Solar Energy Center » Cost Of Solar Power http://www.petererickson.net all about building your own solar energy Sun, 18 Sep 2011 17:21:51 +0000 en hourly 1 http://wordpress.org/?v=3.1 Energy in Afghanistan – Hydroelectricityhttp://www.petererickson.net/article/energy-in-afghanistan-hydroelectricity http://www.petererickson.net/article/energy-in-afghanistan-hydroelectricity#comments Sun, 28 Aug 2011 01:43:57 +0000 http://www.petererickson.net/article/energy-in-afghanistan-hydroelectricity Three hydroelectric plants were opened between 1965 and 1970, at Jalālābād, Naghlu, and Mahipar, near Kabul; another, at Kajaki, in the upper Helmand River Valley, was opened in the mid-1970s. In addition to the Naghlu, Mahi Par, and Kajaki plants, other hydroelectric facilities that were operational as of 2002 included plants at Sarobi, west of Kabul; Pol-e Khomri; Darunta, in Nangarhar province; Dahla, in Qandahār province (restored to operation in 2001); and Mazāre Sharif. In 1991, a new 72-collector solar installation was completed in Kabul at a cost of $364 million. The installation heated 40,000 liters of water to an average temperature of 60°C around the clock. Construction of two more power stations, with a combined capacity of 600 kW, was planned in Charikar City.

The drought of 1998–2001 negatively affected Afghanistan’s hydroelectric power production, which resulted in blackouts in Kabul and other cities. Another generating turbine is being added to the Kajaki Dam in Helmand province near Qandahār, with the assistance of the Chinese Dongfeng Agricultural Machinery Company. This will add 16.5 MW to its generating capacity when completed. Also in operation was the Breshna-Kot Dam in Nangarhar province, which had a generating capacity of 11.5 MW.

Adapted from the Wikipedia article Energy in Afghanistan, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/energy-in-afghanistan-hydroelectricity/feed 0 Amorphous silicon – Applicationshttp://www.petererickson.net/article/amorphous-silicon-applications http://www.petererickson.net/article/amorphous-silicon-applications#comments Sat, 27 Aug 2011 20:43:31 +0000 http://www.petererickson.net/article/amorphous-silicon-applications While a-Si suffers from lower electronic performance compared to c-Si, it is much more flexible in its applications. It may also produce savings on silicon material cost, as a-Si layers can be made thinner than c-Si.

One advantage is that a-Si can be deposited at very low temperatures, as low as 75 degrees Celsius. This allows for deposition on not only glass, but plastic as well, making it a candidate for a roll-to-roll processing technique. Once deposited, a-Si can be doped in a fashion similar to c-Si, to form p-type or n-type layers and ultimately to form electronic devices.

Another advantage is that a-Si can be deposited over large areas by PECVD. The design of the PECVD system has great impact on the production cost of such panel, therefore most equipment suppliers put their focus on the design of PECVD for higher throughout, that leads to lower manufacturing cost.

Amorphous silicon has become the material of choice for the active layer in thin-film transistors (TFTs), which are most widely used in large-area electronics applications, mainly for liquid-crystal displays (LCDs).

Solar cells

a-Si has been used as a photovoltaic solar cell material for calculators for some time. Although they are lower performance than traditional c-Si solar cells, this is not important in calculators, which use very low power. a-Si’s ability to be easily deposited during construction more than makes up for any downsides.

More recently, improvements in a-Si construction techniques have made them more attractive for large-area solar cell use as well. Here their lower inherent efficiency is made up, at least partially, by their thinness – higher efficiencies can be reached by stacking several thin-film cells on top of each other, each one tuned to work well at a specific frequency of light. This approach is not applicable to c-Si cells, which are thick as a result of their construction technique and are therefore largely opaque, blocking light from reaching other layers in a stack.

The main advantage of a-Si in large scale production is not efficiency, but cost. a-Si cells use approximately 1% of the silicon needed for typical c-Si cells, and the cost of the silicon is by far the largest factor in cell cost. However, the higher costs of manufacture due to the multi-layer construction have, to date, make a-Si unattractive except in roles where their thinness or flexibility are an advantage.

Typically, amorphous silicon thin-film cells use a p-i-n structure. Typical panel structure includes front side glass, TCO, thin film silicon, back contact, polyvinyl butyral (PVB) and back side glass. Uni-Solar produces a version of flexible backings, used in roll-on roofing products.

Microcrystalline and Micromorphous Silicon

Microcrystalline silicon (also called nanocrystalline silicon) is amorphous silicon, but also contains small crystals. It absorbs a broader spectrum of light and is flexible.

Micromorphous silicon module technology combines two different types of silicon, amorphous and microcrystalline silicon, in a top and a bottom photovoltaic cell. Sharp produces cells using this system in order to more efficiently capture blue light, increasing the efficiency of the cells during the time where there is no direct sunlight falling on them. Protocrystalline silicon is often used to optimize the open circuit voltage of a-Si photovoltaics.

Large-scale production

Xunlight Corporation, which has received over $40 million of institutional investments, has completed the installation of its first 25 MW wide-web, roll-to-roll photovoltaic manufacturing equipment for the production of thin-film silicon PV modules. Anwell Technologies has also completed the installation of its first 40 MW a-Si thin film solar panel manufacturing facility in Henan with its in-house designed multi-substrate-multi-chamber PECVD equipment.

Adapted from the Wikipedia article Amorphous silicon, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/amorphous-silicon-applications/feed 0 Cubic mile of oil – Replacement of oil by alternative sourceshttp://www.petererickson.net/article/cubic-mile-of-oil-replacement-of-oil-by-alternative-sources http://www.petererickson.net/article/cubic-mile-of-oil-replacement-of-oil-by-alternative-sources#comments Thu, 25 Aug 2011 22:42:54 +0000 http://www.petererickson.net/article/cubic-mile-of-oil-replacement-of-oil-by-alternative-sources While oil has many other important uses (lubrication, plastics, roadways, roofing) this section considers only its use as an energy source.

The CMO is a powerful means of understanding the difficulty of replacing oil energy by other sources. SRI International chemist Ripudaman Malhotra, working with Crane and colleague Ed Kinderman, used it to describe the looming energy crisis in sobering terms. Malhotra illustrates the problem of replacing one cubic mile of oil with energy from five different alternative sources. Such a replacement requires long and significant development.

Allowing fifty years to develop each replacement, one cubic mile of oil could be replaced by any one of these developments:

* 4 Three Gorges Dams, developed each year for 50 years, ”or”

* 52 nuclear power plants, developed each year for 50 years, ”or”

* 104 coal-fired power plants, developed each year for 50 years, ”or”

* 32,850 wind turbines, developed each year for 50 years, ”or”

* 91,250,000 rooftop solar photovoltaic panels developed each year for 50 years

The energy produced is the power rating of the source multiplied by the duration it is operational. These comparisons take into account the variability of available power (solar panels work only during the day, turbines work only when the wind blows).

The environmental, social, and financial costs of such development projects are immense:

*The Three Gorges Dam is the world’s largest, flooding 632& km2, displacing 1.25 million people, and costing roughly US$30 billion.

*A nuclear power plant produces hazardous radioactive waste, raises fears of radiation or nuclear proliferation, requires 10 years to construct for a 40 year lifetime, occupies about 4& km2, and may cost upwards of US$5 billion.

* A 500 MW coal-fired power plant may contribute to acid rain, global warming, and air pollution, occupies about 2& km2, may obtain its fuel via controversial methods such as mountaintop removal, and costs about US$650 million.

* A large wind turbine requires a location with an abundance of steady wind, may be visually obtrusive, can interfere with aviation, needs about 0.16& km2 to avoid interfering with adjacent turbines, and costs about US$2 million.

* A 2.1& kW rooftop solar array requires technical skills for installation, needs a sunny location, presents few aesthetic or environmental problems, covers about 14 m2, but costs around US$15,000.

For comparison, US$3.2 trillion is the approximate gross domestic product of Germany, China, or the United Kingdom. The total land area of New Zealand is about .

At a 2008 market price of US$120 per barrel (US$750/m3), the cost of one CMO was about US$3 trillion.

Adapted from the Wikipedia article Cubic mile of oil, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/cubic-mile-of-oil-replacement-of-oil-by-alternative-sources/feed 0 Economics of climate change mitigation – Energy sector subsidieshttp://www.petererickson.net/article/economics-of-climate-change-mitigation-energy-sector-subsidies http://www.petererickson.net/article/economics-of-climate-change-mitigation-energy-sector-subsidies#comments Thu, 25 Aug 2011 16:43:50 +0000 http://www.petererickson.net/article/economics-of-climate-change-mitigation-energy-sector-subsidies Large energy subsidies are present in many countries (Barker ”et al.”, 2001:567-568). Currently governments subsidize fossil fuels by $557 billion per year. Economic theory indicates that the optimal policy would be to remove coal mining and burning subsidies and replace them with optimal taxes. Global studies indicate that even without introducing taxes, subsidy and trade barrier removal at a sectoral level would improve efficiency and reduce environmental damage (Barker ”et al.”, 2001:568). Removal of these subsidies would substantially reduce GHG emissions and stimulate economic growth.

The actual effects of removing fossil fuel subsidies would depend heavily on the type of subsidy removed and the availability and economics of other energy sources. There is also the issue of carbon leakage, where removal of a subsidy to an energy-intensive industry could lead to a shift in production to another country with less regulation, and thus to a net increase in global emissions.

Policy suggestions

Jacobson and Delucchi (2009) have advanced a plan to power 100% of the world’s energy with wind, hydroelectric, and solar power by the year 2030, recommending transfer of energy subsidies from fossil fuel to renewable, and a price on carbon reflecting its cost for flood, cyclone, hurricane, drought, and related extreme weather expenses.

Adapted from the Wikipedia article Economics of climate change mitigation, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/economics-of-climate-change-mitigation-energy-sector-subsidies/feed 0 Solar bowl – Basic Design Principleshttp://www.petererickson.net/article/solar-bowl-basic-design-principles http://www.petererickson.net/article/solar-bowl-basic-design-principles#comments Thu, 25 Aug 2011 04:43:45 +0000 http://www.petererickson.net/article/solar-bowl-basic-design-principles The technical name of the design is ”Fixed Mirror Distributed Focus Solar Power System”. The main reason for its development was to eliminate the cost of having the mirror move with the sun as a tracking parabolic mirror does.

A fixed parabolic mirror creates a changing image of the sun as it moves along the sky. Only when the sun is directly above the mirror will the light focus in one point. That is why parabolic mirrors track the sun. A spherical mirror creates a constant image independent of the position of the sun. The light, however, is not directed to one point but is distributed on a line from the surface of the mirror to one half radius (along a line that runs through the sphere center and the sun).

As the sun moves across the sky, the fixed mirror aperture changes, resulting in a variation of sunlight concentrated on the focus line. This is called the sinus effect of power output. Although this reduces the overall power output compared with tracking parabolic mirrors, this loss is compensated by lower system costs.

The sunlight concentrated in the focal line is collected using a tracking receiver. This receiver is pivoted on the sphere’s center and usually counterbalanced. The receiver can consist of pipes carrying thermal oil, water or air. Designs have also used photovoltaic cells on the receiver.

Adapted from the Wikipedia article Solar bowl, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/solar-bowl-basic-design-principles/feed 0 NEAR Shoemaker – Spacecraft and subsystemshttp://www.petererickson.net/article/near-shoemaker-spacecraft-and-subsystems http://www.petererickson.net/article/near-shoemaker-spacecraft-and-subsystems#comments Wed, 24 Aug 2011 19:43:17 +0000 http://www.petererickson.net/article/near-shoemaker-spacecraft-and-subsystems The spacecraft has the shape of an octagonal prism, approximately 1.7 m on a side, with four fixed gallium arsenide solar panels in a windmill arrangement, a fixed 1.5 m X-band high-gain radio antenna with a magnetometer mounted on the antenna feed, and an X-ray solar monitor on one end (the forward deck), with the other instruments fixed on the opposite end (the aft deck). Most electronics are mounted on the inside of the decks. The propulsion module is contained in the interior.

The craft is three-axis stabilized and uses a single bipropellant (hydrazine / nitrogen tetroxide) 450 newton (N) main thruster, and four 21 N and seven 3.5 N hydrazine thrusters for propulsion, for a total delta-V potential of 1450 m/s. Attitude control is achieved using the hydrazine thrusters and four reaction wheels. The propulsion system carries 209& kg of hydrazine and 109& kg of NTO oxidizer in two oxidizer and three fuel tanks.

Power is provided by four 1.8 by 1.2 meter gallium arsenide solar panels which can produce 400 watts at 2.2 AU (329,000,000& km), NEAR’s maximum distance from the Sun, and 1800 W at one AU (150,000,000& km). Power is stored in a nine ampere-hour, 22-cell rechargeable super nickel-cadmium battery.

Spacecraft guidance is achieved through the use of a sensor suite of five digital solar attitude detectors, an inertial measurement unit, (IMU) and a star tracker camera pointed opposite the instrument pointing direction. The IMU contains hemispherical resonator gyroscopes and accelerometers. Four reaction wheels (arranged so that any three can provide complete three-axis control) are used for normal attitude control. The thrusters are used to dump angular momentum from the reaction wheels, as well as for rapid slew and propulsive maneuvers. Attitude control is to 0.1 degree, line-of-sight pointing stability is within 50 microradians over one second, and post-processing attitude knowledge is to 50 microradians.

The command and data handling subsystem is composed of two redundant command and telemetry processors and solid state recorders, a power switching unit, and an interface to two redundant 1553 standard data buses for communications with other subsystems. The solid state recorders are constructed from 16 Mbit IBM Luna-C DRAMs. One recorder has 1.1 gigabits of storage, the other has 0.67 gigabits.

The NEAR mission was the first launch of NASA’s Discovery Program, a series of small-scale spacecraft designed to proceed from development to flight in under three years for a cost of less than $150 million. The construction, launch, and 30 day cost for this mission is estimated at $122 million. The final total mission cost was $224 million which consisted of $124.9 million for spacecraft development, $44.6 million for launch support and tracking, and $54.6 million for mission operations and data analysis.

Adapted from the Wikipedia article NEAR Shoemaker, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/near-shoemaker-spacecraft-and-subsystems/feed 0 Feed-in tariff – Feed-in tariffs and grid parityhttp://www.petererickson.net/article/feed-in-tariff-feed-in-tariffs-and-grid-parity http://www.petererickson.net/article/feed-in-tariff-feed-in-tariffs-and-grid-parity#comments Mon, 22 Aug 2011 23:44:50 +0000 http://www.petererickson.net/article/feed-in-tariff-feed-in-tariffs-and-grid-parity Some have argued that feed-in tariffs can be used to accelerate the pace at which renewable energy technologies become cost-competitive with electricity provided from the grid, to obtain grid parity. The rapid deployment of renewable energy under feed-in tariffs seen in countries like Germany, Denmark and Spain has undoubtedly contributed to reducing technology costs, and hence, in accelerating this trend. For instance, wind and solar technology costs have decreased dramatically since the 1960s and 1970s , as the technologies have become more widespread, manufacturing processes have improved, innovations have been incorporated, and gains have been harnessed from economies of scale.

While it is true that large scale deployment of renewable energy technologies contributes to advancing toward grid parity, grid parity itself is a moving target, both in time (i.e. during the course of the day and over the course of years) and in space (i.e. geographically). The price of electricity from the grid varies widely from high-cost jurisdictions such as Hawaii and California, to lower-cost jurisdictions such as Wyoming, and Idaho . Similarly, due to their dependence on diesel generators, islands typically have higher electricity costs than on the mainland. In jurisdictions with time-of-use pricing the electricity price changes over the course of the day, rising during high-demand hours (e.g. 11AM – 8 PM) and declining during low-demand hours.

In certain jurisdictions, wind power, landfill gas, and certain forms of biomass generation are already lower-cost (on a per-kWh basis) than electricity provided from the grid. In fact, “grid parity” has already been obtained in certain jurisdictions that continue to use feed-in tariffs (e.g. the generation cost from landfill gas systems in Germany are currently lower than the average electricity spot market price) And in remote areas, electricity from solar photovoltaics can be cheaper than building new distribution lines to connect up to the main transmission grid.

This makes the notion of grid parity elusive.

As a result, some analysts argue that even when grid parity is “reached” that it will be important to retain the non-price provisions offered by FITs, including purchase guarantees, guaranteed grid access, stable long-term contracts, etc.

Adapted from the Wikipedia article Feed-in tariff, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/feed-in-tariff-feed-in-tariffs-and-grid-parity/feed 0 Sustainable energy – Local green energy systemshttp://www.petererickson.net/article/sustainable-energy-local-green-energy-systems http://www.petererickson.net/article/sustainable-energy-local-green-energy-systems#comments Mon, 22 Aug 2011 00:44:36 +0000 http://www.petererickson.net/article/sustainable-energy-local-green-energy-systems Those not satisfied with the third-party grid approach to green energy via the power grid can install their own locally based renewable energy system. Renewable energy electrical systems from solar to wind to even local hydro-power in some cases, are some of the many types of renewable energy systems available locally. Additionally, for those interested in heating and cooling their dwelling via renewable energy, geothermal heat pump systems that tap the constant temperature of the earth, which is around 7 to 15 degrees Celsius a few feet underground, are an option and save money over conventional natural gas and petroleum-fueled heat approaches.

United States

The advantage of this approach in the United States is that many states offer incentives to offset the cost of installation of a renewable energy system. In California, Massachusetts and several other U.S. states, a new approach to community energy supply called [Community Choice Aggregation] has provided communities with the means to solicit a competitive electricity supplier and use municipal revenue bonds to finance development of local green energy resources. Individuals are usually assured that the electricity they are using is actually produced from a green energy source that they control. Once the system is paid for, the owner of a renewable energy system will be producing their own renewable electricity for essentially no cost and can sell the excess to the local utility at a profit.

Adapted from the Wikipedia article Sustainable energy, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/sustainable-energy-local-green-energy-systems/feed 0 Unified Smart Grid – Advocacyhttp://www.petererickson.net/article/unified-smart-grid-advocacy http://www.petererickson.net/article/unified-smart-grid-advocacy#comments Sun, 21 Aug 2011 02:43:42 +0000 http://www.petererickson.net/article/unified-smart-grid-advocacy According to advocates, the idea of a national system would do for the US energy economy what Dwight Eisenhower’s Interstate Highway System did for efficient distribution of products. Solar power from Arizona would be able to supply manufacturing in Ohio, or evening wind power from the Northeast could be used to supply power peak demand during the day in Nevada. According to leading scientists such as James E. Hansen, construction of such a national grid is essential to any strategy to combat global warming. According to energy independence advocates such as T. Boone Pickens, it is essential for the U.S. economy and its strategic energy interests. Some advocate the system as a candidate for a massive public works project that would stimulate the US economy after the Global financial crisis of 2008.

The “Unified Smart Grid” is promoted by Alliance for Climate Protection (Repower America program) and Al Gore. The cost estimate by Al Gore is $400 billion and would be recovered by tariffs on transmission. The need for a national bulk transmission grid is detailed in T. Boone Pickens’s energy independence plan.

Adapted from the Wikipedia article Unified Smart Grid, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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]]> http://www.petererickson.net/article/unified-smart-grid-advocacy/feed 0 Photovoltaic system – System performancehttp://www.petererickson.net/article/photovoltaic-system-system-performance http://www.petererickson.net/article/photovoltaic-system-system-performance#comments Sat, 20 Aug 2011 23:43:09 +0000 http://www.petererickson.net/article/photovoltaic-system-system-performance At high noon on a cloudless day at the equator, the power of the sun is about 1 kW/m², on the Earth’s surface, to a plane that is perpendicular to the sun’s rays. As such, PV arrays can track the sun through each day to greatly enhance energy collection. However, tracking devices add cost, and require maintenance, so it is more common for PV arrays to have fixed mounts that tilt the array and face due South in the Northern Hemisphere (in the Southern Hemisphere, they should point due North). The tilt angle, from horizontal, can be varied for season, but if fixed, should be set to give optimal array output during the peak electrical demand portion of a typical year.

For large systems, the energy gained by using tracking systems outweighs the added complexity (trackers can increase efficiency by 30% or more). PV arrays that approach or exceed one megawatt often use solar trackers. Accounting for clouds, and the fact that most of the world is not on the equator, and that the sun sets in the evening, the correct measure of solar power is insolation – the average number of kilowatt-hours per square meter per day.

For the weather and latitudes of the United States and Europe, typical insolation ranges from 4 kWh/m²/day in northern climes to 6.5 kWh/m²/day in the sunniest regions. Typical solar panels have an average efficiency of 12%, with the best commercially available panels at 20%. Thus, a photovoltaic installation in the southern latitudes of Europe or the United States may expect to produce 1 kWh/m²/day. A typical “150 watt” solar panel is about a square meter in size. Such a panel may be expected to produce 1 kWh every day, on average, after taking into account the weather and the latitude.

In the Sahara desert, with less cloud cover and a better solar angle, one could ideally obtain closer to 8.3 kWh/m²/day provided the nearly ever present wind would not blow sand on the units. The unpopulated area of the Sahara desert is over 9 million km², which if covered with solar panels would provide 630 terawatts total power. The Earth’s current energy consumption rate is around 13.5 TW at any given moment (including oil, gas, coal, nuclear, and hydroelectric).

Photovoltaic cells’ electrical output is extremely sensitive to shading. When even a small portion of a cell, module, or array is shaded, while the remainder is in sunlight, the output falls dramatically due to internal ‘short-circuiting’ (the electrons reversing course through the shaded portion of the p-n junction). Therefore it is extremely important that a PV installation is not shaded at all by trees, architectural features, flag poles, or other obstructions. Sunlight can be absorbed by dust, fallout, or other impurities at the surface of the module. This can cut down the amount of light that actually strikes the cells by as much as half. Maintaining a clean module surface will increase output performance over the life of the module.

Module output and life are also degraded by increased temperature. Allowing ambient air to flow over, and if possible behind, PV modules reduces this problem. However, effective module lives are typically 25 years or more , so replacement costs should be considered as well.
Adapted from the Wikipedia article Photovoltaic system, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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