Upload
augustine-logan
View
219
Download
0
Tags:
Embed Size (px)
Citation preview
Overview
Wind and solar dependent on many circumstances
Weather and natural disasters can render this technology unreliable
Green energy power plants (e.g. wind farms) capable of producing sizeable amount of energy
Problem: storing this energy to maximize efficiency
Storing energy in batteries provides greater efficiency and less waste and is the missing link to a green future.
Unreliability of Renewable Energy
Feb 2008 – Texas experienced a slump in wind which led to a 1200-MW drop in energy production
Plant was down for 3 hours, and nearly caused a widespread blackout
Fossil fuel plants had to scramble to provide energy
Most solar/wind plants have back-up fossil fuel plants which stay on standby mode until needed
Burn fuel while on standby mode 24/7 Can cancel out some of the green energy
produced by solar and wind
Unreliability of Renewable Energy
Chart from California study Shows the irregular usage of wind throughout the day
Unreliability of Renewable Energy
Chart from Arizona study Shows intermittency of solar energy output
Unreliability of Renewable Energy Combination of
wind power and fossil fuel plants are used leads to increased emissions of NOx and CO2
Advantages of Battery Power Storage Adjustable energy output depending on current
energy needs over long or short time frames Quick start-up
Fossil fuel plants take 10-20 minutes Energy storage can react on a second by second basis
Absolutely no emissions Uses no water resources Quiet Can eliminate the need for distribution lines (ex:
coal trains)
Advantages (cont)
Easy-to-move equipment if energy requirements change Fossil fuel plants take years to
build and can’t be built in urban areas
Bottom line: battery energy storage synchronizes remarkably well with renewable energy sources to produce no greenhouse gas emissions
History of Rechargeable Batteries
1859 – lead-acid battery invented by Gaston Plante Is the most basic battery with cathode and anode
and a current running through it Was heavy and not very feasible for everyday usage
compared to other, nonrechargeable batteries 1880s – new model of lead-acid battery (Camille
Alphonse Faure) Made a lead grid lattice with lead oxide paste
pressed into the grid Formed a plate that could store electricity Multiple plates could be stacked for greater
efficiency Could also be mass produced
History (cont)
For a while, the basic idea behind the lead-acid battery remained the same
1970 – gel electrolytes replaced liquid Called a gell cell Allowed battery to be used in non-upright
position without leaking or failing 1990s – lithium ion battery was invented
Could store a large amount of charge Was very flexible, allowing it to be
adapted into different shapes Is used in many electronics today
Lead-acid Batteries
Lead-acid batteries invented in 1859 Still in use today because they’re reliable and
cheap Can only store a small amount of energy
though The Trojan Battery Company has begun to
connect lead-acid batteries to form a battery bank capable of storing 1 MW of energy
Lithium-ion Batteries
Electrolytes contained in a low-moisture paste
Have a high energy density (high energy content in a small package)
Expected to become cheaper as there is extensive research in the car industry into these batteries
Used in computer batteries and other electronics
No loss of charge when not in use
Lithium-ion Batteries (cont)
Many tests and projects with li-ion batteries all over the world A123 Systems is doing a demonstration in SoCal
which will integrate 32MW of li-ion battery storage with wind turbines
Currently very popular for small energy requirements
Expected to see huge growth – from $795 million in 2011 to $2.2 billion in 2016
Flow Batteries
Can respond extremely fast (within milliseconds) Chemicals used are stored in tanks when not in use When in use, chemicals are pumped in a circuit
between reactors and tanks Therefore energy storage capacity is limited by
capacity of tanks
Flow Batteries (cont)
Not capable of holding a whole lot of electricity A 20-MWh iron-based flow battery requires 500,000
gallons of tank storage and can only supply the needs of 650 homes for a single day
Research is being done to drastically improve this statistic
Even More Types of Batteries
US Advanced Research Projects Agency-Energy (ARPA-e) is sponsoring a multitude of different energy storage projects Projects are still in research and/or development
stage Examples include metal-air ionic
liquid (MAIL) batteries, planar sodium-beta batteries, etc
Comparison
Different battery technologies have advantages and disadvantages that make it suitable for only certain applications
Still no solution that is practical and economical for everything
Liquid Metal Batteries
Concept proposed in 2009 Also known as liquid sodium or molten salt batteries Main advantages
High energy density Inexpensive and readily available materials
Liquid Metal Batteries (cont)
General idea Two materials are melted and used
to form the positive and negative poles of the battery
Same concept as ionization in solutions in chemistry, except with molten substances
There is an electrolyte layer between the two layers of materials which allow charged particles to move through as the battery is being charged or discharged
Basically a salt bridge that allows charge to move through
The Chemistry of Liquid Metal Batteries
Magnesium (2+) is used as negative electrode on top layer
Antimony (4+) is used for positive electrode on bottom layer
Mixture of salts such as magnesium chloride is electrolyte layer
Overall is very efficient because the cycle can be repeated many times with very little loss of energy
Similar idea to a bartender making drinks with distinct layers
The Chemistry of Liquid Metal Batteries (cont) Discharging process: Magnesium atoms ionize (lose
2 electrons) Positive charge builds up in
magnesium layer Forces magnesium ions to
travel through electrolyte layer to other electrode
Magnesium ions reacquire two electrons when they arrive at other electrode
Become normal magnesium atoms and form an alloy with antimony
Recharging process: Battery is connected to source of
electricity Electricity pushes magnesium out
of alloy and across electrolyte layer back into negative electrode
Progress on Liquid Metal Batteries Currently is still in
laboratory stage So far MIT has been
successful with small batteries the size of a shot glass
Now developing a battery the size of a pizza box - 200x more powerful than smaller battery
Donald Sadoway – one of the big brains behind liquid metal batteries
Progress on Liquid Metal Batteries (cont) Encountering problems with
electrolyte evaporation and breakdown of metal components through oxidation
Require high operating temperatures though (400-700 Celsius) which raises safety concerns
Still is very expensive If perfected, will be the most
cost effective and flexible source of battery energy storage
Disadvantages of Battery Energy
Huge problem: each power plant faces its own difficulties
There is no end-all be-all solution for battery-powered energy storage yet
Large differences in geography and weather require different equipment and infrastructure
Technology is still expensive – need more research
Huge amount of planning needs to go into implementation of battery
energy storage
Government support for energy storage
Success of green programs often depends on government mandates and other incentives (such as tax breaks and subsidies)
Example: green automobiles had government support, as did wind and solar (hence their popularity today)
Currently are not enough financial incentives to make energy storage a widespread thing
What to Take Away
Energy storage in the form of battery power can supplement current renewable energy sources such as wind and solar to make a green future a reality.
Many types of large-scale battery storage are still in development and not yet a reality.
More Information
Lots of cool applications of battery power – check it out if interested: http://www.alternative-energy-news.info/technology/battery-power/
Sources
http://www.smartplanet.com/blog/intelligent-energy/liquid-batteries-a-renewable-energy-game-changer/13146
http://www.renewableenergyworld.com/rea/news/article/2011/08/batteries-for-energy-storage-new-developments-promise-grid-flexibility-and-stability
http://www.articleshare.info/the-history-of-rechargeable-batteries/
http://en.wikipedia.org/wiki/Lithium-ion_battery
http://www.megawattsf.com/index.htm