U.S. Spending $50 Million to Hasten Offshore Wind Power

U.S. Spending $50 Million to Hasten Offshore Wind Power
Source: fastcompany
Cape Wind, the first offshore wind project in the U.S., has languished in regulatory limbo for a decade--and construction still hasn't begun. That's not an encouraging track record for offshore wind developers. The Department of Energy hopes to change it, however, with the National Offshore Wind Strategy: Creating an Offshore Wind Industry in the United States, a $50.5 million, five-year comprehensive plan to turn the U.S. into an offshore wind powerhouse. The goal is to develop 54 gigawatts of offshore wind generating capacity by 2030 at a cost of seven cents per kilowatt hour. That's just a few cents more expensive than many fossil fuel-based sources.
The DOE's plan consists of three steps: technology development ($25 million to build better wind turbine design tools and hardware), removing market barriers ($18 million to find the factors limiting offshore wind deployment), and building next generation drivetrains ($7.5 million to make more advanced wind turbine drivetrains).
The U.S. may actually start building offshore wind farms, too. As part of the offshore plan, the DOE identified spots in four states for expedited wind power approval. Delaware, Maryland, New Jersey, and Virginia--all states with over a hundred nautical miles for development--will get early environmental reviews to ease the regulatory process. If all goes well, the DOE expects to give leases to energy developers by the end of the year.
The National Offshore Wind Strategy is the latest in the DOE's plan to supercharge American renewable energy capacity. Last week, the DOE announced the SunShot initiative, a $27 million program to make solar energy as cheap as fossil fuel-generated energy by 2020.

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Solar energy

Energy from sun can be harvested in number of ways. One of the easiest and way is to trap heat directly from sun and use it for water heating. Heated water can be used for residential or industrial purposes. Solar energy can also be converted into electricity. Conversion is done by following two methods.

1.      Solar photovoltaic

2.      Solar thermal

Photovoltaic converts sunlight directly into electricity using PV panels.

Solar thermal uses lenses or reflector to concentrate sunlight heating water to convert into steam and propelling turbine.

Solar energy conversion has a unique characteristic from other conversions. Unlike other methods sunlight converts directly into electrical energy using PV without involving mechanical transformation. Solar energy can also be used directly heating water for residential use. Compared to other methods of electricity production it is a new concept and expansive. A lot of research is carried out to reduce the cost where it can become affordable for domestic use.

Solar energy can also be used for cooking and pasteurization. Solar cooker size ranges from small home cooker to large industrial ones. Solar bowl technology employed by the Solar Kitchen in India. A spherical reflector focuses light along a line perpendicular to the sphere's interior surface, a computer controlled system moves the receiver to intersect this line. Steam is produced in the receiver at temperatures reaching 150 °C and then used for cooking in the kitchen.

Solar energy can be used for water treatment to produce drinkable water from saline or brackish water. Water filled plastic bottles are exposed to sun light for hours. Sunlight treats the contaminated water through two synergetic mechanisms: Radiation in the spectrum of UV-A (wavelength 320-400nm) and increased water temperature. If the water temperatures raise above 50°C, process is three times faster.

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Micro hydro

Source wikipedia

Micro hydro is a term used for hydroelectric power installations that typically produce up to 100 kW of power. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without purchase of fuel.

Micro hydro systems complement photovoltaic solar energy systems because in many areas, water flow, and thus available hydro power, is highest in the winter when solar energy is at a minimum.

Micro hydro is frequently accomplished with a pelton wheel for high head, low flow water supply. The installation is often just a small dammed pool, at the top of a waterfall, with several hundred feet of pipe leading to a small generator housing.

Construction & characteristics

A penstock pipe used in an Afghanistan micro-hydro project
Construction details of a microhydro plant are site-specific, but the common elements of all hydroelectric plants are present. A supply of water is needed — this can be a mountain stream, or a river. Usually microhydro installations do not have a dam and reservoir, relying on a minimal flow of water to be available year-round. Sometimes an existing mill-pond or other artificial reservoir is available and can be adapted for power production. An intake structure is required to screen out floating debris and fish, using a screen or array of bars to keep out large objects. In temperate climates this structure must resist ice as well. The intake may have a gate to allow the system to be dewatered for inspection and maintenance.
Water withdrawn from the source must move along a power canal or a pipe (penstock) to the turbine. If the water source and turbine are far apart, the construction of the penstock may be the largest part of the costs of construction. In mountainous areas, access to the route of the penstock may provide considerable challenges.
At the turbine, a controlling valve is installed to regulate the flow and the speed of the turbine. The turbine converts the flow and pressure of the water to mechanical energy; the water emerging from the turbine returns to the natural watercourse along a tailrace channel.
The turbine turns a generator, which is then connected to electrical loads; this might be directly connected to the power system of a single building in very small installations, or may be connected to a community distribution system for several homes or buildings.

Regulation & operation

Typically, an automatic controller operates the turbine inlet valve to maintain constant speed (and frequency) when the load changes on the generator. In a system connected to a grid with multiple sources, the turbine control ensures that power always flows out from the generator to the system. The frequency of the alternating current generated needs to match the local standard utility frequency. In some systems, if the useful load on the generator is not high enough, a load bank may be automatically connected to the generator to dissipate energy not required by the load; while this wastes energy, it may be required if its not possible to stop the water flow through the turbine.
An induction generator always operates at the grid frequency irrespective of its rotation speed; all that is necessary is to ensure that it is driven by the turbine faster than the synchronous speed so that it generates power rather than consuming it. Other types of generator require a speed control systems for frequency matching.
With the availability of modern power electronics it is often easier to operate the generator at an arbitrary frequency and feed its output through an inverter which produces output at grid frequency. Power electronics now allow the use of permanent magnet alternators that produce wild AC to be stabilised. This approach allows low speed / low head water turbines to be competitive; they can run at the best speed for extraction of energy, and the power frequency is controlled by the electronics instead of the generator.
Very small installations, a few kilowatts or smaller, may generate direct current and charge batteries for peak use times.

Turbine types

Several different types of water turbines can be used in micro hydro installations, selection depending on the head of water, the volume of flow, and such factors as availability of local maintenance and transport of equipment to the site. For mountainous regions where a waterfall of 50 meters or more may be available, a Pelton wheel can be used. For low head installations, Francis or propeller-type turbines are used. Very low head installations of only a few meters may use propeller-type turbines in a pit. The very smallest micro hydro installations may successfully use industrial centrifugal pumps, run in reverse as prime movers; while the efficiency may not be as high as a purpose-built runner, the relatively low cost makes the projects economically feasible.
In low-head installations, maintenance and mechanism costs often become important. A low-head system moves larger amounts of water, and is more likely to encounter surface debris. For this reason a Banki turbine, a pressurized self-cleaning crossflow waterwheel, is often preferred for low-head microhydropower systems. Though less efficient, its simpler structure is less expensive than other low-head turbines of the same capacity. Since the water flows in, then out of it, it cleans itself and is less prone to jam with debris.
Two low-head schemes in England, Settle Hydro and Torrs Hydro use a reverse Archimedes' screw which is another debris-tolerant design. Other options include Gorlov, Francis and propeller turbines.

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Types of Green Energy

This article describes the different types of “green energy” that are currently being used as alternative sources of power.

1.      Hydropower

2.      Geothermal

3.      Biomass

4.      Wind

5.      Solar

Hydro Power

Hydro Power converts energy stored in water to mechanical. Potential energy stored in water is converted in electrical using turbines. Water is stored in large quantity in dams; spillways are installed to control flow of water to turbines. Fast flowing water spins wings of turbine and energy transformation takes place.

Geothermal

Geothermal energy is harvested by tapping heat produced by earth. Geothermal energy is available all over the earth but it is very expansive to put it to work. At place geothermal energy is closer to surface of earth. At these points naturally produced steam or hot water can be tapped easily. Steam or heat is used to spin turbine and electricity is produced. Such natural points exist in US, Philippines, Italy and Pakistan. US has successfully installed Geothermal power plant in California.

Wind

Wind can be used to produce energy by turning large fan like blades around a hub. Wings turn at slow but steady rate at high torque. Slow rotation is converted to high rotation using gears. Gear box is attached to generator produces electricity. Modern wind turbines can produce 600KW-5 MW. Wind turbines are suitable for areas with high wind resources.

Biomass

Biomass is also considered as renewable energy because concentrated energy comes from sun. Energy capturing process is called photosynthesis. This form of energy is not completely green energy because when plants are burned to release energy they produce pollution as well.

Solar

Energy from the sun put to work in any form is solar energy. Solar energy can be used to heat up water for commercial and residential use. Solar energy can be converted into electrical energy. Photovoltaic cells can absorb light from sun excite electron to create a flow of current. Commercially available PVs are still expansive and cannot work when sun is down. Another way to capture solar energy is to concentrate it using mirrors at a boiler unit, produce steam to run turbine. This method needs sun tracker system to focus sunlight at one point.

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