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A Million Cars at Sea

Ever wanted to go on an ocean liner? Cruise ship advertisements idealise the high life to be had on the high seas. What they never say is how much ships pollute. The average ship runs on low grade oil, which can be likened to a sludge that emits more particulate matter than a million cars; more sulfur than seven million cars. And that’s just one cruise liner!

Several Scandinavian ferries now run on hybrid diesel-electric systems but, as in most advances in electric propulsion these days, China is taking the lead, as a cargo ship with a 2.4 MWh battery pack launches in Guangdong. Ironically, the ship will be used to transport dirty coal!

A new all-electric cargo ship with a massive 2.4 MWh battery pack launches in China

Car makers have a problem. They don’t admit it yet. Or maybe they do admit it to themselves, although not in public. Why should they, when enough people are buying bigger cars? Global car sales in 2017 were close to 90 million vehicles in all categories, including SUVs and light trucks. That’s roughly 1 car for every 77 people. Less than 1% of these were electric. How many more cars do we need? Car companies are powerful entities that are in the business of selling dreams; dreams of freedom, of the joy of the open road, dreams of independence. The irony is that as we buy into the dream, we destroy the very foundation on which our dreams are based.

 

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Life After IIASA 1975-2013: Five Years On

February 2018 will mark five years after my retirement from IIASA. These five years have been full of new experiences, travel and writing. My wife and I have also attempted during this time to modify our lifestyle to be as carbon neutral as possible. Measures include living without a car, using a bicycle for shopping and public transport for travel where possible. Trips by air are unavoidable in the lifestyle we’ve chosen, and we’ve attempted to offset this carbon by buying solar panels for a farm school in India and a solar farm in Austria, 8 KW in all. These panels will apparently offset around 8 tons annually, but there’s still more to be done.

I first heard about sea level rise in a talk by paleo-climatologist Herbert Flohn at IIASA sometime in the late 1970s. At that time, many of the information requests that the IIASA library received were about global effects of a nuclear winter in the aftermath of nuclear war. Research themes changed quickly; interest moving to carbon dioxide emissions from fossils fuels, global warming, acid rain and stratospheric ozone.

In the intervening years, the reality of human-induced global warming has been accepted by all but the most ideologically blinkered societies worldwide. Travelling through parts of rural India soon after retirement in 2013, I saw repeated instances of people taking actions to adapt to climate change; water harvesting to compensate for unprecedented droughts, reforestation efforts; introduction of organic farming methods and drought resistant crops. I’d like to think that much of the credit for these adaptation and mitigation actions goes to studies by IIASA and other research institutions worldwide; scientific studies whose results filtered down over decades through the media and drew attention to these problems early on. There’s no way to prove this, and some of the water harvesting systems I saw were really ancient structures brought back into use. See more about that here

Efforts in 2015 and 2016 to help establish a rural education and vocation center failed for a very positive reason. The five acres of land (2 hectares) that had been donated to us for school use by a well-wisher is worth approximately € 300,000 (€65,000 per acre at today’s prices). The donated property was fertile agricultural land and classified as such. The local administrative authorities refused permission to reclassify the plot for use as a school and insisted that the land remain in use for agriculture. This was a positive outcome, because one of our reasons for this choice of location of a school was to prevent displacement of the rural population by expensive housing projects that would only benefit urbanites.

However the effort was not wasted. Since then our local partners have decided to build an organic farm on the land and use the experience gained to encourage the farming practices of communities in neighbouring villages. One function of this farm would be to develop markets for organic produce. We discovered several small companies in the area that offer free midday meals to their workers. They were happy to find a local supply of good vegetables. One enterprising factory owner offered his workers three free meals a day, sourcing all the vegetables from his own backyard. The vegetables he showed us were grown in plastic tubs lined with mats made of nutrient-rich hemp fibers. In fact, the method is so successful that he gives away growing kits free to any of his workers who want one for their own families’ use.

An encounter in early 2017 with a conservationist who runs a hatchery for Olive Ridley turtles on the sea coast near Chennai city led me to Tiruvannamalai, a town 200 km to the south-west. Here is an organic farm school where text-book sustainable living is practiced in the most lively and joyous manner possible. There are around 100 children in the school, ranging in age from 8 to 18. The links below will give an idea of activities at the school.

http://www.marudamfarmschool.org/

https://yourstory.com/2017/12/2-lakh-trees-ngo-regenerating-forest-tamil-nadu/

http://www.theforestway.org/greening/planting.html

In addition to organic farming, environmental conservation and education, the school also works with villagers in the surrounding countryside, reforesting the hill that dominates the temple town, planting around 15,000 trees a year. The school’s efforts inspired us (myself and a few friends in India) to help them become energy self-sufficient, adding 5 KW of solar panels to the three they already had. Together with battery backup, the school is now completely independent of the grid. (photo attached).

This activity led me to a thought. If IIASA’s work ultimately inspired these kinds of sustainability acts, what about IIASA’s own carbon footprint? IIASA’s alumni are scattered all over the world. What if we joined together, wherever we are, and worked to offset IIASA’s carbon emissions? Such actions would benefit our own communities, wherever we may happen to live. To kick-start this effort, I’ve decided to fund the planting of 1000 trees in 2018 through the farm school mentioned above. If each tree sequesters 25 kilos of carbon (as a rule of thumb, regardless of species), this would offset 25 tons of the Institute’s annual carbon emissions.

Should this be a formal organized effort? Readers’ suggestion welcomed here. All we would need is a virtual platform where one can document one’s own efforts and have a running tally. Ultimately the goal is to achieve carbon neutrality, not only for the Institute, but also for the communities in which each one of us lives. But, as for so many initiatives, IIASA could be a starting point.

On a personal note, the years since retirement have been very fulfilling. Thanks to my wife’s job, we were able to spend 2 idyllic years on an island paradise near Hong Kong. This provided background material for a work of fiction, Grace in the South China Sea. There are two sequels in the pipeline (The Trees of Ta Prohm, and Heartwood), to appear in 2018. Look for the earlier books and announcements on the Amazon author page here.

 

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Advice to a Billionaire

Michael Liebreich of Bloomberg New Energy Finance calls you one of three Black Swans in the world of energy and transportation this century; the other two being Fracking and Fukushima. You are often compared to Henry Ford, Thomas Edison, Nikola Tesla, the Iron Man, and shades of Einstein. You have advised Presidents. Heads of state visit your factories to see how they could improve the lives of their citizens. You stepped in without fanfare to donate money and provide power to a hospital in Puerto Rico after the devastation of Hurricane Maria. You issue audacious challenges to yourself and to others and sometimes miss deadlines, but ultimately deliver on your promises. Thousands, perhaps millions of people, speculate against you in the stock markets, hoping to make a quick profit from your failure. So far, they’ve been disappointed. But you put your money where your mouth is, so for every one of these speculative sharks, there are a thousand eager customers for your products and millions of well-wishers who hope you can help save the planet.

And yet you feel alone and unloved. You search for a soul mate and are willing to fly to the ends of the earth to find true love. You must know that love is like a butterfly. Be still and perhaps it will land on you. There are no guarantees, but the chances are infinitely greater if you cultivate stillness. And while you wait, exchange your loneliness for the wealth of solitude. As Hannah Arendt and Plato observed: Thinking, existentially speaking, is a solitary but not a lonely business.

As the father of five children, know also that their childhood is a precious and finite resource that you could use to your benefit and theirs. Childhood ends all too soon, so help them in whatever way you can to make good choices. You seem to have done so for yourself. In the meantime, millions of people around the world wish you well, as I do.

Blades of Grass

Image courtesy 123rf.com

Image courtesy 123rf.com

The recent accession of climate change deniers to positions of power (no names here!)  is very depressing news for those millions of people around the world who don’t totally distrust all media, mistrust all scientific research, or contradict factual evidence. Nevertheless there are many examples of happenings around the world that might not make international headlines because they are not (yet) economically significant. Economically significant or not, these actions are ecologically significant in a global context. These are actions that need to be emulated a hundred-fold, a thousand-fold, a million-fold, in the decade to come. A climate scientist friend told me years ago that the world would not act on the climate issue until it became a globally self-evident crisis. And then, he said, people would come together out of the woodwork at the last minute, to do what is needed to save our planet from irreversible changes; for example, in the interplay between circulation of deep ocean waters and the quantity of atmospheric carbon dioxide absorbed by them.

What follows is a short, incomplete list of the various ways people are coming out of the woodwork.

The 2017 Women’s marches around the world could be a powerful harbinger of things to come. According to Wikipedia: The 2017 Women’s Marches were a series of political rallies that took place in cities around the world since January 21, 2017, with the goal of promoting women’s rights, immigration reform, and health care reform; to counter Islamophobia, rape culture, and LGBTQ abuse; and to address racial inequities (e.g., Black Lives Matter), workers’ issues, and environmental issues. There is a sea change here. The Women’s March took place in cities on every continent. It was a spontaneous coming together on a multitude of human rights issues, much bigger causes than merely protesting against He Who Will Not be Named, he who was merely the catalyst that brought the marchers together. Like blades of grass that probe and emerge through the hardest concrete, these marches are the peaceful means to crack the brittle edifice of patriarchal structures the world over.

Three examples from India, where I happen to be at the moment, underline the environmental component of this sea change:
The small town of Meenangadi in Kerala has pledged to become the first carbon-neutral panchayat (rurally governed community) in India. And they expect to do it by 2020. Here’s an explanation of why they are doing this and what steps are being taken to achieve this goal.
In nearby Cochin (or Kochi, as it has been named by the local administration), the International Airport, call sign COK, is the world’s first completely solar powered airport. BBC News, October 2015.
At Kamuthi, near the town of Madurai in Tamil Nadu, the world’s largest solar power plant built on a single site was completed in 8 months, covering an area of 10 sq. km., with a capacity of 648 MW. Al Jazeera, November 2016. Meanwhile in China, this is topped by the Longyangxia Dam Solar Park with a peak output of 840 MW from solar panels clustered at two adjacent sites near the reservoir.

Other blades of grass sprout everywhere. In Vienna, after the election victory of You-Know-Who on 9 November, hundreds of volunteers went out on to the streets to campaign for the green party candidate in Austria’s presidential election. These volunteers were campaigning against scare-mongering and fear-of-the-other tactics that are habitually practiced by right wing demagogues, unfortunately with some success in the recent past. In many countries around the world, people fed up (pun intended) of industrial agriculture are turning to food production in their back yards, on window sills, on terraces. This awareness of the source of our nutrition makes people appreciate its literally life-giving qualities, bringing back the sanctity of producing our own food. The process brings people together in simple ways and promotes communal harmony. Mayors of cities around the world are networking together to circumvent the inaction of their politicians and lawmakers. I see green fields around the world where millions of tender blades of grass crack the concrete of established practice. I see this in the near future, if the millions who have marched will it so. It’s time now to march, plant, demonstrate, protest, cooperate, sow, reap, make your voice heard, switch off your TV, get off your couch, harvest potatoes, get active.

For more by this author, see his Amazon page here, or the link to Google Play where you can download free sample excerpts from his books.

Fossil Fuels are for Dinosaurs II

Wake up, Donald et al.! According to the Guardian of 6 January 2017,

China now owned:

  • Five of the world’s six largest solar-module manufacturing firms
  • The largest wind-turbine manufacturer
  • The world’s largest lithium ion manufacturer
  • The world’s largest electricity utility

“At the moment China is leaving everyone behind and has a real first-mover and scale advantage, which will be exacerbated if countries such as the US, UK and Australia continue to apply the brakes to clean energy,” he said.

“The US is already slipping well behind China in the race to secure a larger share of the booming clean energy market. With the incoming administration talking up coal and gas, prospective domestic policy changes don’t bode well,” Buckley said.

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Oceans of Lithium

Salar de Uyuni. Source: Wikipedia.en

Salar de Uyuni. Source: Wikipedia.en

Salar de Uyuni in Southwest Bolivia contains an estimated 43 % of the world’s easily recoverable lithium. Together with neighbors Chile and Argentina, the three countries contain 70% of the planet’s reserves. As most people are aware by now, the renewables revolution is gathering momentum, and the world needs lithium, lots of it. The people who follow these trends estimate that Tesla’s Gigafactory alone, when it comes into production, will double world demand for lithium, whose prices have shot up just in the last two months of 2015 (from US$ 6500 to 13,000 a ton in November/December). American, Japanese, Chinese and South Korean companies are already mining around 170,000 tons of lithium worldwide. The Argentinian salares, or salt flats, comprise thousands of square miles in the provinces of Catamarca, Jujuy and Salta. The Salinas Grandes in the latter province is estimated to be the third largest in the world. But the grand-daddy of them all is the Salar de Uyuni in Bolivia that stretches over 10,000 sq.km. To paraphrase Exupéry, Salar de Uyuni is made up of salt, salt salt, and more salt, to a depth of one meter or more. In addition to common salt (sodium chloride), the salars contain other useful chlorides; potassium, magnesium and lithium chloride. The estimated 9 millions tons of lithium contained in this salar, conveniently concentrated by natural evaporation, should be enough to power a global energy revolution or two, but at what cost? Bolivia has suspended mining operations after the local residents opposed it, and Chile is granting no new concessions. These are understandable steps, in the light of what economists call ‘the resource curse.‘ In a nutshell, the resource curse or the resource paradox is that often countries with non-renewable natural resources (like minerals and oil) tend to have lower economic growth and less democracy than countries with fewer natural assets.

Understanding the resource curse does not help the international battery industry or alleviate the world’s need for non-polluting sources of energy, however. The increasing price of lithium is driving research into methods of obtaining it from the most abundant source on the planet, the oceans. Industrial ecologist Robert Ayres confidently predicted to me more than a decade ago that we would get all the lithium we need from the ocean. “There’s billions of tons there,” he said. True, there is an estimated 230 billion tons of lithium in seawater, but at a concentration of 0.14 to 0.25 parts per million, I did not believe it possible to extract it in meaningful quantities at reasonable cost. Changed my tune this week.

Many companies worldwide have been experimenting with various reverse osmosis technologies (the same technology that’s most often used to desalinate seawater) to produce brine concentrates dense enough to make lithium extraction economical. Now there are reports of several companies in a dozen countries that envisage producing lithium from brine concentrates at prices ranging from $1,500 to 5,000 per ton. Here’s an article about one of them.

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Spreading the Sunshine 1: A New Year Message

Even today, in the first half of the twenty-first century, thousands of villages in Africa and Asia (mainly in India) remain off-grid and have no access to electricity. Ever since a three-month stay in Kenya and Tanzania in 1985,  I have dreamt of bringing solar lighting to the smallest villages on these two continents. In Kenya I was astounded to see that, as early as 1985, a few rural families had bought individual solar panels connected to used car batteries to power a single light bulb and the occasional television set. They did this because they had no hope of access to grid electricity in their lifetimes. It’s even more astounding to think that in affluent countries today, the majority of people who drive $ 20,000 cars consider solar power unaffordable without government subsidies. No wonder the world is hotting up! Such economic calculations show how skewed our thinking is.

Of course it was obvious that this journey of a thousand miles begins with a single step. Less obvious was what this first step should be. Mhairi made the first step on a recent (November 2015) visit to a village on the outskirts of a tiger sanctuary in Rajasthan. She made contact with the owner of a handicrafts shop on the edge of the Ranthambore national forest and tiger reserve who helps village craftswomen earn a living by marketing the beautiful tiger paintings, patchwork quilts with mirror designs and appliqué fabrics they make. Dharamveer was thrilled to hear about the idea of installing solar lighting for the nearby villages. He immediately took us to visit three of the 10 surrounding villages. These villagers have limited or no access to electricity. Even the few homes connected to the grid have power only 2 or 3 days a week, so they end up spending 2 to 3 hundred rupees a month on electricity bills or on kerosene for inadequate lighting with lamps. The proposal to pre-finance solar lamps for each household in the village was met with much enthusiasm. They were quite willing to pay 200 to 300 rupees a month for reliable solar lighting. And they were delighted to hear that, at a price of just 499 rupees (US $ 7 at current exchange rates), the lamps would belong to them within three months. Apart from the environmental costs of burning kerosene, the biggest drawbacks are cost and inadequate light for children studying or doing homework.

The Pico lamp, US $ 7 with a 2-year guarantee.

The Pico lamp, US $ 7 with a 2-year guarantee.

The idea we propose is quite simple. We plan to finance around one hundred of these solar lamps initially, to be distributed to a number of households in the ten target villages. Presumably they will be paid for in 3 months from the money the villagers save from their kerosene and electricity bills. We will request voluntary contributions for another 2 months and use the extra money to expand the circle of recipients till all households in the villages are covered. After which one can think of more elaborate systems, for example, like the model shown here that costs 7000 rupees or US $ 100 at today’s exchange rates. Greenlight is a for-profit company started in the US by three engineers, two American and one Indian. Their products have received good reviews in the international press.

The Sun King Home 120 is priced at approx US $ 100.

The Sun King Home 120 is priced at approx US $ 100, can power USB devices and mobile phones.

We have decided on Greenlight’s Sun King model range, based only on our own internet research and news reports. Readers of this blog are invited to give feedback or share their own experiences with different models. I can envisage offering a range of different systems based on cost and reliability. I look forward to hearing from you.

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It’s Raining Electrons in Small Spaces

Four recent reports on new breakthroughs in renewable energy generation and storage technology reinforce the promise that was once made for nuclear power: abundant energy for all, including the poorest in society, even though it may never be “too cheap to meter.”

High Performance Flow Batteries The promise of renewable energy technologies will be fully realized when battery storage becomes reliable enough and cheap enough to even out intermittent flows. Today the problem is partly solved by feeding energy from rooftop panels into the grid and then receiving compensation from the energy utility for the power supplied either in cash or in the form of reduced electricity bills. Looking at a typical electricity bill in Euroland (my own) I see the following charges. The unit price (per KWh) is between 6.5 and 7.3 Eurocents, but after grid charges, network costs and taxes are added, I pay 26 cents per KWh. Ironically, bulk consumers (factories, office blocks and large companies) pay lower rates, around 8 to 15 cents per KWh, depending on level of consumption. Now the whole picture is changed with the advent of low cost storage systems that make home batteries affordable and economical. Imagine home systems that can deliver electricity for all your needs at no cost for twenty to thirty years, once installed, barring the onetime cost of the system. Coming soon, to an affordable home near you.

Silicon cones inspired by the architecture of the human eye. The retina of the human eye contains photoreceptors in the form of rods and cones. Rods in the retina are the most sensitive to light, while cones enhance colour sensitivity. Modelling photovoltaic cells based on the makeup of the retina, researchers have been able to enhance the sensitivity of solar cells to different colours in the sunlight that falls on each cell and thereby increase electricity output by “milking the spectrum” closer to its theoretical maximum. Increasing efficiency of the average rooftop PV cells from the current 18-20 to 30% would make such systems cheaper by far than grid electricity mostly anywhere in the world, even in temperate countries. Coming soon, to a rooftop near you.

Modular biobattery plant that turns biowaste into energy. Biogas plants are old hat. They have undeniable benefits, turning plant, animal and human waste into energy (methane) while leaving behind a rich sludge that is excellent fertiliser. However, good designs are not common and they are sometimes cumbersome to feed and maintain. Now comes an efficient German design that promises to be modular and economically viable even at a small scale. In another development, the University of West England at Bristol has developed a toilet that turns human urine into electricity on the fly (pardon the pun) and the prototype is currently undergoing testing, appropriately enough, near the student union bar. Coming soon, to a poo-place or a pee-place near you.

New electrolyte for lithium ion batteries. Lithium ion batteries using various electrolytes have already become the workhorse of the current crop of electric cars and for medium-sized storage requirements. New electrolyte chemistry discovered at PNNL Labs shows that reductions of upto ten times in size, cost and density are feasible and various electrolyte/electrode combinations are being further tested for production feasibility. Coming soon, to a battery storage terminal near you.

So what should you do, as a concerned global citizen, until you can lay your hands on one of these devices (or all of them) for your own use? Tread lightly on the earth, don’t buy bottled water, reduce energy use, walk when you can instead of driving your car (your arteries will love you for it), buy local produce, eat less meat (your grateful arteries again), think twice before flying off to that conference (think teleconferencing), buy an electric car if you need a new one, and remember that every liter or gallon of petrol you fill into your old one not only fuels your car but potentially also the conflicts in the Middle East and/or lines the deep pockets of Big Oil which definitely does not want your energy independence.

The Flea on the Behind of an Elephant

Scroll backwards in time to the early 1970s. US President Richard Nixon appointed the Atomic Energy Commission (AEC) to produce a study of recommendations on “The Nation’s Energy Future” based on advice from the National Science Foundation (NSF). Requesting the AEC for energy prognoses is akin to asking a tiger for dietary recommendations; there will surely be no vegetables on the menu! Dr. Dixy Lee Ray, chair of the AEC, predicted in her summation of the report that “solar would always remain like the flea on the behind of an elephant.” In the early 1980s I knew another eminent researcher, Dr. Thomas Henry Lee, a Vice President for research under Jack Welch at General Electric, who often stated that nuclear power would produce “energy that is too cheap to meter,” essentially free.

The AEC study, when it was published, proposed a $10 billion budget for research and development with half going to nuclear and fusion, while the rest would be spent on coal and oil. A mere $36 million was to be allocated to photovoltaics (PV). Dr. Barry Commoner, an early initiator of the environmental movement, was intrigued that the NSF had recommended such a paltry amount for solar. In the 1950s he had successfully lobbied for citizen access to the classified results of atmospheric nuclear tests and was able to prove that such tests led to radioactive buildup in humans. This led to the introduction of the nuclear test ban treaty of 1963.

Dr. Commoner’s own slogan (the first law of ecology is that everything is related to everything else) prompted him to question the AEC’s paltry allocation for solar PV, especially since he knew some of the members of the NSF panel who advised on the recommendations. He discovered the NSF panel’s findings were printed in a report called “Subpanel IX: Solar and other energy sources.” This report was nowhere to be found among the AEC’s documents until a single faded photocopy was unexpectedly discovered in the reading room of the AEC’s own library. The NSF’s experts had foreseen in 1971 a great future for solar electricity, predicting PV would supply more than 7% of the US electrical generation capacity by the year 2000 and the expenditure for realising the solar option would be 16 times less than the nuclear choice.

Clearly, the prediction of 7% solar electric generation has not yet happened, but current efficiency improvements in photovoltaics and battery storage technologies point the way to an energy future far beyond what the NSF predicted in 1971. Fifty years from now, it is nuclear power that is likely to be the flea on the behind of a solar elephant.

Renewables: Solar Cells and CO2

For those who despair at the daily news reports of record-breaking summer temperatures and the inexorable onset of global warming, take heed and take hope from the following numbers. The total installed generating capacity of photovoltaic (PV) solar worldwide in 2012 equalled 100 GW, or roughly the equivalent of 100 nuclear power plants. Solar PV is a silent, reliable technology (as long as the sun shines, but see Intermittency below for more on that) with no moving parts and a life expectancy of 20 – 40 years. This currently installed generating capacity uses PV cells that convert sunlight to electricity at efficiencies ranging from 9 to 14 percent, around 10 percent on average.

But there are a number of new generation PV cells in the works in dozens of countries around the world that have achieved efficiencies of 40% under laboratory conditions. These are mostly multi-junction PV cells coupled with a layer of light-focussing elements. These cells are currently too expensive for everyday use but have proved their worth in satellites and at remote research locations. As mass production techniques for each of these new technologies evolve, the price of such systems will come down within a decade to the affordability range of the current crop of monocrystalline cells that are the most commonly used worldwide.

Mass production in China has reduced the prices of monocrystalline cells so much in the past few years that they are now being used in rural areas in India. For a more detailed report by someone active in rural electrification efforts, see the link below.

Click to access PB_Off-grid%20solar%20Power%20in%20Rural%20India.pdf

Intermittency: Solar power is great as long as the sun shines, but what about after dark? Well, there’s wind, for one, but that is intermittent too. The evolving answer to that is storage technology (see my blog of 22nd June: Renewables – 13 next-generation battery designs). Link below

https://aviott.org/2013/06/22/renewables-13-next-generation-battery-designs/

The bottom line is: systems are not perfect, and if anyone wishes to poke holes in an argument, they can and will. So in the end, choice of energy systems comes down to attitudes, opinions and habit. This fact lies at the heart of the renewable energy debate. Proponents of business-as-usual, nested comfortably as they are in a carbon-based economy that has reached a high degree of organizational efficiency over a century, see no need to change, and dismiss all thought of powering the world with renewables instead of coal, oil and gas as it is now.  As Carl Jung pointed out nearly a century ago: Attitudes are more important than Facts, so a proponent of nuclear energy is likely to insist on the relative safety of nuclear technology (an argument that is statistically correct) until the day his own family is forced to shift from their home forever because of uncontrolled radiation release.

For anyone looking for more details on the PV technologies mentioned above, I can recommend the blog postings of the indefatigable Dave Elliott at http://blog.environmentalresearchweb.org/2013/08/17/solar-cells-1/