Nuclear energy too expensive, too slow to battle climate change: report

Nuclear power as a renewable power option is more expensive and slower to implement than alternatives and therefore is not effective in the effort to battle the climate emergency, rather it is counterproductive, as the funds are then not available for more effective options, says a report on the status and trends of the international nuclear industry.
While the number of operating nuclear reactors has increased globally over the past year by four to 417 as of mid-2019, it remains significantly below historic peak of 438 in 2002, according to the World Nuclear Industry Status Report 2019 (WNISR2019), which is being released at the Central European University (CEU) in Budapest. Nuclear construction has been shrinking over the past five years with 46 units underway as of mid-2019, compared to 68 reactors in 2013 and 234 in 1979. The number of annual construction starts has fallen from 15 in the pre-Fukushima year (2010) to five in 2018 and, so far, one in 2019. The historic peak was in 1976 with 44 construction starts, more than the total in the past seven years. WNISR project coordinator and publisher Mycle Schneider stated: “There can be no doubt: the renewal rate of nuclear power plants is too slow to guarantee the survival of the technology. The world is experiencing an undeclared ‘organic’ nuclear phaseout.” Consequently, as of mid-2019, for the first time the average age of the world nuclear reactor fleet exceeds 30 years. However, renewables continue to outpace nuclear power in virtually all categories. A record 165 gigawatts (GW) of renewables were added to the world’s power grids in 2018; the nuclear operating capacity increased by 9 GW. Globally, wind power output grew by 29 per cent in 2018, solar by 13 per cent, nuclear by 2.4 per cent. Compared to a decade ago, nonhydro renewables generated over 1,900 TWh more power, exceeding coal and natural gas, while nuclear produced less. What does all this mean for the potential role of nuclear power to combat climate change? WNISR2019 provides a new focus chapter on the question. Diana Ürge-Vorsatz, Professor at the Central European University and Vice-Chair of the Intergovernmental Panel on Climate Change (IPCC) Working Group III, notes in her Foreword to WNISR2019 that several IPCC scenarios that reach the 1.5°C temperature target rely heavily on nuclear power and that “these scenarios raise the question whether the nuclear industry will actually be able to deliver the magnitude of new power that is required in these scenarios in a cost-effective and timely manner. This report is perhaps the most relevant publication to answer this pertinent question.” Over the past decade, levelised cost estimates for utility-scale solar dropped by 88 per cent, wind by 69 per cent, while nuclear increased by 23 per cent. New solar plants can compete with existing coal fired plants in India, wind turbines alone generate more electricity than nuclear reactors in India and China. But new nuclear plants are also much slower to build than all other options, eg, the nine reactors started up in 2018 took an average of 10.9 years to be completed. In other words, nuclear power is an option that is more expensive and slower to implement than alternatives and therefore is not effective in the effort to battle the climate emergency, rather it is counterproductive, as the funds are then not available for more effective options. The rather surprising outcome of the analyses is that even the extended operation of existing reactors is not climate effective as operating costs exceed the costs of competing energy efficiency and new renewable energy options and therefore durably block their implementation. “You can spend a dollar, a euro, a forint or a ruble only once: the climate emergency requires that investment decisions must favor the cheapest and fastest response strategies. The nuclear power option has consistently turned out the most expensive and the slowest,” Mycle Schneider concludes. The WNISR2019 assesses in 323 pages the status and trends of the international nuclear industry and analyses the potential role of nuclear power as an option to combat climate change. Eight interdisciplinary experts from six countries, including four university professors and the Rocky Mountain Institute’s co-founder and chairman emeritus, have contributed to the report.Source: https://www.domain-b.com
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Oceans in Outer Solar System on Pluto and Large Kuiper Belt Objects, Slowly Freezing Over Time


Credit of NASA, ESA, and A. Feild (STScI)
A new study suggests that Pluto and other large Kuiper belt objects started out with liquid oceans which have been slowly freezing over time.

The accretion of new material during Pluto’s formation may have generated enough heat to create a liquid ocean that has persisted beneath an icy crust to the present day, despite the dwarf planet’s orbit far from the sun in the cold outer reaches of the solar system.

This “hot start” scenario, presented in a paper published June 22 in Nature Geoscience, contrasts with the traditional view of Pluto’s origins as a ball of frozen ice and rock in which radioactive decay could have eventually generated enough heat to melt the ice and form a subsurface ocean.

“For a long time people have thought about the thermal evolution of Pluto and the ability of an ocean to survive to the present day,” said coauthor Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz. “Now that we have images of Pluto’s surface from NASA’s New Horizons mission, we can compare what we see with the predictions of different thermal evolution models.”

Because water expands when it freezes and contracts when it melts, the hot-start and cold-start scenarios have different implications for the tectonics and resulting surface features of Pluto, explained first author and UCSC graduate student Carver Bierson.

“If it started cold and the ice melted internally, Pluto would have contracted and we should see compression features on its surface, whereas if it started hot it should have expanded as the ocean froze and we should see extension features on the surface,” Bierson said. “We see lots of evidence of expansion, but we don’t see any evidence of compression, so the observations are more consistent with Pluto starting with a liquid ocean.”

Extensional faults (arrows) on the surface of Pluto indicate expansion of the dwarf planet’s icy crust, attributed to freezing of a subsurface ocean.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

The thermal and tectonic evolution of a cold-start Pluto is actually a bit complicated, because after an initial period of gradual melting the subsurface ocean would begin to refreeze. So compression of the surface would occur early on, followed by more recent extension. With a hot start, extension would occur throughout Pluto’s history.

“The oldest surface features on Pluto are harder to figure out, but it looks like there was both ancient and modern extension of the surface,” Nimmo said.

The next question was whether enough energy was available to give Pluto a hot start. The two main energy sources would be heat released by the decay of radioactive elements in the rock and gravitational energy released as new material bombarded the surface of the growing protoplanet.

Bierson’s calculations showed that if all of the gravitational energy was retained as heat, it would inevitably create an initial liquid ocean. In practice, however, much of that energy would radiate away from the surface, especially if the accretion of new material occurred slowly.

“How Pluto was put together in the first place matters a lot for its thermal evolution,” Nimmo said. “If it builds up too slowly, the hot material at the surface radiates energy into space, but if it builds up fast enough the heat gets trapped inside.”

The researchers calculated that if Pluto formed over a period of less that 30,000 years, then it would have started out hot. If, instead, accretion took place over a few million years, a hot start would only be possible if large impactors buried their energy deep beneath the surface.

The new findings imply that other large Kuiper belt objects probably also started out hot and could have had early oceans. These oceans could persist to the present day in the largest objects, such as the dwarf planets Eris and Makemake.

“Even in this cold environment so far from the sun, all these worlds might have formed fast and hot, with liquid oceans,” Bierson said.

In addition to Bierson and Nimmo, the paper was coauthored by Alan Stern at the Southwest Research Institute, the principal investigator of the New Horizons mission.

Contacts and sources:
Tim Stephens
University of California - Santa Cruz

Publication: Evidence for a hot start and early ocean formation on Pluto Carver J. Bierson, Francis Nimmo & S. Alan Stern Nature Geoscience (2020https://www.nature.com/articles/s41561-020-0595-0 http://dx.doi.org/10.1038/s41561-020-0595-0  Source: https://www.ineffableisland.com
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