solar powered roadways by scott brusaw come to life with LED's

Solar Roadways wants $1 million to turn the US’ roads into an energy farm
by Daniel Cooper  /  May 9TH 2014

What  if we turned the nation’s highways into solar farms that we could drive along? Scott and Julie Brusaw have been working on that idea, and after a decade of partially-successful flirting with the US Government, they’re taking to Indiegogo to ask us to fund the next phase of their solar roadway. Each interlocking hexagonal segment is covered with toughened and textured glass that’s capable of withstanding 250,000 pounds. Beneath that, you’ve got a solar panel, a series of LED lights and a heating element that’ll keep the ice and snow off the hardware in winter. The lights are used to replace conventional traffic lights, offering constantly updating safety warnings and guide lines that can adapt to traffic conditions on the fly.

The system would require a trench running down one side, which would hold the power cables, but could also be used as the backbone for a potential new high-speed data network. As each panel would also be connected, it’d instantly report a fault back to a maintenance engineer, and also track its location, should someone decide to steal one for their own nefarious uses. Naturally, a nationwide, decentralized power grid could potentially guarantee energy independence and provide near-limitless power for our EVs and homes. That’s why the couple is asking for a whopping $1 million required to hire the materials scientists, civil and structural engineers necessary to turn the panels from neat idea to workable project. There are plenty of pitfalls, and we’re wondering if heating the ground to keep the roadway clear wouldn’t in itself cause more climate change, but hopefully that’s another issue that your cash could fix.

smart streets and solar roadways produces energy for the power-grid

Solar Roads Could Power The Entire Country
by Adele Peters   /  May 9, 2014

There are nearly 18,000 square miles of roads in the U.S., an area that’s bigger than the entire states of New Hampshire and Massachusetts combined. By some estimates, there are also as many as 2 billion parking spaces. Since most of that pavement is soaking up sun all day long, a couple of entrepreneurs had an idea: Why not put it to use generating solar power? The Solar Roadways project, now crowdfunding on Indiegogo, hopes to re-pave the country in custom, glass-covered solar panels that are strong enough to drive on while generating enough power to light the road, melt ice and snow, and send extra energy to cities. Eventually, if every paved surface was covered in the product, the panels would produce more power than the nation uses.

The project began eight years ago, when founders Scott and Julie Brusaw decided to take a chance on developing an idea that no one thought would work. “Driving on glass had never been done,” says Scott Brusaw. “We had a few big hurdles in the beginning. How do you put a traction surface on glass so the first time it rains everybody doesn’t slide off the road? How do you make glass tough enough to withstand the weight of 18-wheelers? What happens if someone’s walking out of Home Depot and drops an eight-pound sledgehammer?”

Glass, it turns out, is stronger than you might think. “You first mention glass, people think of your kitchen window,” Brusaw says. “But think of bulletproof glass or bomb resistant glass. You can make it any way you want. Basically bulletproof glass is several sheets of tempered glass laminated together. That’s what we have, only our glass is a half inch thick, and tempered, and laminated.” It’s strong enough to easily withstand cars, fully loaded trucks, and even 250,000-pound oil drilling equipment. The textured surface means it isn’t slippery, and since it can self-power small heaters inside to melt ice in winter, it’s supposedly safer than an ordinary road. It also powers small LED lights inside that can light up dividing lines and spell out warning messages–if motion sensors detect a deer crossing the road, the lights can automatically tell drivers to slow down.

At parking lots or rest stops along highways, the panels could power a continuous network of charging stations for electric cars. Eventually, the designers believe it may be possible to charge the cars directly through the road as they drive. In the future, driverless cars could also use the panels to continuously report their location. Since the whole road is wired, it’s also easy to maintain: If one panel stops working, all of the other panels around it call a local repair shop with the exact location. “A guy can come out and repair it in five minutes,” Brusaw says. “Compare that to pothole repair.” Using the $1 million they hope to raise on Indiegogo, the company plans to hire more engineers and continue refining the current product, testing it first on parking lots and smaller roads before moving on to highways across the entire country. Hunting down the funding to cover the U.S. (or even a significant portion) in solar roadways, however, will be an insanely big challenge.

solar powered roadways by scott brusaw come to life with LED's
parking lot solar cells, LED’s, heating elements, and the textured glass surface

Solar Roadways installs energy harvesting parking lot
by  / April 24, 2014

About 8 years ago, an electrical engineer and his counselor wife started throwing around an idea to replace asphalt on highways and byways throughout the US with electricity-producing solar panels that were tough enough to be driven upon. The idea blossomed into a project, where the panels featured built-in LEDs that could “paint the road” with markings and warnings, and could be heated to prevent snow and ice build up. The US Federal Highway Administration paid for the couple to produce a working prototype, which they did, and then again to expand the concept into an operational parking lot setup. As the latter contract comes to an end, the Solar Roadways project has released photos of the (almost) completed installation at its Idaho electronics lab. Now the team is dipping into crowd-funding waters with a campaign to raise funds for the move into commercial production.

Many roads, highways, parking lots or driveways can spend much their daytime unused. Sunlight can even break through gridlock to the road below. In 2006, Scott and Julie Brusaw hatched a plan to make use of all that untapped energy by replacing asphalt with toughened PV panels that would also include embedded lighting to act as road markings and driver alerts, as well as communication and power cables to replace overhead lines. The project received funding from the US Dept of Transportation to the tune of US$100,000 in August 2009, and work began on the first proof-of-concept prototype. By February 2010, the first 12 x 12 ft (3.7 x 3.7 m) road panel (made up of 16 smaller connected panels) was ready, complete with embedded LEDs that could be programmed to deliver custom messages. The proof-of-concept Phase I prototype didn’t include any PV cells and lacked the custom-hardened glass with integrated heating element for the upper face, but it served to demonstrate that the proposed electronics worked as promised. The team also built smaller crosswalk panels featuring load cells to test a pedestrian/wildlife detection mechanism, which would flash instructions to slow down when a weight was detected on the surface. Around this time, Scott Brusaw was invited to give a TED talk in Sacramento (which is worth a watch as it details much of the project’s inspiration, history and aims), and the project went on to win first prize in two of GE’s Ecomagination challenges.

The first hexagonal panels are installed outside the Solar Roadways electronics lab

After entertaining the world media circus for a while, and traveling around the country to deliver talks on the project, funding was secured in June of 2011 for the second phase of development – to create fully functional parking lot. Work on the electronics began immediately, and a site next to the electronics lab prepared for ground breaking. The Brusaws and their small, but dedicated, team of volunteers revealed a new hexagonal road panel design in July 2013, that would allow them “to handle curves easily and we designed the shape, macro and micro textures for stability, traction, strength.” The first batch of the completed new panels were ready for installation and testing by September. Spin forward to the end of last month, and the first photos of the now operational Solar Roadways parking lot were released. Each of the new panels features PV cells and circuit boards, 128 programmable LEDs, a heating element to help deal with ice and snow, and are topped with “super-strength” textured glass (which has exceeded expectations in load, traction and impact resistance testing). “Half of our prototype parking lot is mono-crystalline, while the other half is poly-crystalline,” Julie Brusaw told Gizmag. “The parking lot is equivalent to a 3600-watt solar array. The power collected is dependent upon the amount of sunshine received. So as with all solar, it will produce more in some parts of the country and world than others. We’ve moved power and data cables to a Cable Corridor alongside the road/parking lot,” she continued. “This provides easy access the power/data companies. It will give the cables a home and eliminate the need for overhead wires that are unsightly and subject to ice/breakage. The other way the power companies are handling it now is to bury them (sometimes right next to gas lines) in the dirt and dig them up with a shovel for access. So we can make utility companies’ work much easier and safer. Our system can also eliminate cell phone dead spots by installing a ‘leaky’ cable in the Cable Corridor. Our corridor can be a home for all kinds of cables including TV, fiber optic for high speed internet, phone, etc.” A section in the installation’s Cable Corridor has been included to store, treat and redistribute storm water, and the Brusaws sourced recycled glass and were able to incorporate 10 percent in the aggregate of the base layer of the prototype.

Currently, some 69 percent of the layer directly under the glass of each hexagonal unit is made up of photovoltaic cells, but that will increase to 100 percent prior to commercial production. Before that can happen, though, the Solar Roadways project has hit Indiegogo (starting, appropriately enough, on Earth Day) to help raise enough money to hire a team of engineers and other professionals, streamline the production process and move into manufacturing proper. A lofty funding target of $1 million has been set, and the project will receive all funding, even if the campaign goal is not met. Rewards include t-shirts, coffee mugs, a backer’s name engraved on one of the prototype’s 396 mounting hole covers, and samples of the toughened glass.

solar powered roadways by scott brusaw come to life with LED's
the hexagons utilize 36-watt solar panels, with 69-percent surface coverage by solar cells

This Couple Is Making Roads Out Of Solar Panels, And They Actually Work
by EMILY ATKIN  /  May 14, 2014

Finding a way to replace regular, concrete roads with ones that could better serve a sustainable world has long been Scott and Julie Brusaw’s dream. Lately, the couple has been working on that dream so much that — at least on Tuesday — they didn’t even sleep. “All of the publicity is keeping us hopping,” Julie said by e-mail on Wednesday afternoon, after Scott had fallen asleep. “I have over 6,800 unanswered emails in my inbox right now. Not counting all of the thousands I have responded to of course!”

If every roadway in the country were replaced with Solar Roadways — a huge feat, admittedly — Julie and Scott estimate that enough solar energy could be generated to entirely substitute power generated from fossil fuels, and then some. Combined with the fact that the roads could charge electric vehicles (and thereby increase the viability of those vehicles) the couple estimates that the roads would, if installed everywhere, have the ability to cut American greenhouse gas production by 75 percent. The couple also contends that the roadways would pay for themselves over time because of the fact that they generate power.

Now that the prototype is nearly finished (it still needs some mastic filling between the panels, and software for LED patterns), the couple’s hometown city of Sandpoint, Idaho is looking to be its first customer. If that happens, it would be the first solar-powered parking lot in the world. A far cry from an actual road, but a step, Julie said. “We want to install a sufficient number of parking lots, sidewalks, driveways etc., that we feel ready before moving on to roads,” she said. “However, we have potential customers waiting from all over the country and all over the world, so we are hoping to move very quickly.If we meet our goal on Indiegogo, that will enable us to hire our initial team, and gear up for production.”

Artist's rendition of a Solar Roadway in downtown Sandpoint, Idaho.
Artist’s rendition of a Solar Roadway in downtown Sandpoint, Idaho {Sam Cornett}


In 2012, designboom covered the first prototype stage of american electrical engineer scott brusaw’s system of solar powered roads. conceived as an initiative to change the face of national highways by re-purposing them with photo-voltaic panels, the idea for ‘solar roadways’ was to introduce smart streets capable of directly inputting energy into ‘the grid’. if realized, the concept could essentially power an entire country with the generated electricity.

solar powered roadways by scott brusaw come to life with LED's
artist’s rendition of a sidewalk/parking lot application in sandpoint, idaho

Now in it’s second prototyping stage, the project has been further developed as a modular photovoltaic (PV) paving system that can withstand the heaviest of trucks – up to 120,000 kilograms. the plan would see the ‘solar road’ panels installed on highways, parking lots, driveways, sidewalks, bike paths and even playgrounds. the system is based on centralized power stations, and distribution is handled through transmission lines and relay centers. each panel has its own microprocessor, which communicates wirelessly with the surrounding panels – they monitor each other for malfunctions or problems.

solar powered roadways by scott brusaw come to life with LED's
the panels can withstand the heaviest of trucks – up to 120,000 kilograms. electric vehicles will be able to charge with energy from the parking lots and driveways, and after a roadway system is in place, mutual induction technology will allow for charging while driving.


Our long range goal is to cover all concrete and asphalt surfaces that are exposed to the sun with Solar Road Panels. This will lead to the end of our dependency on fossil fuels of any kind. We’re aware that this won’t happen overnight. We’ll need to start off small: driveways, bike paths, patios, sidewalks, parking lots, playgrounds, etc. This is where we’ll learn our lessons and perfect our system. Once the lessons have been learned and the bugs have all been resolved, we’ll plan to move out onto public roads.

Imagine one major fast-food chain retrofitting their parking lots across the nation: an all-electric vehicle (EV) could now recharge in those parking lots when needed. This removes the range limitation for EVs (eliminating their need to be recharged at home every night) and makes them far more practical. People would be more likely to trade in their internal-combustion engine vehicles for all-electric vehicles.

A new hexagonal road panel was revealed in July 2013

Other businesses would see the advantage of retrofitting their parking lots: they could either go off-grid or put a huge dent in their monthly electric bill. They would also attract more customers, who would eat or shop in their stores as their EVs recharged in their parking lots. As more businesses jump on board, the EVs become more and more practical. With businesses going solar (rather than using electricity created by burning fossil fuels) and more drivers opting for EVs (over gas/diesel engines), the beginning of the end of fossil fuel dependency would finally be at hand.

After the Solar Roadways technology is proven in parking lots, then the next logical step would be residential roads, where speeds are slower than highways and trucks are not as common. The final goal should be the nation’s highways. We’re already investigating using mutual inductance to charge EVs traveling over the Solar Road Panels. While it may not (although we don’t know this yet) provide enough electricity to completely charge the EV in motion, it would certainly extend its range.

Comment by Scott Brusaw  / September 18 2007

Hi everyone,
I’m Scott Brusaw, co-inventor and project director of the Solar Roadways project. I’m sorry that I missed the opportunity to address the concerns raised here when these comments were originally posted. Someone just told me about this article. I appreciate all of the discussion, pro and con. When I explain the concept to people, a few of them (usually scientists and other engineers) grasp the concept immediately and I enjoy watching their eyes light up, but mostly I see confused faces at first or hear comments like “pie in the sky” until I’ve talked long enough to present the whole vision. When people take the time to understand the entire project, I’ve found that perhaps 98% love the idea. If you just take a few parts of the idea in isolation, it might not seem to make sense. The article presented here at TreeHugger gives only a smattering of the information on my website, I appreciated the comment from Doug, who pointed out that if you actually read the website, most of the criticisms given here are addressed. I hope the other comment writers will explore the website as well, to learn what the project actually entails.

Nick, you challenged anyone to come up with just one good reason for putting solar panels on roads. If you will go to our website, you will find dozens. And your assumption regarding how I came up with this idea is incorrect. Solar Roadways is an intricate system for revamping our entire transportation infrastructure, not a random idea to slap some solar cells on the roadways. There are some things not yet covered on the website, so I’ll try to give your some detail here.

Let’s cover some cost figures:
Saul Wall, your comments about the problems with current road construction certainly come into play when it comes to the numbers of how this can financially be feasible. Let me start off by making a correction: the target cost for a 12’ by12’ Solar Road panel is $10K, not $5K. We picked this target price to be competitive with current (actually 2006) costs of asphalt roads. The most realistic number we could place on the cost per square foot of asphalt road (in the US) was $16.00 (this does not include maintenance or snow removal). We met with the director of the Idaho Transportation Department and presented this number to him after finding it on the Internet. After thinking it through for a mile of roadway, came to the conclusion that it was “in the ball park”. If correct, then a 12’ by 12’ section of asphalt road costs (12x12x16) $2304 to build. Unfortunately, the average US road is only designed to last seven years before it must be ripped up and repaved. We’re designing our Solar Road Panels to last over 20 years, so in fairness, you’d have to triple the cost of the asphalt roads (3 x $2304 = $6912) for a real comparison. So we’re at $6912 for (what I like to call) “dumb asphalt” roads – they just sit there and absorb heat and return nothing but potholes and heartache. Keep in mind that eliminating the need for coal-fired power plants and (God-forbid) nuclear power plants, we can roll all of the money that would be spent on future power plants into the Solar Roadways. Consider too, that the Solar Road Panels will be generating and distributing power (along with cable TV, telephone, high-speed internet access, etc.) to homes and businesses everywhere. It is difficult to calculate the cost savings over today’s conventional delivery methods, but I think it’s fair to say that this brings the costs of asphalt and Solar Road Panels into the same ballpark.

The Idaho Transportation Department was excited about the idea of building roads out of new materials, primarily because asphalt is petroleum based, and the cost of asphalt is projected to skyrocket over the next five years. That $16 per square foot will begin to sound attractive. The experts, along with OPEC, estimate that the world will run out of oil in 50 years. Since OPEC is known to lie about their oil reserves (they’re only allowed to sell a certain percentage of their reserves each year and their reserve numbers haven’t changed in ten years), my guess is that we’ve got about 20 years of oil left. What will we make our roads out of then? Some posters protest that the Solar Roadways will cost too much. The money is going to be spent anyway- repaving and maintaining our current roads, parking lots, and driveways. Why not get something out of it (clean, renewable energy among other things) and solve the climate crisis in the process? Chris mentioned building solar panels over the highways. That would simply double the cost of current road construction and not solve the problem of, “what are we going to replace the asphalt with?”

smart streets and solar roadways produces energy for the power-grid
snow test – powered row is snow/ice free 

Non-existing technology:
Some mention has been made of the “not-yet-existing” technology. In truth, the only non-existing part of the Solar Road Panel is the top surface: the glass that you actually drive upon. Being an engineer, I knew early on that the surface would have to withstand the static and dynamic forces of a fully loaded semi-truck locking up its brakes at 80mph – no easy task. I prepared a list of specifications for this glass surface, including (but not limited to) the following: it must be fire-proof, transparent in one direction, provide traction at least equivalent to current asphalt roads, be able to withstand sand, salt, magnesium chloride, and every other material known to be used for snow/ice removal, be anti-glare, etc. I sent these specifications to the three top materials science research laboratories in the US: Penn State University Research Institute, MIT, and the University of Dayton Research Institute respectively. This past February, I visited the University of Dayton Research Institute. They assured me that the material for the top surface of our Solar Roadway Panel could be created – it would just take time and money. In April, Penn State invited me to attend the 1st International Workshop on Scientific Challenges of New Functionalities in Glass in Arlington, Virginia. I presented our Solar Roadways project to the group, and made some interesting contacts. I was invited to travel to Penn State’s Research Institute to present our project to their faculty. Walt Mills, from Penn State, wrote a nice article about the entire trip. You can see the article at:… I learned a great deal about glass during this trip. I had no idea how many properties and uses glass had. For instance, self-cleaning glass exists, which may solve the problem about keeping it clear of road grime. Obviously, curved sections must be made available. Much like our old childhood racing tracks, the Solar Road Panels could be produced in any size and shape.

solar powered roadways by scott brusaw come to life with LED's
excess power produced by the system can feed surrounding neighborhoods

Other concerns:
I’ve heard other complaints: how much CO2 will be produced by manufacturing Solar Road Panels? That’s like complaining that Al Gore uses jet fuel to enlighten the world about Global Warming. Here’s my best answer: yes – the first manufacturing facility will probably use coal-fired electricity to produce the first run of Solar Road Panels. If this is true, then the first panels will contribute to the CO2 emissions that cause Global Warming. However, the first Solar Road Panels that roll off the assembly line will go directly out to the parking lot, where they will be installed and connected to form the very first Solar Roadways parking lot. Soon after, the manufacturing facility (and all that follow it) will take itself “off-grid” and provide its own power.

What happens during gridlock or when parking lots are full? What about sections of the road that never see sunshine? The short answer is that it doesn’t matter: every Solar Road Panel is an energy storage unit. You would even install them in tunnels that never see the light of day. They won’t collect energy, but they’ll store energy collected by the other Solar Road Panels. Since we’ll be producing three times the amount of electricity actually used (by the US), only one-third of the Solar Road Panels ever need to be exposed to sunlight.

solar powered roadways by scott brusaw come to life with LED's
LEDs can be programmed to dimmed or even turned off

I appreciate the “elegant energy solution” remark by Ken Fabos and the encouragement from Mark about thinking, “outside the box”. I believe that is exactly what will be required to solve the Global Warming problem – and it needs to happen quickly. Initial calculations show that this project alone would eliminate approximately half of the Global Warming problem. The other half could be eliminated by solving the biggest problem with all-electric cars: the need for places to plug in to allow for long trips. This would mean the end of our dependence on foreign oil, and the current concern that we are running out of oil. Coal mining would no longer be needed. In response to Nick Butcher’s comment that “It’s a solar panel people, it doesn’t matter where you put it”. Actually it does. The largest obstacle to solar power today is the logistical nightmare of getting the power into the power grid. The Solar Roadways solve that problem by BECOMING the power grid with the capacity to send power wherever it’s needed.

Sam-Hec is thinking along the lines of the project with his mention of solar powered call boxes. That is one of the features of the solar roadways. Add to that cell stops where hybrid and fully electric cars (which will likely become the norm) will plug in to recharge, stoplights powered with the energy from the road, embedded LEDs lighting the road lines for safer night driving, snow and ice free roads for safer winter driving, the millions of animals lives that will be saved by keeping them off of the roads, the beautiful scenery you will be enjoying thanks to the new lack of utility poles and power stations, no more “dead zones” for cell phones, and the handy warnings this smart road will give you when there is a problem ahead and you just might want to take a detour. The panels will be available for purchase for driveways and walkways if you’d like to power your house while keeping them free of snow and ice and I guess, if you still want to, you could put one on your roof….

I’d welcome more questions and comments.
Thanks, Scott Brusaw

Energy breakthrough uses sun to create solar energy materials
A new technology uses sunshine directly in the production of solar energy materials {Graphic by Ki-Joong Kim}

Energy breakthrough uses sun to create solar energy materials  /  Apr 03, 2014

In a recent advance in solar energy, researchers have discovered a way to tap the sun not only as a source of power, but also to directly produce the solar energy materials that make this possible.  This breakthrough by chemical engineers at Oregon State University could soon reduce the cost of solar energy, speed production processes, use environmentally benign materials, and make the sun almost a “one-stop shop” that produces both the materials for solar devices and the eternal energy to power them.

The findings were just published in RSC Advances, a journal of the Royal Society of Chemistry, in work supported by the National Science Foundation. “This approach should work and is very environmentally conscious,” said Chih-Hung Chang, a professor of chemical engineering at Oregon State University, and lead author on the study. “Several aspects of this system should continue to reduce the cost of solar energy, and when widely used, our carbon footprint,” Chang said. “It could produce solar energy materials anywhere there’s an adequate solar resource, and in this chemical manufacturing process, there would be zero energy impact.”The work is based on the use of a “continuous flow” microreactor to produce nanoparticle inks that make solar cells by printing. Existing approaches based mostly on batch operations are more time-consuming and costly. In this process, simulated sunlight is focused on the solar microreactor to rapidly heat it, while allowing precise control of temperature to aid the quality of the finished product. The light in these experiments was produced artificially, but the process could be done with direct sunlight, and at a fraction of the cost of current approaches “Our system can synthesize solar energy materials in minutes compared to other processes that might take 30 minutes to two hours,” Chang said. “This gain in operation speed can lower cost.”In these experiments, the solar materials were made with copper indium diselenide, but to lower material costs it might also be possible to use a compound such as copper zinc tin sulfide, Chang said. And to make the process something that could work 24 hours a day, sunlight might initially be used to create molten salts that could later be used as an energy source for the manufacturing. This could provide more precise control of the processing temperature needed to create the solar energy materials State-of-the-art chalcogenide-based, thin film solar cells have already reached a fairly high solar energy conversion efficiency of about 20 percent in the laboratory, researchers said, while costing less than silicon technology. Further improvements in efficiency should be possible, they said.Another advantage of these thin-film approaches to solar energy is that the solar absorbing layers are, in fact, very thin – about 1-2 microns, instead of the 50-100 microns of more conventional silicon cells. This could ease the incorporation of solar energy into structures, by coating thin films onto windows, roof shingles or other possibilities.

Map shows distributed generation (mostly solar photovoltaic or PV) on each circuit compared to 15% of peak electricity demand, or “load” on each circuit

Photovoltaics proved so successful in Hawaii that the local utility, HECO, has instituted policies to block further expansion
by Anne C. Mulkern and ClimateWire  /  Dec 20, 2013

William Walker and his wife, Mi Chong, wanted to join what’s seen as a solar revolution in Hawaii. Shortly after buying their Oahu home earlier this year, they plunked down $35,000 for a rooftop photovoltaic system. The couple looked forward to joining neighbors who had added panels, to cutting their $250 monthly power bills and to knowing they were helping the environment. Their plans shifted the day after the PV panels went up in early October. The Walkers learned from a neighbor about a major change in the local utility’s solar policy. It led to those 18 panels sitting dormant nearly three months later.Hawaiian Electric Co., or HECO, in September told solar contractors on Oahu that the island’s solar boom is creating problems. On many circuits, the utility said, there’s so much solar energy that it poses a threat to the system and a safety issue. Studies are needed on whether grid upgrades are necessary. If they are, residents adding solar must foot the bill. And starting immediately, contractors and residents would need permission to connect most small rooftop systems to the grid.The new HECO policy was included deep in the text of emails the Walkers’ solar contractor had sent, but it escaped their notice before installation. They’re now paying $300 per month on a loan for the panels, plus the $250 electric bill. “It goes from frustration to outrage,” William Walker, 33, said of his reaction. “We hear the excuses that HECO provides, that they put out there at least as far as the justification. There’s really not a lot of substantiation. My belief is it’s purely profit-motivated, to keep people away from PV and keep them on the grid.” HECO officials called it a needed precaution. “We can’t allow circuits to become dangerous,” said Peter Rosegg, a utility spokesman. “We can’t allow circuits to become unreliable because there’s too much PV on those circuits.”The policy change halted what has been a solar surge in Hawaii. Installations there jumped 169 percent last year from 2011. More than 4 percent of households have photovoltaics. Hawaii last year led the nation in the portion of its electricity that comes from solar, with 2.6 percent. The Aloha State burns oil to make electricity, and prices for the fuel have jumped in recent years, igniting demand for alternatives. The state’s tax credit for solar energy made it additionally appealing (ClimateWire, May 6). The new struggle on Hawaii foreshadows what the rest of the country could face as solar moves closer to the mainstream, several involved in the debate said. “Hawaii is a crystal ball into what every other state is going to have to look at as they start reaching higher and higher levels of solar activity,” said Robert Harris, executive director of Sierra Club Hawaii. “There is a national debate about what is the future model of the utility. That is happening in real time in Hawaii.”

‘I am from the future’
The Hawaii development comes amid battles in California, Arizona and Colorado over the future of net energy metering (NEM). That policy — which exists in some form in 43 states and the District of Columbia — lets households with renewable energy earn bill credits for surplus power delivered to the grid. Utilities in states with growing levels of solar have argued that fixed fees and other changes are needed because customers with net metering bill credits don’t pay their fair share of transmission and distribution charges. The Golden State’s Legislature has ordered the California Public Utilities Commission to retool NEM by 2015. The new program will need to be “based on electrical system costs and benefits to nonparticipating ratepayers.” Arizona’s utility regulator last month approved a hike in the surcharge that solar customers with net metering pay the state’s largest utility. The Arizona Corporation Commission ordered workshops to study the value and costs associated with NEM. Conversations about net metering are beginning in Louisiana, parts of Texas, Illinois, New York and Massachusetts (ClimateWire, Dec. 11). Charles Wang, with the Hawaii ECO Project, at a solar conference in San Diego earlier this month warned people from other states that Hawaii is a “cautionary tale” and “something that you will face down the road in your marketplaces. I am from the future,” Wang told a room of industry and environmental representatives. “The utility is that 800-pound gorilla. If you push it to the corner of the room, it’s going to fight back. That’s what’s happening right now.”

The HECO policy is only for Oahu, but a similar rule already is in effect on Maui and the Big Island. It’s more controversial on Oahu, however, because it’s home to about 80 percent of the state’s population. About 900,000 people live on Oahu. On Oahu, 10 percent of utility customers will have rooftop solar by year-end, Rosegg said. That compares with California, where it is 2 to 3 percent, he said. And demand for new connections for PV has been heavy. “These applications were rolling in at such an aggressive rate. … We simply had to get advance notice that these were coming in,” Rosegg said. The utility’s grid wasn’t designed for power to go two directions, Rosegg said. The ability for PV to make more power than would be used in a neighborhood creates a situation where there is “overvoltage.” The energy can flow back to the substation, he said, which can lead to reliability problems and possibly surges. And if crews are working in the area, there’s a potential danger. Others say the utility fears more solar expansion and hasn’t developed a plan to adjust. “It’s no doubt a threat, and down the road utilities have to seriously look at their business model,” said Leslie Cole-Brooks, Hawaii Solar Energy Association executive director. “It’s a whole new era because these technologies are available.” The HECO change has triggered a push for help from the state’s Legislature when it reconvenes Jan. 15. Sierra Club Hawaii and others are working on potential bills to ease the burden on homeowners. Measures could include helping the utility make grid improvements, said Harris with Sierra Club Hawaii. The goal is to make sure more renewable energy can come online, he said, and to develop a way to pay for it that is “fair and equitable” for all customers.

System closing soon?
The new edict for Oahu mostly focuses on grid circuits where power available from rooftop solar reaches or exceeds 100 percent of the minimum daytime load, the low point of the total power that customers on a circuit are using. Areas at that level will require interconnection requirements studies. Circuits at 75 percent could also need the studies. Residents who want to add solar in other parts of Oahu must apply with HECO and wait for approval. About one-fourth of circuits on Oahu are at 100 percent, Rosegg said. At the current rate of adoption, Harris said, all electrical circuits controlled by the utility could be closed to small-scale solar within six months. HECO, meanwhile, is planning interconnection studies on what it calls “representative” circuits “already heavily loaded with PV.” It will use the results to evaluate other circuits and tell customers who want to add solar what they’d need to pay to upgrade the grid. Changes could include adding grounding transformers or increasing the capacity of a substation, Rosegg said. The utility’s analysis won’t be finished until early next year.

Hawaii’s solar market slowed dramatically after HECO’s letter. Permits for photovoltaic projects issued on Oahu fell to 1,246 in October, down 49 percent from a high of 2,433 a year earlier. Last month they were at 1,040, a 48 percent drop from 1,996 in November 2012. Marco Mangelsdorf, president of ProVision Solar on the Big Island, pulled the data from the Honolulu County and city planning website. Before the HECO policy change, Walter’s Electric — based on the Big Island — was setting company records for solar installations. The last three months of the year look especially promising, said company President Kaimi Walter Chung. “It looked like we were going to have our best quarter,” Chung said. “We were ramping up to do a lot of jobs.” Now Walter’s Electric has 70 customers on Oahu and 50 on other islands waiting for installation approval. Chung has had to focus more on the electrical services his company provides. Other solar companies have developed new sales strategies to attract business, including selling the idea of independence. Island Pacific Energy ran a full-page advertisement in the local paper promoting the idea of buying batteries for solar storage and sidestepping HECO’s rule. “Get solar now,” the ad said. “No waiting for utility approval. No added grid upgrade costs.” Poncho’s Solar ran an ad telling people they can opt for batteries and “avoid those extra costs.”

Systems would have to be independent of the grid to sidestep the safety review and potential grid upgrade costs, Rosegg said. Disconnecting from the grid is not realistic for most people, Chung said. The current state of battery technology means they have to be replaced after a few years, he said. And putting a system with batteries on a typical house would cost $40,000 versus $25,000 for one without the storage component, he said. Moreover, the battery portion isn’t eligible for the tax credits. “Eventually, I guess that’s how people are going to have to go, but I don’t think it’s feasible” right now, Chung said.

Installing solar without approval
Some customers are going forward with solar despite HECO’s new policy. Ron Hayashi, 61, this week had solar panels installed on his Oahu home, despite not having HECO approval to connect to the grid. The neighborhood where he lives already has solar capacity at 100 percent of the minimum daily load. Hayashi withdrew money from his 401(k) in order to buy a $14,800 solar system for his house. He wanted to get it connected by year’s end to take advantage of state and federal tax credits. After factoring those in, the electric bill savings from the panels will mean the investment is paid back in just under two years, he said. Hayashi bought a system with batteries called an “energy shifter” and believes — based on what his solar contractor told him — that HECO cannot refuse to connect the home once the utility’s safety study is complete. He needs to be connected for the system to work. “If I use the energy shifter, they cannot refuse you,” Hayashi said.

Cole-Brooks with the Hawaii Solar Energy Association said she and other advocates are talking to HECO about making accommodations for households that have batteries but want to be connected to the grid. There’s not a safety issue posed by those systems, she said, because extra power is going into the batteries and not the grid. But Rosegg with HECO said that right now there is no special treatment for systems that have batteries. Because there’s confusion about the rules, he said, the utility plans to run an advertisement in the local paper in a few days cautioning people that even if they are buying systems with batteries, they need to first contact HECO. “Nobody has a special dispensation to connect to the grid,” Rosegg said. “Everybody has to go through the process. If an inspection is needed, we’ll do that. If upgrades are needed, we’ll do that. Everybody is treated the same.”



Electricity-Generating Plants to Bring Clean Energy to Off-Grid Locations
by Julie M. Rodriguez / 03/19/14

Dutch start-up called Plant-e has developed a way to use living plants as a continuous source of clean energy – all that’s needed is a light source, carbon dioxide, water, and, of course, a field or patch of plants. The system works best in wetlands or watery fields like rice paddies, but it doesn’t matter if the water is brackish or polluted, so areas unsuitable for growing crops could be repurposed as a power source. There’s no complicated infrastructure to install, which makes it super easy to bring electricity to isolated regions that are currently without power.

The theory behind the Plant-e system is surprisingly simple. When plants create food using photosynthesis, a large portion of the organic matter generated is actually excreted by the roots into the soil. That organic matter gets munched on by microorganisms living in the soil, which release electrons as a byproduct of this consumption. By placing an electrode near the roots, it’s easy to harvest this waste energy and turn it into electricity. The process is similar to elementary school science projects that create a battery out of an apple or potato, but with the added benefit of leaving the plants completely unharmed by the process. Tests have shown that the plants will continue to grow normally in the presence of electrodes, providing a constant source of power day and night. A prototype green roof using this technology is already being tested in the Netherlands. Currently, the Plant-e team is able to generate enough energy to power a cell phone, but the hope is that soon this method will be able to harvest a significant amount of electricity — maybe even enough to power a house.

Stanford researchers harvest electricity from algae, unkempt pools become gold mines
by Joseph L. Flatley  / April 15 2010

While we’ve seen plenty of stabs at viable green energy, from underwater turbines to the Bloom Box, we’re always up for another. Running along the same lines as Uppsala University’s algae-based batteries, researchers at Stanford are generating electrical current by tapping into the electron activity of individual algae cells. The team designed a gold electrode that can be pushed through a cell membrane, which then seals around it. The cell, still alive, does what it does best (photosynthesis), at which point scientists harvest chemical energy in the form of electrons. According to Stanford University News, this results in “electricity production that doesn’t release carbon into the atmosphere. The only byproducts of photosynthesis are protons and oxygen.”

Scientists Discover Methods of Harvesting Electricity from Plants
by , 05/09/13

When it comes to capturing solar energy, plants are first in their class. Able to function at nearly 100 percent quantum efficiency, they can produce an equal number of electrons for each photon captured. Using these photons to split water into hydrogen and oxygen, the resulting electrons are able to create sugars that help the plant to live and reproduce. Researchers at the University of Georgia have developed a way to harness the power of the photosynthetic process to generate a clean form of electricity. Ramaraja Ramasamy, assistant professor in the UGA College of Engineering, explained how his team manipulated the biology for human advantage. During photosynthesis, electrons freed from water molecules go towards producing sugars for the plant’s survival. Structures within the plant cell called “thylakoids” store the energy from the sun. The scientists were able to alter proteins within the thylakoids to interrupt the pathway along which electrons flow, placing the thylakoids against a backing of carbon nanotubules 50,000 times finer than a human hair. Acting as an electrical conductor, the nanotubules were able to take the electrons from the plant and move them along a wire. During experiments, the process resulted in current levels that were twice the power of current systems. While more work needs to be done to bring the technology to market level, the developments could potentially improve the function of solar panels, remote sensors, and other electronic equipment. “Clean energy is the need of the century,” said Ramasamy. “This approach may one day transform our ability to generate cleaner power from sunlight using plant-based systems.” Instead of noisy generators, turbines, or coal-fire stations, it is possible that we may one day have real “power plants” in our neighborhoods.

Table Lamp Powered Completely by Tomatoes
by  / 04/15/10

We all know tomatoes pack a powerful acidic punch, but we never thought we’d see one lighting up a room! Cygalle Shapiro of Israel-based d-VISION has created an incredible LED lamp that is completely powered by real, edible tomatoes. Currently exhibited at the Milan Furniture Fair, the design collects energy from a chemical reaction between tomato acids, zinc, and copper. This design doesn’t only explore advances in lighting technology – its also an art piece that sends clear and powerful social-conscience messages about where and how we receive energy.

d-VISION‘s tomato lamp calls attention to the amount of natural resources needed to produce even the smallest amount of power for everyday living. Although the tomato lamp utilizes an organic energy source, it still takes a considerately large amount of tomatoes just to power one lamp. The lamp holds power until the tomatoes go stale, signaling a beginning and end to energy sources. The designer highlights value by creating the tomato-powered circuits and lamp completely out of gold.



A Navy fuel ship replenishes the the U.S.S. Mount Whitney on the Mediterranean Sea in October 2013. (U.S. Navy photo by Mass Communication Specialist 1st Class Collin Turner/Released)
A Navy fuel ship replenishes the the U.S.S. Mount Whitney (right) on the Mediterranean Sea in October 2013

U.S. Navy Wants to Fuel Ships Using Seawater
by Carl Engelking  / April 8, 2014

The U.S. Navy’s Arleigh Burke-class destroyer typically burns 1,000 gallons of petroleum fuel an hour. Most of the Navy’s fleet shares the same ravenous appetite for fuel, and refueling these massive warships can interrupt missions and present challenges in rough weather. However, researchers at the U.S. Naval Research Laboratory have now proven that it’s possible to power engines instead with a cheap, convenient supply of fuel: seawater. Scientists have spent nearly a decade laboring to turn the ocean into fuel. The breakthrough, demonstrated in a proof-of-concept test, was made possible by a specialized catalytic converter that transforms carbon dioxide and hydrogen from seawater into a liquid hydrocarbon fuel.

The development of a liquid hydrocarbon fuel is being hailed as a game changer. If Navy ships create their own fuel they can remain operational 100 percent of the time, rather than conducting frequent fuel-ups with tankers while at sea, which can be tricky in rough weather. A catalytic converter extracts carbon dioxide and hydrogen from water and converts the gases into liquid hydrocarbons at a 92 percent efficiency rate, and the resulting fuel can be used in ships’ existing engines. The feasibility of the approach was demonstrated in the test on April 2, when researchers flew a model airplane using the fuel from seawater. “This is the first time technology of this nature has been demonstrated with the potential for transition, from the laboratory, to full-scale commercial implementation,” said Navy research chemist Heather Willauer in a news release Monday. The next major step is to build the infrastructure to convert seawater into fuel on a massive scale. The Navy would first start mass-producing fuel in land-based operations, which would be the first step toward installing fuel generation systems on ships. The Navy predicts the seawater fuel would cost about $3-6 per gallon, and could be commercially viable within a decade.


“Navy researchers at the U.S. Naval Research Laboratory (NRL), Materials Science and Technology Division, demonstrated proof-of-concept of novel NRL technologies developed for the recovery of carbon dioxide (CO2) and hydrogen (H2) from seawater and conversion to a liquid hydrocarbon fuel. Fueled by a liquid hydrocarbon – a component of NRL’s novel gas-to-liquid (GTL) process that uses CO2 and H2 as feedstock – the research team demonstrated sustained flight of a radio-controlled (RC) P-51 replica of the legendary Red Tail Squadron, powered by an off-the-shelf (OTS) and unmodified two-stroke internal combustion engine. Using an innovative and proprietary NRL electrolytic cation exchange module (E-CEM), both dissolved and bound CO2 are removed from seawater at 92 percent efficiency by re-equilibrating carbonate and bicarbonate to CO2 and simultaneously producing H2. The gases are then converted to liquid hydrocarbons by a metal catalyst in a reactor system. “In close collaboration with the Office of Naval Research P38 Naval Reserve program, NRL has developed a game-changing technology for extracting, simultaneously, CO2 and H2 from seawater,” said Dr. Heather Willauer, NRL research chemist. “This is the first time technology of this nature has been demonstrated with the potential for transition, from the laboratory, to full-scale commercial implementation.”

CO2 in the air and in seawater is an abundant carbon resource, but the concentration in the ocean (100 milligrams per liter [mg/L]) is about 140 times greater than that in air, and 1/3 the concentration of CO2 from a stack gas (296 mg/L). Two to three percent of the CO2 in seawater is dissolved CO2 gas in the form of carbonic acid, one percent is carbonate, and the remaining 96 to 97 percent is bound in bicarbonate. NRL has made significant advances in the development of a gas-to-liquids (GTL) synthesis process to convert CO2 and H2 from seawater to a fuel-like fraction of C9-C16 molecules. In the first patented step, an iron-based catalyst has been developed that can achieve CO2 conversion levels up to 60 percent and decrease unwanted methane production in favor of longer-chain unsaturated hydrocarbons (olefins). These value-added hydrocarbons from this process serve as building blocks for the production of industrial chemicals and designer fuels. In the second step these olefins can be converted to compounds of a higher molecular using controlled polymerization. The resulting liquid contains hydrocarbon molecules in the carbon range, C9-C16, suitable for use a possible renewable replacement for petroleum based jet fuel.

The predicted cost of jet fuel using these technologies is in the range of $3-$6 per gallon, and with sufficient funding and partnerships, this approach could be commercially viable within the next seven to ten years. Pursuing remote land-based options would be the first step towards a future sea-based solution. The minimum modular carbon capture and fuel synthesis unit is envisioned to be scaled-up by the addition individual E-CEM modules and reactor tubes to meet fuel demands. NRL operates a lab-scale fixed-bed catalytic reactor system and the outputs of this prototype unit have confirmed the presence of the required C9-C16 molecules in the liquid. This lab-scale system is the first step towards transitioning the NRL technology into commercial modular reactor units that may be scaled-up by increasing the length and number of reactors. The process efficiencies and the capability to simultaneously produce large quantities of H2, and process the seawater without the need for additional chemicals or pollutants, has made these technologies far superior to previously developed and tested membrane and ion exchange technologies for recovery of CO2 from seawater or air.”

artist's conception of a pilot plant off China's coast

Ocean Thermal Power Will Debut off China’s Coast
by Daniel Cusick and ClimateWire / May 1, 2013

Forty years of research and development by Lockheed Martin into harnessing energy from steep differentials in ocean temperatures will see its first commercial deployment in China. There, a resort developer has partnered with the U.S. defense and aerospace giant to build a 10-megawatt power plant using ocean thermal energy conversion (OTEC) technology. A recently signed agreement between Lockheed Martin, of Bethesda, Md., and the Beijing-based Reignwood Group should lead to the completion of the alternative energy plant by 2017 in waters off southern China’s Hainan Island. The platform-based power plant will be the largest OTEC application developed to date, according to Lockheed, supplying 100 percent of the power needed for the resort, which will be marketed as a low-carbon real estate development.

The technology involves heating warm surface water to produce steam that drives a turbine generator. Then colder water is pumped from 800 to 1,000 meters below the ocean surface to condense the steam back into liquid form. Dan Heller, Lockheed Martin’s vice president of new ventures for Mission Systems and Training, said the relationship with Reignwood, a diversified firm with holdings in the energy, minerals, aviation and resort business, solidified as Lockheed engineers went searching for suitable locations to build a pilot-scale OTEC facility. For several years, Lockheed has tested the technology at a site in Hawaii in partnership with Makai Ocean Engineering, the Energy Department and the U.S. Navy. But several obstacles, including high upfront costs and securing a partner for a long-term project, kept such efforts from growing into a scaled power plant, according to sources familiar with the testing program.

Duke Hartman, a spokesman for Makai Ocean Engineering, said that his firm continues to work on OTEC applications in partnership with the Navy, and that the Pentagon has retained its goal of developing a 5-10 MW pilot plant off the island of Oahu and eventually a commercial plant of up to 100 MW. “The Navy wants a thriving OTEC industry because they would benefit from it,” Hartman said. Imagine being able to tow a semisubmersible power plant to almost any corner of the world, he added. Hartman said Makai is supportive of Lockheed Martin’s work in China and hopes to be able to participate in the project in some way. “The biggest obstacle to OTEC is economies of scale,” he said. “You get a lot more bang for your buck if you go bigger.” He estimated that a 100 MW OTEC plant would cost in excess of $1 billion to build using current technologies, and that the cost would not be significantly lower for a scaled-down plant. Lockheed Martin’s Heller said that Reignwood will bear the full cost of the 10 MW project in south China and that the two firms will continue to seek opportunities to expand OTEC’s foothold in Asia.

U.S. sites with potential
In the United States, Heller noted that several sites, including Hawaii and Florida, have demonstrated potential for commercial OTEC plants, and that Lockheed continues to work to identify partners for OTEC projects at home. But, he said, when the company began surveying locations for a commercial plant, “China was a very logical place to start” due to its need for clean energy alternatives as well as its location near some of the world’s most ideal oceanographic conditions. Reignwood, he said, was recommended as a development partner because of its commitment to use clean energy to power its resort communities. Heller said Lockheed Martin will use the Reignwood project to help prove OTEC’s viability as an energy resource with the long-term goal of “building an industry around OTEC,” which has applications beyond electricity generation such as seawater desalination and hydrogen production. And unlike other renewable energy sources, OTEC can be relied on for 24-hour, base-load power. Lockheed has a team of about 20 engineers working on its OTEC program, and that number is likely to go up as the Reignwood project moves closer to the construction phase. “Even before the announcement, we’ve had a tremendous response when it became evident that we were going to make this a reality,” Heller said.

A prototype osmotic power plant in Tofte, Norway.
The world’s first osmotic energy plant has been operating for more than three years in Tofte, Norway, on the Oslofjord inlet. Statkraft is seeking to ramp up its efforts to produce renewable energy from the physical interaction of saltwater and freshwater.

Salt Power: Norway Project Tries Osmotic Energy
by Dean Clark  /  January 7, 2013

Tofte, an hour south of Oslo on the inlet known as Oslofjord, is home to a waterfront cellulose factory and not much else. But for more than three years, Norwegian energy company Statkraft has been rather quietly testing the technology in the world’s first osmotic power plant, in a renovated wing of the town’s factory. With a meager two to four kilowatts of capacity, barely enough power to foam a cappuccino, the plant is a decidedly small start. But the Norwegian Center for Renewable Energy (SFFE) pegs the global potential of osmotic power to be about 1,370 terawatt-hours per year, about equivalent to the current electricity consumption of Eastern Europe and Russia combined. So Statkraft is now seeking to ramp up its work, while researchers around the world are joining in the effort to harness a new form of renewable energy from the saltwater that covers more than 70 percent of the Earth’s surface.

Power from Movement
Osmotic power, also known as “salinity gradient” power, relies on a rather basic physical process: diffusion. Salty water molecules tend to move into freshwater nearby. It happens wherever rivers meet the sea, creating energy in the form of heat.  Place a semipermeable barrier between the saltwafter and the freshwater, and the diffusion of molecules through the membrane is osmosis. For decades, reverse osmosis has been used to filter water. Sidney Loeb, the American chemical engineer who is credited with developing a practical reverse osmosis process in the 1950s, later developed a technique for capturing the energy in the rush of saltwater to the freshwater side of a membrane. Statkraft estimates it spent over ten years and more than 100 million kroner (about $12 million USD) in research funds to help develop one of these techniques, pressure retarded osmosis (PRO), in the prototype facility at Tofte. It’s a big investment for a facility that has only enough capacity to operate a coffee machine, but size of output isn’t the key metric for researchers at this point. Statkraft views the Tofte experiment as a lab for learning how to capitalize on osmotic power´s huge potential and strong environmental credentials. Independent experts see the potential. “It´s a very clean process,” said Friso Sikkema, senior specialist in power generation and renewables at DNV Kema, a leading research firm in the field based in the Netherlands.

Osmotic power generation is carbon-free, and Statkraft reports that its plant´s main byproduct is brackish water. Questions remain however, concerning future large-scale operations and their effect on salinity levels or how pretreatment processes might impact local marine life. Bruce Logan, director of the Hydrogen Energy Center and Engineering Energy and Environmental Institute at Penn State University says he is “optimistic osmotic power can play an important role,” but cautioned “there´s not enough work going on in terms of developing inexpensive membranes tailored for the process.” Even though membrane technology is still in its early stages, the force currently generated by the experimental process can be significant. With pressures at the Norwegian test site reaching 12 bar on the seawater side, “it’s like creating an artificial waterfall of 120 meters” (394 feet), according to Statkraft’s head of osmotic power, Stein Erik Skilhagen. In this early-stage experiment, though, the flow of water is more a trickle than a cascade, so power output at Tofte is still small.

Interest in the renewable energy source is growing internationally. NASA has been working on osmotic systems for the treatment of wastewater aboard spacecraft, and is now investigating the PRO method with tertiary treatment, or PRO/TT, with the aim of developing technology that can purify water and create energy at the same time. Hydro-Québec, the largest electricity generator in Canada and the largest producer of hydroelectric power in the world, is partnering with Statkraft on next-stage development of PRO technology. It is looking into the feasibility of osmotic energy along Canada’s long coastline. Japan’s Tokyo Institute of Technology opened its Osmotic Power Research Centre in 2010, the year before a devastating earthquake and tsunami crippled the Fukushima Daiichi nuclear plant and led to a rethinking of the nation’s energy future. Akihiko Tanioka, the researcher leading the osmotic effort, argues that the flow volume of Japan’s rivers contain the potential energy capacity to replace five or six nuclear reactors if osmotic plants were situated where rivers run into the sea.

Natural Battery
Researchers in the Netherlands are working on an alternative to PRO—reverse electrodialysis, or RED. DNV Kema´s Sikkema said the process, essentially, is “creating a natural battery.” In the RED approach, the osmotic energy of mixing fresh and salt water is captured by directing the solution through an alternating series of positively and negatively charged exchange membranes. The resulting chemical potential difference creates a voltage over each membrane and leads to the production of direct electric energy. While less developed than PRO, the RED process may eventually become popular for a lower initial cost structure. “PRO calls for complex machinery, chambers and turbines and generators.  Economy of scale plays a large role.  In our (RED) technology, we produce electricity directly from difference in fresh and saltwater,” said Sikkema.

With all the upsides, why isn’t osmotic power already warming homes around the world? Infrastructure for the process is currently very expensive. Statkraft estimates that a PRO plant that can supply power for 30,000 homes would need to be the size of a sports stadium and require 5 million square meters of membrane. Add to that the challenge of creating intake water clean enough to keep from fouling the membranes, and there are some costly hurdles to overcome. But proponents like Skilhagen point out that the development of osmotic power will follow a curve like that of other green energy sources. “You have to compare it with other renewables: wind, hydro and solar, for example. There is a high level of investment in the beginning, but the technology will mature and become more attractive in future. Osmotic’s environmental benefits will make it a useful part of the future low-carbon energy mix if costs can be brought in line with other renewables.” Penn State’s Logan says development of inexpensive membrane technology will be key to establishing a realistic price point for osmotic energy. The next step for Statkraft is to ramp up from the prototype at Tofte to a larger pilot plant that will generate more energy and be connected to the grid. The company has applied for permits to construct a pilot on the west coast of Norway.

Continuous Sustainable Power Supply: Benthic Microbial Fuel Cell

Research chemist and branch head at the Center for Bio/Molecular Science and Engineering at the U.S. Naval Research Laboratory (NRL), Dr. Lenny Tender, speaks with Department of Defense Armed with Science on cutting-edge research to address the growing concerns of carbon-based energy consumption and the reduction in carbon dioxide (CO2) emissions. Co-inventor of the microbial fuel cell (MFC), which persistently generates electrical power in marine environments, Tender is an internationally recognized leader in MFC research that spans implications in alternative, carbon-neutral energy generation that address pressing needs of the Navy, Department of Defense (DoD), and the nation.

To get long-term data on the state of the oceans is very difficult because oceanographic sensors are constantly running out of battery power. What the benthic fuel cell does is generate electricity indefinitely using microorganisms naturally residing on the sea floor. “At the bottom of the marine environment we have sediment, the mud at the bottom of a harbor, river, lake, or the ocean, which has quite a bit of fuel in it, organic matter which microbes draw upon to satisfy their energy needs,” Tender says. “You can think of anything that has ever lived in the marine environment, phytoplankton, sea creatures, etc. When they die, they settle on the sea floor and, like leaves on the lawn, start decomposing—and this represents a pretty potent fuel source for marine microorganisms to produce energy in the form of electricity.”

There are thousands of oceanographic instruments that are deployed every year by the Navy. Naval fleets around the world, science organizations, and academic researchers studying climate get a relatively short picture of what is occurring over time. This is due to the limited lifetime of batteries typically used to power oceanographic instruments. In comparison, the benthic MFC can operate indefinitely, owing to the immense reservoir of fuel and oxidants that it draws upon in the marine environment. Tender’s research in benthic MFC development, therefore, has significant implications to future Navy capabilities with respect to persistent in-water Intelligence, Surveillance, and Reconnaissance (ISR) operations for warfighters in riverine, estuarine, and close-in littoral environments.

With funding from the Bill and Melinda Gates Foundation, Tender has expanded his MFC research to include wastewater treatment. Whereas conventional treatment processes consume significant power—an issue that confronts the DoD and developing countries alike—MFCs may enable power generation from wastewater treatment. As Tender describes, approximately five percent of U.S. electricity consumption goes to treating wastewater. The inherent energy represented by the organic matter, which is the fuel in the wastewater, can instead be used to generate electricity. Expanding on this idea, Tender says, this provides an opportunity to flip that equation upside down and to actually think of wastewater treatment plants as power stations. “The funding we have with the Gates Foundation is to help Third World communities. In other areas of the world, most don’t treat wastewater, so people can get very sick. If we can come in and say ‘well, not only can we treat the wastewater, but knock down the prevalence of disease and provide you with electricity,’ that’s the interest of the Gates Foundation that holds a similar interest to that of the DoD.” Tender describes other applications stemming from this research that he says will go way beyond just generating energy on the sea floor. “One of the things my team and I are pursuing now, that I’m very excited about, is the idea of using microorganisms as catalysts on electrodes to generate fuel from carbon dioxide,” Tender said. “This is an opportunity to start drawing on the carbon dioxide that’s already in the atmosphere and generating a fuel, basically running the combustion process in reverse.”

In the case of his microbial fuel cell, microbes oxidize organic matter residing in marine sediment or wastewater and transfer the acquired electrons to the anode. This results in the generation of electrical power, but also carbon dioxide. By running the process in reverse, it is possible to use microbes to reduce carbon dioxide back into forms of organic matter that can serve as transportation fuels, using electrons donated from cathodes and solar-generated electricity. However, the trick, says Tender, is finding candidate microbes that are very good at accepting electrons from cathodes and reducing carbon dioxide—components that he says his team has already identified. For Tender, the benthic microbial fuel cell has opened up an entire line of research that he believes will have a much higher impact than powering oceanographic sensors on the sea floor.