With low emissions of pollutants such as nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter as well as dramatically lower emissions of carbon dioxide (CO2),

CostChief among the problems associated with fuel cells is how expensive they are. Many of the component pieces of a fuel cell are costly.

InfrastructureIn order for PEMFC vehicles to become a viable alternative for consumers, there must be a hydrogen generation and delivery infrastructure. This infrastructure might include pipelines, truck transport, fueling stations and hydrogen generation plants

The best known early fuel cell experiments were performed in 1842 by the British physicist and lawyer, Sir William R. Grove (1811-1896)

Due to easily accessible and large amounts of oil and the invention of the combustion engine (Carl Friedrich Benz and Gottlieb Daimler), fuel cells were forgotten until the middle of the 20th century. In the US Apollo space programme, fuel cells exhibited their first renaissance in the 1960’s. 

Fuel cell development has been slowed down by a fear of hydrogen as a fuel. It is commonly believed that hydrogen is an extremely explosive and dangerous gas. Most of this belief was founded in 1937, when the hydrogen-filled zeppelin “Hindenburg” caught fire and crashed in Lakehurst, USA.

One of the first applications for fuel cells based on their advantageous properties was in the US space program.

Compared to IC engines, fuel cells have practically no polluting exhaust like NOx and sulphides.

It is generally acknowledged that the feasibility and durability of fuel cells in automobiles has been proven. The major focus now is on cost reduction

Tides are caused by the gravitational pull of the moon and sun, and the rotation of the Earth. Near shore, water levels can vary up to 40 feet due to tides. Dam of the Tidal Power Plant on the Estuary of the Rance River, Bretagne, France Source: Stock photography (copyrighted) Tidal power is more predictable than wind energy and solar power. A large enough tidal range — 10 feet — is needed to produce tidal energy economically.

The United States has no tidal plants and only a few sites where tidal energy could be produced economically. France, England, Canada, and Russia have much more potential to use this type of energy.

Tidal turbines are basically wind turbines in the water that can be located anywhere there is strong tidal flow. Because water is about 800 times denser than air, tidal turbines have to be much sturdier than wind turbines. Tidal turbines are heavier and more expensive to build but capture more energy.

Where Does Tidal Energy Come From? The gravitational force of the Earth stops the ocean from floating off into space, just like everything else. The Moon also has a very weak gravitational effect on the Earth, which is not normally noticable as far as falling teacups are concerned, but the ocean, which can flow around the globe to even out differences, is noticably affected.

Can Already Cost Under $.06 per Kilowatt Hour * Pneumatic devices, such as the oscillating water column (OWC), use wave motion to compress and decompress air, and drive a turbine. * Float-based devices utilise a buoyant float moving with the waves, reacting against a sea bed anchor in order to harness energy. * Spillover devices utilise wave height to replenish a reservoir of seawater, which runs a turbine. * Raft-type devices use the relative motion of adjacent rafts or pontoons to harness wave energy. * Moving-body devices articulate in the water, inducing motion, which may be used to drive a hydraulic motor.

Tidal stream devices extract energy from the diurnal flow of tidal currents (caused by the gravitational pull of the moon). Unlike wind and wave power, tidal streams offer entirely predictable output. However, as the lunar cycle is of around 25 hours’ duration, the timing of peak outputs differs by around an hour each day and tidal energy cannot be guaranteed at times of peak demand.

However, several large grid-connected demonstration projects are expected to enter the water in the near future. Tidal stream is thus a few years behind wave energy.

Waves are generated by wind passing over the surface of the sea. As long as the waves propagate slower than the wind speed just above the waves, there is an energy transfer from the wind to the waves.

The first known patent to utilize energy from ocean waves dates back to 1799 and was filed in Paris by Girard and his son.[12] An early application of wave power was a device constructed around 1910 by Bochaux-Praceique to light and power his house at Royan, near Bordeaux in France

Once the wave energy is captured at a wave source, power must be carried to the point of use or to a connection to the electrical grid by transmission power cables.[2

ocean waves is long considered substantive kinetic resource

Ocean waves are a tertiary form of solar energy, in that unequal heating of the Earth’s surface generates wind, and wind blowing over water generates waves. Despite the fact that nearly 75% of the Earth’s surface is covered with water, waves are a largely unexplored source of energy, compared with the progress that has been made in harnessing the sun and wind.

What is wave energy? Waves are generated by the passage of wind across the surface of the sea.  Energy is transferred from the wind to the waves.  Waves travel vast distances across the ocean and at great speed and the energy is concentrated near the water surface.  The energy within a wave is proportional to the square of the wave height.  Therefore a two-meter high wave has four times the power of a one-meter high wave. The longer and stronger the wind blows over the surface of the sea, the higher, longer, faster and more powerful the sea is.

Although wave energy is a form of concentrated wind energy, as it has often travelled over large distances it is regularly out of phase with the local wind conditions.  Wave energy can therefore help to balance output variability from other renewable sources and maximise the efficient use of the electricity networks.   Wave energy is also more predictable than many other forms of renewable energy, such as wind or solar, and can be forecast accurately up to five days in advance.

Wave energy is clean and renewable!  It is one of the last renewable energy forms which mankind has yet to harness, and its potential is huge.

Big cities need large amounts of electricity to function. Often, this is transported from generating sites located in remote areas hundreds or even thousands of kilometers away. The question is how to move as much electricity as possible from renewable generation sites like hydro plants and wind parks without impairing the function of the power networks that need it.

One of the challenges of renewable power generation like wind and solar power is that it can be interrupted, and this variability affects the stability of the power produced

The "smart grid" will create a power network that is more reliable, flexible, secure and efficient

The cost of producing ethanol varies with the cost of the feedstock used and the scale of production. Approximately 85 percent of ethanol production capacity in the United States relies on corn feedstock. The cost of producing ethanol from corn is estimated to be about $1.10 per gallon.

Because a gallon of ethanol contains less energy than a gallon of gasoline, the production cost of ethanol must be multiplied by a factor of 1.5 to make an energy-cost comparison with gasoline. This means that if ethanol costs $1.10 per gallon to produce, then the effective cost per gallon to equal the energy contained in a gallon of gasoline is $1.65. In contrast, the current wholesale price of gasoline is about 90 cents per gallon.

A major hurdle facing commercial biodiesel production is the cost of producing the fuel. Vegetable oil seed procurement, transport, storage and oil extraction accounts for at least 75 percent of the cost of producing biodiesel. The cost varies depending on the feedstock used. For example, based on the market price for industrial rapeseed grown in Washington and Idaho, the estimated cost of producing biodiesel is $2.56 per gallon of rapeseed methyl ester. Recent estimates put the cost of production in the range of $1.30 per gallon (using waste grease feedstock) to $2.00 or more per gallon using soybean oil.

"Our study found that any biofuel that causes clearing of natural ecosystems will increase global warming," Joe Fargione, a scientist for The Nature Conservancy, told CTV.ca.

He said converting natural areas into croplands results in tons of carbon being emitted into the atmosphere -- a carbon 'debt' that outweighs any benefits.

The first tidal power station was the Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France.[8] It has 240 MW installed capacity.

Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The incoming water was contained in large storage ponds, and as the tide went out, it turned waterwheels that used the mechanical power it produced to mill grain. [1] The earliest occurrences date from the Middle Ages, or even from Roman times.[2][3] It was only in the 19th century that the process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe.[

Tidal energy use harnesses the water flow created primarily by the moon orbiting the Earth. As water is pulled toward the gravity of the moon, currents are created that can turn generator turbines.

Tidal energy use involving dams creates many of the same environmental concerns as damming rivers. Tidal dams restrict fish migration and cause silt build up which affects tidal basin ecosystems in negative ways. Systems that take advantage of natural narrow channels with high tidal flow rates have less negative environmental impact than dammed systems. But they are not without environmental problems. Both systems use turbines that can cause fish kills. But these are being replaced by new, more fish friendly turbines. The art and science of environmentally friendly hydro engineering is well advanced and will certainly be applied to any tidal energy project.

Because of intermittency and variable flow problems of tidal energy, it is a very limited resource. The DOE Tidal Energy link, above, states that there are only about 40 really good sites on Earth with high enough flows to be considered economically practical

Tidal energy is one of the oldest forms of energy used by humans. Indeed, tide mills, in use on the Spanish, French and British coasts, date back to 787 A.D.. Tide mills consisted of a storage pond, filled by the incoming (flood) tide through a sluice and emptied during the outgoing (ebb) tide through a water wheel. The tides turned waterwheels, producing mechanical power to mill grain. We even have one remaining in New York- which worked well into the 20th century.

Tidal power is non-polluting, reliable and predictable.Tidal barrages, undersea tidal turbines - like wind turbines but driven by the sea - and a variety of machines harnessing undersea currents are under development. Unlike wind and waves, tidal currents are entirely predictable.

A tidal range of at least 7 m is required for economical operation and for sufficient head of water for the turbines

The United States has enough wind resources to generate electricity for every home and business in the nation. But not all areas are suitable for wind energy development.

What is wind energy? Wind energy (or wind power) refers to the process by which wind turbines convert the movement of wind into electricity. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Humans use this wind flow for many purposes: sailing boats, pumping water, and also generating electricity. Wind turbines convert the kinetic energy of the moving wind into electricity.

Birds and bats are occasionally killed in collisions with wind turbines. Like any form of development, wind projects can also negatively impact wildlife by altering habitat. Over the past two decades, the impact of wind development on birds has been greatly reduced by improvements in turbine design and particularly through improved project and turbine siting.

Advantages

Solar energy is free - it needs no fuel and produces no waste or pollution.

Handy for low-power uses such as solar powered garden lights and battery chargers, or for helping your home energy bills.