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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Wind Science, Energy, and Growing Prevalence

Wind is the kinetic energy of molecules in the air. Wind has powered ships and mills for centuries or longer.

Modern windmills convert the wind into rotational energy by allowing the air molecules to bombard the blades, turning them. The blades are connected to turbines, which generate electricity from that rotational energy.

Wind energy is one of the cleanest forms of energy available because it doesn’t require a fuel or produce greenhouse gas or other bi-products, outside of those from production and maintenance of equipment and transmission.

Wind turbines themselves take up only a small area compared to their generating potential, making it possible to install them on agricultural, forest, or grazing lands.

RAPID GROWTH

In just ten years, wind power in the United States grew more than ten-fold, from just over 2,000 megawatts in 1999 to more than 34,000 megawatts in 2009, when wind accounted for 9 percent of renewable energy produced in the country and more than geothermal and solar combined.

Here’s an animated map of wind development from 2000 to 2010.

Texas, Iowa, and Minnesota had the greatest wind capacity in 2010. Additionally, at least 27 other states used wind to generate electricity that year.

DRAWBACKS TO WIND ENERGY

Wind is an intermittent resource, meaning that the windmills can’t continuously and predictably produce energy. They only work when the wind blows, and they can only work as hard as the wind is blowing at that time.

Research is ongoing into predicting what regions of the country have significant wind resources suitable for wind development, a process that requires computer programming and meteorological knowledge.

Furthermore, public and private researchers are working to produce better models of wind on an hourly, daily, and seasonal basis to make it easier for wind energy producers to forecast their output and sell it ahead of time.

Another major hurdle to wind power is that it is expensive compared with fossil fuel-based electricity. Modern windmills cost a lot to design and build, especially as they have to be strong enough to endure extreme weather, even though they will mostly operate in moderate weather. That makes competing with other energy sources difficult without government intervention.

Some people don’t like the way windmills look, and windmills can also kill bats and birds, though newer designs have slower and less deadly blades. A 2010 study published in the Journal of Ornithology estimated that windmills kill around 440,000 birds every year. However, the same study showed that house cats kill more than 1,000 times that number, as many as 500 billion per year.

SOURCES
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What Is A Nuclear Reaction?

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Photovoltaic Cells, Solar Power, and LEDs

Most of the world’s energy can go back to our sun. Every day we are heated by its electromagnetic rays, and plants use the sun’s energy to make sugars and ultimately proteins and other good things to eat. Fossil fuels were also once made from these plant and other organisms that relied on the sun’s energy millions of years ago. Today, humans can convert the sun’s energy directly into electricity, through solar thermal and solar photovoltaic systems.

SOLAR THERMAL OR PHOTOVOLTAIC?

Solar panels, also called solar thermal, convert sunlight to heat and then heat to electricity. Photovoltaic cells, or solar cells, convert sunlight directly into electric current by way of carefully-engineered semiconductor materials.

Though solar photovoltaics are more efficient converters of sunlight, they are also more expensive.

As of May 2011, the world’s largest solar power plant is a concentrating solar thermal power plant in the Mohave desert in California. Solar Energy Generating Systems has a capacity of 310 megawatts and uses parabola-shaped reflective troughs to concentrate electromagnetic radiation.

The world’s largest solar photovoltaic plant is probably the Sarnia Solar Project in Ontario, Canada. It has a capacity of roughly 80 megawatts.

HOW SOLAR THERMAL WORKS

Sunlight heats a design element (water, air, chemical fluids), and that thermal energy is transmitted for other applications, such as heating water, heating space, or generating electricity. In solar thermal power plants, sunlight heats a specialized fluid, which in turn heats water into steam, which can run turbines and produce electricity.

Solar thermal power plants use concentrators that bounce the sunlight off elliptical mirrors to a central tube, in which the specialized fluid lies.

HOW PHOTOVOLTAICS WORK

Photovoltaic cells are made of specialized diodes. Electrons (natural components of atoms) in the photovoltaic cells absorb light, which excites them to a state where they can be conducted as electrical current. This difference in energy, between the valence band (the state of a normal electron staying around its home atom) to the conduction band (electron free to move between atoms) is called the band gap.

Solar photovoltaic farm in Indonesia. Photo by Chandra Marsono.

Well-engineered photovoltaics have a band gap that coincides with the energies of as broad a spectrum of light as possible, to convert the maximum amount of the sunlight into electricity.

As sunlight energy pops electrons into the conduction band and away from their home atoms, an electric field is produced. The negatively-charged electrons separate from the positively-charged “holes” they leave behind, so that when electrons are freed into the conduction band, they move as electric current in the electric field, electricity.

PHOTOVOLTAICS ARE MADE OF SPECIALIZED MATERIALS

An ever-expanding variety of semiconductor materials can be used to make solar cells; universities and companies worldwide are researching these options, from special bio-plastics to semiconductor nanocrystals. Nonetheless, the photovoltaic cells available today require precise manufacturing conditions and are therefore far more expensive to produce than solar panels.

Silicon has to be processed under clean room conditions — carefully regulated atmospheres — to remove impurities and prevent introducing contaminants, both of which can change the band gap. Thin film-based photovoltaics require special production methods, like chemical vapor deposition. Semiconductor processing also uses strong acids and often dangerous chemicals for etching.

Today, commercially-sold cells are made from purified silicon or other crystalline semiconductors like cadmium telluride or copper indium gallium selenide.

WHERE DO WE GET THE STARTING MATERIALS?

Silicon is plentiful in the Earth’s crust. Cadmium is a readily available but highly toxic heavy metal, as is arsenic, another chemical used in some cells. As tellurium demand is only recently rising in response to solar demand, it’s unknown what the global supply is for this unusual element but it may be quite abundant. Photovoltaics are a lively area of research, and the future production and environmental costs of starter materials, production, and pollution are difficult to predict.

California, Massachusetts, Ohio, and Michigan produced the most photovoltaics in 2009. However, that year, 58 percent of photovoltaics were imports, primarily from Asian countries like China, Japan, and the Philippines.

LED TECHNOLOGY: MORE THAN HEADLAMPS

Photovoltaic cells work in the opposite direction of light-emitting diodes, or LEDs. LEDs are used interchangeably with other lighting, like light bulbs. However, LED’s work in a completely different manner, far closer to the way photovoltaics work.

Click here see a bar chart comparing how much energy is used by various light sources.

LEDs absorb energy in the form of electricity, exciting electrons into the conduction band. When the electrons in the semiconductor material drop back into the valence band from the conduction band, they emit energy in the form of photons, or electromagnetic radiation.

It’s a highly efficient process because energy isn’t wasted on producing heat, which happens with standard tungsten filament bulbs. LEDs also last a much longer time as they do not have filaments to burn out, and because they are very small and several units are used to replace one large traditional lamp, they do not all burn out at once. That makes LEDs a good choice for stoplights or other safety critical applications.

 

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The Global Energy Mix and Policies

 On this page, you can find energy information about the world’s most populated countries: China, India, the United States, Indonesia, Brazil, Pakistan, Bangladesh, Nigeria, Russia, and Japan. For fossil fuel information about any country, see online tables here.

A nation’s sources of energy hinge on so many factors, from what’s naturally available to geography, political history, and relative wealth.

Even though energy demand is increasing rapidly across the globe, the International Energy Agency estimates a fifth of the world population lacks access to electricity, and a whopping 40 percent of people still use traditional biomass – like wood chips – for cooking. People who live without the energy infrastructure of electricity depend on portable petroleum fuels, manure and methane gas produced from manure, wood, grass, and agricultural wastes. Because these sources of energy are informal, it’s difficult to track and include them in statistics.

World electricity and energy demands are escalating. Countries are expanding energy investment to non-fossil sources like biofuels, wind, solar, and geothermal. At the same time, they are competing to secure access to coal, natural gas, and petroleum both at home and abroad.

 

Nowhere has rapid energy growth been more conspicuous than in the world’s most populated country, China. While most countries saw moderate energy growth in the same period, this Asian nation doubled energy use in less than a decade – see graph – and surpassed the United States in total energy use in 2009, according to International Energy Agency estimates. Until 2009, the United States lead the world in total energy consumption, though not per person consumption, for decades. For a list of the top 30 countries by total energy consumption see here.

Meanwhile, less than 42 percent of people in Africa had electricity at home in 2009. South Asians seemed better off than Africans that year, at 62 percent, but the real story is much more diverse. Nearly 100 percent of Chinese had access to electricity, while in Burma, only 13 percent had access. Worldwide almost 78 percent of people had access to electricity in 2009, according to the International Energy Agency.

 

ENERGY IN THE WORLD’S MOST POPULATED COUNTRIES

 

CHINA (Pop. 1.3 billion)

Between 2008 and 2035, China may triple its electricity demand, adding power plant capacity equal to the current U.S. total, the International Energy Agency projects in one scenario of the 2010 World Energy Outlook.

China is the world’s most populated country and also the world’s largest energy consumer. China gets most of its energy from coal, 71 percent in 2008. China is also the world’s biggest coal producer but only third, behind the United States and Russia, in coal reserves.

In 2008, China generated another 19 percent of its energy from oil, which it imported from all over the world, more than half came collectively from Saudi Arabia, Angola, Iran, Oman, Russia, and Sudan. China used to export its oil, but by 2009 automobile investment was expanded by so much, the country became the second largest oil importer (United States is first).

China is in hot pursuit of securing as much oil as possible, as the nation’s reliance on imported oil is growing far more rapidly than its oil production. Several powerful, national oil companies provide the domestic oil, both from on and off-shore sources. Furthermore, China has purchased oil assets in the Middle East, Canada, and Latin America, and it also conducts oil-for-loan exchanges with other countries, $90 billion worth since 2009, according to the U.S. Energy Information Administration.

Only a small proportion of China’s energy comes natural gas, produced domestically and imported in liquified form, but that may change as prices lower and liquified natural gas terminals are constructed.

China is the world’s biggest user of hydroelectric power, which made up 6 percent of energy and 16 percent of electricity in 2009. The country’s Three Gorges Dam, the world’s largest hydroelectric project, is expected to begin operating in 2012. Nuclear power accounts for only 1 percent of total consumption. However, China’s government predicts it will have seven times its current nuclear capacity by 2020.

A homemade oven. West Bengal, India, 2009.

Detailed data on energy in China can be found here.

 

 

 

 

 

 

INDIA (1.2 billion)

India is the world’s largest democracy. Though India’s population is close to that of China’s, it is only the world’s fifth largest energy user, behind the United States, China, Russia, and Japan.

Like China, India’s electricity comes mostly from coal. However, India doesn’t have enough electricity for everyone, and only 65 percent of the population has access to electricity.

Instead, many Indian use fuels at home for lighting and cooking. A 2004-2005 survey by the government found more than 40 percent of rural Indians used kerosene instead of electricity for home lighting. The same survey showed that for cooking, 74 percent of Indians used firewood and wood chips, 8.6 percent used liquified petroleum gas, 9 percent used dung cakes, and 1.3 percent used kerosene.

India produces oil domestically, but like China, the rate of India’s increasing oil consumption far outstrips its production. India therefore has to import oil; in 2009 its most significant sources were Saudi Arabia, Iran, Kuwait, Iraq, the United Arab Emirates, Nigeria, Angola, and Venezuela, in descending order.

India doesn’t have the electricity capacity to serve its population but aims to add many thousands of megawatts in the near future.

Like China, India has nuclear power, with 14 nuclear plants in operation and another 10 in planning, the reactors purchased from France and Russia.

 

UNITED STATES (300 million)

Until China recently outpaced it, the United States was the biggest energy consumer in the world, though per capita use isn’t the highest but in the same range as several developed countries worldwide and less than the per capita use in Canada. The United States relies on petroleum, coal, and natural gas, as well as a small part nuclear, hydroelectric, and various non-fossil sources. The Unites States has significant oil, coal, and natural gas reserves, as well as the potential for significant investment in solar, off and on-shore wind, and biofuels.

The mix of fuels that provide electricity varies widely from region to region. Find a map of fuel mix by U.S. region from the Edison Electric Insitute here.

For more U.S. information:

-Fossil fuel use in the United States, go here.
-U.S. greenhouse gas emissions and energy here.
-U.S. sources of energy, see here.

 

INDONESIA (250 million)

Indonesia is an archipelago of more than 17,000 islands — 6,000 are inhabited — and it is home to 76 active volcanoes and a significant undeveloped geothermal capacity, estimated at 28 gigawatts, about as much total electricity capacity as Indonesia had in 2008.

Indonesia’s energy demand is growing rapidly, split between coal, natural gas, and petroleum sources. Traditional sources of energy like wood and agricultural waste continue to be used, particularly in rural areas and remote islands, and the International Energy Administration estimates these fuels provide about a quarter of the country’s energy.

Indonesia exports coal and natural gas. In the past, the country also exported more oil than it used, but as of 2004 that balance changed. By 2009, the country suspended its membership in the Organization of Petroleum Exporting Countries (OPEC) because it was using so much of its own oil.

 

BRAZIL (200 million)

Tropical Brazil is the largest country in South America both in area and population, and it is the third largest user of energy in the Americas, after the United States and Canada.

Made from sugar cane, Brazil’s ethanol production is the world’s second largest, after the United States, which makes ethanol from corn.

Brazil produces almost as much petroleum as Venezuela and produces slightly more fuel than it consumes.

While Brazil depends on oil for other energy applications like transportation, the country gets an astounding 84 percent of electricity from hydroelectric dams. Brazil also has two nuclear power plants.

PAKISTAN (190 million)

Pakistan has limited access to electricity and energy sources, and its rural population still relies on gathered fuels like wood for heating and cooking.

In 2009 around 60 percent of the population had access to electricity, far better than its neighbor Afghanistan, at just 15 percent. Nonetheless, even with access, most of the population can’t rely on electricity unless they are wealthy enough to own generators. Pakistan suffers from lengthy blackouts, even in its cities, in part because of poor transmission infrastructure and widespread electricity theft. The situation is also aggravated by lack of capacity planning, insufficient fuel, and irregularities in water supply for hydroelectric.

In 2010, angry citizens protested violently after lengthy blackouts — as long as 18 hours according to Reuters — plagued the country. That summer, Pakistan has nowhere near enough electricity for its peak needs, which were roughly 25 percent more than its total production capacity. The widespread blackouts crippled the country’s textile industry, its biggest source of exports, and some reports suggest that hundreds of factories were shuttered as a result of sporadic power.

Meanwhile, several proposals for gas pipelines through Pakistan have yet to get solidified, including one from Iran to Afghanistan (which is opposed by the United States).

 

BANGLADESH (160 million)

Like nearby Pakistan and India, with which it shares cultural and political histories, Bangladesh also suffers from electricity shortages. Only 41 percent of Bangladeshis had access to electricity in 2009, according to the International Energy Administration.

Most of the electricity in this delta nation is generated from natural gas, with smaller amounts each from oil, coal, and hydroelectric sources. More than 30 percent of the country’s energy comes from biomass, agricultural wastes, and other combustible, renewable materials.

In 2011, Bangladesh signed a contract with oil company ConocoPhillips, allowing off-shore drilling for natural gas, despite internal protests that insisted Bangladesh should keep more of the gas for its own. The agreement gives 20 percent to Bangladesh.

 

NIGERIA (160 million)

Nigeria is Africa’s most populous country, and it is world famous for its oil, most of which is exported for sale by huge foreign oil companies like Royal Dutch Shell, ExxonMobil, Chevron, ConocoPhillips, Petrobras, and Statoil. Roughly 65 percent of government revenue comes from the oil sector, and around 40 percent its oil exports are sent to the United States. Nigeria also holds the largest natural gas reserves in Africa.

Extensive oil development has wreaked havoc on Nigeria’s ecology. Oil spills have polluted Nigeria’s water, affecting both fishing and agriculture. Much of Nigeria’s natural gas is flared rather than being collected and sold for fuel. Flaring involves burning off naturally-occurring gases during petroleum drilling and refining, resulting in  environmental degradation, greenhouse gas emissions and loss of revenue.

Even though Nigeria is fossil fuel-rich, only 47 percent of the population have access to electricity, and less than a fifth of energy in that country came from petroleum and natural gas in 2007, reflecting the widespread use of more traditional fuels like wood. Nigeria only used 13 percent of petroleum it produced in 2009.

 

RUSSIA (140 million)

Russia has significant wealth in fossil fuels, including the largest natural gas reserves and the second largest coal reserves, after the United States. In 2009, Russia produced more oil even than Saudi Arabia, mostly from Western Siberia. In 2009, Russia exported far more oil than it used, and 81 percent of its exports went to Europe, notably the Netherlands and Germany.

Russia is also the third largest consumer of energy in the world.

The country has a well-developed pipeline system to transport oil from remote regions, a system which is almost entirely controlled by a single state-run company, Transneft.

Like Nigeria, Russia flares gas in the process of drilling and refining oil, and in 2008 Russia flared more gas than any other country in the world, 1,432 Bcf of natural gas, more than double Nigeria’s output and equivalent to the annual greenhouse gas emissions for 1.4 million passenger cars, according the calculator on the U.S. Environmental Protection Agency website and data from the U.S. Energy Information Administration.

Russia operates 31 nuclear reactors, half of which employ a similar design to the ill-fated Chernobyl plant in the Ukraine.

 

JAPAN (130 million)

Japan doesn’t have significant fossil fuel resources, one reason that much of its electricity industry relies on nuclear power. It is the world’s third largest user of nuclear power.

Japan is the world’s third larger oil consumer, and it does produce some oil domestically. However, it also imports a lot of oil and natural gas, the later in the form of liquified natural gas, or LNG. Almost half of its energy came from imported oil in 2009, and just 16 percent of Japanese energy came from a domestic source.

Japan also invests heavily in foreign oil, including in the United Arab Emirates, the Congo, Algeria, Russia, Australia, Papua New Guinea, Brazil, Canada, the United Kingdom, Vietnam, and Indonesia, to name a few.

As of June 2011, Japan is still recovering from a massive earthquake and tsunami that devastated its northeast coast on March 11, 2011, forcing the shutdown of several nuclear reactors as well as damaging refineries, oil and gas generators, and electricity transmission infrastructure.

Japan imports most of its oil from the Middle East: Saudi Arabia, Iran, Kuwait, the United Arab Emirates, and Qatar together supplied 77 percent of imports in 2009.

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Major sources of energy/their advantages and disadvantages

There is no easy answer to what is the best source of energy or electricity. Is the priority reliability, affordability, the economy, international human rights, limiting greenhouse gas emissions, preserving environmental resources, or human health?

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It’s undeniable that today — whether we like it or not — humans worldwide are overwhelmingly dependent on fossil fuels: coal, oil, and natural gas. Everything eaten, worn, lived in, and bought is tied to availability of fossil fuels. Even if 100 percent of politicians were determined to stop using them today, society has neither the electricity grid nor the vehicular and industrial technology to sustain the current American lifestyle on non-fossil sources of energy. Yet.

When comparing sources of energy, it’s easy to forget how universal fossil fuels are. These sources continue to dominate for reasons that are difficult to measure, like political influence, advertising clout, and control over energy infrastructure. Other sources have disadvantages purely because they don’t fit in as well.

Volume brings another difficulty in comparing sources of energy. There is so much more fossil energy, and it’s been used for a long time, so we know a lot more about its hazards and benefits. More modern technologies are harder to quantify. Some are renewable but still pollute (biofuels), some are very clean except in accidents or waste disposal (nuclear). Most electricity sources (renewable or not) use steam turbines, and all the water to make steam has to come from somewhere, but how important should that factor be?



Clicking the graphic above will give an abbreviated chart comparing sources line by line, but that doesn’t provide anywhere close to the whole story.

Each of the following topics compares the major sources of energy  through a different lens. Though environmental and local issues may seem the most important to those of us who don’t own power plants or utility companies, the cost of energy drives which sources are actually in place today and which sources will see investment tomorrow.

 

 

 

 

 

 

 

 

 

 

 


Source: U.S. Energy Information Administration

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The electricity grid: A history

Drawing by Thomas Edison in 1880 patent file. From the U.S. National Archives.

In the early days of electricity, energy systems were small and localized. The Pearl Street Station in New York City, launched in 1882, was the first of these complete systems, connecting a 100-volt generator that burned coal to power a few hundred lamps in the neighborhood. Soon, many similar self-contained, isolated systems were built across the country.

During this era, two major types of systems developed: the AC and DC grids. Thomas Edison, who designed Pearl Street, was a proponent of direct current (DC). In a direct current, the electrons flow in a complete circuit, from the generator, through wires and devices, and back to the generator.

William Stanley, Jr. built the first generator that used alternating current (AC). Instead of electricity flowing in one direction, the flow switches its direction, back and forth. AC current is what is used almost exclusively worldwide today, but in the late 1800s it was nearly 10 years behind DC systems. AC has a major advantage in that it is possible to transmit AC power as high voltage and convert it to low voltage to serve individual users.

From the late 1800s onward, a patchwork of AC and DC grids cropped up across the country, in direct competition with one another. Small systems were consolidated throughout the early 1900s, and local and state governments began cobbling together regulations and regulatory groups. However, even with regulations, some businessmen found ways to create elaborate and powerful monopolies. Public outrage at the subsequent costs came to a head during the Great Depression and sparked Federal regulations, as well as projects to provide electricity to rural areas, through the Tennessee Valley Authority and others.

By the 1930s regulated electric utilities became well-established, providing all three major aspects of electricity, the power plants, transmission lines, and distribution. This type of electricity system, a regulated monopoly, is called a vertically-integrated utility. Bigger transmission lines and more remote power plants were built, and transmission systems became significantly larger, crossing many miles of land and even state lines.

As electricity became more widespread, larger plants were constructed to provide more electricity, and bigger transmission lines were used to transmit electricity from farther away. In 1978 the Public Utilities Regulatory Policies Act was passed, making it possible for power plants owned by non-utilities to sell electricity too, opening the door to privatization.

By the 1990s, the Federal government was completely in support of opening access to the electricity grid to everyone, not only the vertically-integrated utilities. The vertically-integrated utilities didn’t want competition and found ways to prevent outsiders from using their transmission lines, so the government stepped in and created rules to force open access to the lines, and set the stage for Independent System Operators, not-for-profit entities that managed the transmission of electricity in different regions.

Today’s electricity grid – actually three separate grids – is extraordinarily complex as a result. From the very beginning of electricity in America, systems were varied and regionally-adapted, and it is no different today. Some states have their own independent electricity grid operators, like California and Texas. Other states are part of regional operators, like the Midwest Independent System Operator or the New England Independent System Operator. Not all regions use a system operator, and there are still municipalities that provide all aspects of electricity.

Who has the authority over transmission is also equally convoluted. Individual states control some aspects of the lines on their soil, but the rules are implemented by the operators. And others are managed by the North American Reliability Council, the Federal Energy Regulatory Commission, and the Department of Energy.

In today’s market, some states are deregulated and some are not. Even in non-deregulated states, different companies own the power plants and the utilities to which you write your monthly checks.

 

Check out BURN’s special, The Switch: The Story of America’s Electrical Grid.

For details about how electricity gets to you today, see Power Grid Technology and the Smart Grid.

For more information about how electricity is bought and sold, see the Electricity Marketplace.

 

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The Connection Between Greenhouse Gases, Climate Change & Global Warming


 

WHAT IS THE DIFFERENCE BETWEEN CLIMATE CHANGE AND GLOBAL WARMING?

Climate change is the shift in long-term, global weather patterns due to human action; it’s not exclusive to warming or cooling.

Climate change includes any change resulting from different factors, like deforestation or an increase in greenhouse gases. Global warming is one type of climate change, and it refers to the increasing temperature of the surface of Earth. According to NASA, the term global warming gained popular use after geochemist Wallace Broecker published a 1975 paper titled Climatic Change: Are We on the Brink of a Pronounced Global Warming?

Since 1880, the average surface temperature of the Earth has increased by roughly 0.9 degrees Fahrenheit, but the rate it’s increasing is faster than that, depending on which region you live in. If you’re closer to the equator, temperatures are increasing more slowly. The fastest increase in temperatures in the United States is in Alaska, where average temperatures have been increases by more than 3 degrees Fahrenheit per century. For a graph of average global temperatures by year, see the NASA website here.

 

HOW GREENHOUSE GASES RELATE TO CLIMATE CHANGE

Greenhouse gases are those thought to contribute to the greenhouse effect, an overall warming of the Earth as atmospheric gases trap electromagnetic radiation from the sun that would otherwise have been reflected back out into space.

Noteworthy greenhouse gases are methane, nitrous oxide, carbon dioxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These gases are thought to affect the climate directly and indirectly, even though they constitute only a small fraction of the blanket of gases that make up the atmosphere.

Currently, the composition of the atmosphere is mostly nitrogen and oxygen, with just 0.033 percent carbon dioxide and all other gases accounting for even less.

 

WHICH GASES CONTRIBUTE THE MOST?


According to 2010 models cited by NASA, 20 percent of the greenhouse effect is attributed directly to carbon dioxide and 5 percent to all other greenhouse gases. The remaining 75 percent of the greenhouse effect is thought to be due to water vapor and clouds, which are naturally-occurring. However, even though carbon dioxide and the other greenhouse gases are such a small percentage of the total gas in the atmosphere, they affect when, where and how clouds form, so greenhouse gases have some relevance when it comes to 100 percent of the greenhouse effect. Carbon dioxide is thought to modulate the overall climate, like a atmospheric thermostat.

Some greenhouse gases are produced in natural processes, like forest fires, animal manure and respiration, or volcanic eruptions. However, the majority of new greenhouse gases are produced from industrial processes and energy production.

The four largest human sources of U.S. greenhouse gases in 2009 were energy, non-fuel use of fossil fuels, natural gas production, and cement manufacture, in descending order. Non-fuel, greenhouse gas-producing applications of fuels include industrial production like asphalt, lubricants, waxes and other . Emissions related to cement manufacture happen when limestone (calcium carbonate) is reacted with silica to make clinker, the lumps ground to make cement. ( Emissions of Greenhouse Gases in the United States 2009: Independent Statistics & Analysis.)

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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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