transatomic power

They discovered a math error in their fundamental assumptions and it turned out to not work after all.

http://www.transatomicpower.com/wp-content/uploads/2015/04/TAP-White-Paper-v2.1.pdf

Specifically, we have realized that our initial analyses of spent nuclear fuel (SNF) core loadings were centered around inaccurate assumptions about reactor behavior that, upon detailed review, had to be corrected. This led to the conclusion that while the reactor can achieve criticality on an SNF fuel load and an SNF fuel feed, it cannot maintain criticality for sufficient lengths of time to produce a sustainable net-negative waste profile.

The results have prompted a shift in focus to reducing the rate at which waste is produced while simultaneously utilizing the current commercial 5% LEU supply chain. Our new work has shown significant reductions in waste generation compared to large LWRs, and the TAP reactor is one of the only advanced reactor designs to accomplish this using 5% enriched fuel.

Hastelloy N used in fabricating the MSRE

http://www.thmfgrcs.com/ORNL-TM-3063.pdf

SUMMARY AND CONCLUSIONS, PAGE 87

The heats of Hastelloy N used in fabricating the MSRE have shown a systematic deterioration of mechanical properties with increasing neutron fluence. The material exposed for the longest period of time in the core has reached a thermal fluence of 1.5 x 10^21 neutrons/cm2 and a fast fluence (> 50 kev) of 1.1 X 10^21 neutrons/cm2. These values are quite close to those anticipated for future reactors with a 30-year design life.

The ductility of the material was too low, but the microstructure was free of irradiation-induced voids and defects other than helium bubbles. Several heats of the modified alloys have been exposed to the MSRE and these have better postirradiation properties. They also seem to have good corrosion resistance.

The standard Hastelloy N removed from the core shows some evidence of corrosion. The corrosion seems generally to be due to the selective removal of chromium, as predicted by prenuclear tests.

Some observations that have not been explained adequately are

(1) the presence of grain-boundary cracks in the straps that held parts of the surveillance assembly together,
(2) the modified microstructure near the surface, and
(3) the formation of intergranular cracks originating from the surface when irradiated materials are strained.

One of the modified alloys, heat 67-504, was exposed to the cell environment. The fluence was higher in the core, but the postirradiation properties were superior to those of the material exposed to the cell environment.

We presently have no explanation for the observed behavior.

unreliable energy is especially harmful for the most vulnerable members of society.

Researchers are discovering that unreliable energy is especially harmful for the most vulnerable members of society.

https://arstechnica.com/science/2019/12/pricing-electricity-by-demand-hits-poor-elderly-disabled-harder/

The motivating principle behind demand-response pricing is that demand is flexible. People can put off running their clothes dryer, or put up with a few hours of somewhat warmer temperatures. But that's actually not true for everyone. The elderly and disabled, for example, may not tolerate even a few hours of elevated temperatures or could have medical equipment that simply can't be shut down. This could also hit the poor harder, as they tend to live in housing with less efficient appliances and poor insulation.

To find out whether there was any evidence that this sort of uneven impact was taking place, researchers Lee White and Nicole Sintov tracked a trial run of demand-response pricing. The trial took place in an unnamed utility in the US Southwest during summer. Because of the heat, there tends to be a spike in demand as people get home from work and turn on the air conditioning. To lower this demand, the utility raised the price of electricity used during this peak, offering two different plans. One simply had elevated prices for the whole period where demand was elevated; the second used even higher prices but limited them to a shorter period at the time of highest demand.

To figure out how this affected vulnerable groups, the researchers got thousands of the participants to fill out surveys regarding their experience.

The results confirmed some of the worries. The elderly and disabled ended up paying more than others under the same pricing scheme. (Households with children saw no significant change.) On the plus side, the lower-income households managed to use the policy to cut down on their costs relative to others on a similar pricing setup. Not surprisingly, however, they reported increased discomfort during the period of the test, presumably because they ran the air conditioning less often.

Bright Days for NanoSolar

When NanoSolar was founded in 2002, the Palo Alto (Calif.) solar-energy startup drew plenty of skepticism. After all, the dot-com bubble had been reduced to a soap stain two years earlier, just months after 34-year-old NanoSolar founder and Chief Executive Officer Martin Roscheisen had sold his e-mail list service eGroups to Yahoo! (YHOO) for $450 million. Now he was jumping right into the next hyped-up sector: alternative energy.

It didn't help that NanoSolar's investors included Google (GOOG) founders Larry Page and Sergey Brin, and Benchmark Capital, the venture-capital firm that struck e-gold with eBay (EBAY). What did a bunch of dot-com millionaires know about solar energy?

Quite a bit, it turns out. Three years later, things are looking much brighter. In the next six weeks, NanoSolar plans to begin building a factory in the San Francisco Bay area that could pump out as many as 200 million solar cells—semiconductors that convert sunlight to electricity—each year. That will be enough to fill 2 million average-sized panels.

NanoSolar's management claim the company's printing process is less expensive and more efficient than vacuum-based processes that have been used to make most thin-film cells in the past. And they say their cells will generate as much electricity as silicon cells—at one-fifth to one-tenth the cost. "We will be the cost leader," says Brian Sager, co-founder and vice-president of finance and corporate development.

What makes him so sure? First, a recent worldwide shortage of polysilicon has caused a scarcity of silicon solar cells and driven up prices. Second, NanoSolar has assembled a fortress-like portfolio of patents and trade secrets to keep its ink, product design, and printing process proprietary. The company believes no one will be able to copy what it is doing.

Another big plus for the company is the talent that comes along with its latest financing. Investors in the round include heavy hitters from the solar industry. Stuttgart private-equity firm Grazia Equity previously funded the world's largest installer of solar panels, Hamburg-based Conergy. Dimbach (Germany)-based Beck Energy designs and builds solar-power plants. And Christian Reitberger, a Munich-based partner at global private-equity firm Apax Partners, was an early investor in Thalheim (Germany)-based Q-Cells, the world's largest independent maker of silicon-based solar cells.

The keen German interest is no coincidence. With a 47% share, Germany is the world's largest solar heating market. The country's Environment Ministry subsidizes about 40% of the outlay for solar plants that heat drinking water. About one-quarter of NanoSolar's recent $100 million financing consists of subsidies and incentives from various governments, including Germany's. Now, NanoSolar just needs to make all that support pay off.

http://www.businessweek.com/stories/2006-06-25/bright-days-for-nanosolar

Soitec Solar 1 EIR

The concentrator photovoltaic (CPV) system uses a dual-axis tracking system. The components of the dual-axis tracking system include modules, described below, that are placed on the tracking system, the tracker unit, and the tracker control unit. Generally and from this point forward throughout the EIR, the CPV system is referred to as “trackers.” Two types of sensors are used to ensure that the focal point of the concentrated sunlight is exactly on the solar cells at every moment of the day:

(1) astronomical positioning and
(2) a solar sensor that seeks to position the trackers precisely perpendicular to the sun to ensure optimum system performance.

The entire trackers module assembly dimensions are approximately 48 feet across by 25 feet tall. Each tracker would be mounted on a 28-inch steel mast (steel pole), which, depending on wind loading and soil conditions at the site, would be installed by: (1) inserting the mast into a hole up to 20 feet deep and encasing it in concrete, (2) vibrating the mast into the ground up to 20 feet deep, or (3) attaching the mast to a concrete foundation sized to adequately support the trackers.

The ultimate height of each tracker in its most vertical position depends on how it is installed because installing the mast into a concrete foundation may increase the tracker height. In its most vertical position and assuming the use of a concrete foundation, however, the top of each tracker would not exceed 30 feet above grade, and the lower edge would not be less than 1 foot above ground level. In its horizontal “stow” mode (for high winds), each tracker would have a minimum ground clearance of 13 feet, 6 inches.

Soitec’s Concentrix modules, which are manufactured in San Diego County (Rancho Bernardo), are made up of a lens plate (Fresnel lens) and a base plate on which high-performance solar cells are mounted. The Fresnel lens focuses sunlight concentrated by a factor of 500 on the solar cells beneath.

The solar cells are optimized multi-junction solar cells (GAInP/GaInAs/Ge) in which three different types of solar cells are stacked on top of one another. Each cell is designed to convert a certain range of the solar spectrum: short-wave radiation, medium-wave radiation, and infrared. For almost 20 years, multi-junction solar cells have been used in space applications.

The solar modules are lightweight and surrounded by airflow both inside and outside the module. As a result, heat dissipates quickly from a solar panel. The normal operating temperature for solar modules is 20 degrees Celsius (°C) above ambient temperature; therefore, on a typical summer day at 40°C (104°F), the panel temperature would be approximately 60°C (172°F). When accounting for irradiance (a measure of solar radiation energy received on a given surface area in a given time), wind, and module type, it is expected that the peak module temperatures in the summer would be between 65°C and 70°C (149°F and 158°F), and the peak module temperatures in the winter would be between 35°C and 40°C (95°F and 104°F).

Although the CPV panels would be hot to the touch as a result of solar energy absorption, CPV panels are designed to absorb light energy inwards towards the panel to produce electricity. As opposed to mirrors which redirect the sun, CPV modules use Fresnel lenses to concentrate sunlight inside the module to produce electricity, and therefore, they would not noticeably affect the temperature of the surrounding area; temperatures below the modules would be nearly the same as ambient temperatures in ordinary shade.

Solar: Ivanpah and concentrated sunlight

Some have asked why not just build a big greenhouse to collect the sun's heat?

Let's do a simple carnot efficiency calculation.

Round off 25C to 300K.

Let's suppose your greenhouse gets up to 120F/322K.

Then your systems efficiency is never better than 1 - (300/322) = 6.8%.

Ivanpah is designed to run at 1013F/818K or 1 - (300/818) = 63%.

So it will cost 1/10 as much as the greenhouse.

http://www.energy-tech.com/article.cfm?id=32913

As a standalone solar thermal system, I suspect the economics on this plant are very bad because no matter how hard you look for the details of the contracts they have with the utilities, the only thing you can find about the cost per kWh is that it's a secret. Obviously it is so high that everyone involved is scared to death of the public/ratepayers finding out. And like everyone else, I have to ask "where do they go" to lower costs.

If you assume a future where a higher percentage of sources are unreliable then obviously there is more value in a reliable source. But if you look at thermal storage, no one has been able to make that economical and how do you lower the cost of salt to improve that?

But Ivanpah has one trick up its sleeve: they cleverly sited themselves right next to a large natural gas pipeline. If the utilities have a need for more on-demand power, Ivanpah simply needs to install a natural gas burning boiler and they will be able to make steam and turn the generators any time needed.

Another future possibility would see Ivanpah converted to a hybrid facility called an integrated solar combined-cycle plant. On the generation side, it would be a two stage turbine like any other combined cycle plant: first a high temperature gas turbine whose exhaust goes into a boiler for a steam turbine.

On the hot side, the working fluid would first run through the solar tower for preheating and then into the gas fed "boiler" for superheating.

GE is working with eSolar to develop this kind of technology.

http://www.technologyreview.com/news/425012/ge-invests-in-solar-thermal-company/

The sad thing is that solar power doesn't get any better than Ivanpah. 

The site is ideal: desert with lots of useless land and clear weather to give maximum solar intensity. It's as far from Germany as you can get in terms of site suitability.

The technology is elegant: the collection method is simple and cheap glass mirrors. No toxic chemicals for manufacturing, no toxic waste to dispose of when panels reach EOL and the price just doesn't get any lower.

The electricity generation process has merit too. Their unique ultra-high temperature system means high carnot efficiency: 63%.

Compare that to the typical solar cell's efficiency of just 15%.

http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/

Still, the economics look bad and this system basically proves it's impossible to improve it very much.

Of course, Carnot efficiency is a "not to exceed" value. In reality, it is expected to

"operate at 18 percent efficiency and earn a capacity factor of 30 percent.

This performance should make the 392-MW facility more efficient than plants with crystalline-silicon panels, thin-film cells or rival thermal technologies using parabolic mirrors, according to analysts, as the efficiency of utility-scale crystalline silicon and thin-film plants is likely less than 12 percent."

http://www.greentechmedia.com/articles/read/is-ivanpah-the-worlds-most-efficient-solar-plant 

Solar: Great news for Nanosolar

On Wednesday, Nanosolar pulled back the curtain on its thin-film photovoltaic cell technology — which it claims is more efficient and less expensive than that of industry leader First Solar — and announced that it has secured $4.1 billion in orders for its solar panels.

Martin Roscheisen, Nanosolar’s chief executive, said customers included solar power plant developers like NextLight, AES Solar and Beck Energy of Germany.

http://green.blogs.nytimes.com/2009/09/09/41-billion-in-orders-for-thin-film-solar/