Saved By the Sun

Saved By the Sun

PBS Airdate: April 24, 2007

NARRATOR: Solar power has long been effective for small electronic devices and for a certain kind of individual who grooves on the sun. But as worldwide demand for electricity increases, so does the burning of fossil fuels to create it, which is contributing to global warming and the dangerous climate conditions that may result. This is forcing us to take a fresh look at a clean energy source with the potential to revolutionize power production.

NATHAN LEWIS (California Institute of Technology): Your only choice that can meet the insatiable human appetite for energy is the sun.

NARRATOR: Worldwide, the demand for clean energy is revitalizing the solar industry, and new solar panels are sprouting up everywhere. In America, more and more roofs are sporting solar panels, and owners like the results.

PHIL REAVIS, JR. (Somerville, Massachusetts): I love it.

NARRATOR: But solar power has been around since the gas crisis of the 1970s, and it's yet to make a serious contribution to the energy needs of the nation.

VIJAY VAITHEESWARAN (The Economist): For decades, solar has been the energy of tomorrow. Unfortunately, it's also been a field of failed promises, as well.

NARRATOR: There's the obvious problem...

STERLING BURNETT (Energy Policy Analyst): When the sun doesn't shine, it's not generating electricity.

NARRATOR: ...and the cost.

PEDRO PIZARRO (Southern California Edison): Solar panels tend to be more expensive than fossil fuel resources.

NARRATOR: But new technology, giant solar power plants and innovative business models are beginning to take this clean energy source to the next level.

But can solar power provide enough electricity to meet the demands of the 21st century? Up next on NOVA: Saved by the Sun.

NARRATOR: If it were up to this man...

LARRY KAZMERSKI (U.S. Department of Energy/National Renewable Energy Laboratory): Hey, Paula. This is Kaz.

NARRATOR: ...sun power would have taken off long ago.

Larry Kazmerski works at the National Renewable Energy Lab in Golden, Colorado. He's been trying to improve solar technology ever since Jimmy Carter put solar panels on the White House. And he survived Ronald Reagan taking them down and slashing his budget, which no president has yet to restore to 1980 levels. But he's never lost faith in the sun.

Kazmerski's office looks like a cross between a mad scientist's lab and a head shop. Kaz, as he's called by everyone, even designs solar ties. An unabashed solar optimist, he's studied virtually every aspect of solar science and has become a collector of solar history.

1958 BELL SOLAR BATTERY (TV Advertisement): Yet, in this modern age, men have at last harnessed the sun with the Bell Solar Battery. Portable radios powered by sunlight have already been made as laboratory models.

LARRY KAZMERSKI: This is 1958, pretty risqué for that time. And by the way, I have that radio. This is the radio; it's a transistor radio that runs off of solar cells that are on the top here. It doesn't work perfectly, but then I tell people that, you know, I'm just a little bit older than this radio, and I have parts of me that don't work anymore either.

NARRATOR: In 1979, Kaz was in attendance at the solar panel's main coming out party, although the sun was nowhere to be found the day President Carter visited N.R.E.L.

LARRY KAZMERSKI: I'm afraid that the solar gods weren't shining here on our Solar Energy Institute, and it started raining and then got cold; we got sleet; it snowed. We had brought in a big photovoltaic array—it was about 30 kilowatts—and here is President Carter, standing in front of this 30-kilowatt array, reaching out with his hand and thought he would help a little bit by wiping the surface of these solar cells.

And I remember I was able to grab the President's arm, at that time, 'cause I was really afraid, thinking that this would be the first time that an American president had been electrocuted by solar technology. And I didn't think this would do our technology very good.

NARRATOR: But it's not the threat of electrocution that is solar technology's greatest drawback, it's the in and out and up and down nature of the sun.

All solar panels, or photovoltaics, use sunlight to produce electricity. The stronger the rays, the more juice they produce.

It's a simple process that begins with the individual solar cells that make up a panel.

LARRY KAZMERSKI: If you were small enough and could crawl inside one of those solar cells, it would just be a hubbub of activity.

NARRATOR: A solar cell is like a sandwich; the top part is for protection, the bottom is its base and the middle layer, made of silicon, is where the action is.

When particles of sunlight, called photons, strike individual atoms of the silicon, they easily break the weak bond between silicon's nucleus and its outer orbit of electrons. Once freed, the electrons travel to the top of the silicon layer, where they move in a current along metal conducting strips. Then it's across the panels to wires that feed the electricity to the house.

Today's solar panels produce twice as much electricity as earlier models, and they're cheaper than ever. These benefits are helping to create a solar renaissance from sunny California to leafy New England.

Once too heavy and cumbersome for most roofs, today's panels are extremely easy to live with, which suits new enthusiasts like Phil Reavis just fine.

PHIL REAVIS, JR.: You install it and forget about it. There is no fuss, no muss.

NARRATOR: And no batteries like the old days, because most owners stay wired to the local power grid and don't need batteries for nighttime power.

PHIL REAVIS, JR.: The house is just like a hybrid car. Half the time, it runs off the solar panels and half the time energy is coming in from the grid. I love it.

NARRATOR: The Reavises live in Somerville, Massachusetts, a few minutes drive from downtown Boston. Phil is an industrial designer; his wife Trecia is in personnel, and their son, P.J., wants to be a pilot.

The Reavises were the first in their community to go solar.

PHIL REAVIS, JR.: I started thinking about solar energy, solar panels, the environment, probably back in the '70s, when I was a teenager, during the first energy crisis. And back then, I was thinking, "Boy, when I grow up, I'm going to do stuff differently than my parents are doing right now." And, unfortunately, it's taken me 30 years to actually make that happen.

NARRATOR: Bill and Debbie Lord are passionate advocates for solar power. Their custom-designed home, near Kennebunkport, Maine, is their second solar house and is prominently featured in solar magazines.

Bill Lord has a Web site for the curious, and he offers onsite tours for those interested in converting to solar.

He begins his show and tell in the basement.

BILL LORD (Kennebunkport, Maine): This is our power generation station; this is where we convert the electricity that comes down from the roof to household current. When the sun hits the panels on the roof, it agitates the electrons in the panels. The electrons come down the wires to these inverters. It's direct current. Most homes don't operate on direct current. They operate on alternating current. So these two white boxes are converting it to household A.C.

NARRATOR: In addition to their solar electricity panels, the Lords have solar hot water panels that feed a radiant heating system in their floors. With large insulated tanks to store the sun-heated water, they have vastly lowered their gas bills as well as their electric bills.

BILL LORD: The system handles itself. It turns itself on in the morning, it shuts itself off at night. We can be far away and it still works on our behalf.

NARRATOR: Meaning his house is producing electricity whether he uses it or not. And what he doesn't use goes back to the grid for other houses to use. And since the utility company gives him credit for the excess electricity, something called net metering, Bill's bill is shockingly low.

BILL LORD: On a monthly basis, we pay $7.47 to be hooked up to the power company. Essentially, we pay nothing for electricity.

NARRATOR: With over 40 states offering similar net metering credits, why aren't America's rooftops crammed with solar panels?

LARRY KAZMERSKI: The first question, of course, as a consumer is, "How much is this going to cost me?" That's the sticker shock.

For a normal house you need between two kilowatts and four kilowatts of photovoltaics. And this is going to run you someplace between about $15,000 to $28,000.

NARRATOR: And if you have a large house and add solar hot water panels as the Lords did, the price can go even higher.

BILL LORD: The active solar elements on the house cost about $50,000.

NARRATOR: And it's the high cost of solar power that underlies most arguments against it.

VIJAY VAITHEESWARAN: Right now, solar panels are not very efficient and they're expensive.

HOWARD HAYDEN (Physicist): The only people that have those solar collectors are really very wealthy people.

NARRATOR: But is this really true?

TRECIA REAVIS (Somerville, Massachusetts): Well, last I checked, we weren't very wealthy.

NARRATOR: The Reavises are a two-income, middle class family, with a budget that won't allow many extravagances.

TRECIA REAVIS: We're, kind of, building our home. We have a son who is in school and, you know, we have a lot of other things that we could be doing, that we need to do.

NARRATOR: But when they learned the state of Massachusetts would pay half the cost of their panels, they jumped at the opportunity.

TRECIA REAVIS: I don't think we would have done it without the state support.

NARRATOR: The Massachusetts grant made what would have been a $24,000 investment $12,000. Fourteen states currently offer similar incentives. And then there's the additional benefit of net metering.

PHIL REAVIS, JR.: This is the bill for this month, and it's $129. And it probably would be double that last year about this time.

NARRATOR: On average, Phil Reavis now pays less than half what he once paid for electricity. He doesn't save as much as Bill Lord since he doesn't have as many panels. But saving money was never his only goal.

PHIL REAVIS, JR.: I know that I'm reducing my carbon footprint on the world. I feel great about having the panels installed.

NARRATOR: A sentiment shared by virtually everyone who goes solar.

BILL LORD: It's not about payback. It's about, first, treading lightly on the environment, not using fossil fuels to do the work that other homes require fossil fuels to use.

And over the last 11 years, 70 tons of CO₂ have not been put into the atmosphere because we've been using solar power.

NARRATOR: Power plants that use fossil fuels are responsible for 40 percent of the carbon dioxide pumped into the atmosphere every day. And rising CO₂ levels are a major cause of global warming.

DANIEL SCHRAG (Harvard University): Human society is burning coal, oil and gas to get energy. And the result of that burning is carbon dioxide. The CO₂ level has never been this high for millions of years.

Now, carbon dioxide is a greenhouse gas. And what that means is it is very good at absorbing heat that is emitted from the Earth's surface. And some time in the next 50 years, we're literally going to go off the scale here.

The Earth's atmosphere acts like a greenhouse, absorbing some of that heat energy and radiating it back, ultimately increasing the surface temperature of the Earth by a small amount.

NARRATOR: And this rise is contributing to severe weather conditions that seem to be growing worse each year.

DANIEL SCHRAG: The expected consequences of climate change, I think, many people are familiar with: flooding in some places, droughts in other places, melting of glaciers—which cause sea-level to rise—bigger, more powerful hurricanes, and a variety of other unusual climate effects.

But what actually scares me are the unexpected ones. It's the surprises that really hurt people.

NARRATOR: Concern over global warming has helped boost panel sales 600 percent since 2000, as more people try to do their part to stave off the crisis. But all the solar panels in America produce only two coal plants' worth of electricity, an amount not even close to meeting the power requirements of a major city.

And more power is what every city needs, especially when the weather turns hot and air conditioning use soars.

NEWSMAN 1: A dangerous heat wave is making people miserable from coast to coast and is now blamed...

NEWSWOMAN 1: More than 100 deaths are being blamed on 12 days of extreme heat.

NEWSMAN 2: Triple digit temperatures, reports of 120 degrees in some places...

NEWSWOMAN 2: And that is putting a terrible strain on the power companies and the people who depend on them.

NARRATOR: It's July 25th, 2006, week two of a record-setting Los Angeles heat wave. And nowhere is the heat more intense than in the Grid Control Room at Southern California Edison and on its Grid Control Manager, Tom Botello.

It's Botello's job to direct the electricity generated by the region's power plants to homes and businesses, traffic signals and hospitals, and everywhere in between. But the very nature of electricity makes this all a high stakes poker game, where the losers could be us.

VIJAY VAITHEESWARAN: You can't store electricity like you can store lots of other things, like bananas or copper or other commodities. And that's why you're always going to need a grid manager. And these are very courageous men and women who are asked to do the impossible, to predict tomorrow, or the next hour, how much electricity supply we're going to need, based on how many people might turn on their air conditioner or how many factories might suddenly decide to go into high-output mode.

NARRATOR: Although Botello tries not to show it, this is about as stressful as a job can get, as the heat wave is forcing SoCal's 13,000,000 customers to use more electricity to keep things cool. And this is when most blackouts occur.

TOM BOTELLO (Southern California Edison): What causes blackouts is when there is insufficient supply on the system to serve the customer demand.

NARRATOR: The current heat wave is producing dozens of localized blackouts that are being blamed for scores of deaths and millions in economic losses.

NEWSWOMAN 3: The elevators died with the power, leaving one man trapped inside.

NARRATOR: But things could get worse if grid managers cannot find additional electricity to keep ahead of the demand.

PEDRO PIZARRO: When we hit that summer afternoon at 4:00, and everybody's going home and turning on their air conditioners, our system load shoots up.

NARRATOR: Although SoCal has a small amount of solar power feeding the grid, it's only a drop in the bucket. So managers call for additional electricity from their 30 natural gas plants and from the state's two nuclear reactors; and they start buying power from neighboring states that use coal-fired plants, by far the worst CO₂ emitters.

With the city at risk of a major power failure, global warming will just have to wait.

PEDRO PIZARRO: The reality is that today, with available technology, you need fossil fuels to have the kinds of fast response units that can follow load and maintain our system and balance.

NARRATOR: Despite their best efforts, grid managers are running out of ways to combat this summer's power crisis. In a bold move, Tom Botello decides to ask certain factories, office buildings and schools to go offline, voluntarily, to conserve power.

TOM BOTELLO: The entire Western grid could be vulnerable if we did not take these emergency actions to disconnect certain portions of our system—non-critical customers—for an hour at a time.

NARRATOR: But with more high temperatures on the way, no one knows if this measure will work. If it doesn't, the city faces the dangerous prospect of massive blackouts and the inevitable chaos that would follow.

But by day 14, Los Angeles's weather finally cools, and so does the demand for more electricity.

This summer's crisis is over. But there is little sense of relief. With global warming contributing to the hottest summers on record, there will likely be many more heat waves to come. And each new emergency underscores just how much our current survival depends on fossil fuels and how our future survival may depend on how quickly we get rid of them.

DANIEL SCHRAG: Once the oceans start to warm, once the ice starts to melt...very difficult to reverse those trends. And so by the time we really notice that it's catastrophic, it may be too late to do anything about it.

NARRATOR: Nuclear plants produce electricity that is virtually carbon-free, so building more of them could help slow global warming. But public fears over accidents and atomic waste have halted new plant construction everywhere in America.

Renewable energies, like wind and solar power, don't have nuclear's drawbacks, but unless we can vastly increase their output, and do so at competitive prices, they will never play a major role in our energy mix.

But on the edge of the Mojave Desert, about a three-hour drive from Los Angeles, sits a sleeping giant with the capacity to produce megawatts of clean electricity.

OPERATOR 1: Sun's popping out.

OPERATOR 2: Time to rise and shine.

Welcome to Kramer Junction.

NARRATOR: Kramer Junction is the largest solar power plant in the world, occupying an area bigger than New York's Central Park.

OPERATOR 3: Sun angle is 8.5, and we are positioned at 8 degrees.

NARRATOR: It was built 20 years ago, in response to the energy crisis of the 1970s, and, today, makes enough electricity to power 150,000 homes in the greater Los Angeles area.

Called a solar thermal plant, Kramer Junction uses mirrors, not silicon panels, to turn sunlight into electricity. The parabolic shape of the mirrors is the key. Each row of shiny troughs tracks with the movement of the sun to continuously focus the blazing hot rays on this glowing tube of synthetic oil.

KENNETH KINDSCHI (Kramer Junction, California): Now, while these mirrors are cool to the touch, the H.C.E. tubes can reach up to 750 degrees.

NARRATOR: The scalding hot oil flows to the power plant, where the scorching tube passes through a vat of water, instantly boiling it and creating jets of pressurized steam. The steam is directed to turbines that spin out electricity just like a fossil fuel plant. And there are no emissions but excess steam.

KENNETH KINDSCHI: We use this instead of conventional fossil fuels to generate the electricity that's tied onto the grid.

NARRATOR: In the Mojave Desert alone, there is enough sunlight to power all of Los Angeles County and the rest of the country, as well. But Kramer Junction is the only solar facility out here. The obvious question is, "Why?"

PEDRO PIZARRO: What communities are going to be willing to cede the amount of open space that would be required for making that a reality? You also have to layer onto that the transmission requirements to get that big field of solar mirrors connected to the grid where customers are.

VIJAY VAITHEESWARAN: When you transmit power, you lose power, just by the nature of transmitting through copper wires. But it also costs money. It's always better to produce electricity closer to where you need it.

NARRATOR: America's second big thermal plant is doing just that. It's being built just outside the ravenous market for electricity known as Las Vegas. So it will avoid the high transmission costs faced by Kramer Junction and should become a major source of electricity for this fast-growing city.

But plants like this need lots of sun and huge tracts of land. So the future for this form of solar power may lie only in the open vastness of the desert Southwest.

And for some observers, all solar power has a critical limitation that will keep it from ever becoming a major source of electricity anywhere.

STERLING BURNETT: The sun doesn't always shine. And when the sun doesn't shine, it's not generating electricity. And we don't have the batteries, yet, to store the energy properly.

NARRATOR: Without the ability to store the daytime power they produce, solar thermal plants shut down at night and stop making electricity.

HOWARD HAYDEN: Solar is absolutely marvelous technology for numerous kinds of applications, running your calculator so you don't have to replace batteries and running remote things. It just isn't going to run the United States. It can't even come close.

NARRATOR: But other countries aren't so sure.

Driving on Germany's autobahn, at speeds sure to get you a ticket in America, a curious sculpture lines the motorway. It's a "Great Wall" of solar panels, and this stretch feeds the power grid in Munich. This is Germany's answer to getting more renewable energy, thousands of solar panels producing millions of watts of electricity.

And this man is largely responsible.

HERMANN SCHEER (Member, The German Bundestag): We are in a very deep energy crisis. Fossil fuels are running out and created a climate disaster. The only real and realistic option is the general replacement of fossil and atomic energies by renewables.

NARRATOR: Hermann Scheer has been Germany's leading advocate for renewable energy for more than two decades. A long-term Member of Parliament, in 2000, Scheer won support for his National Renewable Energy Act, which requires Germany to produce 20 percent of its electricity from renewable sources by 2020.

Although detractors said this goal was impossible, the country is already ahead of schedule and could even reach 30 percent renewables by 2020.

So why is Germany, a country hardly known for sunshine, going over the moon for solar? The answer is simple: cash incentives.

HERMANN SCHEER: With our Renewable Energy Act, we gave each producer of solar power, even a very, very small one, a price guarantee to give his power to the grid. That means to sell it.

NARRATOR: Anyone who puts up solar panels will get about 50 cents per kilowatt hour for the electricity they send to the grid. But they pay only about 20 cents for the electricity they buy from the grid. So at the end of the month, panel owners almost always make a profit.

LARRY KAZMERSKI: Didn't take long for the Germans to figure out that this is worth it. They can make money. So they started to rent space, even on their neighbors' roofs to slap up photovoltaics.

NARRATOR: With the government's cash incentives, any open space has become fair game for solar panels, regardless of who or what gets in the way. And since the price of electricity is fixed for 20 years, most panel owners will easily recoup their investment. And the grid receives a huge infusion of new solar energy.

The government's cash incentives are getting everyone into the act. Like his ancestors before him, Heinrich Gartner raised cash crops and animals on the family farm. Then three years ago he added something new to the mix: solar panels, 10,000 of them, that supply power to about 1,500 nearby homes.

The National Renewable Energy Act had convinced this pig farmer to become a power producer.

HEINRICH GARTNER (Buttenwiesen, Germany): It was one of my hobbies to play with electricity or something like that, but here it's a power plant. We produce about 1,000,000 kilowatt hours of electricity here, with these solar panels. And the amount of money was, for the whole installation, about 5,000,000 U.S. dollars.

It was a lot of work to convince the bank.

NARRATOR: But Gartner got his loan because of the government's price guarantees.

HEINRICH GARTNER: We have a fixed price for the next 20 years that is guaranteed. That means we have, every year, an income of about 550- to 600,000 U.S. dollars.

NARRATOR: After loan payments and other expenses, Gartner's profit is less than $60,000 a year, so he hasn't given up his pigs yet. But his solar farming has far greater potential.

HEINRICH GARTNER: I am still a farmer. I'm still breeding pigs. But the hunger for electricity is even bigger than for food at the moment, in Germany. We can produce, here, really green power. There's no atomic waste or carbon dioxide emission. We want to show that it is possible to make electricity that doesn't do a lot of bad things.

That's an important point, because I want to give my farm, later on, to my junior, as my father gave it to me.

NARRATOR: But what about apartment dwellers and other citizens who don't own solar panels? How satisfied are they with the government's generous support of solar power?

JOACHIM PFEIFFER (German Parliament): We have one of the highest energy prices in the world, and that's really a great problem for the normal consumers. They have to spend a lot of their household's income for electricity.

NARRATOR: Germany has always had high electricity rates, about double the rates in America. And the government's renewable program has added an additional 15 to 20 dollars per month to the average bill. But, so far, there's been little public opposition and Hermann Scheer thinks he knows why.

HERMANN SCHEER: The prices are a little higher than the average of other countries, but people know, with these additional costs, they contribute directly to a clean future for all. Therefore, 80 percent of the people accept that.

NARRATOR: And Germany's support of renewable energy has had a surprising impact on the economy. The country now boasts a thriving solar industry that has become the darling of investors the world over.

This one plant in Germany's Solar Valley, produces almost a million solar cells a week. In just a few years, Germany has become the world leader in solar cell production.

The industry has created 170,000 new jobs and mass production is dropping the retail price of solar panels lower and lower. So the future of German solar power looks bright, although it still has its detractors.

VIJAY VAITHEESWARAN: Some people look at Germany and see that the subsidies that were lavished on the solar industry have successfully produced a big solar manufacturing industry. And they say, "See, it was worth it." I would say be careful in drawing that conclusion. Simply because something has taken off doesn't mean it's sustainable.

NARRATOR: But to Hermann Scheer, solar power is not only sustainable, it's the best alternative we have to fossil fuels.

HERMANN SCHEER: Fossil fuels create increasing economic problems for all, rising prices at the same time of depleting resources. They create political conflicts, they create military conflicts. They create environmental damages. And that means our children subsidize our energy, and for this subsidy, we destroy the environment. This is a contradiction which could not be carried anymore.

NARRATOR: Within the next two decades, Germany's solar panels and wind generators could be providing one third of the country's electricity, which would reduce its total CO₂ emissions considerably. By contrast, the United States currently gets only one percent of its energy from solar and wind.

There is a growing consensus in Washington that America should be producing more renewable energy. But so far, there is no movement to create a national incentive program like Germany's.

But one trend is showing real promise here, and it's not being led by government but by business.

This Whole Foods market is in Ridgewood, New Jersey. At first glance it's pretty much like any other Whole Foods: neat and bright, with lots of great looking food at premium prices.

CASHIER (Whole Foods): Hi, would you like paper or plastic?

NARRATOR: But there is one thing different about this particular store. The roof is covered with solar panels. They look expensive, but Whole Foods didn't pay a cent for them. They're owned by a solar energy power company called SunEdison. Its founder and CEO is Jigar Shah.

JIGAR SHAH (SunEdison): We help companies like Whole Foods move to solar power. SunEdison and its investors pay all of the upfront costs for these solar systems, and Whole Foods promises to buy the power over a long-term contract.

NARRATOR: Jennifer McDonnell is a Green Mission specialist for Whole Foods.

JENNIFER McDONNELL (Whole Foods, Green Mission Specialist): And we use a lot of energies. And solar power powers everything in this store, from lighting to the steamers, slicers, the coolers, freezers, anything that requires electricity, even the registers.

So it's important for us to look at ways to make that energy clean and be aware of the amount of energy that we use.

NARRATOR: Solar panels on this store complement, do not replace energy from the grid.

JIGAR SHAH: The solar power only produces 15 percent of the store's use all year around. But it produces between 50 and 100 percent of its energy needs during the daytime. And that's the time when the power from the utility company is the most expensive.

NARRATOR: This is especially true in the summer.

LARRY KAZMERSKI: During the summer months, when you have all this air conditioning demand during the day—you know, it's 95 degrees with 98 percent humidity outside—you're not paying seven cents a kilowatt-hour. You're paying up to 30 cents a kilowatt-hour during the summer.

JIGAR SHAH: Whole Foods' air conditioning bills are the highest when the sun is beating down on their roof. That's when these solar panels are producing the most power.

NARRATOR: So at these peak hours, solar power is cheaper than grid power. And there's more potential energy savings for the store.

Electricity rates fluctuate with the price of fossil fuels. And since most experts expect fuel prices to rise, the SunEdison deal has an added benefit for Whole Foods.

JIGAR SHAH: We are guaranteeing Whole Foods a fixed price, for 20 years, from these solar panels. That's something that their traditional utility company can't promise them.

NARRATOR: How much Whole Foods saves over the next 20 years will depend on the cost of their conventional energy, but SunEdison knows precisely how much it will make from the Whole Foods deal.

JIGAR SHAH: I know exactly how much sun is going to hit these panels every year. I know exactly how long these panels are going to last, which is about 40 years. And because of that, just based on interest rates and based on my cost of installation, I can figure out exactly whether these systems will be profitable or unprofitable from day one.

VIJAY VAITHEESWARAN: If you look at companies, like SunEdison, who are helping retailers put up solar panels on their roofs, you're suddenly seeing a linkage of the capital markets—which have traditionally been very reluctant to get into solar energy—with the retail sector. That's how you do things in America. You link the technology to the capital, and that's where the rubber hits the road.

NARRATOR: Or where the sun hits the panel.

But in the end, can green stores like Whole Foods and innovative companies like SunEdison really make a difference?

JENNIFER McDONNELL: Businesses can make a difference in the energy mix in our country. And I think they have to, because capitalism is what America is built on. And we expect businesses and entrepreneurs to step up to the plate and bring solutions to the challenges that we face as a country. And solar is—or any renewable energy—to me, is the right thing for business to get involved in.

NARRATOR: And supermarkets aren't the only candidates for large solar installations.

JIGAR SHAH: With all of the municipal buildings, all of the distribution centers, all of the schools, all of the other big, large, flat roofs that every typical city has, you can meet between 20 and 40 percent of the peak power needs of an average American city.

NARRATOR: There are other large-roof technologies that could create more solar power for the grid. One of the most promising is flexible solar sheeting that can cover very large areas and potentially supply more power than conventional panels.

Still, rooftop solar arrays are not very efficient. Even now the very best panels and coverings convert only 15 percent to 20 percent of the sun's rays into electricity, about half the conversion efficiency of a coal plant.

SARAH KURTZ (National Renewable Energy Laboratory): We'd like to be able to improve upon that, so we've been researching how to use more sophisticated materials to put together a high efficiency cell.

NARRATOR: Back at the National Renewable Energy Lab, Sarah Kurtz leads a team that is developing something called a multijunction solar cell. It looks like a miniature version of a normal solar cell, but even at this tiny size, it's much more powerful because it contains several micro-thin layers of light-absorbing materials.

The light from the sun is revealed as a band of colors, each color a different wavelength of energy. Traditional silicon solar cells absorb only the red spectrum of the sun's rays. The rest of the energy bands are blocked.

SARAH KURTZ: You could do better if you could use two different types of materials, or even three different types of materials, to attune them to the color of the light that's coming down.

NARRATOR: The extra layers allow the cell to absorb additional wavelengths of light, greatly increasing its efficiency.

The potential of multijunction cells as a power source was recently revealed on, of all places, Mars. The robotic rovers roaming the Red Planet were originally projected to last about three months. But they're still functioning more than three years after their momentous landing, thanks in large part to multijunction solar cells developed in Sarah Kurtz's lab.

But the rovers' cells cost millions of dollars, so they're probably light years away from the consumer market.

NATHAN LEWIS: And right now, no rooftop-based system uses these multijunctions.

If you have multijunctions you can get more of the energy out of the sun. The trick is to get more energy out than the extra cost that it cost you to make that extra set of layers in it.

We need to take these nanostructures and put them into a...

NARRATOR: Caltech's Nathan Lewis believes solar technology has to become much cheaper before it can make a serious impact, and he's hoping nanotechnology will help him do that.

NATHAN LEWIS: So we're working on using nanostructures—nanotubes, nanoparticles—where nano means really tiny. I'm trying to use these materials to capture and convert and store sunlight in new ways.

NARRATOR: But that's not all.

NATHAN LEWIS: We want things that are so cheap that you could treat them like paint at Home Depot. And you'll paint your roof or paint your house with it. So, that would really lower the cost of solar electricity a lot.

NARRATOR: Here's how Lewis's nanopaint might work: First, you need to roll out a layer of something to help conduct the electricity, a thin sheet of plastic with an aluminum coating would do. You also need wires that will ultimately conduct the electricity to the house.

Now, you're ready for Lewis's solar paint. Its key ingredient, a compound called titanium oxide, is processed into nanotubes that point toward the sun like blades of grass.

NATHAN LEWIS: TiO₂ is an incredibly common cheap chemical. It's in toothpaste. It's the pigment in white paint, these little tiny particles.

NARRATOR: And when photons of sunlight strike individual TiO₂ atoms, they knock loose electrons, just like they do to silicon atoms in a solar cell. And if you put a positively-charged clear coating over the paint, the negatively-charged freed electrons start moving to the wires and down to the inverter boxes so the kids can watch TV.

So far, Lewis has only tested small amounts of what he calls "dye-based cells" in the lab, but the results are promising.

NATHAN LEWIS: The dye-based solar cells, right now, in some small test samples are 10 percent efficient. Silicon cells, the best ones are 20 percent efficient. So we have a ways to go, but we are within shooting distance.

NARRATOR: He still needs to get his magic goo cheaper, and he needs to see how it will hold up under real weather conditions. But even at 10 percent efficiency, solar paint could produce a whole lot of electricity at bargain basement prices.

The most promising solar innovations are years away from becoming practical back on Earth. So some experts believe we should wait before more fully committing to solar power.

But high in the Colorado Rockies, lives a prominent energy expert who believes the solar technology we have now is good enough to be put to far greater use.

Meet Amory Lovins. Beneath his mild demeanor lurks an acid-tongued critic of U.S. energy policy.

AMORY LOVINS (Energy Use Innovator): We do have a national energy policy. It's basically to keep wasting lots of energy. Import it at whatever price and by whatever means are necessary, and keep stealing from our kids, and keep screwing up the climate. You may think this is a senseless, immoral and wasteful energy policy, and you'd be right.

NARRATOR: A physicist by training, Lovins is appalled by the low priority given to developing new sources of energy.

AMORY LOVINS: The amount of research money going into energy, public and private, has shrunk several-fold, at the time when we need it the most. And it's shrinking even further. This is just crazy.

NARRATOR: He is universally recognized as one our most creative thinkers about energy use and misuse.

AMORY LOVINS: It's cheaper to save fuel than to buy fuel. It's profitable. That's why smart companies do it like mad, to improve their bottom line.

NARRATOR: His ideas help businesses make money by operating more efficiently. And he's not shy about his ultimate goal.

AMORY LOVINS: My biggest project is helping the United States get completely off oil by the 2040s.

NARRATOR: One reason Lovins is so confident about changing our energy future is that he's done it here in his own house.

AMORY LOVINS: There are actually two different solar electric systems and a bunch of Chinese nickel-iron batteries that store electricity for lighting and other uses at night. We have one meter for the electricity we buy, another for the electricity we sell—and the utility sends us a check for that one.

And we don't lose much heat, because the building is super-insulated. All of the windows face, more or less, south. No doubt the archaeologists will conclude that this was a temple to some primitive solar cult, which I guess is about right.

NARRATOR: Everything in the house is energy efficient, even the pots and pans.

AMORY LOVINS: Still pretty hot.

NARRATOR: And he's designed a solarium that uses the sun for all it's worth.

AMORY LOVINS: Here, in the middle of the house, is an area I call the jungle. We've harvested here 28 banana crops, mango, papaya, loquat, passion fruit, grapes. We've had meter long iguanas teaching advanced lizarding, a little African pygmy hedgehog that runs around at night, eating bugs.

It's really a fun thing to have in the middle of your house, especially when it's blizzarding outside and you come in and grab a tomato as you swing by.

We're collecting in here heat, light, hot air, hot water and photosynthesis.

NARRATOR: Lovins is keenly aware of what solar energy, even in the raw, can provide, and he's pleased that many of us are finally catching up to him.

AMORY LOVINS: Solar power is the fastest growing source of energy in the world. In 2005 it was a $38 billion global industry, growing tens of percent a year. So the solar revolution seems finally to be happening for real.

NARRATOR: This is especially true for the two billion people who have had little or no access to grid electricity. Throughout India, Asia and Africa, thousands of villagers are beginning to use inexpensive solar panels to charge batteries or electric lanterns so they can do things at night that were once difficult or dangerous.

Here in the developing world, solar power is providing new opportunities for education and economic development, supplying electricity that can help societies modernize with renewable energy rather than fossil fuels.

In the United States, California is leading the charge for more renewable energy. There's even a plan to get solar panels on a million roofs.

But nationwide, solar power, even in combination with other renewables, will have to achieve a far greater percentage of our energy mix, probably as much as 20 percent to 30 percent over the next two decades if we want to significantly reduce our CO₂ emissions.

So is this target realistic?

STERLING BURNETT: Solar and wind together currently produce less than one percent. I don't think in 20, 25 years it's going to be 20 percent. I don't see a growth curve like that.

LARRY KAZMERSKI: I think it's fairly certain that, by 2025, we might be getting 25 percent of our electricity from solar. That's realistic. That's not too farfetched.

NARRATOR: With such extreme perspectives, it's difficult to predict where our energy mix, or our planet, will be in 20 years. But if we wait until then, and don't like what we see, will it be too late to do anything about it?

PHIL REAVIS, JR.: When I became a father, I really started to worry about the environment and the shape of the environment. With all the stuff in the news, I just felt, "What is my son inheriting? My god, we're just making a mess of all this." Thinking the back to the '70s, man, if everybody started installing solar panels back then, we'd be in much better shape, really, for the future of the planet.