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Fuel Cell Principle A fuel cell is an electrochemical energy converter. It converts chemical energy into electrical energy by two separated electrochemical reactions. In a hydrogen-fuelled polymer electrolyte membrane fuel cell (PEMFC), hydrogen is oxidised to protons and electrons at the anode. Protons migrate through the membrane electrolyte to the cathode. As the membrane is an electric insulator, electrons are forced to flow in an external electric circuit. At the cathode, oxygen reacts with protons to produce water, which is the only waste product

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

Ocean waves are caused by the wind as it blows across the sea. Waves are a powerful source of energy.

How it works There are several methods of getting energy from waves. One of them works like a swimming pool wave machine in reverse. At a swimming pool, air is blown in and out of a chamber beside the pool, which makes the water outside bob up and down, causing waves.   At a wave power station, the waves arriving cause the water in the chamber to rise and fall, which means that air is forced in and out of the hole in the top of the chamber. We place a turbine in this hole, which is turned by the air rushing in and out. The turbine turns a generator.

Once you've built a wave power station, the energy is free, needs no fuel and produces no waste or pollution.

Wind is simply air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. One example of this uneven heating can be found in the daily wind cycle.

The Daily Wind Cycle During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating wind. At night, the winds are reversed because the air cools more rapidly over land than over water. In the same way, the atmospheric winds that circle the earth are created because the land near the Earth's equator is heated more by the sun than the land near the North and South Poles. Wind Energy for Electricity Generation Today, wind energy is mainly used to generate electricity. Wind is a renewable energy source because the wind will blow as long as the sun shines

Like old fashioned windmills, today’s wind machines (also called wind turbines) use blades to collect the wind’s kinetic energy. The wind flows over the blades creating lift, like the effect on airplane wings, which causes them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity. With the new wind machines, there is still the problem of what to do when the wind isn't blowing. At those times, other types of power plants must be used to make electricity.

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.

Method Cents/kW-h Limitations and Externalities WindCurrently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable. 4.0 - 6.0 Cents/kW-h Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power. GeothermalCurrently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable. 4.5 - 30 Cents/kW-h New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock. HydroCurrently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable. 5.1 - 11.3 Cents/kW-h Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems. SolarCurrently supplies approximately 0.8% of the global electricity demand. 15 - 30 Cents/kW-h Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.

Tide 2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.

Method Cents/kW-h Limitations and Externalities GasCurrently supplies around 15% of the global electricity demand. 3.9 - 4.4 Cents/kW-h Gas-fired plants and generally quicker and less expensive to build than coal or nuclear, but a relatively high percentage of the cost/KWh is derived from the cost of the fuel. Due to the current (and projected future) upwards trend in gas prices, there is uncertainty around the cost / KWh over the lifetime of plants. Gas burns more cleanly than coal, but the gas itself (largely methane) is a potent greenhouse gas. Some energy conversions to calculate your cost of natural gas per kwh. 100 cubic feet (CCF)~ 1 Therm = 100,000 btu ~ 29.3 kwh. CoalCurrently supplies around 38% of the global electricity demand. 4.8 - 5.5 Cents/kW-h Increasingly difficult to build new coal plants in the developed world, due to environmental requirements governing the plants. Growing concern about coal fired plants in the developing world (China, for instance, imposes less environmental overhead, and has large supplies of high sulphur content coal). The supply of coal is plentiful, but the coal generation method is perceived to make a larger contribution to air pollution than the rest of the methods combined.

According to the government, geothermal has the potential to supply the United States with 20% of our electricity needs.

The capital cost of geothermal development is expensive, however; 2/3rds are drilling costs. Yet as we overcome some of these technology challenges and make the process more standardized it is believed that geothermal can supply up to 20% of the United States electricity needs by 2050. But innovation and investment in initial steps need to happen now.

Over 19,000 MW of non-residential PV project applications have been approved under its FiT scheme as of the end of May.

Over 19,000 MW of non-residential PV project applications have been approved under its FiT scheme as of the end of May.

With a 2013 forecast of 8.5 GW and 7 GW respectively, China and Japan are on pace to be the top installers this year. PV installations in the United States continue to grow and are forecasted to reach approximately 4.5 GW in 2013. Other major markets forecasted in 2013 are Germany at 4 GW, Italy at 2 GW, UK at 1.5 GW and India at 1 GW.

The Life-cycle greenhouse-gas emissions of solar power are in the range of 22 to 46  g/kWh depending on if solar thermal or solar PV is being analyzed, respectively. With this potentially being decreased to 15 g/kWh in the future.[71] For comparison (of weighted averages), a combined cycle gas-fired power plant emits some 400-599 g/kWh,

Organic matter is one such source. Materials like corn and soybeans have oil extracts that can be converted to ethanol or biodiesel

more sustainable than petroleum, meaning they can be regrown and remain productive with less negative impact on our ecosystem.

Some biofuels that provide more long-term benefits may prove too expensive to pursue

Unlike fossil fuel power plants, no smoke is emitted from geothermal power plants, because no burning takes place; only steam is emitted from geothermal facilities. Emissions of nitrous oxide, hydrogen sulfide, sulfur dioxide, particulate matter, and carbon dioxide are extremely low, especially when compared to fossil fuel emissions. The binary geothermal plant, which currently represents around 15% of all geothermal plant capacity, along with the flash/binary plant, produce nearly zero air emissions. Even dry steam plants, which are considered to have the highest levels of air emissions, are considered environmentally benign compared with fossil fuels. For example, Lake County, California, downwind of The Geysers, has met all federal and state ambient air quality standards for almost 25 years. There are 21 power plants at The Geysers, comprising a significant complex of electric generation facilities, yet even despite this, air quality is excellent. At The Geysers, air quality has even improved as a result of geothermal development because hydrogen sulfide, which would ordinarily be released naturally into the atmosphere by hot springs and fumaroles, instead now passes through an abatement system that reduces hydrogen sulfide emissions by 99.9%. (1) See also Myth #2.

1) Individual silicon based (most commonly) cells called photovoltaics (PV) make up the modern day solar panel. These PV cell clusters perform the task of converting incoming sunlight directly into electricity. 2) Wires attached to the panels transport the converted electricity to a piece of equipment called an inverter. The job of the inverter is to convert the solar generated Direct Current (DC) electricity into the type of power your home can use, which is called Alternating Current (AC). 3) After the electricity travels through the inverter, the AC electricity is then transported via wire to your breaker panel to meet your home’s electric demands. 4) The process doesn’t end there, though. There are times when your panels will generate more power than you consume and times when you aren’t generating enough electricity (night times and periods of low light). When your panels are not generating enough solar electricity, you will continue to get power from your local utility. However, when you’re generating a surplus of solar electricity, that excess clean energy will be “net metered” to your local utility grid and you may earn a credit on your power bill for that net metered electricity.

Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings.

At a geothermal power plant, wells are drilled 1 or 2 miles deep into the Earth to pump steam or hot water to the surface.

hot springs, geysers, or volcanic activity, because these are places where the Earth is particularly hot just below the surface.

The Pelamis is an offshore wave energy converter that uses the motion of waves to generate electricity.

The machine operates in water depths greater than 50m and is typically installed 2-10km from the coast. The machine is rated at 750kW with a target capacity factor of 25-40 per cent, depending on the conditions at the chosen project site. On average one machine will provide sufficient power to meet the annual electricity demand of approximately 500 homes.

The Pelamis machine is made up of five tube sections linked by universal joints which allow flexing in two directions. The machine floats semi-submerged on the surface of the water and inherently faces into the direction of the waves. As waves pass down the length of the machine and the sections bend in the water, the movement is converted into electricity via hydraulic power take-off systems housed inside each joint of the machine tubes, and power is transmitted to shore using standard subsea cables and equipment.