Today's technological advancements have developed more efficient means of harnessing and using renewable energy sources, and these sources are gaining increasing popularity.

They offer us alternatives to nonrenewable energy sources such as oil, coal and natural gas which, when burned can cause acid rain and contribute to the overall warming of the Earth known as the " Greenhouse Effect ." Existing renewable energy installations are making significant contributions to the US energy supply, and research activities are demonstrating the far-reaching impact that a greater reliance on renewable energy sources could have on our country's energy security. In addition, on-going and planned research offers still more possibilities.

 

Solar Power

Solar PowerThere are so many incredible benefits that are offered by solar energy. It is time to take advantage of solar panels for your home.

Solar thermal systems need sunlight rather than the more diffuse light which can be harnessed by solar PV. A solar thermal power plant has a system of mirrors to concentrate the sunlight on to an absorber, the energy then being used to drive turbines – concentrating solar thermal power (CSP).

About 2.55 GWe of CSP capacity worldwide (end of 2012), three-quarters of this in Spain, supplies a proportion of the solar electricity. More CSP is under development . 

Solar energy producing steam can be used to boost conventional steam-cycle power stations.

Solar is renewable until the sun goes red giant and gobbles us up in a few billion years. Nuclear is as renewable as the actinide elements & water present in any rocky/watery body in any solar system in any galaxy. Geothermal, by the way, is nuclear.

The Solar industry should stop competing directly with base load generation and focus on the applications where solar and PV truly make sense. The sun doesn't always shine and the wind does not always blow so we do need base load power that is always on line.

By 2030, solar will be cheaper than fossil fuel and batteries will be good enough to run your car... and your house overnight. Are we to believe people won't convert on a massive scale without any government intervention? And we don't need 100% conversion. 90% or 80% would be fine.

Industry, also, will want cheaper electricity, and so will convert. It's a done deal, the obstacles will melt away. Also, it snowballs once it starts to get going, as with the utilities in Germany. So it's already happening, and the USA will be like Germany in 2025.

Like wind and solar, landfill-gas is a renewable source of energy endorsed by the Environmental Protection Agency as an alternative to fossil fuels, like natural gas, coal and oil. Using landfills, we produce over 550 megawatts of electricity, which is enough to power moresolar-panels than 440,000 homes. This amount of energy is equivalent to offsetting over 2.2 million tons of coal per year.

A significant role of solar energy is that of direct heating . Much of our energy need is for heat below 60 o C, eg. in hot water systems. A lot more, particularly in industry, is for heat in the range 60-110 o C.

 

Together these may account for a significant proportion of primary energy use in industrialized nations. The first need can readily be supplied by solar power much of the time in some places, and the second application commercially is probably not far off. Such uses will diminish to some extent both the demand for electricity and the consumption of fossil fuels, particularly if coupled with energy conservation measures such as insulation.

After years of hoopla, wind and solar combined produce less than 1% of the world's energy. It now appears that renewables may remain permanently insignificant.

However, a distinct advantage of solar and to some extent other renewable systems is that they are distributed and may be near the points of demand, thereby reducing power transmission losses if traditional generating plants are distant.

Of course, this same feature sometimes counts against wind in that the best sites for harnessing it are sometimes remote from population, and the main back-up for lack of wind in one place is wind blowing hard in another, hence requiring a wide network with flexible operation.

Wind Energy

Wind energy is an excellent and abundant renewable resource. The same winds that rustles leaves and turn umbrellas inside out can be harnessed to spin turbines and produce electricity. Learn about the wind resources in and around San Francisco, how wind turbines work, and what role wind energy can play in helping San Francisco achieve its renewable energy goals.

Renewable-EnergyWind technology is one of the fastest growing industries in the United States. With a high demand for green energy, we can help you gain the skills to succeed as a Wind Turbine Technician while making the world a better place.

Wind turbines have a high steel tower to mount the generator nacelle, and have rotors with three blades up to 50m long. Foundations require a substantial mass of reinforced concrete. Hence the energy inputs to manufacture are not insignificant. Also siting is important in getting a net gain from them.

In the UK the Carbon Trust found that small wind turbines on houses in urban areas often caused more carbon emissions in their construction and fitting than they saved in electrical output.

Wind technology is one of the fastest growing industries in the country. With a high demand for green energy, we can help you gain the skills to succeed as a wind turbine technician, while making the world a better place.

Wind turbines of up to 6 MWe are now functioning in many countries, though most new ones are 1-3 MWe. The power output is a function of the cube of the wind speed, so doubling the wind speed gives eight times the energy potential.

In operation such turbines require a wind in the range 4 to 25 metres per second (14-90 km/hr), with maximum output being at 12-25 m/s (the excess energy being spilled above 25 m/s). While relatively few areas have significant prevailing winds in this range, many have enough to be harnessed effectively and to give better than a 25% capacity utilization.

Wind power is hardly much better. According to the Nature Conservancy, it takes 30 times the land for windmills to produce as much electricity as a nuclear power plant.

The wind blows more over night, and wind and solar compliment each other quite well. There are several other methods of storage, including pumped hydro and grid batteries and underground compressed air and flywheels. EV batteries once they become common enough can also be used to store electricity.

Sun, wind, waves, rivers, tides and the heat from radioactive decay in the earth's mantle as well as biomass are all abundant and ongoing, hence the term "renewables". Only one, the power of falling water in rivers, has been significantly tapped for electricity for many years, though utilization of wind is increasing rapidly and it is now acknowledged as a mainstream energy source.

Solar energy's main human application has been in agriculture and forestry, via photosynthesis, and increasingly it is harnessed for heat. Electricity remains a niche application for solar. Biomass (eg sugar cane residue) is burned where it can be utilised. The others are little used as yet.

Like wind and solar, landfill-gas is a renewable source of energy endorsed by the Environmental Protection Agency as an alternative to fossil fuels, like natural gas, coal and oil. Using landfills, we produce over 550 megawatts of electricity, which is enough to power more than 440,000 homes. This amount of energy is equivalent to offsetting over 2.2 million tons of coal per year.

Because wind turbine output is so variable, for planning purposes its potential output is discounted to the level of power that can be relied upon for 90% of the time. In Australia that figure comes to 7% of installed wind capacity, in Germany it is 8%, which is all that can be included as securely available (ie 90% of the time).* On the 90% availability basis, other technologies can be counted on for much higher reliability, and hence the investment cost per kilowatt reliably available is much less.

Offshore wind turbines harness kinetic energy of moving air over oceans and convert it to electricity. Currently there are no offshore wind facilities in the U.S. There are permit applications offshore Nantucket Island (MA) and Long Island (NY) in federal waters and off Texas in state waters. There are other proposals offshore (state and/or federal waters) for Rhode Island, New Jersey and Delaware.

Additionally, solar and wind locations can be design in such a way that they can still be used for agriculture and other uses. It's awfully hard to work up numbers on land use when the land is being used in two or three ways.

Today we are well advanced in meeting that challenge. Wind turbines have developed greatly in recent decades, solar photovoltaic technology is much more efficient, and there are improved prospects of harnessing tides and waves. Solar thermal technologies in particular (with some heat storage) have great potential in sunny climates. With government encouragement to utilize wind and solar technologies, their costs have come down and are now in the same league as the increased costs of fossil fuel technologies due to likely carbon emission charges on electricity generation from them.