You are browsing the archives of 2009 November.

Last month, the National Renewable Energy Lab released their State of the State report - a 231 page document (PDF) that tracks the progress of renewable energy development, as well as the policies and support mechanisms being implemented to encourage this development.

The exhaustive report provides a detailed picture of the status of renewable energy development in each of the U.S. states using a variety of metrics and discusses the policies being used to encourage this growth.

The five major categories are: biomass, geothermal, solar, wind and hydroelectric growth.

Data is tracked from 2001-2007, and includes factors such as state tax incentives, renewable energy access laws and production incentives. Page 104 of the document summarizes state renewable energy development policies.

All renewables combined only account for about 8% of the nation’s energy generation. Interestingly, solar generation is the lowest producing renewable energy, producing only 0.01 percent. The highest producing renewable energy is hydropower, with almost 6 percent.

However, wind resources experienced the largest growth of the renewable energy technologies in recent years, increasing 30% from 2006 to 2007. Solar electricity generation has increased at a much slower rate, with gains of only 12.7% between 2001 and 2007.

The statistical analyses reveal several interesting results. States that implemented net-metering legislation in 2005 had significantly more renewable energy generation in 2007 than states without such a policy. However, this analysis does not find any single model for a renewable portfolio standard that is correlated with significant increases in development.

The report shows positive correlations between the total number of market transformation policies within a given state (including both barrier reduction and technology accessibility policies) and the total megawatt-hours (MWh) of renewable energy generated within that state. This relationship is particularly true when considering individual renewable energy resources.

In 2007, generation from renewable resources constituted 8.49% of total national electricity generation.

Solar energy still represents a small but growing fraction of total renewable energy generation. This portion is likely to grow in future surveys given the increasing numbers of concentrating solar power projects are being either proposed or have come online after 2007, particularly in the Southwestern states.

Wind energy accounted for the largest percentage of nationwide growth in renewable generation between 2001-2007, as well as between 2006-2007. Generation from wind resources grew by 411% from 2001 to 2007, and by 30% from 2006 to 2007.

The state that provides the highest generation of wind energy is Texas, followed by California.

Washington state provides the grid with the highest amount of electricity generated from renewable resources, with a total of 82,559,749 MWh. See page 172 to find your own state’s ranking.

Kansas leads the pack in total growth of renewable energy generation, with a growth of 70,236 between 2001-2007. See page 176 to see where your state ranks.

California provides the overwhelming majority of solar power, with a kWdc amount of 528,262. New Jersey follows second with 70,236 kWdc.

Also provided is an overview of 14 contextual factors that may affect renewable energy development and policy effectiveness at the state level. Each state has a unique set of circumstances, and the same contextual factors may affect states differently, depending on specific state conditions. From a qualitative perspective, all 14 factors influence the bottom-line economics for renewable energy projects. The interplay among the various contextual factors is less quantified at this point. An increased understanding of these interactions – and how policies can be used to account for and take advantage of the interactions – will improve the future effectiveness of policy design and implementation.

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John (Jack) Mecholsky is a professor in the Department of Materials Science and Engineering Department at the University of Florida. Mecholsky is also past member of the ACerS Board of Directors.

Mecholsky is associated with the Dental Biomaterials Program, Biomedical Engineering, and the Veterinary College. His research focuses on biomaterials, fractal analysis, fractography and the application of fracture mechanics to the failure analysis of advanced ceramics and composites.

In this video, Mecholsky explains the benefits of using fractal geometry to study fractures in ceramic materials and to have a framework for studying certain properties of materials at any scale. He also provides some of the potential applications for studying and understanding materials failures.

8 minutes.

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Porsche announced in a press release that they are offering a lithium-ion replacement starter (main) battery that weighs in at just 13 pounds vs. 35 pounds for the traditional lead acid battery. “Less weight naturally means greater agility and driving dynamics,” Porsche notes. This four-cell battery runs 1,904 euros which, Porschephiles will be quick to agree, isn’t all that much for a Porsche option. It’s available on the 2010 Porsche 911 GT3, 911 GT3 RS, and Boxster Spyder.

Porsche says the two batteries have the same fastening points, connections, and voltage range. Dimensions are the same except the lithium battery is 2.8″ lower. It has a capacity of 18 amp-hours vs. 60 Ah for a standard lead-acid battery, but the Li-ion battery delivers all its power, Porsche says, while a standard battery delivers about 30% of what’s available. Porsche also says the Li-ion battery has more charge-discharge cycles and is quicker to recharge. Porsche recommends against using the lithium battery below 32 degrees because of its characteristics. You can charge it and jump-start like a normal battery and the internal electronics protect against overcharge situations.

Just to be clear: This is not a hybrid battery. It’s the main battery.

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Installation of ECC bridge link slab: (a) location of ECC slab, (b) placement of reinforcing steel within link slab segment, (c) pouring of ECC material and (d) finishing of exterior surface. Credit: Li, J. of Material Structures

I’ve posted before about Victor Li’s work at the University of Michigan using engineered cementitious composites.

A new paper by Li recently became available regarding a demonstration project in which ECC is being tested on a bridge deck within Michigan to replace a conventional joint within the deck.

ECC is in the family of materials known as high performance fiber reinforced cementitious composites. According to Li, ECC has the ability to strain harden under uniaxial tension while forming large numbers of microcracks up to an ultimate strain capacity typically over 4 percent, a level that he says is 400 times that of normal concrete. Under high levels of tensile strain, ECC does not form cracks with large crack width openings (e.g., between 50 µm and 70 µm). Designers can tailor the material on three phases within the composite: the fiber, matrix and fiber/matrix interface.

This particular application for ECC is aimed at coming up with solutions for a growing problem facing highway engineers. In the U.S. bridge deterioration is a big concern, and one problematic area is the
mechanical expansion joints in bridges. These joints are placed between sections of bridge decking, and are necessary because of the changing dimensions of these sections of deck that occur because of thermal expansion or other forms of thermal deformation.

Unfortunately, these joints deteriorate fairly quickly, begin to leak and then bigger problems begin. For example, in colder climates, water containing de-icing salts corrode the ends of the steel girders or penetrate into the rebar in precast concrete deck slabs. At best, costly repairs have to be made. At worst, a catastrophic failure of the bridge can result.

In response, engineers have essentially figured out a way to eliminate these expansion links in new bridges. But, the dilemma is what to do about existing structures.

Li’s idea is to retrofit bridges with ECC ‘‘link slabs’’ by removing the expansion joint and replacing a portion of the two adjacent decks with a section of ECC material overtop the joint. From the exterior, it would appear as a continuous deck surface.

ECC link slab schematic: Credit: Li, J. of Materials and Structures

In a demonstration project sponsored by the Michigan Department of Transportation, completed in 2005, a 225 mm thick, 5.5 m x 20.25 ECC link was added to a demonstration bridge. Thirty cubic meters of the ECC as delivered by standard ready-mix concrete trucks from a batching plant in a mix supervised by Li’s team.

Full scale load tests showed that the ECC link slab did not alter the supported nature of the bridge spans, and that ample strain capacity of the ECC is reserved for temperature-induced straining as designed.

The good news is that, so far, the performance of this link slab remains has stayed constant. More long-term performance monitoring and other demonstrations will be needed, but Li is optimistic that an ECC link slab will provide an excellent expansion joint replacement option for highway engineers.

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Back in June we reported on a futuristic design of wind power generators: vertical axis turbines.

Now researchers at the University of Virgina are developing a smaller, more efficient wind turbine uniquely designed to generate power in low-wind-speed areas. And they are building these turbines with a vertical axis, reports the Richmond Times-Dispatch.

The group is still seeking funding to create a full-size model that will have blades that extend 100 feet in diameter and spin along a vertical axis. Most wind turbines in operation today have much larger blades that extend up to 200 feet and spin along a horizontal axis.

“Most of the larger turbines are set for 14 to 15 miles per hour,” he said. “What we’re trying to do is get something that will work effectively in the 11 to 12 mph range.”

The design also will feature a turbine shaft levitated with magnets, which will reduce friction and consequently increase efficiency, says UVA mechanical engineering professor Jim Durand. Durand is also co-director of the Jefferson Wind Energy Institute

The overall design, Durand said, “is a combination of things that are aimed and optimized for low wind speeds.”

Paul Allaire, and UVA professor and the other co-director of the JWEI, will bring to the project his expertise on magnetic bearings. Allaire told the school’s newspaper, the Cavalier, in October that the goal is to first operate a 8-feet tall scale model in a wind tunnel that generates wind up to about 12 miles an hour. He said model was mainly a proof-of-concept step. “It’s very small and won’t generate much energy, so the plan is to build a 150-foot version, [which] would look like a cell tower.” The ultimate goal is to develop a system that can of produce 50 kilowatts of power.

Even with growing interest in wind power worldwide, the U.S. market for home wind turbines remains small, less than 0.002 percent of the national market. According to the American Wind Energy Association, however, this small wind turbine market is expected to grow dramatically over the next four years - from a total of 80 installed megawatts in 2008 to 1,700 MW in 2013. Already, installations in 2008 - 17.3 MW - marked a 78 percent increase over 2007.

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