Catching CO² to Make Some Useful Fuel

George Washington University’s Dr. Stuart Licht and colleagues have published the first experimental evidence of their new solar thermal electrochemical photovoltaic (STEP) process, which combines electrical and chemical pathways to convert CO2 to carbon or to carbon monoxide for subsequent use in synthesizing a range of industrially relevant products including hydrocarbon fuels.

According to the research team the STEP process is fundamentally capable of converting more solar energy than either photovoltaic or solar thermal processes working alone.

The STEP process uses a high temperature solar powered electrolysis cell to capture CO2 in a single step. Solar thermal energy decreases the energy required for the endothermic conversion of carbon dioxide and kinetically facilitates electrochemical reduction.  Meanwhile visible light solar energy generates the electric charge to drive the electrolysis.

STEP Process Block Diagram. .

For the experiment, the team used a concentrator solar cell to generate 2.7 volts at a maximum power point, with solar to electrical energy efficiencies of 35% under 50 suns illumination, and 37% under 500 suns illumination. The 2.7 V is used to drive two molten electrolysis cells in series at 750 °C and three in series at 950 °C.

At 950 °C running at 0.9 V, the electrolysis cells generate carbon monoxide at 1.3-1.5 amps, and at 750 °C at 1.35 V generate solid carbon formation at similar amps.

Step Process Forms Solid Carbon. .

The George Washington team also was thoughtful enough that the supporting information published along with the paper details the methodology and the materials used in the experiment.

Of great note and acclaim the research team addresses the questions of material resources, saying, “are sufficient to expand to process to substantially impact (decrease) atmospheric levels of carbon dioxide.”  This perspective is rarely observed in research papers and the inclusion by the George Washington team deserves notation and gratitude.  The information gives the research depth of understanding and better chances of improvement.

The key materials issues raised: “A related resource question is whether there is sufficient lithium carbonate, as an electrolyte of choice for the STEP carbon capture process, to decrease atmospheric levels of carbon dioxide. 700 km2 of CPV plant will generate 5

They Say The Wind Can Provide Reliable Power

The Department of Energy’s National Renewable Energy Lab (NREL) asserts in a study released last month that the power grid for five western states – Arizona, Colorado, Nevada, New Mexico and Wyoming – the WestConnect territory – could operate on as much as 30 percent wind and 5 percent solar without the construction of extensive new infrastructure.

WestConnect System Map. Click image for the largest view.

The wind is packed with kinetic energy – molecules in motion that can be used to make other molecules move such as commonly seen windmill water pumps, or used to compress gas and converted into electricity.  When it blows.  When the wind is becalmed, there isn’t any energy other than the latent heat. When the NREL made its assertion one had to read the study.

Dr. Debra Lew, project manager for the study, said in her statement, “If key changes can be made to standard operating procedures, our research shows that large amounts of wind and solar can be incorporated onto the grid without a lot of backup generation.”

The situation now has it that large coal, natural gas or nuclear plants would always need to stand ready to provide backup power whenever the wind ceased to blow or clouds blocked the sun.

The NREL scientists looked at that supposition head on and found that ‘stand ready’ would be largely baseless when the parameters were optimized.  It concluded that in the West, a broad distribution of wind turbines and solar generation would essentially smooth out the supply of renewable power.  Lew explained simply, “When you coordinate the operations between utilities across a large geographic area, you decrease the effect of the variability of wind and solar energy sources, mitigating the unpredictability of Mother Nature.”

Called ‘The Western Wind and Solar Integration Study” it examines the benefits and challenges of integrating enough wind and solar energy capacity into the grid to produce 35 percent of its electricity by 2017. The study finds that this target is technically feasible and does not necessitate extensive additional infrastructure, but does require key changes to current operational practice. The results offer a first look at the issue of adding significant amount of variable renewable energy in the West and will help utilities across the region plan how to ramp up their production of renewable energy as they incorporate more wind and solar energy plants into the power grid. (Pdf download – 20.6MB)

The technical analysis performed in the study shows that it is operationally possible to accommodate 30 percent wind and 5 percent solar energy penetration. To accomplish such an increase, utilities will have to substantially increase their coordination of operations over wider geographic areas and schedule their generation deliveries, or sales, on a more frequent basis. Currently generators provide a schedule for a specific amount of power they will provide in the next hour. More frequent scheduling would allow generators to adjust that amount of power based on changes in system conditions such as increases or decreases in wind or solar generation.

Being a government animal the NREL looks at the policy issues rather than the costs to the ratepayers.  But one can infer some significant fuel costs will be taken out from the calculation when the study says integrating wind as suggested “would also decrease fuel and emissions costs by 40 percent.”  That assertion deserves some testing considering the governments record in making predictions.

The study suggests the results would come with other benefits.  Existing transmission capacity can be more fully utilized to reduce the amount of new transmission that needs to be built.   Coordinating the operations of utilities to facilitate the integration of wind and solar energy can provide substantial savings by reducing the need for additional back-up generation, such as instant on natural gas-burning plants.

And the fly in the thinking is that use of wind and solar forecasts in utility operations to predict when and where it will be windy and sunny is essential for cost-effectively integrating these renewable energy sources. Yet the meteorologists are getting quite good when only looking hours out.

When one looks at a map of the territory involved it doesn’t seem farfetched at all.  While not using the deep resources of the Midwest or the Northwest the five states when combined for managing intermittency do have what looks like a solid 35 percent or better power resource potential.

Event though the study is from a government agency, the study was undertaken by a team of wind, solar and power systems experts across both the private and public sectors.  It’s a long list of contributors.  The work is mainly an operations study, rather than a transmission study, although different scenarios model different transmission build-outs to deliver power. Using a detailed power system production simulation model, the study identifies operational impacts and challenges of wind energy penetration up to 30% of annual electricity consumption.

The NREL page links to the pdf as well as the earlier Eastern Wind Integration and Transmissions study page with a pdf link to the 17.8 MB download.

Many thoughtful people discount wind for valid reasons.  But the fact remains the energy in moving air is significant and one way to overcome the intermittency issue without having massive electron storage is to well, get organized.

Getting organized and planning things out over a big resource base has great potential that mustn’t be overlooked.

Source: New Energy and Fuel

A Path to the Artificial Leaf

A new recipe based on the chemistry and biology of natural leaves that could lead to working prototypes of an artificial leaf that capture solar energy and use it efficiently to change water into hydrogen fuel was reported the 239th National Meeting of the American Chemical Society last week.

Tongxiang Fan, Ph.D. and colleagues Di Zhang, Ph.D. and Han Zhou, Ph.D. with the State Key Lab of Matrix Composites at Shanghai Jiaotong University, Shanghai, China presented a design strategy to produce the long-sought artificial leaf, which could harness Mother Nature’s ability to produce energy from sunlight and water in the process called photosynthesis.  Cleverly the goal isn’t building an organic chemical; rather it’s the short step of gathering out the H2 from water.

The team decided to take a closer look at the leaf, nature’s own photosynthetic system, with plans to use its structure as a blueprint for their next generation of artificial leaf systems. The structure of green leaves provides an extremely high light-harvesting efficiency. In leaf architecture are structures responsible focusing and guiding of solar energy into the light-harvesting sections of the leaf, and other functions.

Dr. Fan said, “This concept may provide a new vista for the design of artificial photosynthetic systems based on biological paradigms and build a working prototype to exploit sustainable energy resources.”  Fan pointed out that using sunlight to split water into its components, hydrogen and oxygen, is one of the most promising and sustainable tactics to escape current dependence on coal, oil, and other traditional fuels.

When burned, those fuels release carbon dioxide, the main greenhouse gas.  Fan also alluded to combustion of hydrogen, by contrast that forms just water vapor. That appeal is central to the much-discussed “Hydrogen Economy.”  Some auto companies, such as Toyota, have developed hydrogen-fueled cars. What’s missing is a cost-effective and sustainable way to produce hydrogen.

Artificial Leaf Process Graph. .

The scientists decided to mimic the natural architectural design in the development of a blueprint for artificial leaf-like structures. That led them to report their recipe for the “Artificial Inorganic Leaf” (AIL), based on the natural leaf and titanium dioxide (TiO2) – a chemical already recognized as a photocatalyst for hydrogen production.

The team first infiltrated the leaves of Anemone vitifolia, a native Chinese plant – with titanium dioxide using two-step process. Using advanced spectroscopic techniques; the scientists were then able to confirm that the structural features in the leaf favorable for light harvesting were replicated in the new TiO2 structure.

The artificial leaves are eight times more active for hydrogen production than TiO2 that has not been “biotemplated” as the team did with the A. vitifloia.  The artificial leaves are more than three times as active as commercial photo-catalysts as well.

Next, the scientists embedded nanoparticles of platinum into the leaf surface. Platinum, along with the nitrogen found naturally in the leaf, helps increase the activity of the artificial leaves by an additional factor of ten.

During the report at the American Chemical Society meeting Fan reported on various aspects of Artificial Inorganic Leaf production, their spectroscopic work to better understand the macro- and microstructure of the photocatalysts, and their comparison to previously reported systems. The activity of these new “leaves” is significantly higher than those prepared using classic routes. Fan attributes these results to the hierarchical structures derived from natural leaves.

Fan said, “Our results may represent an important first step towards the design of novel artificial solar energy transduction systems based on natural paradigms, particularly based on exploring and mimicking the structural design. Nature still has much to teach us, and human ingenuity can modify the principles of natural systems for enhanced utility.”

As lab experiments go, this is quite encouraging.  One hopes that the results can translate up to prototypes and on to demonstration and scale up.  But that’s a far way to go.  The insight though, is extraordinary.  The innovation is clever.  The notion that hydrogen could be produced daily in part or in full of individual needs and used with very short storage periods puts more practicality into a “hydrogen economy” concept.

Yet one has to doubt, even should this level of technology become widespread that a “hydrogen economy” is practical.  Without low cost fuel cells as an example, to get to electrical output for use, hydrogen is a very limited fuel.  Like photovoltaic, solar hydrogen production will require solar exposed land area per person, which in urban settings is in very low proportion indeed.

Post written by: New Energy and Fuel

Solar Energy Farm for Crayola Crayons

On November 19, executives from Binney and Smith, also known as Crayola to millions of youngsters worldwide, broke ground on a 15-acre solar farm in Forks Township, Pennsylvania.

Crayola, known the world around for its multicolored array of wax pencils, known as crayons, was founded in 1885 and now makes 120 different colors to amuse children and adults. The concept is old; the solar farm, which is expected to begin producing electricity early in 2010, is new but reflective of the company’s commitment to environmental stewardship, according to Executive Vice President Peter Ruggiero.

The 15 acres, owned by Crayola, are being leased by Allentown-based PPL Corp., an energy and energy services provider with about 12,000 megawatts of generating capacity and operations worldwide, and Reading-based UGI Energy Services, a natural gas and electric utility subsidiary of UGI Corporation.

The land borders Plainfield Township, and the two energy companies will foot the bill for the solar farm’s design and build-out, as well as the farm’s operation over time. The panels themselves are being installed by Perrysburg, Ohio-based First Solar, a thin-film manufacturing firm with a solid reputation for quality which recently broke the $1-per-watt manufacturing barrier.

When completed, the 26,000-panel farm will deliver 1.9 megawatts of clean, renewable solar energy and will be, according to the Pennsylvania Dept. of Environmental Protection’s John Hanger, one of the largest installations in the state.

The solar farm will provide about 10 percent of the Crayola factory’s annual electricity usage under a power purchase agreement with the utilities, and will prevent about 1,900 tons of greenhouse gases like carbon dioxide, nitrogen oxide and sulfur dioxide per year – all of which are produced by generating electricity with fossil fuels like coal, oil and natural gas. The output, 1.9 megawatts, is enough to power about 1,500 average American homes.

This, according to calculations by the U.S. Environmental Protection Agency, or EPA, is the same as removing 325 cars from the road, reducing gasoline consumption by 200,000 gallons, or planting 400 acres of pine forest.

Funding for the project, via the American Recovery and Reinvestment Act, or ARRA, provided $1.5 million in grant money, with an estimated $10.5 million in matching funds from private sources.

Energy production, usage and other data for the solar farm will be made available through a solar energy display at the Crayola Factory in downtown Easton.

Cooler Planet is a leading solar resource for connecting consumers and commercial entities with local solar Installers. Cooler Planet’s solar panel resources and solar energy page contains articles and tools to help with your solar project.

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