David Anthony’s Last Question – Can We Power the US Solely off of Solar?

By Tao Zheng, with David Anthony, an active cleantech venture capitalist, who passed away in April 2012.

 The sun is the champion of all energy sources, in terms of capacity and environmental impact. The sun provides earth with 120,000 terawatt (TW) energy, compared to technical potential energy capacity of single digit TWs from other renewable sources, such as wind, geothermal, biomass and hydroelectric. More energy from the sun hits the earth in one hour than all of the energy consumed on our planet in entire year. In the last blog, we estimated that the technical potential of electricity generation from rooftop photovoltaics (PV) can take over 1/3 of U.S. electricity consumption demand. The next question is: can we power the U.S. solely by solar energy, technically? The answer will rely on development of utility-scale solar farms and energy storage solutions.

Assuming the rest 2/3 of U.S. electricity demand can be fulfilled by utility-scale PV solar farms, we can estimate how much land required to install such solar farm systems. The total U.S. electricity demand in 2009 was 3,953 TWh with 1% annual growth projection in next 25 years. Two third of U.S. electricity demand is about 2,635 TWh. The PV power density is calculated with a weight-averaged module efficiency using market share for the three most prevalent PV technologies today: crystalline silicon, cadmium telluride, and CIGS. The resulting PV power density is 13.7 MW/million ft2, assuming an average module efficiency of 18.5% in 2015. If we assume 10 hours/day and 200 days/year with sunshine, the annual available sunshine time is 2,000 hours. The total land required for solar farms to generate 2,635 TWh, can be calculated as:

Total Land Required = Total Energy Generated / PV power density / Annual available sunshine time

                                 = 2,635,000/13.7/2000 = 96.2 ×109 ft2 = 8,937 km2 @ 100 × 100 km

Therefore, to generate energy equivalent to 2/3 of U.S. electricity demand, we need to install solar panels in a tract of land with size of 100 by 100 km, the area about 0.1% of U.S. land. Technically, to provide electricity for entire U.S. demand, we only need to cover PV-accessible residential and commercial rooftop with solar panels and install solar farms in desert area equivalent to 0.1% U.S land. In addition to rooftop and desert, there are many opportunities for installing PV on underused real estate, such as parking structure, airports, and freeway margins. PV can virtually eliminate carbon emissions from the electric power sector.

In comparison, Nathan Lewis, professor at Caltech, predicted a solar farm with land size of 400 by 400 km to generate 3 TW energy to power entire America. The represented area is about 1.7% of U.S. land size, comparable to the land devoted to the nation’s numbered highways. As shown in Figure 1, the red square represents the amount of land need for a solar farm to match the 3 TW of power demand in the U.S. Of the 3 TW energy, only 10% represents electricity demand, and the rest represents other energy needs, such as heating and automobile. Thus, Lewis’ calculation is consistent with our estimation: 10,000 km2 solar farms can generate enough electricity to fulfill 2/3 U.S. demand.

Figure 1. Solar Land Area Requirement for 3 TW Solar Energy Capacity to Power Entire U.S. Energy Demand. (Source: Prof. Nathan Lewis group at Caltech).

One of big challenges using solar to power U.S. grid is intermittency of sunlight. Solar energy is not available at night, and the variable output of solar generation causes voltage and frequency fluctuations on power network. Energy storage technology can smooth the output to meet electricity demand pattern. There are many grid energy storage technologies, from stationary battery to mechanical storage methods. Pumped hydro technology is clearly a better choice for solar energy storage, due to its high energy capacity, low cost, and public safety assurance.

For solar to have a dominant role in the electric power generation mix, in addition to power storage infrastructure, upgrading America’s transmission grid is required. In contrast to traditional electricity generation, solar power collections are distributed across numerous rooftops or centralized in utility-scale farms. Distributed solar requires grid operators to install smart grid technology to monitor power supply and demand and balance thousands of individual generators with central power plants. The current century-old transmission grid needs to be upgraded with high-voltage lines to carry electricity from remote solar farms to consumers. The American Recovery and Reinvestment Act (ARRA), signed into law by President Obama in 2009, has directed $40 billion to accelerate the grid infrastructure transformation.

The U.S. photovoltaic market has been growing quickly in recent years. In 2010, the U.S. installed 887 megawatts (MW) of grid-connected PV, representing 104% growth over the 435 MW installed in 2009. Current trends indicate that a large number of utility-scale PV power plants are in the south and southwest areas, such as in the sunny deserts of California, Nevada and Arizona. For example, the Copper Mountain Solar Facility in Boulder City, Nevada, is one of the U.S. largest solar PV plants with 48 MW capacity, as shown in Figure 2.

Figure 2. One of the U.S. Largest Solar Plants, the Copper Mountain Solar Project with 48 MW photovoltaic in Boulder City, Nevada.

Historically, solar PV deployment has been limited by economic factors, since solar energy is too expensive to compete with traditional fossil fuels, due to lack of economies of scale. However, the cheapest solar cells are now being produced for as little as 70¢ per watt. They are selling for about $1.26 per watt, with prices expected to drop to $1.17 next year. Most anticipate the price of solar module, such as thin film, will hit 50¢ per watt within four or five years. First Solar, the world’s largest maker of thin-film solar panels, has told investors that production costs will range between 52¢ and 63¢ per watt by 2014. When companies can produce solar photovoltaic modules for less than 50¢ per watt, solar energy will reach grid parity. Grid parity refers to the point at which the cost of solar electricity rivals that of traditional energy sources, such as coal, oil, or nuclear. The solar module price drop is driven by cheaper manufacturing costs, lower costs for such crucial raw materials as silicon, and rapidly improving technology. A recent study even claims solar grid parity is already here today, based on a legitimate levelized cost of energy (LCOE), calculated the cost in $/kwh. The value of LCOE is determined by the choice of discount rate, average system price, financing method, average system lifetime and degradation of energy generation over the lifetime. Figure 3 illustrates the effect of initial installed cost and energy output on the LCOE value. For a PV system with production cost at $0.5/W, the initial installed system cost will be $1.5-$2/W, after considering labor cost and module margin. If we assume energy output is 1500 kWh/kW/yr, which is reasonable in south west area in the U.S., the LCOE value in Figure 3 will fall in the range between $0.06/kWh and $0.08/kWh, the lower side of grid parity value for the U.S. residential electricity rates range.

Figure 3. LCOE contours in $/kWh for solar PV systems for energy output versus initial cost of the system for a zero interest loan, discount rate of 4.5%, degradation rate of 0.5%/yr and 30 year lifetime (Courtesy of Prof. Joshua Pearce at Queen’s University)

Based on the analysis above, it is reasonable to believe we can power the U.S. electric grid solely by solar PV, technically and economically. Thomas Edison had a great quote on solar energy: “We are like tenant farmers chopping down the fence around our house for fuel when we should be using Natures inexhaustible sources of energy — sun, wind and tide. … I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.”


David Anthony was the Managing Director of 21Ventures, LLC, a VC management firm that has provided seed, growth, and bridge capital to over 40 technology ventures across the globe, mainly in the cleantech arena. David received his MBA from the Tuck School of Business at Dartmouth College in 1989 and a BA in economics from George Washington University in 1982. David passed away in April 2012. 

Tao Zheng is a material scientist in advanced materials and cleantech industry. He held 20+ patents and patent applications, and published many peer-reviewed papers in scientific journals. Tao Zheng received his B.S. degree in polymer materials sciences from Tsinghua University in China, and a Ph.D. degree in chemical engineering from University of Cincinnati. He obtained his MBA degree with distinction in finance and strategy from New York University, Stern School of Business, where he was designated as “Stern Scholar” and received “Harold Price Entrepreneurship Award”. 

Concentrating (on) Utility-Scale Solar Energy

Last week, at the invitation of organizer Green Power Conferences, I attended their Solar Power Generation USA conference in Las Vegas.

Of course, there are innumerable events pertaining to the solar energy space, and each needs its own niche of differentiation.  This conference pertained solely to utility-scale solar power projects.  In other words, this is the remaining part of the solar industry when rooftop and off-grid installations are excluded.

“Focus” is a key word that describes this portion of the solar industry, because the two primary technologies for large-scale solar projects both employ lenses to concentrate sunlight to achieve lower costs per unit of energy produced.

Concentrating solar power (CSP) involves the use of lenses to focus sunlight on a vessel containing a liquid.  As the liquid is heated, it then drives a steam turbine to generate electricity.  At a conceptual level, this type of power generation has been used for decades in conventional utility powerplants fired by fossil fuels (coal, oil or natural gas), only with CSP the sun is being harnessed to provide the heat.

Concentrating photovoltaics (CPV) involves the use of lenses to focus sunlight on super high-efficiency PV cells.  In contrast to conventional PV modules, which have conversion efficiencies of less than 20% (i.e., less than 20% of the sun’s energy is converted into electricity), CPV enables conversion efficiencies approaching 40%.

Common to both technologies, a typical power project entails several modular installations spread over a sizable chunk of land — usually patches of desert — aggregating to tens or even hundreds of megawatts, with a common point of interconnection to the utility grid.  See, for example, the Ivanpah project of 392 megawatts being developed in California by BrightSource Energy.

The overall message was that CPV and CSP projects can be undertaken today, with power purchase agreements priced at 10 cents/kwh or lower.  A key theme expressed at the conference was the “bankability” of CSP and CPV — no doubt, to assure the risk-averse universe of bank financiers, utility off-takers, and project developers in the audience.   Although not necessarily household names for Americans, the involvement of such large publicly-traded (albeit European) corporations as Areva (Euronext: AREVA.PA), Acciona (BMAD: ANA), Abengoa (BMAD: ABG) and Soitec (Euronext:  SOIT.LN) should give comfort that adequate financial wherewithal stands behind CSP or CPV projects to support long-term warranties. 

Each of these concentrating solar technologies has its advantages and disadvantages.  CPV makes more sense than CSP where water is very expensive, because CPV doesn’t involve the steam cycle.  On the other hand, unlike CPV, CSP’s thermal inertia enables energy storage that can extend the power production period beyond solely the daylight hours, and also “rides through” passsing clouds with minimal power fluctuations, thereby reducing the need for CSP owners/operators to purchase ancillary services (e.g., voltage control, frequency regulation).  This tends to make CSP a higher-value power generation solution for grid operators than CPV.

In any event, CPV and CSP will not dominate the world.  They are only economically viable where direct normal irradiation (DNI) — known to the lay-person as clear sunlight — is very high.  Thus, CSP and CPV will not be ubiquitous, but rather a solution only in certain (typically sparsely-populated) parts of the world, and thus will remain only a minority segment of the solar industry, which will be dominated by conventional PV. 

Even so, it is possible to imagine these technologies being widely adopted in deserts in the decades to come — and there is a lot of desert footprint on this Earth.  That growth potential is why some of the big names listed above have been concentrating their attention on concentrating solar energy.

Wind, Water and Sun can Power Our 240 Million Cars and Everything Else

Mark Jacobson Lecture Our Promising Future of Electric Cars Powered by Renewable Energy

Our Promising Future of Renewable Energy

The cleanest solutions to global warming, air pollution and energy security are wind, water, and solar power (WWS).  As Dr. Mark Jacobson walks me through the numbers of his, Dr. Mark Delucchi, and their teams’ multi-year study, the renewable energy solution stands out as the clear winner. Dr. Jacobson is a Professor of Civil and Environmental Engineering at Stanford University and an advisor to the U.S. Department of Energy.

Wind power has been doubling in capacity about every three years. It’s now over 200 GW; in 3 years it will be over 400 GW. 36 U.S. states generate enough wind power to replace one or more coal or nuclear power plants.  U.S. wind grew 39 percent in recession year 2009. In a growing number of global locations from Hawaii to Denmark, wind is the least expensive way to generate power. Their WWS study includes both on-shore wind power, which is plentiful from Texas through the Dakotas and offshore with enormous potential along our Pacific and Atlantic coasts and our Great Lakes.

Solar includes the photovoltaics that cover homes and the faster growing PV that covers commercial roofs. It also includes the grid-scale PV and concentrating solar power (CSP) that generates the equivalent power of a natural gas or coal plant. The water in WWS includes hydropower, our most widely used source of renewable energy, and geothermal power, which uses steam to drive turbines.  Water also includes emerging, wave and tidal power generation.

WWS can meet all of our needs for electricity. WWS can also meet all of our need for heat and for transportation.

At the same time that we see high growth of WWS, especially wind and solar power, we are also experiencing transformational growth of electrified transportation. Mark Jacobson points out that electric propulsion is four times as efficient as internal combustion. Health concerns, energy security, and economics make combustion a loser. Every year we see more battery electric vehicles (BEV), electric rail, and even hydrogen fuel-cell vehicles (HFCV) such as the 20 buses that transported 100,000 visitors during the last Winter Olympics.

From a technology standpoint WWS can meet all of our needs in 20 to 40 years.  How far and how fast we move to reduce greenhouse gas and health-damaging emissions depends more on politics, sunk-costs and inertia than on what is feasible.  Faced with the growing threats of global warming such as heat waves, water scarcity, failed food production, continued growth of WWS is essential.

Electric Cars End Our Dependency on Oil and WWS Ends Our Dependency on Coal

By 2015, several forecasts put one million to 1.5 million electric cars on the U.S. road. Having recently purchased a Nissan Leaf, I believe the forecast. My electricity bill is a fraction of what I paid at the gas station to put on the same miles. With current incentives, my electric car cost $22,000. Prices are likely to decline for electric cars while gasoline prices are forecasted to increase.

Mark Jacobson has driven his Tesla Roadster 16,000 miles. He charges his Tesla with the same solar photovoltaics that power his entire house. By going Mark Jacobson Driving Tesla Our Promising Future of Electric Cars Powered by Renewable Energyto energy efficient electric appliances and solar water heating, their utility bill is at the minimum needed for a couple of gas burners on the stove for a few favorite meals. Mark and his wife don’t just talk about the transition to WWS – they live it.

With the 240-mile range of his Tesla Roadster, range has rarely been an issue. Yes, on a trip to Sacramento, he had to plug his Level 1 charger into the outlet in his motel room, extending the cord out the window to his electric car. On one trip to Modesto, he had to convince his hotel manager to turn-off their decorative water fountain so that he could use the fountain’s electric outlet to trickle charge overnight. The vast majority of the time, he is riding on sunlight.

Public charging infrastructure is expanding, renewable energy growth continues, and lithium battery prices fall as gasoline and diesel increase in cost. Our cars are getting cleaner and more electric.

Jacobson and Delucchi looked at the lifecycle impacts of different types of cars and various fuels. Alternatives were ranked according to their impacts on global warming, pollution that impacts our health, water supply, land use, security issues such as terrorism and other impacts. The study evaluated nuclear, coal and natural gas with sequestration, advanced biofuels, and included hybrid and plug-in hybrids vehicles. Our best scoring alternatives, in the following order, are electric vehicles using renewable energy:

  1. Wind – BEVs
  2. Wind – HFCVs
  3. CSP – BEVs
  4. Geothermal – BEVs
  5. Tidal – BEVs
  6. PV – BEVs
  7. Wave – BEVs
  8. Hydro – BEVs

Pure battery-electric cars were the big winner in their study with most of their power coming from wind and solar charging. Hydrogen from wind electrolysis scores best for vehicles requiring extended range such as buses, ships using hybrid hydrogen fuel cell propulsion, and aircraft using liquefied hydrogen combustion. Mark Jacobson’s articles for Scientific American, Energy Policy, testimony to Congress and the EPA, and more can be accessed at his Stanford website.

The study used existing technology that can scale to broad commercial deployment. At first glance, growing to 11.5 TW of WWS globally looks impossible, a closer look shows that many of the study’s assumptions are conservative because only today’s technology is considered. The shift to electric vehicles powered with renewable energy will be easier if vehicles are built with much lighter materials, or if we succeed with breakthrough battery chemistry such as lithium air. The electric car/renewables scenario timetable also improves as U.S. drivers continue their trend of driving fewer miles thanks to record urban density, transit, flexwork, and aging boomers.

In Energy Policy Jacobson and Delucchi write, “”Although we focus mainly on energy supply, we acknowledge and indeed emphasize the importance of demand-side energy conservation measures to reduce the requirements and impacts of energy supply. Demand-side energy conservation measures include improving the energy-out/energy-in efficiency of end uses (e.g., with more efficient vehicles, more efficient lighting, better insulation in homes, and the use of heat exchange and filtration systems), directing demand to low-energy use modes (e.g., using public transit or telecommuting instead of driving)….”

Vehicle to Grid and other Storage

A 100% WWS United States must deal with the variability of wind and solar. This is an important reason that wind, water, and solar power are all needed to meet our 24/7 demands. Large-scale deployment of wind and solar will require a Supergrid network of high-voltage lines that can move electricity from mid-American wind farms and desert solar plants to cities and industry. With a national Supergrid, WWS is largely achievable without storage and even without using pricing and demand response (DR) to make energy demand more level. He walked me through a California study that he co-lead in 2005 showing that WWS would meet 99% of California needs, even during peak hours on a burning summer day. With our growing use of DR, intelligent energy management, and storage, large scale WWS can be deployed more quickly.

Byron Shaw of GM quipped, “Cars are like cats, they sleep 22 hours per day.” Most cars are parked when the grid faces peak demands. Why not let people make money charging at night at a discount and sell electricity back to the grid at peak at premium pricing? The model works well for individuals and businesses with solar power.

Jacobson and Delucchi write, “The use of EV batteries to store electrical energy, known as ‘‘vehicle-to-grid,’’ or V2G, is especially promising, albeit not necessarily easy to implement…. In order for V2G systems to provide operating reserves to compensate for hourly variations in wind power (again when wind power supplies 50% of US electricity demand), 38% of the US LDV fleet would have to be battery-powered and be on V2G contract.”

Yet 38 percent will not need to sign V2G contracts because V2G is just one of many ways to store wind and solar power until needed. Utilities currently use nighttime wind energy to pump water uphill. The next day at peak hours the water flows downhill driving generators. Grid-scale batteries, compressed air storage, and storage towers coupled with concentrating solar plants are all in early stage use.

Easier than It Looks

Meeting 100 percent of our energy and transportation needs with wind, water, and solar power seems as daunting as putting a man on the moon. Mark Jacobson and Mark Delucchi state in Energy Policy, “With sensible broad-based policies and social changes, it may be possible to convert 25% of the current energy system to WWS in 10–15 years and 85% in 20–30 years, and 100% by 2050. Absent that clear direction, the conversion will take longer. “

Their WWS scenario can meet our electricity, heat, and transportation needs. The technology is here, but it will take considerable political will to overcome the subsidies, market barriers, and change required to meet all needs with WWS.

In several ways, the transition will be easier in the United States. We already have more vehicles than people with drivers license, in contrast to the explosion of middle class drivers in Asia now buying their first car.

In the United States we have achieved strong growth of wind and solar. Now we are successfully deploying smart grids and electric cars. WWS does not require technology breakthroughs, yet dramatic innovation is likely in the next two decades in battery technology, solar efficiency, and urban mobility that requires fewer car miles.

Jacobson and Delucchi only assume reasonable progress in energy efficiency. New lighting technology, such as LED, can cut 80 percent of lighting’s 27 percent of total electricity demand. Making electricity cheap during vehicle charging hours and more expensive during peak hours will make a huge difference. In the United States, 80 percent WWS is achievable in the next two or three decades. 100 percent is like putting a man on the moon – it looked impossible until we did it.

14 Ways that Solar Power Costs will Decrease Sharply

Solar power continues to grow by over 30 percent annually. Solar panels cost 100 times less than in the 1970s. Solar is clean, often generated at or near where electricity is needed, and not at the mercy of fluctuating coal or uranium prices.

The timing for solar energy growth is excellent. Voters have lost their appetite for spending billions to try to make coal clean while carrying the burdens of health damage. Similarly, most voters do not want to pour billions into loan guarantees for expensive nuclear power in the wake of the disaster in Japan.

In this decade, installed solar will drop to half its current cost. Such cost reductions will take more than lower costs of silicon panels and thin-film. Process and policy are now key areas for cost reduction. I recently attended the 3rd Annual Solar Leadership Summit hosted by SolarTech. With progress in these areas, solar costs will drop in half:

  1. Manufacturing scale
  2. Efficiency
  3. Balance of System
  4. Installation
  5. Right Size
  6. Right Place
  7. Improve Interconnect
  8. Markets not Monopolies
  9. Policy
  10. Process
  11. Financing
  12. Concentrate
  13. Hybrid Systems
  14. Storage

Manufacturing scale

Ten solar manufacturers in China produce over one gigawatt of solar panels. High manufacturing volumes, lower labor costs, and favorable government policy have helped lower costs. Morningstar estimates that China has a 20 to 30 percent manufacturing cost advantage and that Trina is producing crystalline silicon cells for 78 cents per watt.


China may be winning the c-Si cost battle, but First Solar uses thin-film innovation to lower cost. First Solar is increasing manufacturing capacity from 1.5 to 2.3GW per year, including manufacturing in low cost countries such as Vietnam. Last year it improved its CdTe module efficiency from 11.1 to 11.6 percent to deliver 75 cents per watt cost. GE announced 12.8 percent efficiency with its CdTe panels. In 2013 it will have a new 400 MW plant online. Honda is betting on CIGS thin film. Venture capitalists are betting on exciting emerging companies as the efficiency and cost battle intensifies.

Balance of System

Dr. Alex Levran, President of the RE Division of Power-One, asked the industry to measure system efficiency in harvesting energy, rather than just evaluate inverters efficiency with specific solar modules. He identified areas for cost savings including eliminating the grounding of inverters. This is not done in Europe and it lowers inverter efficiency. Europe uses 1,500-volt systems. In the U.S., 600 volts is common. Modular inverters are need for quick repair. He feels that a 10-cent/watt goal is feasible in 2 to 3 years with the right component costs.


Experienced conference participants agreed that a major variability in annual electricity generated from a solar project is how well it is installed. Square feet can be used optimally or poorly. The slope of panels needs to be ideal. The quality of wire and installation affect longevity and output. SolarTech is working with industry groups and community colleges to insure a growing pool of skilled labor.

Right Size

The highest U.S. growth will be in the middle market of 100 kW to 20 MW at locations near load centers. Urban commercial roofs, industrial yards, and parking structures are good examples. The price per watt benefits from economy of scale, flabor costs, shared balance of system. Installed solar is cheaper by the megawatt than kilowatt. These segments appeal to electric utilities that face RPS requirements in 30 states. Commercial distributed solar is often well matched with the location of electricity demand, minimizing transmission and distribution investment. For example, transit operators including LA Metro, New Jersey Transit, and MARTA are among the dozens of agencies heavily investing in solar in the 100kW to MW category. Public Transportation Renewable Energy Report

Right Place

My wife and I recently rode our bicycles to a 5 MW solar installation in the middle of San Francisco. The panels are mounted at ground level on the cement cover of a local water reservoir. Labor and construction costs are lower on the ground than on old roofs that may need to be upgraded to support the weight and maintenance of solar. Near ground, such as erecting steel grids to cover parking structures, can also be more cost effective than roof-mounted systems.

Improve Interconnect

A public utility can make it easy, difficult, or impossible to connect to their system. Follow the money. Some solar makes them money; some costs them. Some projects provide RPS credit; some do not.

Markets not Monopolies

I once shared lunch with a public transit manager who wanted to cover a transit line with megawatts of solar power and a water wholesaler who wanted to buy the power. It was a win-win and the numbers worked, except that they were legally required to put the local public utility in the middle. The utility wanted to build a new natural gas power plant. Somehow, the solar numbers no longer worked. Laws need to be changed, so that micro grids and markets can work without utility monopoly power.


Installation of solar power is complicated by having 21,500 local codes to deal with beyond the National Electric Code. Permitting can take weeks. Inspection outcomes and reworks are variable costs due to lack of one national code. Promising is DOE’s Solar America Board of Codes and Standards (Solar ABCs).


“The solar industry is at a critical turning point, where the technology is here, yet the overhead process costs keep prices high and force customers to navigate through a complicated process,” said Doug Payne, executive director of SolarTech.  “There is no reason that it should take three months for a customer to adopt solar, when it takes half that time to remodel your kitchen and only a few days to get a new water heater.  The Solar Challenge aims to make solar adoption easier and faster for customers, while simultaneously creating the local jobs and economic growth that follow. “


Solar financing needs to be as easy as getting a mortgage loan. Instead, many solar projects fail to get financed. Lenders need more certainty in the annual output expected from projects for 20 years. Standard spreadsheets and models would help. More certainty about government policy or an established carbon market would greatly help. Major players that could aggregate many projects would add diversity, certainty and simplify rating and securitizing large portfolios. In Europe, feed-in tarrifs have greatly simplified financing.


Concentrated photovoltaics, in the lab, have demonstrated 41 percent efficiency; roughly double the c-Si being installed. Now what is needed is low cost manufacturing of CPV, 20-plus year reliability, and effectiveness over a range of light-source angles. Also, in the pipeline are gigawatts of concentrating solar-thermal utility scale plants. The big challenge for these plants is years of site approval and high-voltage lines to load centers.

Hybrid Systems

Mark Platshon, Vantage Point Venture Partners is optimistic that installed solar will reach $2 per watt. The magic dollar per watt would require PV to be reduced to 30 cents per watt. Hybrid systems could lower the total cost taking advantage of common infrastructure and interconnect with hybrid systems such as solar and natural gas, roof PV and BIPV, and solar on existing light and power poles. Victor Abate, GE’s VP of Renewable Energy Business, stated the GE has sold 60 megawatts of its thin-film solar to NextEra, an existing GE wind customer. Abate said, “We are an energy company and expect to supply full solutions.” He suggested that if ten percent of GE’s wind farms added hybrid solar, the new 400MW GE factory would be sold out for six years.


Solar power often delivers when electricity is most needed, such as hot summer days when air conditioning is blasting. Storage of off-peak solar for peak use would add to solar energy’s value. One approach is concentrating solar thermal with molten salt storage. For PV, utilities are piloting a variety of promising grid storage, some as large as 150MW using compressed air, advanced batteries, and even flywheels. In the next decade, major storage could come from electric vehicle to grid.

Public Transportation uses more Renewable Energy

By John Addison (9/30/09). More Americans ride on public transit than any time in the past 50 years as more live in cities and most watch their transportation costs. Remarkably, transit operators are moving more people, yet reducing our dependency on oil and generating less carbon emissions. Increased use of solar, other renewables, vehicle electrification, and low-carbon fuels are all part of solution.

New Jersey Transit is preparing for a future where parked cars can be charged with sunlight while people use public transportation. New Jersey Transit is installing 402 kW solar canopies on the rooftops of two large parking garages at the Trenton Amtrak Transit center.

These parking structures are also equipped with 110v charging stations for electric vehicles and plug-in hybrids. Participating in the opening ceremony was the Mid-Atlantic Grid Interactive Cars (MAGIC) consortium, which includes the University of Delaware, Pepco Holdings, PJM Interconnect, Comverge, AC Propulsion, and the Atlantic County Utilities Authority, created to further develop, test, and demonstrate vehicle-to-grid technology.

A few years ago, Los Angeles Metro invested $5 million to install 2MW of solar power as part of a three-year plan to install solar panels on every Metro Bus and Rail facility within its Los Angeles County service area. For example, the solar panels installed on Metro Bus Division 18’s maintenance building rooftop and shading parking structures consist of about 1,600 solar panels that generate 417 kilowatts of electricity, enough power pay for itself in 10 to 11 years.
Now LA Metro will receive $4,466,000 to make its rail system more energy efficient. Red Line Westlake Rail Wayside Energy Storage System: Install wayside energy storage substation (WESS) at Westlake passenger station is at-grade level on the high-speed heavy rail subway Red Line. The nearby traction power substation will be switched off when the WESS is operating. The WESS flywheel technology captures regenerative braking energy when trains slow or stop and transfer back to same train or another train when it starts or accelerates, reducing energy demand and peak power requirements.

This month, the federal administration announced $100 million in Economic Recovery Act funding for 43 transit agencies that are pursuing cutting-edge renewable energy and efficiency technologies to help reduce global warming, lessen America’s dependence on oil, and create green jobs. The 43 winning proposals were submitted by transit agencies from across the country as part of a nationwide competition for $100 million in American Recovery and Reinvestment Act of 2009 (ARRA) funds. Selection criteria included a project’s ability to reduce energy consumption and greenhouse gas emissions and also to provide a return on the investment. The Federal Transit Administration reviewed more than $2 billion in applications for these funds.

AC Transit in Oakland, California, is awarded $6,400,000 to increase photovoltaic capacity to generate “green” hydrogen: Install multiple PV modules at its Central Maintenance Facility in Hayward. Combined with AC Transit’s already-installed solar capacity, this solar installation will produce the renewable electricity equivalent to what will be required to produce 180 kg/day of “green” hydrogen for 12 buses carrying up to 5,000 riders daily, for the current 3 zero-emission buses that carry about 1,000 riders daily.

VIA Metropolitan Transit, San Antonio, Texas, was awarded $5,000,000 to replace conventional diesel transit buses with 35-ft composite body electric transit buses. The project includes quick-charging stations at this terminal layover in route to recharge bus batteries. Grid sourced electrical energy used to recharge the bus batteries will be augmented with solar energy collected with panels procured and installed under this project.

The nation is becoming less dependent on oil as record numbers escape solo driving in gridlock and increasingly use public transit. Electrification of light-rail and buses coupled with renewable energy makes this transportation greener.

Clean Fleet Report Summary of RE Projects

John Addison publishes the Clean Fleet Report and speaks at conferences. He is the author of the new book – Save Gas, Save the Planet – now selling at Amazon and other booksellers.

Real Security after 9/11

Op-Ed by John Addison (9/11/08). My ninth trip to teach a workshop at Two World Trade Center never happened because of the great tragedy 9/11. For years Sun Microsystems, my former employer, had invited me to conduct a series of workshops about technology and strategy. Much of the Wall Street ran on Sun servers, Java applications, and Sun network technology. Reliability, performance, and the ability to recover from disaster were reasons that New York continued to run after the disaster. Sun’s tagline was reality – “The Network is the Computer.”

On September 11, 2001, thanks to heroes like Avel Villanueva the hundreds of people working for Sun Microsystems in Two World Trade Center all quickly evacuated the building and survived. When Avel saw the damage and fire at One World Trade Center, he paged everyone at Sun to leave Two World Trade Center as quickly, “Please, with calmness, go to the nearest exit. This is not a drill. Get out.” He repeated this from the reception area several times. Only after several pages and inspecting the vast 25th and 26th floors did Avel personally leave. Three minutes later the second plane hit Two World Trade Center.

Although it must have been difficult to continue working after such a tragedy, the people at Sun understood that New York depended on their ability to keep working. Within 24 hours almost all Sun employees were doing their jobs at other Sun locations, homes, even nearby cafes. Sun effectively used its own networking technology with an iWork program that enables employees to work at home, at an office near their home, or be highly productive anywhere with a mobile device and wireless network connection.

Flexwork is one way that we are now more secure. The vital work of millions can continue even if a building cannot be accessed or part of a city is closed. Wireless and Web 2 enable collaboration, communication, and knowledge work to continue anytime and anywhere. People are most effective working some days at one location, other times at home, others at a customer or supplier location. We can take advantage of the new flexible workplace solutions to annually save millions of wasted hours and billions of dollars of fuel. Flexible Work Article

Every time that we go through an airport, we are aware that important steps have been created to make U.S. entry and travel more secure. Yes, despite the hassle and loss of some privacy, Homeland Security has been valuable in keeping terrorism at bay.

As our current president reminds us, “We are addicted to oil.” As we continue to spend billions for oil for countries hostile to our way of life, we continue in the words of Thomas Friedman to “finance both sides of the war on terror.” In his new book, Hot, Flat, and Crowded, the Pulitzer Prize winning author shows us how to be free of this addiction.

Americans are not waiting ten years to replace a fraction of our foreign oil with new oil from Alaska. Americans are reducing our oil use now. Confronted with high prices at the pump, U.S. citizens drove 12 billion fewer miles in one month. People are taking advantage of flexwork, public transit, car pooling, sharing rides and sharing vehicles. Two car households are buying fuel efficient cars and increasingly keeping their gas guzzlers parked. 40,000 Americans now drive electric vehicles that do not use a drop of oil. In ten years, we will be driving millions of electric vehicles. EV Reports

Twenty-three percent of our increased supply of electricity in 2007 was from renewable energy. We have enough wind to power the nation including transportation. We have enough solar. Scientific American Article Yes, it will take time, money, high-voltage lines to major markets, and added jobs. Green is producing green. While many areas of our economy are currently suffering, renewable energy and energy efficiency are growing rapidly creating jobs and corporate profits. Global Trends in Sustainable Energy Investment 2008

Real security requires more than airport checks, less foreign oil, and cleaner transportation. Real security starts with the commitment to give our children a better world. Future generations deserve nourishing food, clean water, and protection from disease. Global warming has now put over one billion at risk of not getting enough water and food. Glaciers are disappearing. Water systems are stressed as oceans rise and water tables deplete. Hurricanes attack our coastal cities with increased intensity. Draughts weaken our ability to grow food at affordable prices.

Yes, there are those in Congress who are chanting “drill, drill, drill,” but we cannot end our addiction to oil with more oil. Elected to represent their people, not special interests, these legislators threaten to stop funding renewable energy unless Big Oil can drill anywhere it pleases. Others want to undermine states rights, removing their ability to regulate greenhouse gas emissions within their state.

Fortunately there are wise leaders in both parties committed to put a limit on our greenhouse gas emissions, encourage conservation, put us on a path to a sustainable future that is more secure for our children.

In Mr. Friedman’s new book he recalls a Chinese proverb, “When the wind changes direction, there are those who build walls and those who build windmills.” America can renew its world leadership with innovative solutions to an emerging climate crisis. We can lead in wind power, solar, geothermal, building efficiency, materials that are lighter and stronger, zero emission cars and zero emission cities. From information technology to clean technology, from flexwork to sustainable communities, let’s build windmills not walls.

We can be inspired by heroes like Avel Villanueva who got everyone to safety. We can also celebrate the millions of ordinary heroes who are building a more secure future for our children by living a more sustainable life today.

Copyright 2008 © John Addison. Permission to reproduce on the web with preservation of this notice. Portions of this article will be included in John Addison’s upcoming book.

Do more than just carry your camera

by Cristina Foung

My favorite green product of the week:
the Nova solar camera bag from Eclipse Solar Gear

What is it?
The Nova solar camera bag first and foremost is a camera bag. It’s a large cavity bag that can hold an SLR and 3 lenses. It also comes with adjustable foam dividers so you can tailor the inside to work for your gear.

But what makes it really exceptional is that the top of the bag has a solar charging module. It is compatible with any 12V car adapter.

Why is it better?
I’m sure I’m not the only one who occasionally forgets to charge her camera batteries before heading out the door. It can be a pretty tragic situation if you get your camera out to take some photos and you’re out of juice. With the Nova, you’ve got a way to charge up even if you’re away from an outlet. The only draw back is that you can’t be time pressured – depending on the amount of sunlight, it could take 4 to 6 hours to charge your cell phone or your digital camera.

And of course, harnessing the sun’s energy is a great way to cut back on emissions associated with electricity generation. It also let’s you off the hook for remembering to unplug your charger from a wall socket (boo vampire power).

Where can you find it?
You can get it directly from Eclipse Solar Gear for $139.95. Or you could enter the Gimme Some Action contest and win one for free!

Besides her green products column on Cleantech Blog, Cristina is a passionate advocate for green living at the Green Home Huddle at, which focuses on electric cars, energy efficient appliances, and other green products.

Breakthrough in solar energy storage

The hydrogen economy is heralded in certain quarters as the green alternative to oil as an energy carrier. At present the vast majority of hydrogen generated is generated from natural gas. So right now a hydrogen fuel cell car, is most likely still ultimately reliant on a fossil fuel source, natural gas, to provide the hydrogen required. In the future of course the thesis is that we could use renewable energy sources to split water into hydrogen and oxygen and generate our hydrogen in that way, thus getting away entirely from fossil fuels.

There was an interesting development on this front reported in the media last week. Scientists at the Massachusetts Institute of Technology University have developed an efficient method of using solar energy solar energy to produce hydrogen from water. Nothing new there I hear you say. But the breakthrough appears to be the use of some specific catalysts which make the process of splitting the water into hydrogen and oxygen much more efficient and therefore viable.
There is no doubt catalysts can work some magic and if they have identified something that can do this here, they may well be on to something.

Daniel Nocera of the Massachusetts Institute of Technology in Boston, said the discovery could remove one of the major obstacles that has prevented solar power from being taken up widely as a viable alternative to fossil fuels such as oil and gas.
“The discovery has enormous implications for the large-scale deployment of solar since it puts us on the doorstep of a cheap and easily manufactured storage mechanism. The ease of implementation means that this discovery will have legs,” Dr. Nocera said.

So will solar panels and water solve our energy problems? Dr. Nocera thinks so stating that ‘sunlight has the greatest potential of any power source to solve the world’s energy problems given that in one hour enough energy from the Sun strikes the Earth to provide the entire planet’s energy needs for a year’.

Now there is another group out there, more of a fringe element perhaps, which is proposing the idea that you run your car on water. There is some interesting discourse and commentary on this in the green tech gazette. If you really want the hyperbola and sales pitch on this, check out ‘Run Your Car with Water

The basic premise is that you can use electrical current from the alternator in your car to split water into hydrogen and oxygen. The hydrogen is then burned along with the gasoline which helps increase fuel efficiency. I have to say I am very skeptical about this. I am inclined to think there is no such thing as a free lunch. The First Law of Thermodynamics states that: In any reaction, energy cannot be created or destroyed. The energy to split the water has to come from somewhere and in your car the energy source is your gasoline. If you use the alternator in your car to run your A/C it consumes fuel, so too would running your alternator to generate hydrogen. In fact the new Toyota Prius will have solar panels on the roof to power the A/C for this very reason.
However ….. a caveat to this, may be if there is a synergistic or catalytic effect of co-burning hydrogen with gasoline which makes the whole process more efficient (at present your typical car is about 20% efficient, i.e. 20% of the energy in your gasoline tank goes into moving the vehicle, the rest is lost mostly as waste heat).

Also if you were able to use say for example the braking energy of the car to generate electricity and use this electricity to split hydrogen, THEN you would be taking advantage of wasted mechanical energy to produce that hydrogen fuel. Again, the Toyota Prius already takes advantage of this phenomenon to power the battery.

Paul O’Callaghan is the founding CEO of the Clean Tech development consultancy O2 Environmental. Paul is the author of numerous papers on environmental technologies and lectures on Environmental Protection technology at Kwantlen University College. He is chair of a technical committee on decentralized wastewater management in British Columbia, is a Director with Ionic Water Technologies and an industry expert reviewer for Sustainable Development Technology Canada.