Today’s Army – the march toward better batteries

REF generators for site

A series of diesel generators on a mini-grid power a Combat Outpost at Ft. Bliss. REF is working on better, lighter ways to bring power to soldiers based around the world. (Alex Chadwick/Burn)

 

The U.S. Army’s Rapid Equipping Force – REF for short – is a little-known agency making big changes in how soldiers fight. It was created after an officer saw a video of soldiers trying to clear an Afghan cave with a rope and grappling hook – why not robots, he wondered?

That was 10 years ago, and as BURN host Alex Chadwick reports, since then REF has become an innovator in many fields, including energy.

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Storing Energy: Fuel Cells and Beyond

Fuel input for hydrogen-fuel-cell-powered vehicle. Photo from Siemens PLM in Cypress California.

Storing energy is important for both long-term and short-term uses: to meet changes in energy supply and demand and to iron out irregularities in energy output, whether that’s in a car engine or on the power grid.

Unfortunately, we can only store a tiny fraction  of the electricity we produce in a single day. Instead, power plants have to send their thousands of megawatts of electricity to the right place, at the right time. For more details about electricity transmission, see Power Grid Technology.

Our current electric grid has various quick storage solutions to help make energy delivey smooth, and we use energy storage in cars, phones, and anything else that needs to be moved around. However, batteries and other storing options leave much to be desired.

Devices like capacitors and flywheels can store energy for extremely short periods.  Few technologies exist to store large amounts of energy over time periods ranging to several days: only pumped (water) storage is widely used to store energy on the scale of a power plant.

As energy sources are expanding to include more renewable and intermittent resources like wind and solar onto the electricity grid as we try to both meet growing energy demand and control greenhouse gas emissions. Likewise, there is increased interest in having reliable energy storage for vehicles, instead of gasoline and diesel fuels.

 

BATTERIES

Depending on the type of battery, these devices can store energy on location, like at home or in the car, in a laptop or cell phone. Note that though batteries and fuel cells can help integrate renewable energy sources, most electricity is still generated from fossil fuels. Both charging batteries and making hydrogen for fuel cells  thus produce greenhouse gas through reliance on the prevailing sources of electricity, and using these devices is less efficient than plugging into the wall because there’s always energy loss to byproducts like heat.

Batteries store chemical energy. Chemical reactions in the battery release that energy as needed. Eventually all the starting materials of the reaction are consumed and the battery is dead, or at least unusable until it’s recharged. There are many kinds of batteries, made of a wide array of chemicals. Polysulfide Bromide (PSB), Vanadium Redox (VRB), Zinc Bromine (ZnBr), Hydrogen Bromine (H-Br), and sodium sulfide batteries are some that the electricity industry has interest in.

Electric utilities use lead-acid batteries, which can be recharged, but there is research into other materials for utility and transportation use. Some of the best batteries used today for cars are nickel metal hydride and lithium ion.

 

HYDROGEN FUEL CELLS

Hydrogen fuel cells aren’t the same as batteries, but they can serve a similar purpose. Fuel cells are lumped with batteries because they both function through stored chemical energy. However, in practice, fuel cells are more like engines. They run off hydrogen “fuel” and produce energy and waste products, mostly  water vapor. As long as hydrogen keeps being added, the cell can run, just like a gasoline engine can keep running as long as more gasoline is added. A battery has a finite amount of energy unless it’s recharged with electricity.

For more about how to make hydrogen for fuel cells, see The hydrogen economy, hydrogen sources, and the science behind these.

For a description of different hydrogen fuel cells in development right now, see here.

 

FLYWHEELS

One way to smooth bumps in electricity delivery is through flywheels, which store energy in the form of rotational kinetic energy. A spinning potter’s wheel stores the energy of a good kick to be used moments later to mold a clay pot, and flywheels operate on a similar principle. In automobile engines, flywheels ease the transition between bumpy firing pistons and the drive shaft.

Flywheels can store energy for limited periods of time, from seconds to a few minutes.

 

PUMPED STORAGE

Pumped storage (of water) is the only widely-used method for storing huge amounts of energy for long periods of time. The United States has a capacity of more than 20,000 megawatts of pumped storage, according to the National Hydropower Association.

During times of excess electricity production, that excess energy is used to pump water to a higher altitude, increasing its gravitational potential energy. When extra energy is needed, the water is allowed to flow back down by way of turbines, turning that potential energy back into electricity.

For a figure of pumped storage see the National Hydropower Association

 

OTHER WAYS TO STORE ENERGY

Other technologies are constantly being investigated for energy storage. Compressed air storage is when air is forced into spaces like mines or caves and held at high pressure, using up energy in the process. When the compressed air is let out again, it can turn turbines to generate electricity.

Thermal energy storage exploits the difference in temperature between a system and the environment. In the late 1800s, Americans used thermal energy storage by cutting blocks of lake ice during the winter and storing them underground packed in insulating wood shavings. When the summer rolled around, they retrieved that stored ice to make food cold, exploiting the difference in temperature to force thermal energy out of the food.

Thermal energy storage can also happen in the other direction. Electricity or other forms of energy can be used to heat various materials, which are stored in insulated containers. Later, when the energy is needed, the hot materials can heat water into steam, and that steam can push turbines, which in turn produce electricity.

Thermal energy storage can also be used through ocean energy.

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Audio Features: Alex Chadwick Discusses Electric Cars on Marketplace

Testing the voltage of a battery at the Electric Car Conversion Conference in Cape Girardeau, MO.

Testing the voltage of a battery at the Electric Car Conversion Conference in Cape Girardeau, MO.

BURN host Alex Chadwick is following a just emerging movement of electric car conversion — replacing internal combustion engines with electric motors and batteries. He learned about a possible battery breakthrough at a gathering of car converters.

Could there be a battery technology breakthrough? “The rise of the green dragster” aired on APM Marketplace December 9, 2011:

In September 2011, an international group of car and technology enthusiasts gathered in Cape Girardeau, MO for the first EVCCON — the Electric Vehicle Conversion Convention. They came from China and New Zealand, Amsterdam and Ontario, and from throughout the U.S. to exchange ideas, swap stories, and drive really really fast down a taxiway at the Cape Regional Airport.

Burn host Alex Chadwick and Burn correspondent Sean Collins spoke with Jack Rickard, who publishes a weekly electric vehicle news magazine and produced this conference:

Burn: An Energy Journal has partnered with public radio’s Marketplace to bring you Energy news and stories, as told through the business and economics prism that has made Marketplace one of public radio’s most listened to programs. BURN and Marketplace are both distributed by American Public Media.

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Power Grid Technology

The electricity industry has three main components: the power plants, the transmission lines, and the distribution to you through utilities.

 

Mostly, three different entities operate these components. A power company owns a plant, some non-profit transmission company is responsible for the transmission, and a utility distributes the electricity to users.

Transmission may seem boring and straightforward — just a bunch of wires — but transmission is probably the most complex and sophisticated part of electricity.

 

WHY TRANSMISSION IS IMPORTANT

We only have the capacity to store the tiniest fraction of electricity produced in a single day. Electricity has to be generated within moments of when its used.

Many thousands of megawatts of power plant capacity are operating right now, and all that power has to be delivered to the right place, right now, too. It’s happening every day, even as individual power plants are pulled off line for service, even as fuel prices fluctuate, or weather conditions change and there’s a heat wave and everyone cranks up their air conditioning, or a major line goes down and there’s suddenly far too much electricity being generated.

Imagine what happens when your source of energy is wind, and the wind dies down. How do you fill the hole? How do we plan for that? It’s all part of the complexity of transmission, and the authorities in charge of it, who also are responsible for reliability and operating the power markets.

The price of electricity fluctuates by hour, as electricity demand rises and falls throughout the day [link to MM if it’s ever constructed]. It can be ten times the price in the middle of the day, when air conditioners and industries are running full blast. But did you know that the price is also different depending on where you are geographically?

Imagine if a single, high voltage line goes down. It’s not only that the people expecting that power won’t get it. Physics dictates that the surrounding lines will instantly be carrying more, and they may go down too, or their flows may change direction. Suddenly, in that instant, the price of electricity on one end of the line become sky high as there’s a lack of electricity, and the price at the other end drops down to nearly zero because there’s too much electricity going there.

Many of these details – energy market administration, the reliability of the power, the price – hinge on the electricity grid and how it’s run and where the lines are.

 

WHY TRACKING TRANSMISSION DATA IS COMPLEX

There is no national electricity grid. The country is divided into the Eastern Interconnected System, the Western Interconnected System, and the Texas Interconnected System. Our grids also interact with the Mexican and Canadian grids in some places.

To complicate matters, a large number of authorities are in charge of electricity transmission, and the authorities don’t all work the same way. There are Independent System Operators in some regions and Regional Transmission Organizations in others, and there are many tiny municipalities all over the country. There are eight regional reliability councils, map here, and the whole smorgasbord is overseen by the Federal Energy Regulatory Commission.

 

A PATCHWORK OF ELECTRICITY MARKETS

On top of the regulatory diversity, which is not really divided by state, energy markets rules are divided by state. For example, all of New England is lumped together when it comes to transmission, under the New England Independent System Operator. Yet, each state in New England has different environmental laws, electricity rate rules, and so forth. For more about electricity markets, go here.

Each region has different rules about when or if it publishes data about how much electricity was used, who used it, and when it was used. But these regions aren’t divided exactly along state lines.

To track how much electricity individual homes used yesterday is almost impossible. Electricity load numbers are all mixed up with industrial and municipal uses, divided along regions that aren’t quite counties or states. Furthermore, in some parts of the country, authorities claim that the electricity demand data is confidential, at least until it has to be submitted to the Federal Energy Regulatory Commission once per year.  That makes it hard for the public, the government, and research institutions to get information about how we use energy.

 

SMART GRID: WHERE OH WHERE IS THE ELECTRICITY NOW?

When electricity leaves the power plant, we don’t know exactly where it goes, and as stated before, the authorities who know anything are diverse and follow different rules. Yes, we have extremely complex math to model where it is. Yes, we can go out and measure the lines. Yes, individual power plant companies know how much they’re producing. But do we have a national ability to know what is going on everywhere on the grid? No.

But we could.

That is the idea behind the smart grid: know what is going on instantaneously. The idea encompasses technologies for high voltage lines and for low voltage and individual users. It includes tracking electricity and also handling data wirelessly.

Applications for this information could be endless, from encouraging less energy use during peak hours to sociological studies and beyond.

 

SMART METERS

We are only tracking the total energy used over a month. If there aren’t special meters and ways to relay information, we don’t know how much an individual or a neighborhood is using right now. Someone from the electric company would have to get in a truck and go to your home or your neighborhood and measure.

Instead, with smart meters, information about hourly use can be read instantly by the power company and by you, the user.

Having a meter connected to a pleasant interface like a monitor or a webpage allows an individual to take control of their own energy use in a way that was vague and theoretical before.

We can track when people use electricity, where and when there are inefficiencies, pinpointing power outages and how widespread they are. Lumping geographical hourly data together, there’s no end to interesting aspects to study, even into the realms of sociology and psychology.

However, smart meters are new, and the technology is still developing, which means there’s opportunities for many mistakes or poorly functioning equipment. In 2011 a California utility found that a small proportion of meters were malfunctioning if the internal temperatures rose too high.

 

For more information about the electricity market see here.

Also see the Basics of Electricity.

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