power stations.  Anywhere.  And that's without a carbon tax.  Introduce a $30 per tonne carbon tax and coal generators are toast.
  • It also means that despite Trump and his gang of climate-denying, oil- and coal-loving cabinet, despite the Republican cognitive dissonance about global warming, the renewables revolution is irreversible.  For a start, it's happening now in developing countries including China, not just rich developed countries.  Second, even in the USA, the switch to renewables is being driven not just by regulation, but by price.  And the states in the "wind corridor" might vote Republican but they're also very fond of their wind turbines and the cheap power they generate.
  • These developing countries and the US are installing both wind and solar, even though solar is cheaper, because the two together minimise the storage needed.  For now, the variability of renewables supply will be compensated for by gas.  In future, storage (CSP and batteries) will take the place of gas peaking power plants.  So demand for natural gas prolly hasn't peaked.  Yet.
  • The reverse auction (i.e., targeting the lowest not the highest price) is an extremely effective method to slash renewables costs. Are you listening Australia?  Germany?
  • I keep on saying this, so I'm beginning to sound like a record (remember them?) with a scratch.  But there are now no technical nor economic reasons  why we cannot aggressively switch electricity generation to renewables.   Global temps are rising by 0.2 deg C per decade.  Even though global CO2 emissions have probably peaked, they're not falling fast enough. We need to stop making excuses, stop listening to the lies of the denialists, and move.


From the Tages Anzeiger, a Swiss newspaper.

Saturday, January 14, 2017

How much land for solar?

The latest rather feeble tactic I've seen from a denialist is to assert that we can't switch to renewables because they'd take up too much land.  It's nonsense of course.

From Ramez Naam

We’ll probably never power the world entirely on solar, but if we did, it would take a rather small fraction of the world’s land area: Less than 1 percent of the Earth’s land area to provide for current electricity needs.

The second to last column tells us that, weighted by how much electricity they actually produce, large solar PV facilities need 3.4 acres of total space (panels + buildings + roads + everything else) for each Gwh of electricity they produce. 
That leads to an output estimate of 0.294 Gwh / year / acre, and virtually the same total area, around 50,000 square kilometers in the US, or 0.6% of the continental US’s land area.   
So, consider that: 
1. The built environment in the US (buildings, roads, parking lots, etc..) covered an estimated 83,337 square kilometers in 2009, or roughly 166% of the area estimated above. (Likely this area would not be as efficiently used, of course. But it could make a significant dent.) 
2. Idled cropland in the US, not currently being used, totaled 37.2 million acres in 2007, or roughly 150,000 square kilometers, roughly three times the area needed. 
3. “National Defense and Industrial” lands in the US (which includes military bases, department of energy facilities, and related, but NOT civilian factories, powerplants, coal mines, etc..) totaled 23 million acres in 2007, or roughly 93,000 square kilometers, nearly twice the area needed to meet US electricity demand via solar. Presumably much of that land is actively in use, but it gives a sense of the scale. 
4. Coal mines have disturbed an estimated 8.4 million acres of land in the US. That works out to around 34,000 square kilometers, not too far off for the estimate from solar, and doesn’t include the space for coal power plants. And coal currently produces around only 40% of US electricity and hasn’t been above 60% in decades. To scale coal to 100% of US electricity would have required far more land than is required to meet that same demand via solar. Other analysis says the same: Counting the size of coal mines and their output, solar has a smaller land footprint per unit of energy than coal. 
And the solar estimate of ~50,000 square kilometers, of course, is with solar systems already deployed. It doesn’t take into account the possibility of future systems with higher efficiencies that could reduce the land footprint needed.
Read more here.

It's a bit more complicated with wind farms.  According to this piece from NREL (doing for wind what this piece did for solar):

Excluding several outliers, the average value for the total project area was about 34 ± 22 hectares/MW, equal to a capacity density of 3.0 ± 1.7 MW/km2.

This implies an output of  about 3.1 GWh/acre/year from a wind farm.  But unlike solar farms, farming can continue on the ground even as the turbines turn overhead.  If you read the NREL article in full, you'll see the problems they had estimating actual land use, and their calcs are correct only if you assume the land can't be used for anything else.  This snippet from this article about UK wind farms says:

A standard wind farm of 20 turbines will extend over an area of about 1 square kilometre, but only 1% of the land is used for the turbines, electrical infrastructure and access roads. The rest of the land can be used for farming or natural habitat.

My guess is, if you allow for the fact that most of the land in a wind farm has two uses, once again, even if we were to get 100% of power from wind farms, it would still only take about the same as solar: under one percent of land area.

Moral of the story: no, we will not be constrained by the availability of land from switching to renewables.

Wednesday, January 11, 2017

The tiger is out of its cage

Tesla has announced that battery cell production has begun at its gigafactory in Nevada.  Well, one in the eye for the Tesla haters, but not really earth-shattering news.  Except for this:

With the Gigafactory online and ramping up production, our cost of battery cells will significantly decline due to increasing automation and process design to enhance yield, lowered capital investment per Wh of production, the simple optimization of locating most manufacturing processes under one roof, and economies of scale. By bringing down the cost of batteries, we can make our products available to more and more people, allowing us to make the biggest possible impact on transitioning the world to sustainable energy.

[My underlining.  Read the original new release here]

Now Tesla has already reduced the cost of batteries by nearly 50% in one year.  And that's before it started producing its own batteries.  So what does a significant decline mean?  30%?  50%?  Whichever percentage, it's massive.   Up until a couple of years ago, lithium-ion battery costs fell by 15% per annum, which seemed really fast then!

Storage has been the missing link in the roll out of renewables.  For storing solar from the 9 am to 3 pm insolation peak for evening demand, or for smoothing out the random cyclical variability of wind supply, storage is essential if we are to go to 100% renewables in electricity generation, and of course it's essential for electrifying transport.   I've talked about CSP here and here.   That's a good option for utility level solar plus storage.

But for households, small businesses, and small town "micro-grids", rooftop solar PV plus batteries increasingly seems like a marriage made in heaven, and the attraction only gets hotter as battery costs fall.  I predict it will be the norm for households with solar to also have one Tesla Powerwall, which won't quite store enough for a day's usage, here in Australia, anyway, but will take us a long way towards it.  As long as the electricity suppliers pay half of nothing for the solar-generated electricity we put back into the grid, behind-the-meter batteries are going to be attractive.  That's in most countries outside the US, and especially Australia, where feed-in tariffs are sometimes zero, while electricity bought from the grid costs 25 cents per KWh.

The fall in battery costs means that the cost of an electric car will also cross that magical line where they have the same sticker price as petrol-driven cars.  They are already cheaper to run, because electric cars are more efficient, require far less maintenance, and depreciate slower.  They're far more fun to drive, much quieter and smoother, and produce no direct pollution.  If their sticker price is the same as a petrol (gasoline) car, then the only remaining negatives will be charging time and the absence of charging stations.  But those are mostly relevant only for long journeys, once you have more than 160 kms (100 miles) of range, as most ppl commute less than 100 k's (60 miles) per day, and so will only need to charge their cars at home overnight.

So if battery costs halve again over, say, the next 18 months, we are going to see an explosive growth in EV sales.  And as EV sales take off, the supercharging network will grow, and at some point petrol service stations will either close down or convert to EV charging stations offering you tea, coffee and a snack while your EV charges.  There will come a point where petrol-driven cars are less convenient than electric cars, where range anxiety will be something only owners of petrol cars experience,

Alternatively, those with electric range anxiety will buy a plug-in hybrid.  But my guess is that there will only be a brief period (5 years?) when they're financially worth it, because essentially hybrids have two engines and two energy storage devices, with all the disadvantages and expense of petrol vehicles.  Once there are superchargers everywhere, why bother about a petrol backup?

Tesla is inexorably and irreversibly shifting the energy landscape.  Thanks to them, we will all ultimately be able to live with cheap, reliable carbon-free energy.  And that shift is happening far faster than we thought, even just a year ago, let alone 5 years ago.  Trump and his dotty climate-denying, oil-loving buddies won't be able to stop it.  Actually, I don't think, after this latest news, they'll even be able to slow it.  The tiger is out of its cage.

Sunday, January 8, 2017

CSP on steroids

The Crescent Dunes CSP facility, via PowerMag

CSP stands for 'concentrated solar power', with 'with storage' always understood.  In fact, the Ivanpah CSP plant, which is the biggest in the US, doesn't have storage, but the Crescent Dunes facility at Tonopah  in Nevada has 10 hours' worth.  You can read an excellent detailed article about the Crescent Dunes plant here.

On a normal day, Crescent Dunes begins generating power around 10 a.m., reaches full power around noon, and stays there until 10 p.m. to midnight per the terms of its PPA, which calls for 12 to 14 hours of generation a day. This helps NV Energy meet peak evening demand, and Crescent Dunes shuts down as that demand falls late at night. 
But that’s only what it’s contracted to do for the utility. The PPA, in fact, doesn’t exploit the plant’s full capabilities. By reducing its net output slightly, Crescent Dunes can actually operate 24 hours a day, banking excess thermal energy while the sun shines and using it to generate steam all night. As a proof of concept, SolarReserve ran the plant for a continuous 120-hour period during July. While doing so, it was able to maintain full power for most of the day, only ramping down to about 60% power during the early morning hours. 

SolarReserve has an array of new plants in various stages of development that will be less expensive and even more efficient than Crescent Dunes, Smith said. Two near-term examples will move substantially past what the company has achieved in Nevada. 
The 100-MW Redstone project in South Africa, which breaks ground this fall and will incorporate 12 hours of storage, should see about a 30% decrease in construction costs from Crescent Dunes, as well as reduced construction times. The 260-MW Copiapó project in Chile, with 14 hours of storage, plans to bid its power at under $70/MWh, without subsidies. That plant, using two solar towers and an additional 150 MW of PV generation, is being designed from the ground up to operate as a 24-hour-a-day baseload facility.
Other projects are in the works in China and Australia, Smith said. “We have an agreement with Shenhua, China’s largest coal generator, to build a 10-tower facility, and another agreement with State Grid Corp. to build another 10 towers, though they may not be all on the same site.” 

[Read more here]

SolarReserve is planning a new CSP plant in Nevada, which will be the largest solar plant in the world, more than 10 times larger than the Crescent Dunes one:

The race to build the world's largest solar power plant is heating up. California-based energy company SolarReserve announced plans for a massive concentrated solar power (CSP) plant in Nevada.   
SolarReserve CEO Kevin Smith told the Las Vegas Review-Journal that the $5 billion endeavor would generate between 1,500 and 2,000 megawatts of power, enough to power about 1 million homes. That amount of power is as much as a nuclear power plant, or the 2,000-megawatt Hoover Dam and far bigger than any other existing solar facility on Earth. 
SolarReserve's Sandstone project involves at least 100,000 mirrored heliostats that capture the sun's rays and concentrates it onto 10 towers equipped with a molten salt energy storage system. The molten salt, heated to more than 1,000 degrees, then boils water and creates a steam turbine that can drive generators 24/7. 
Compared to photovoltaic arrays, the appeal of CSP systems is that solar power can be used after sunset. 
"It's really the ability to provide renewable energy that's available on demand 24 hours a day," Smith told NPR. 

[Read more here]

This single plant will provide about 4.5% of California's peak electricity needs.

Note that the electricity from the first CSP plant, Crescent Dunes, was contracted at $US135/MWh, after subsidy, but that the Chile plant costs US$70/MWh, though that includes PV (photo-voltaic, i.e., solar) panels which would reduce the cost.  The big advantage of CSP over battery storage is that the CSp tanks containing the molten salts don't degrade over time as batteries do.

Lazard costs the cheapest CSP at US$119/MWh, and PV with battery at $92/MWh  (although I question their battery degradation rate of 1.5% per annum; I think that's way too low.  But they are more expert at this than I am).  The costs of both technologies  are falling fast, and I'm not sure which will win out in the end.  Probably we'll use both, PV plus batteries at homes and small businesses, CSP at utility level.  Whichever wins, in sunny places around the world there will be no technical or economic difficulty switching to 100% renewable electricity generation.

[P.S.  Some have expressed concern at birds who are killed flying through the concentrating beams.  The fewer birds incinerated, the better.   Fortunately, they've fixed that problem]

Monday, January 2, 2017


The electricity demand of a single house or small business is unpredictable from minute to minute. The graph below shows a typical demand profile of an individual household monitored every 2 minutes.


However, when you aggregate the demand from millions of households, it becomes reasonably predictable from day to day and month to month.  The chart below shows Californian electricity demand on a hot day in 1999 (it doesn't show net demand, that is, demand net of power generated by solar panels, which produces the "peaking duck" curve)


There are still fluctuations of course, with daytime demand peaking at twice the level that demand falls to at its low point in the wee hours of the morning, but the curves are much smoother.  On hot days, conveniently, the demand peak partially coincides with a likely supply peak from solar.  With a few hours of storage, solar could provide for all daytime demand, at least for places between latitudes 35 or 40 N and S.

Now the key point here is that if the grid had to be built to supply the peak power demands of each individual household, electricity would be extremely expensive.  That's why "going off the grid" is too expensive to do, no matter how tempted we are by the outrageous electricity prices and network fees charged by our utilities.  An individual house or small business would need far too much capacity to make sure it never ran out of power.  For the grid as a whole, far less spare capacity is needed, because individual peaks and troughs are averaged out.  This spare capacity is often provided by gas peaking plants, which can start up quickly and turn off quickly whereas most "baseload" power (coal and nuclear) can't be easily scaled up or down.

The same averaging process is true when you are looking at individual sources of supply too, including the variable supply from renewable generating sources.  Take a look at the chart below (from this website)  It shows the wind output of various Australian wind farms expressed as a percentage of total capacity.  The black line shows total Australian wind farm output, also as a percentage of total capacity.  See how individual wind farms can fluctuate from nearly 100% of capacity down to 0% in the space of a few hours, but how the total of all wind farms across the country (the black line) varies between 30% and 50%.  On average, over time, Oz wind farms produce 30 to 35% of nameplate capacity.


This is all relevant because when we're working out how much backup or storage we need, there are some who maintain that each wind or solar farm needs 100% backup from a conventional fossil fuel generator.  And of course, this makes wind and solar appear impossibly expensive (that's the point, I suspect).  But we don't actually need that much back up or storage.  Here're  the views of the CSIRO (Commonwealth Scientific and Industrial Research Organisation), an Australian independent government-funded research body:

CSIRO Energy chief economist Paul Graham says that additional storage is not needed for up to 40 to 50 per cent wind and solar penetration. That’s because the grid can rely on existing back-up ( built to meet peaks in demand and for when coal and gas “baseload” generators trip or need to be repaired).

Beyond those levels, storage needs to be part of the equation. But again, not as much as many would think. But as the back-up generators gradually exit the grid, they can be replaced by various storage types, until storage then becomes the principal form of back-up and grid security on the grid.The CSIRO modelling showed that at very high levels of wind and solar, a maximum of half a day’s average demand was needed for storage. In some areas of the grid, only around three hours might be needed.

This is an important point, because some renewable critics say that about a week’s worth of storage is needed, and multiples of wind and solar capacity required for back up. These would be the same people that argue that climate science is a hoax, but it is a view that has more traction than it should.

Graham says the CSIRO modelling indicated that at those very high levels, about 0.8GW of back-up was required for about every GW of wind and solar capacity. This is around the same amount of back up capacity currently needed by centralised power plants to meet peak demand and outages.

[Read more here; my emphasis]

What's true for Australia is likely true for most other geographies where power is generated from a variety of sources, except as I discuss here, countries in high latitudes where the majority of renewable power will come from wind.  Though note that the CSIRO's forecasts assume that more than half of Australia's power will be wind generated by 2050.

Lazard have recently updated their LCOEs for different generation sources, and for the first time have provided an estimate of solar with 10 hours of storage.  They come up with a cost of US$92/MWh.   Average coal (in the US, ignoring the implicit cost of pollution, i.e., without a carbon tax) is $100/MWh.    Combined cycle natural gas is cheaper, averaging US$63/MWh, but as the chart below shows, natural gas prices fluctuate widely.  And if--when--fracking is curtailed because of its environmental costs, the price is likely to rise further.  So in future gas may not be cheaper than solar plus batteries, even without a carbon tax.


 You might notice that though output from an generator fuelled by fossil fuels is stable, apart from outages, its costs are not stable; while on the other hand output from renewable energy sources is variable, but its costs are fixed, because its "fuel" is free.  A sort of  Heisenberg uncertainty principle for electricity generation.  But utilities and users value price stability as much as they value supply reliability,  Even if gas is cheaper, they might still find the price and supply stability promised by renewables plus storage as very attractive.

Lazard has made a much more detailed costing of storage than I was able to.  What it shows is that for most of the world, even when you add in the necessary storage, solar can provide us with all our electricity needs.  And when I say most of the world, I mean India, China, Africa, the southern  US and Europe, Australia and South America., as you can see from the chart below.  These regions can all be powered from solar plus storage.  Right now.  As cheaply as or more cheaply than coal.  And with more stable costings than gas.  Even without a carbon tax.  These locations might also have wind energy, and that's a bonus, because the output from wind plus solar is on average less variable than the output of either alone.  But they can do it on solar.  Right now.

Global temperatures are rising by 0.2 deg C per decade on average.  If it takes us 2 decades to switch our entire generation fleet to renewables, and to electrify most transport, temperatures will still have risen by another 0.4 deg C.  The 1 deg C rise we've already had has caused enough problems.  We can't afford to wait, and now we have no reason to either.  Switching to renewables is now affordable.  And it won't cost us the earth.

Solar industry employment