New high-capacity sodium-ion
New high-capacity sodium-ion could replace lithium in rechargeable batteries
University of Birmingham scientists are paving the way to swap the lithium in lithium-ion batteries with sodium, according to research published in the Journal of the American Chemical Society.
Lithium-ion batteries (LIB) are rechargeable and are widely used in laptops, mobile phones and in hybrid and fully electric vehicles. The electric vehicle is a crucial technology for fighting pollution in cities and realising an era of clean sustainable transport.
However lithium is expensive and resources are unevenly distributed across the planet. Large amounts of drinking water are used in lithium extraction and extraction techniques are becoming more energy intensive as lithium demand rises - an 'own goal' in terms of sustainability.
With the ever increasing demand for electric cars, the need for reliable rechargeable batteries is rising dramatically, so there is keen interest in finding a charge carrier other than lithium that is cheap and easily accessible.
Sodium is inexpensive and can be found in seawater so is virtually limitless. However, sodium is a larger ion than lithium, so it is not possible to simply "swap" it for lithium in current technologies. For example, unlike lithium, sodium will not fit between the carbon layers of the ubiquitous LIB anode, graphite.
The scientists needed to find new materials to act as battery components for sodium-ion batteries that will compete with lithium for capacity, speed of charge, energy and power density.
Running quantum mechanical models on supercomputers, Dr Andrew Morris's team from the University of Birmingham's Department of Metallurgy and Materials was able to predict what happens when sodium is inserted into phosphorus.
In collaboration with Dr Lauren Marbella and Professor Clare Grey's team at the University of Cambridge, who performed the experiments which have verified the predictions, they found that the phosphorus forms helices at intermediate stages of charging.
The researchers identified the final composition of the electrode, which provides a final capacity of charge carriers seven times that of graphite for the same weight. This gives us fresh insights into how to make high-capacity sodium-ion anodes.
Dr Andrew Morris said: "This is a huge win for computational materials science. We predicted how phosphorus would behave as an electrode in 2016 and were now able, with Professor Grey's team to provide insights into experiment and learn how to make our predictions better. It's amazing how powerful combined theory-experimental approaches are."
Hawaii's solar powered island
This is Hawaii's solar powered island
Tesla will power the Hawaiian island of Kauai with solar panels and its giant battery packs.
Tesla officially unveiled the project Wednesday morning in Kauai following opening remarks by CTO JB Straubel and David Ige, governor of Hawaii. Tesla partnered with the Kauai Island Utility Cooperative (KIUC) to launch the project.
The solar farm is composed of 54,978 solar panels with 13 megawatts of solar generation capacity. Tesla has also installed 272 of its large commercial battery, Powerpack 2, to store the solar energy to use at night.
The project is expected to reduce fossil fuel use by approximately 1.6 million gallons per year, Tesla estimates. Tesla will begin turning on the massive solar system in phases.
Tesla is diving into solar energy following its acquisition of SolarCity last November. Tesla is also powering nearly the entire island of Ta’u in American Samoa with solar power and its Powerpacks.
KIUC signed a contract with Tesla to purchase 1 kilowatt-hour of electricity for $.139 over a 20-year time frame.
Before Tesla acquired SolarCity, the two companies agreed in February 2016 to use Tesla's 52 MWh Powerpack to bring 20 years of power to Kaua’i, so this project has been in the works for quite a bit.
No additional nuclear in SA's electricity plan...
No additional nuclear in SA's electricity plan, government punts renewable energy
Government has thrown its weight behind renewable energy in the new integrated resources plan (IRP).
Minister of Energy Jeff Radebe on Monday gazetted the long-awaited IRP. Radebe had met with the National Economic Development and Labour Council (Nedlac) on Friday to finalise the IRP.
The policy outlines South Africa’s electricity plan given the demand outlook up to 2030, Radebe explained.
The plan will see no increase in use of nuclear energy up until the year 2030, Radebe confirmed. There will be detailed technical analysis to see how much may be needed post 2030- up until 2050, he said. “Up until 2030 there is no envisaged increase.”
During the briefing Radebe explained that electricity demand on the grid has been declining on an annual basis. “For the financial year ending March 2018 the actual total electricity consumed is about 30% less than what was projected in IRP 2010,” said Radebe.
Further Eskom’s existing generation plant performance is not at expected levels. Plant availability is below the IRP 2010 assumptions of 80% and above, the minister said.
The new IRP has taken into account the changing electricity demand and technology costs have been updated, and considerations were made on the constraints to renewables.
The recommended plan uses the least cost plan as a starting point, without constraints to renewable energy, Radebe said. It includes coal, hydro power, existing PV (photovoltaic), wind and gas.
Additional capacity up until 2030 will be sourced from coal (1 000 MW), hydro (2 500 MW), PV (5 670 MW), wind (8 100 MW) and gas (8 100 MW)
The total installed capacity mix in 2030 will be 34 000 MW coal (or 46% of total installed capacity), 1 860 MW nuclear (or 2.5%), 4 696 MW hydro (or 6%), 2 912 MW pump storage (or 4%), 7 958 MW PV (10%), 11 442 MW wind (15%), 600 MW concentrated solar power (1%) and 11 930 MW gas (16%).
Radebe said that although coal installed capacity will be lower than the current installed base, it will still contribute 65% of energy volumes. Nuclear will only contribute about 4%.
Responding to questions about the impact the IRP will have on the coal sector and particularly jobs, Radebe said that the department has prepared a document for stakeholders “dealing with issues for a just transition”, as the plan is focused on renewable energy.