Working Progress of Wind Turbines

A wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. View the wind turbine animation to see how a wind turbine works or take a look inside.

Wind is a form of solar energy and is a result of the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and the rotation of the earth. Wind flow patterns and speeds vary greatly across the United States and are modified by bodies of water, vegetation, and differences in terrain. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.

Types of Wind Turbines

Modern wind turbines fall into two basic groups: the horizontal-axis variety, as shown in the photo to the far right, and the vertical-axis design, like the eggbeater-style Darrieus model pictured to the immediate right, named after its French inventor. Horizontal-axis wind turbines typically either have two or three blades. These three-bladed wind turbines are operated "upwind," with the blades facing into the wind.

Wind turbines can be built on land or offshore in large bodies of water like oceans and lakes. Though the United States does not currently have any offshore wind turbines, the Department of Energy is funding efforts that will make this technology available in U.S. waters.

Sizes of Wind Turbines

Utility-scale turbines range in size from 100 kilowatts to as large as several megawatts. Larger wind turbines are more cost effective and are grouped together into wind farms, which provide bulk power to the electrical grid. In recent years, there has been an increase in large offshore wind installations in order to harness the huge potential that wind energy offers off the coasts of the U.S. 

Single small turbines, below 100 kilowatts, are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.

Learn more about what the Wind Program is doing to support the deployment of small and mid-sized turbines for homes, businesses, farms, and community wind projects.

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Oil Spill Assessment

 

Exponent scientists have more than 40 years of experience in assessing the impacts associated with oil spills, providing consulting services to most of the major international oil companies, as well as pipeline, oilfield engineering design and service companies. In addition, our scientists have supported U.S. and international governments in responding to and assessing spill impacts.

Our services include:

• Emergency environmental response - cleanup and monitoring chemistry 
  • Source characterization/fingerprinting 
  • Contamination assessment 
  • Background and baseline assessment 
• Monitoring and NRDA 
  • Exposure and bioavailability assessment 
  • Shoreline surveys and ecology studies - impact and recovery 
  • Restoration 
• Database development 
• Geospatial analyses 
• Training

Emergency Environmental Response – Cleanup Monitoring Chemistry

Rapid environmental response is critical to the effective oil spill management. Exponent scientists are on call for immediate response to oil spill incidents. Our response experience focuses on environmental monitoring, assistance to spill clean-up efforts, ephemeral sampling and hydrocarbon chemistry. In complex cases involving releases into urban estuaries or industrial settings a strong scientific approach is critical to reconstructing the release, assessing injury, establishing causation, and defining the baseline. Our scientists and engineers excel in the area of source characterization and petroleum fingerprinting, and our clients rely on our combined experience in petroleum fate in the environment to accurately assess impacts and allocate those impacts to various sources.

Monitoring and Natural Resource Damage Assessment (NRDA) 

One of Exponent’s core, signature business areas is that of NRDA. Exponent has been a pioneer and a trusted consultant on NRDA issues since the first regulations were developed. Our team has unparalleled experience and depth in supporting industry in the area of NRDAs under the Oil Pollution Act (OPA), and under state claims. The fate of spilled oil in the environment must be understood in order to predict the potential for exposure of ecological receptors. Exponent’s team of petroleum chemists and toxicologists have extensive experience with determining exposures associated with oil spills, as well as issues related to the persistence and bioavailability of oil in the environment, and the use of biomarkers as measures of exposure. Our clients rely on our combined experience in contaminant assessment and biological injury assessment, along with our knowledge of transport pathways to help assess injury and allocate those injuries to various sources.

Geospatial Analysis

Exponent scientists have evaluated the geospatial implications of different oil spill response strategies on shoreline impacts. Our work has focused on the development of a GIS from base shoreline maps obtained from aerial photographs. The analysis of possible shoreline impacts from oil spills relies, in part, on the type of shoreline being affected. Our team of aerial imagery and GIS specialists evaluated the shoreline typing, and have determined that the usability of aerial photographs to populate a GIS system, and hence to assess oil spill impact and persistence, is highly dependent on the timing and quality of the aerial images. This finding is especially important when it comes to the timing of tides and image acquisition where significant offsets and errors in shoreline typing can occur without such recognition. 

 

Database Development

Exponent has developed a customizable database and interface to store, summarize, and display environmental data from a wide variety of sites and investigations, and has been customized for oil spills. Analytical data, photographs, chromatograms, and scanned documents can be linked to individual data points. The database has a web-tool protected interface that is setup for individual users and includes customized data selection tools which allow simplified searches, selection and download of data sets based on end-user needs. The data output(s) from the database can be Access or Excel format spreadsheets that can be downloaded by the user for further data analysis and interpretation. Thus no knowledge of Access will is required of the end-users.

Training

Exponent scientists have conducted oil spill training programs and seminars for clients worldwide. The training includes all of the environmental issues and response strategies and methods that are part of the short and long term response efforts. Our primary focus is on environmental sampling, NRDA, environmental monitoring and chemical fingerprinting, but also includes shoreline assessment, toxicity assessment and other oil spill related issues.

Exponent Oil Spill Experience

• Amoco Cadiz 
• Argo Merchant
• Bayway Refinery (Arthur Kill)
• Cosco Busan 
• Deepwater Horizon
• Ever Reach
• Exxon Valdez
• Haven
• Ixtoc I
• Katina
• Kure
• Kuroshima
• Martinez Refinery (Suisun Bay)
• New Carissa
• Newton Lake
• North Cape
• Perth Amboy (Arthur Kill)
• Prestige
• ROPME Sea
• Tsesis 

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Aluminium is the most abundant metal in the earth’s crust.

The aluminium-containing bauxite ores gibbsite, böhmite and diaspore are the basic raw material for primary aluminium production.

Proven, economically viable reserves of bauxite are sufficient to supply at least another 100 years at current demand. While demand for bauxite is expected to grow as demand for high quality aluminium products increases, new reserves will be discovered or become economically viable.

Gibbsite is an aluminium hydroxide (Al(OH)₃), while böhmite and diaspore are both aluminium-oxide-hydroxides (AlO(OH)). The main difference between the latter two is that diaspore has a different crystalline structure to böhmite. Differences in ore composition and presence of iron, silicon and titanium impurities influence their subsequent processing.

90% of the world’s bauxite reserves are concentrated in tropical and sub tropical regions.

Large blanket deposits are found in West Africa, Australia, South America and India as flat layers lying near the surface, extending over an area that can cover many square kilometres. Layer thickness varies from less than a metre to 40 metres in exceptional cases, although 4 – 6 metres is average.

In the Caribbean, as well as in Southern Europe, bauxite is found in smaller pocket deposits, while interlayered deposits occur in the United States, Suriname, Brazil, Guyana, Russia, China, Hungary and the Mediterranean.

Bauxite is generally extracted by open cast mining, being almost always found near the surface, with processes that vary slightly depending on the location. Before mining can commence the land needs to be cleared of timber and vegetation. Alongside this process may be the collection of seeds and/or saplings, for inclusion in a seedbank, which will form the basis of post-mining revegetation of the site. Next the top soil is removed and is usually also stored for replacement during rehabilitation.

The layer under the top soil is known as the “overburden”. On some surface deposits there is no overburden, and on others, the bauxite may be covered by up to 20 metres of rock and clay. On average, overburden thickness is around 2 metres.

The bauxite layer beneath the overburden is broken up using methods such a blasting, drilling and ripping with very large bulldozers. Once the bauxite is loosened into manageable pieces it is generally loaded into trucks, railroad cars or conveyors and transported to crushing and washing plants or to stockpiles, before being shipped to alumina refineries, which are generally located close to bauxite mines.

Unlike the base metal ores, bauxite does not require complex processing because most of the bauxite mined is of an acceptable grade. Ore quality can be improved by relatively simple and inexpensive processes for removing clay, known as “beneficiation”, which include washing, wet screening and mechanical or manual sorting. Beneficiating ore also reduces the amount of material that needs to be transported and processed at the refinery. However, the benefits of beneficiating need to be weighed against the amount of energy and water used in the process and the management of the fine wastes produced.

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Cement Production Manufacturing Proccess

Cement is a fine powder which sets after a few hours when mixed with water, and then hardens in a few days into a solid, strong material. Cement is mainly used to bind fine sand and coarse aggregates together in concrete.  Cement is a hydraulic binder, i.e. it hardens when water is added.

There are 27 types of common cement which can be grouped into 5 general categories and 3 strength classes: ordinary, high and very high.  In addition, some special cements exist like sulphate resisting cement, low heat cement and calcium aluminate cement.

The quarry is the starting point

Cement plants are usually located closely either to hot spots in the market or to areas with sufficient quantities of raw materials. The aim is to keep transportation costs low. Basic constituents for cement (limestone and clay) are taken from quarries in these areas.

A two-step process

Basically, cement is produced in two steps: first, clinker is produced from raw materials. In the second step cement is produced from cement clinker. The first step can be a dry, wet, semi-dry or semi-wet process according to the state of the raw material.

Making clinker

The raw materials are delivered in bulk, crushed and homogenised into a mixture which is fed into a rotary kiln. This is an enormous rotating pipe of 60 to 90 m long and up to 6 m in diameter. This huge kiln is heated by a 2000°C flame inside of it. The kiln is slightly inclined to allow for the materials to slowly reach the other end, where it is quickly cooled to 100-200°C. 

Four basic oxides in the correct proportions make cement clinker: calcium oxide (65%), silicon oxide (20%), alumina oxide (10%) and iron oxide (5%). These elements mixed homogeneously (called “raw meal” or slurry) will combine when heated by the flame at a temperature of approximately 1450°C. New compounds are formed: silicates, aluminates and ferrites of calcium. Hydraulic hardening of cement is due to the hydration of these compounds. 

The final product of this phase is called “clinker”. These solid grains are then stored in huge silos. End of phase one.

From clinker to cement

The second phase is handled in a cement grinding mill, which may be located in a different place to the clinker plant. Gypsum (calcium sulphates) and possibly additional cementitious (such as blastfurnace slag, coal fly ash, natural pozzolanas, etc.) or inert materials (limestone) are added to the clinker. All constituents are ground leading to a fine and homogenous powder. End of phase two. The cement is then stored in silos before being dispatched either in bulk or bagged.

What is concrete?

Concrete is a solid material made of cement, water, aggregates and often with admixtures. When fresh, it has a certain workability and takes the form of the mould into which it is put. When set and hardened, it is as strong as natural stone and resists time, water, frost, mechanical constraints and fire. Typically, concrete is the essential material used in all types of construction [residential (housing), non-residential (offices) and civil engineering (roads, bridges, etc.)].

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Geothermal Powerplant Energy

Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.

Almost everywhere, the shallow ground or upper 10 feet of the Earth's surface maintains a nearly constant temperature between 50° and 60°F (10° and 16°C). Geothermal heat pumps can tap into this resource to heat and cool buildings. A geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger-a system of pipes buried in the shallow ground near the building. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water.

In the United States, most geothermal reservoirs of hot water are located in the western states, Alaska, and Hawaii. Wells can be drilled into underground reservoirs for the generation of electricity. Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine. Hot water near the surface of Earth can be used directly for heat. Direct-use applications include heating buildings, growing plants in greenhouses, drying crops, heating water at fish farms, and several industrial processes such as pasteurizing milk.

Hot dry rock resources occur at depths of 3 to 5 miles everywhere beneath the Earth's surface and at lesser depths in certain areas. Access to these resources involves injecting cold water down one well, circulating it through hot fractured rock, and drawing off the heated water from another well. Currently, there are no commercial applications of this technology. Existing technology also does not yet allow recovery of heat directly from magma, the very deep and most powerful resource of geothermal energy.

Many technologies have been developed to take advantage of geothermal energy - the heat from the earth. NREL performs research to develop and advance technologies for the following geothermal applications:

Geothermal Energy Technologies:

• Geothermal Electricity Production
  Generating electricity from the earth's heat.
• Geothermal Direct Use
  Producing heat directly from hot water within the earth.
• Geothermal Heat Pumps
  Using the shallow ground to heat and cool buildings.

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Biomass Energy

Biomass energy or bioenergy - the energy from organic matter - for thousands of years, ever since people started burning wood to cook food or to keep warm.
And today, wood is still our largest biomass energy resource. But many other sources of biomass can now be used, including plants, residues from agriculture or forestry, and the organic component of municipal and industrial wastes. Even the fumes from landfills can be used as a biomass energy source.
The use of biomass energy has the potential to greatly reduce our greenhouse gas emissions. Biomass generates about the same amount of carbon dioxide as fossil fuels, but every time a new plant grows, carbon dioxide is actually removed from the atmosphere. The net emission of carbon dioxide will be zero as long as plants continue to be replenished for biomass energy purposes. These energy crops, such as fast-growing trees and grasses, are called biomass feedstocks. The use of biomass feedstocks can also help increase profits for the agricultural industry.

Biomass Energy technology applications:

• Biofuels
  Converting biomass into liquid fuels for transportation.
• Biopower
  Burning biomass directly, or converting it into a gaseous fuel or oil, to generate electricity.
• Bioproducts
  Converting biomass into chemicals for making products that typically are made from petroleum.

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Hydrogen Power System Fuel Cell

Hydrogen is the simplest element. An atom of hydrogen consists of only one proton and one electron. It's also the most plentiful element in the universe. Despite its simplicity and abundance, hydrogen doesn't occur naturally as a gas on the Earth - it's always combined with other elements. Water, for example, is a combination of hydrogen and oxygen (H₂O).

Hydrogen is also found in many organic compounds, notably the hydrocarbons that make up many of our fuels, such as gasoline, natural gas, methanol, and propane. Hydrogen can be separated from hydrocarbons through the application of heat - a process known as reforming. Currently, most hydrogen is made this way from natural gas. An electrical current can also be used to separate water into its components of oxygen and hydrogen. This process is known as electrolysis. Some algae and bacteria, using sunlight as their energy source, even give off hydrogen under certain conditions.

Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. NASA has used liquid hydrogen since the 1970s to propel the space shuttle and other rockets into orbit. Hydrogen fuel cells power the shuttle's electrical systems, producing a clean byproduct - pure water, which the crew drinks.

A fuel cell combines hydrogen and oxygen to produce electricity, heat, and water. Fuel cells are often compared to batteries. Both convert the energy produced by a chemical reaction into usable electric power. However, the fuel cell will produce electricity as long as fuel (hydrogen) is supplied, never losing its charge.

Fuel cells are a promising technology for use as a source of heat and electricity for buildings, and as an electrical power source for electric motors propelling vehicles. Fuel cells operate best on pure hydrogen. But fuels like natural gas, methanol, or even gasoline can be reformed to produce the hydrogen required for fuel cells. Some fuel cells even can be fueled directly with methanol, without using a reformer.

In the future, hydrogen could also join electricity as an important energy carrier. An energy carrier moves and delivers energy in a usable form to consumers. Renewable energy sources, like the sun and wind, can't produce energy all the time. But they could, for example, produce electric energy and hydrogen, which can be stored until it's needed. Hydrogen can also be transported (like electricity) to locations where it is needed.
Flowing water creates energy that can be captured and turned into electricity. This is called hydroelectric power or hydropower.
The most common type of hydroelectric power plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine.
Another type of hydroelectric power plant - called a pumped storage plant - can even store power. The power is sent from a power grid into the electric generators. The generators then spin the turbines backward, which causes the turbines to pump water from a river or lower reservoir to an upper reservoir, where the power is stored. To use the power, the water is released from the upper reservoir back down into the river or lower reservoir. This spins the turbines forward, activating the generators to produce electricity.
A small or micro-hydroelectric power system can produce enough electricity for a home, farm, or ranch.

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