Thursday, October 19, 2017

Penn State Team Devises New Control Strategy to Enhance EV Battery Performance when Driving in Cold Temperatures

 Comparison of energy balance between the “Battery Heating While Driving” case and the base case during simulated US06 drive cycle tests at −40 °C. (Credit: Zhang et al.) Click to Enlarge.
Researchers at Penn State, with a colleague from EC Power, have devised a new control strategy that can rapidly restore EV battery power and permit full regeneration while driving at temperatures as low as −40 °C.  The strategy involves heating the battery internally during regenerative braking and rest periods of driving.

In a paper in the Journal of Power Sources, they report that this technique fully restores room-temperature battery power and regeneration in 13, 33, 46, 56 and 112 seconds into uninterrupted driving in 0, −10, −20, −30 and −40 °C environments, respectively.  Correspondingly, the strategy significantly increases cruise range of a vehicle operated at cold temperatures—49% at −40 °C in simulated US06 driving cycle tests.  Based on their findings, the team suggests that smart batteries with embedded sensing/actuation can significantly improve their performance compared to more conventionally controlled counterparts.
Drastically reduced driving range is a major challenge for electric vehicles (EVs) operating at subzero temperatures as it exacerbate drivers’ range anxiety.  Two technical problems of Li-ion batteries are particularly long-standing.  First, regenerative braking is restricted or completely turned off at cold temperatures due to the phenomena of lithium plating that could severely reduce battery life and increase safety hazards.  Second, there is significant power loss, up to 10 fold at −30 °C, due to sluggish reaction kinetics, slow diffusion, reduced electrolyte conductivity, and increased solid-electrolyte interface (SEI) resistance at low temperatures.

Great efforts have been made to increase battery power at cold temperatures, notably reformulating electrolytes, hybridizing batteries with high-power supercapacitors, and preheating batteries before driving.  Among these approaches, battery preheating has been extensively investigated due to its relatively simple implementation.  But preheating is slow, typically tens of minutes, and inconvenient, prohibiting instantaneous mobility of EVs.

Here we demonstrate an active control strategy that can rapidly restore EV battery power while driving, which eliminates any need to wait for preheating.  This control strategy represents a new paradigm allowing batteries to be actively controlled and manipulated.  We also demonstrate, through simulated US06 driving cycle tests and an energy balance analysis, that power restoration while driving could significantly increase EV driving range by fully recuperating braking energy and significantly increasing utilization of energy stored.

—Zhang et al.
Read more at Penn State Team Devises New Control Strategy to Enhance EV Battery Performance when Driving in Cold Temperatures

Wednesday, October 18, 2017

  Wednesday, Oct 18

Global surface temperature relative to 1880-1920 based on GISTEMP analysis (mostly NOAA data sources, as described by Hansen, J., R. Ruedy, M. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., 48, RG4004.  We suggest in an upcoming paper that the temperature in 1940-45 is exaggerated because of data inhomogeneity in WW II. Linear-fit to temperature since 1970 yields present temperature of 1.06°C, which is perhaps our best estimate of warming since the preindustrial period.

America’s Climate Refugees Have Been Abandoned by Trump

The Obama administration was slowly working on a plan to deal with the problem.  The Trump administration isn’t interested.

President Donald Trump visits Puerto Rico after Hurricanes Irma and Maria. (Credit: Evan Vucci/AP) Click to Enlarge.
As hurricane after hurricane ravages Puerto Rico and the Gulf Coast, the Trump administration has quietly walked away from a government-wide effort to help the growing number of American communities whose very existence is threatened by climate change.

In the final year of the Obama administration, nearly a dozen federal agencies—led by the Department of Housing and Urban Development—began laying the groundwork for a cohesive federal approach to the so-called climate refugee problem.  In December 2016 a top HUD official signed a memorandum of understanding, which would have committed these agencies to work together to develop a strategy for relocating homes, infrastructure, and—in some cases—entire municipalities put at risk by rising seas, melting permafrost, and more dangerous storms.

But since then, the group has done nothing, according to current and former officials familiar with the effort.  No other agency appears to have signed off on HUD’s plan, and it has never gone into effect.

It might not be surprising that a president who calls global warming a Chinese hoax would be slow to address its impacts.  But for those in the most vulnerable parts of the country, there’s no time to wait.  With each severe storm comes the prospect of evacuation and destruction.  Thousands are left temporarily displaced or stranded.  This cycle, made worse with climate change, is becoming too much for some residents; relocation may soon be their only option.  But without a clear government plan to address the problem—and pay for a solution—finding a new home will be all but impossible.

Read more at America’s Climate Refugees Have Been Abandoned by Trump

A More Climate-Resilient Puerto Rico?

Along with addressing acute crises facing Puerto Rico as a result of Hurricane Maria damages, talk emerges about rethinking its electrical system going forward.

Trees and power lines downed by Hurricane Maria. (Credit: U.S. Air Force photo by SSgt.Michelle Y. Alvarez-Rea) Click to Enlarge.
Some 90 percent of Puerto Rico, a U.S. territory for well over a century, was still without power approaching a month after hurricane Maria ravaged the Caribbean island. Ninety percent.

The island’s electricity infrastructure was already in bad shape before Hurricane Maria hit on September 20, but in its wake the island’s 3.4 million residents lost all power.  As the island struggles forward, one issue to be considered involves how best to rebuild its severely damaged infrastructure – particularly its electrical system.

Even as it faces an immediate and devastating humanitarian crisis, an emerging viewpoint is that the island should think twice before restoring its electrical system as it’s existed in the past … powered with imported fossil fuels, largely centralized, frequently unreliable, and in dire financial straits. Instead, this reasoning goes, Puerto Rico should plan for more resilient, distributed infrastructure – resilient to the inherent economic vulnerabilities of island living, and resilient also to the punishing consequences of climate change.

One idea: A high-tech solar grid
Tesla, Inc. CEO Elon Musk on October 4 exchanged Twitter messages with Puerto Rico Governor Ricardo Rossello to float the idea of building a high-tech solar grid on the island. Drawing on the resources of another of his start-ups, SolarCity, Musk brings direct experience to the table.  He’s worked on a similar project on the island of Ta-au in American Samoa, on a solar project on the Hawaiian island of Kauai, and on other installations elsewhere abroad.

The idea basically involves building a distributed grid populated by solar panels, and not relying on one or a handful of large power plants.  The panels can feed into large batteries that can be linked together into self-contained “microgrids”.

Tesla already has sent hundreds of its Powerwall battery systems to Puerto Rico, Investors Business Daily reported on October 6.  Meanwhile, Sonnen GmbH, a German provider of energy-storage systems, began deliveries to Puerto Rico in late September as part of a plan to install microgrids serving 15 emergency relief centers.

Lighting up Puerto Rico ‘much quicker’
Wind, solar, and even kinetic energy from the ocean are all abundantly available in a place like Puerto Rico.  And solar power, combined with adequate electricity storage systems, strikes many as a good place to start.

As far as building a distributed grid, Rossello seemed gung-ho in a recent Time magazine story.  “We can start dividing Puerto Rico into different regions … and then start developing microgrids,” he said.  “That’s not going to solve the problem, but it’s certainly going to start lighting up Puerto Rico much quicker.”

Read more at A More Climate-Resilient Puerto Rico?

China's President Xi Says Will Continue Years-Long War on Smog

Chinese President Xi Jinping speaks during the opening of the 19th National Congress of the Communist Party of China at the Great Hall of the People in Beijing, China. (Photo Credit: Reuters) Click to Enlarge.
China will keep up its years-long battle against smog to ensure “blue skies” and promote a “revolution” in clean energy, President Xi Jinping said on Wednesday at the opening ceremony of a key Communist Party congress.

Improving the notoriously toxic air across the northern regions of the world’s second-largest economy has been a cornerstone of Beijing’s economic and social policy in recent years.

China has ordered factories to cut output in a bid to enforce bigger emission cuts in coming months and avoid a repeat of the near-record levels of choking smog that enveloped key northern areas at the start of the year.

In the long term, it has also launched a series of measures to curb the use of coal, the nation’s favorite fuel, and boost use of renewable power, like wind and solar.

The government will also take measures to improve rural areas by restoring soil and waterways, Xi added, as China moves to modernize its vast agricultural sector.

Read original at China's President Xi Says Will Continue Years-Long War on Smog

Tuesday, October 17, 2017

  Tuesday, Oct 17

Global surface temperature relative to 1880-1920 based on GISTEMP analysis (mostly NOAA data sources, as described by Hansen, J., R. Ruedy, M. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., 48, RG4004.  We suggest in an upcoming paper that the temperature in 1940-45 is exaggerated because of data inhomogeneity in WW II. Linear-fit to temperature since 1970 yields present temperature of 1.06°C, which is perhaps our best estimate of warming since the preindustrial period.

A New Way to Harness Wasted Methane

Approach developed at MIT could help curb needless 'flaring' of potent greenhouse gas.

Flaring (Credit: Financial Tribune) Click to Enlarge.
MIT chemistry professor Yogesh Surendranath and three colleagues have found a way to use electricity, which could potentially come from renewable sources, to convert methane into derivatives of methanol, a liquid that can be made into automotive fuel or used as a precursor to a variety of chemical products.  This new method may allow for lower-cost methane conversion at remote sites.  The findings, described in the journal ACS Central Science, could pave the way to making use of a significant methane supply that is otherwise totally wasted.

Existing industrial processes for converting methane to liquid intermediate chemical forms requires very high operating temperatures and large, capital-intensive equipment. Instead, the researchers have developed a low-temperature electrochemical process that would continuously replenish a catalyst material that can rapidly carry out the conversion.  This technology could potentially lead to "a relatively low-cost, on-site addition to existing wellhead operations," says Surendranath, who is the Paul M. Cook Career Development Assistant Professor in MIT's Department of Chemistry.

The electricity to power such systems could come from wind turbines or solar panels close to the site, he says.  This electrochemical process, he says, could provide a way to do the methane conversion -- a process also known as functionalizing -- "remotely, where a lot of the 'stranded' methane reserves are."

Already, he says, "methane is playing a key role as a transition fuel."  But the amount of this valuable fuel that is now just flared away, he says, "is pretty staggering."  That vast amount of wasted natural gas can even be seen in satellite images of the Earth at night, in areas such as the Bakken oil fields in North Dakota that light up as brightly as big metropolitan areas due to flaring.  Based on World Bank estimates, global flaring of methane wastes an amount equivalent to approximately one-fifth of U.S. natural gas consumption.

When that gas gets flared off rather than directly released, Surendranath says, "you're reducing the environmental harm, but you're also wasting the energy."  Finding a way to do methane conversion at sufficiently low cost to make it practical for remote sites "has been a grand challenge in chemistry for decades," he says.  What makes methane conversion so tough is that the carbon-hydrogen bonds in the methane molecule resist being broken, and at the same time there's a risk of overdoing the reaction and ending up with a runaway process that destroys the desired end-product.

Catalysts that could do the job have been studied for many years, but they typically require harsh chemical agents that limit the speed of the reaction, he says.  The key new advance was adding an electrical driving force that could be tuned precisely to generate more potent catalysts with very high reaction rates.  "Since we're using electricity to drive the process, this opens up new opportunities for making the process more rapid, selective, and portable than existing methods," Surendranath says.  And in addition, "we can access catalysts that no one has observed before, because we're generating them in a new way."

Read more at A New Way to Harness Wasted Methane