Renewable Energy Setting New Records

Non-hydro renewable energy sources (i.e., biofuels, biomass, geothermal, solar, wind) set new U.S. records for both production and consumption in the first half of 2018, according to a SUN DAY Campaign analysis of data just released by the U.S. Energy Information Administration (EIA) (https://bit.ly/2OH87mv).

EIA’s latest “Monthly Energy Review” (with summary statistics for the first six months of 2018) reveals that output by non-hydro renewables increased by 7.04% to 4.530 quads (quadrillion Btu) compared to the first half of 2017 (4.232 quads). Solar energy accounted for the largest percentage increase (25.4%), followed by wind (11.2%), biofuels and biomass (2.4% each), and geothermal (1.0%). As a share of total domestic production from all energy sources, non-hydro renewables accounted for nearly a tenth (9.80%).

Including hydropower, renewable energy sources accounted for 13.05% of domestic energy production and 11.76% of consumption. Hydropower’s output actually dropped by 7.0% during the first six months of 2018 compare to the same period in 2017. Consequently, energy production by renewable sources including hydropower grew by only 3.17% compared to the previous year while consumption increased by just 2.54%.

Notwithstanding its decreased generation, hydropower still maintained its role as the leading renewable source accounting for 24.85% of renewable energy production, followed closely by wind (23.37%), which has now moved ahead of biomass (22.73%) and biofuels (19.44%); solar and geothermal provided 7.86% and 1.76% respectively.

The increased output and consumption of renewable energy, however, was less than that of fossil fuels (i.e., coal, gas, oil) whose production grew 8.80% and use by 4.76% during the first half of 2018. In addition, electrical generation by the nation’s nuclear reactors increased by 4.05%. As a consequence, renewable energy’s share of total domestic energy production actually declined from 13.61% in the first half of 2017 to 13.05% in 2018; renewables’ share of energy consumption also dropped from 11.97% to 11.76%.

The expanded production and use of fossil fuels, which accounted for 77.83% of domestic production in the first half of 2018, have resulted in an increase of 3.28% in U.S. carbon dioxide (CO2) emissions from energy consumption. While CO2 emissions from coal dropped 4.79%, that decline was more than offset by an increase of 12.67% in CO2 emissions from natural gas well as higher emissions from oil and biomass (1.91% and 1.76% respectively). Oil remains the primary source of energy-related CO2 emissions (42.40%), followed by natural gas (29.84%), coal (21.51%), and biomass (6.24%).

About SUN DAY Campaign
The SUN DAY Campaign is a non-profit
research and educational organization
founded in 1992 to aggressively promote
sustainable energy technologies as
cost-effective alternatives to nuclear power
and fossil fuels.

from: https://www.ases.org/renewable-energy-setting-new-records/

Golden Sandwich

Golden Sandwich Converts 85% of Visible Light into Electricity

Scientists have developed a photoelectrode that can harvest 85 percent of visible light in a 30 nanometers-thin semiconductor layer between gold layers, converting light energy 11 times more efficiently than previous methods.

In the pursuit of realizing a sustainable society, there is an ever-increasing demand to develop revolutionary solar cells or artificial photosynthesis systems that utilize visible light energy from the sun while using as few materials as possible.

The research team, led by Professor Hiroaki Misawa of the Research Institute for Electronic Science at Hokkaido University, has been aiming to develop a photoelectrode that can harvest visible light across a wide spectral range by using gold nanoparticles loaded on a semiconductor. But merely applying a layer of gold nanoparticles did not lead to a sufficient amount of light absorption, because they took in light with only a narrow spectral range.

In the study published in Nature Nanotechnology, the research team sandwiched a semiconductor, a 30-nanometer titanium dioxide thin-film, between a 100-nanometer gold film and gold nanoparticles to enhance light absorption. When the system is irradiated by light from the gold nanoparticle side, the gold film worked as a mirror, trapping the light in a cavity between two gold layers and helping the nanoparticles absorb more light.

Left: The newly developed photoelectrode, a sandwich of semiconductor layer (TiO2) between gold film (Au film) and gold nanoparticles (Au NPs). The gold nanoparticles were partially inlaid onto the surface of the titanium dioxide thin-film to enhance light absorption. Right: The photoelectrode (Au-NP/TiO2/Au-film) with 7nm of inlaid depth traps light making it nontransparent (top). An Au-NP/TiO2 structure without the Au film are shown for comparison (bottom). (Misawa H. et al., Nature Nanotechnology, July 30, 2018) (click on image to enlarge)

To their surprise, more than 85 percent of all visible light was harvested by the photoelectrode, which was far more efficient than previous methods. Gold nanoparticles are known to exhibit a phenomenon called localized plasmon resonance which absorbs a certain wavelength of light.

“Our photoelectrode successfully created a new condition in which plasmon and visible light trapped in the titanium oxide layer strongly interact, allowing light with a broad range of wavelengths to be absorbed by gold nanoparticles,” says Hiroaki Misawa.

From the left: Quan Sun, Hiroaki Misawa, Xu Shi, Kosei Ueno, Tomoya Oshikiri of the research team at Hokkaido University.

When gold nanoparticles absorb light, the additional energy triggers electron excitation in the gold, which transfers electrons to the semiconductor.

“The light energy conversion efficiency is 11-times higher than those without light-trapping functions,” Misawa explained.

The boosted efficiency also led to an enhanced water splitting: the electrons reduced hydrogen ions to hydrogen, while the remaining electron holes oxidized water to produce oxygen­­ — a promising process to yield clean energy.

“Using very small amounts of material, this photoelectrode enables an efficient conversion of sunlight into renewable energy, further contributing to the realization of a sustainable society,” the researchers concluded.

Hokkaido University

Home batteries: What are they, and is it worth it for you to get one?

Rooftop solar panels are common in Arizona thanks to abundant sunshine, but to get even more use from the technology, homeowners are beginning to pair them with large home batteries.

Batteries allow homeowners to store their surplus electricity, rather than send it to the grid in exchange for credit from their electric company.

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