First lets look at what we are using currently to meet our energy needs, coal and nuclear energy, and how ecologically damaging they are.

To start, most existing coal plants release many different toxins directly into the air we breathe, from sulfur to lead and mercury. Even the newer plants coming on line, which reduce toxins dramatically, still produce massive quantities of CO2, a greenhouse gas and a direct cause of global warming. Natural gas is far more benign but still produces large quantities of CO2 when used to produce electricity. How much CO2 is released – a 5-kilowatt solar system will prevent the release of nearly 10,400 pounds of CO2 every year for the life of the system. The average home uses 8,000-kilowatt hours per year. A coal power plant producing that much electricity emits about 18,000 pounds of CO2 per year.

When coal is burned, carbon dioxide, sulfur dioxide, nitrogen oxides, and mercury compounds are released. For that reason, coal-fired boilers are required to have control devices to reduce the amount of emissions that are released. Mining, cleaning, and transporting coal to the power plant generate additional emissions. For example, methane, a potent greenhouse gas that is trapped in the coal, is often vented during these processes to increase safety.

Secondly, large quantities of water are needed to remove impurities from coal at the mine. These large quantities of water are used for producing steam and for cooling systems. When coal-fired power plants remove water from a lake or river, the fish and other aquatic life can be affected, as well as animals and people who depend on these aquatic resources. At the same time, pollutants build up in the water used by the power plant boiler and cooling system. If the water used in the power plant is discharged to a lake or river, the pollutants in the water can harm fish and plants.

Last, the burning of coal creates solid waste, called ash, which is composed primarily of metal oxides and alkali. On average, the ash content of coal is 10 percent. Solid waste is also created at coal mines when coal is cleaned and at power plants when air pollutants are removed from the stack gas. Much of this waste is deposited in landfills and abandoned mines, although some amounts are now being recycled into useful products, such as cement and building materials.

So, you may say, what about nuclear power? While nuclear power plants do not emit carbon dioxide, sulfur dioxide, or nitrogen oxides – fossil fuel emissions are associated with the uranium mining and uranium enrichment process as well as the transport of the uranium fuel to the nuclear plant. Nuclear power plants also use large quantities of water for steam production and for cooling. When nuclear power plants remove water from a lake or river, fish and other aquatic life can be affected. Water pollutants, such as heavy metals and salts build up in the water used in the nuclear power plant systems. These water pollutants, as well as the higher temperature of the water discharged from the power plant, can negatively affect water quality and aquatic life.

Waste generated from uranium mining operations and rainwater runoff can contaminate groundwater and surface water resources with heavy metals and traces of radioactive uranium. Every 18 to 24 months, nuclear power plants must shut down to remove and replace the “spent” uranium fuel. This spent fuel has released most of its energy as a result of the fission process and has become radioactive waste.

All of the nuclear power plants in the United States together produce about 2,000 metric tons per year of radioactive waste. Currently, the radioactive waste is stored at the nuclear plants at which it is generated, either in steel-lined, concrete vaults filled with water or in above-ground steel or steel-reinforced concrete containers with steel inner canisters. This waste will remain radioactive for many thousands of years.

As you can see, the more solar power is used, the more it helps our environment. By investing in solar today you are investing in your future and your children’s future and you do this by combating global warming and reduce our nation’s dependence of foreign energy sources. And, you are helping in the reduction of CO2 emissions and protecting clean water sources. It’s amazing how such a small change in one’s life can do so much. ARI Green Energy is a manufacturer of wind generator technologies. Visit them today for a full line of wind turbines and solar technology solutions. Think green.

Article Source: http://www.articlealley.com/article_830778_45.html

About the Author:  Author: Robert Bell

We want to look at the needs of energy of the United States and the world and compare with the practical size installations of solar power stations needed to replace that.

The question of completely replacing all fossil fuel or all other sources of electricity and other energy is much more complex than just looking at the numbers. Probably replacing the other sources in just electricity production is simpler but still in addition to simply adding capacity, changes of large scale are needed in the national grid configuration.

Replacing resources used to produce other energy, other than electricity, is even more complex. That will mean changing how energy is being transported and used. While electricity is a type of energy easy to transport what may  need to be changed is the way it is utilized at the end consumer – industrial, residential or transportation. That will involve changes and costs again more than the ones related to replacing the source with solar power stations.

The current electricity generation capacity in the US is about 1TW (1,000,000 MW). About 395 GW (1GW = 1,000 MW) is from natural gas, 315 GW from coal, 100 GW from nuclear, 100 GW from hydroelectric 56GW from oil products, 30 GW from renewables  other than hydro, and other small components.

We will look at these numbers separately to see what it will take to replace the more urgent ones of them – coal, oil etc.

The US total energy consumption, not just electricity is 3.5 TW. Most of the difference between just electricity and this number is made up of energy produced from oil so we are not going to try to break this down. We will look at this as one of our theoretical targets.

The world total energy consumption is at around 16 TW of which 4.5TW is electricity.

So, lets build a scale of the different stages that theoretically can be achieved in solar replacing other energy sources.

For our calculations we will assume installation / construction cost for one 1MW of $5m. This is a number ($5/Wp) we think smaller than the recent historic numbers for cost to install solar capacity. But we want to factor for future falling prices of solar modules and other components and overall improving efficiency in the industry. Anyone is free to factor the $ numbers we have if they believe $7/Wp or $10Wp is a better number.

For surface area needs we will assume 200 kW per acre. With different design and technology 800kW per acre is possible but we will go with the low number on this to be on the safe side. Since 1 sq mile is 640 acres, with our assumption we will have 128 MW per sq mile.

We tried to display this comparison between energy currently produced by different sources and capacity needed in solar in gigawatts (GW), cost of  installation in billion dollars ($bn), land area needed in sq. miles, marks of different countries GDP, and land areas of different geographic locations (certain US states in this case).

Click here or on the graph below to see it in full scale.

On the above diagram, since it uses a linear scale for the capacity, cost and land and the large values (world energy needs) are much larger than the smaller ones (oil and coal for electricity in the US), the small values are not given a good presentation. So here we put the same numbers on a logarithmic scale for the solar capacity, cost and land requirements. We have much better clarity on the comparisons now for the smaller values.

Click here or on the graph below to see it in full scale.

We think in general our study is much more important in reference to the smaller values. They deal with some levels of scale of capacity that are practically easier to achieve in terms of replacing with solar. We are talking about the unquestionably very polluting coal and oil burning for electricity. Again – look at the numbers to replace oil products used for electricity generation in the US we only need $280b and spending that will create jobs, help growth in technology and give all sorts of other economic and social benefits.

The numbers given in our study in reference to the higher levels – world electricity and total energy consumption are simply for getting a better view of the comparative size of all levels.

Related Reading:

Solar Energy Nanotechnology Can Replace Fossil Fuels – SF Chronicle

Argument: Abundant solar energy can replace fossil fuels and slash emissions

Replacing fossil fuels: the scale of the problem

Alternative Sources of Energy Can Help to Save Our Planet

The potential of solar energy for replacing fossil fuels

newnet news – Scalable electric power from solar energy

Can alternative energy effectively replace fossil fuels

Solar Power – Europe Rallies Behind Nanotechnology To Wean World From Fossil Fuels

Resources:

http://www.eia.doe.gov/cneaf/electricity/epa/epa_sum.html

http://en.wikipedia.org/wiki/Energy_use_in_the_United_States

http://www.eia.doe.gov/oiaf/ieo/ieoecg.html

http://en.wikipedia.org/wiki/List_of_U.S._states_by_area

http://en.wikipedia.org/wiki/List_of_countries_and_outlying_territories_by_area

http://en.wikipedia.org/wiki/List_of_metropolitan_areas_by_population

http://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nominal)

SolarByTheWatt.com

What do we mean? Much too often watt hour (Wh) and the derivatives kilowatts hour (kWh) and megawatts hour (MWh) – as a measure of produced energy – are used wrongly instead of watt (W) or it’s derivatives kilowatt (kW) and megawatt (MW) and the other way around.

Let’s deal first with the well known kilo- and mega- prefixes. These are used to make a 1,000 and 1,000,000 of any unit. So 1kW equals 1,000W and 1,000,000W equals 1,000kW which also equals 1MW. Same goes for Wh – 1MWh = 1,000 kWh = 1,000,000 Wh. This was the easy part – kilo = thousands, mega = millions.

Now let’s look at the difference between W (watt) and Wh (watt hour). This is what confuses people more.

The watt (W) is a unit of measure for the power output a machine can produce. Strictly speaking from science point of view this is the amount of work (as in the scientific term) a machine can do (the amount of energy it can output) in a unit of time. Since the more standard scientific units for work (energy) and time are joule (J) and second (s) the standard unit of measure for power is actually a joule per second  (J/s). That is what is used more often in reference to mechanical devices and to chemical phenomena. In electricity the equivalent  is Watt (W) and mathematically 1W is exactly equal 1J/s. When a machine outputs 1 joule of energy every second it is said that the machine is working at 1W power.

So, a watt (W) is a measure of power – the ability for a machine to do work or produce energy in an amount of time. Another way of looking at it is as the speed at which a machine can output energy. If it can output energy at a rate of 1 joule per second that is power of 1 watt.

This is why power and watts (W), correspondingly kilowatts (kW) and megawatts (MW) should be seen as the potential of a machine to output certain amount of energy per unit of time. In energy production industries, like the solar energy industry, machines/generators (solar power stations, any other solar system) are given a number called watts peak (Wp) which is the nominal power they can output. So if a system is rated at 500 Wp that means the system can produce 500 joules of energy per second. If it is easier for you to think of energy produced per hour you have to multiply by the number of seconds in an hour – 36,600.

For those who are good at volts (V) and amperes (A) – if a generators outputs 1A current at 1V voltage the machine is working at 1W. Yes, that simple – power in watts is equal voltage in volts by current in amps.

The other unit – watt hour (Wh) is the unit of measure for amount of energy. If a machine with a power of 1W works for an hour it will produce 1Wh of energy. Now, wait a second, why did we suddenly switch from seconds to hours. Well if in the previous statement we replaced the word hour with second everything would have been correct but the unit of measure for amount of energy would also have to be watt second Wc – this is not used practically. The unit in use in the energy industry and electricity is watt hour (Wh). This is also how usually electricity is sold and priced. If you look at your utility bill you will see you are paying certain cents per Wh, well actually to confuse you now more you are paying cents per kWh but you already know why the k- is in front – the price is for 1,000 watt hours not for one small watt hour.

If we have to look again at the example with volts and amperes – if an electrical system is outputting 1A of electric current at 1V of voltage it outputs 1W of power. If that same system  works for 1 hour it would produce 1Wh energy, for 1,000 hours – 1kWh. At the regular household voltage of 110V a light bulb that uses 0.5A current consumes 55W (110V x 0.5A), in a thousand hours it will burn 55kWh and if you are paying $0.09 for kWh that will cost you $4.95.

Also in respect of generating electricity by solar panels, module – if a solar panel’s rating is at 100W and 25V that means at peak conditions the panel will be outputting 4A current (25Vx4A=100W) and every hour of peak performance will be producing 100W x 1h = 100Wh energy.

OK,  so let’s summarize and see how we should correctly use the units of measure.

Power is measured in watts (W) and systems usually have a rated peak power in watts (W). This of course could be in kilowatts (kW) and megawatts (MW) if it is a large number. Power should be perceived as the rate at which it produces energy (joules per second).

So correct expressions with it will be: “… the station has peak power of 300kW … ” or “.. the solar park’s capacity is 2MW … ” etc.

Energy, or amount of energy, is measured in watt hours (Wh) or the corresponding kilowatt hour (kWh) and megawatt hour (MWh) and it is the useful amount of work output by the system. This is why consumers or the grid pays in cents per watt hour (Wh). If a system works at 100 kW power for an hour it will produce 100 kWh, if this is paid at $0.09 per kWh that would earn $9.00.

Correct expressions using energy and Wh will be: “… the system will produce 500 MWh per year …” or “… the system will generate 700kWh per day …”

What are examples of wrongly put statements. “The power station will produce 15MW per year”. MW is power it is the rate at which energy is produced so it can not be per year, or per day, or per hour. If we know it will work at a capacity of 15MW we should simply say “… will produce 15MW …” may be add “…of electric power…”.

If we want to say “per year” (or per other period) we should calculate what the expected nominal insulation is (in the case of solar power stations and working, up-hours hours for other systems) for that period (that will usually be hours for that period, like in 1,400 hours insolation per year), multiply by the nominal power in watts and we will get watt hours. So then we can say “… the system will generate 700 MWh of electric energy per year…”.

Also often in news reports journalists will write that certain system will be able to power that many households. And this is the correct expression – “able to power (or feed with electricity) certain number of households”. A household needs certain power in kilowatts (kW) let’s say 4kW. So a 400kW station will be bale to feed 100 households. The incorrect statement is “… the system will power 100 households per year …”. We do not need “per year”. It will power the 100 house holds as long as it is operational – 10 years, 20 years – whatever the plan is.

As with all articles on SolarByTheWatt.com, please, do comment on this one, especially if you have recommendation of what to improve to make the content more useful and readable for you.

Related resources:

Wikipedia – Watt

Wikipedia – Kilowatt Peak

Wikiepedia – Kilowatt Hour

How Stuff Works – Amps, Watts and Volts

SolarByTheWatt.com

In the latest version of the Resources page we have interesting reference to information on UL listing of solar equipment.

SolarByTheWatt.com

Solar Panels, cheap alternative way to produce electricity for the home, is one-step in the right direction for reducing our dependence on foreign fuels, which individuals can take on their own.  Solar panels that are used to produce electricity are also known as a photovoltaic panel.  A photovoltaic panel is an assembly of interconnected photovoltaic cells or solar cells.   Solar crystalline cells are a crystalline-based structure that is able to take sunlight and convert it into electricity.  The more photovoltaic cells that are on a panel, the more electrical current can be produced.  In order for the solar panels to be useful in practical applications of an alternative electrical source, they must be constructed in a certain way.  The solar cells must be:

1. Electrically connected to each other as well as the rest of the system.
2. Protected from physical damage from situations such as hail, wind and snow, because some types of solar cells are brittle.
3. Protected from moisture such as rain and humidity so the metal contacts don’t get corroded, or the cells don’t form an oxide layer, which will decrease performance.
4. Electrically insulated, especially under rainy conditions.
5. Sturdily mounted.

Since sunlight is really made from a huge range of electromagnetic frequencies, solar cells only are able to convert a small percentage of sunlight into useable electricity.  Solar cells can now be created to maximize their efficiency by using the different frequency ranges of sunlight, yet that would require an additional device to separate the different frequencies and shine them on the appropriate group of solar cells that are designed to specifically convert that frequency of sunlight.  It is estimated that this technique would increase the efficiency of solar cells by 50%.  Currently without this method, solar cell efficiencies are in the range of 5 to 19%, which is actually a higher efficiency than solar panels produced in earlier years.  There are new processes being researched, which will concentrate the solar light to the photovoltaic modules and can raise the efficiency up to 30%.  With today’s technology, the average solar panel can produce about 140 watts of electricity.

Solar panels create electricity from an unlimited source, the Sun, which is a major benefit for using them.   When the Sun stops shining, not having electricity will be the least of your concerns.  The traditional standard crystalline silicone solar cell modules have about a 25 year life span.  Over 4 million of these modules were sold in 2007 alone.

Solar panels provide a cheap alternative to energy in the long run because the power source is isn’t a fossil fuel and creates electricity from a renewable resource and the byproducts are not carbon dioxide, or other waste products that will damage or affect the environment.  Old solar panels can be recycled so they don’t end up in landfills.  It is easier now than ever to create a solar system for your home and reduce your energy costs needed to power your home.

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You can power your home with solar energy by using solar panels you build yourself for under $200 if you know the right information. Read reviews on info products that show you how to create solar panels cheap. These popular DIY solar panel info guides  can get you quickly on your way. Get more information on solar panels cheap and solar power.

Article Source: http://www.articlealley.com/article_755933_27.html

Author:  B. Hopkins