General Questions

Solar energy can be converted into electricity primarily in two ways:

  1. Photovoltaics (PV), where sunlight is converted directly into electricity, and
  2. Concentrating Solar Power (CSP) (also synonymous to Solar Thermal), heat is extracted from sunlight and converted into other forms of energy like electricity.

Photovoltaics is the direct method of converting sunlight into electricity using a device known as a solar cell.

A. When semiconductors such as silicon are exposed to sunlight, they produce small amounts of electric charge (electrons and holes). A well-designed solar cell separates this charge to form a positive and negative terminal. Hence, these terminals produce a voltage, and when connected to an external circuit, cause a current flow. In this way, a solar cell in the Sun works just like a battery.

Semiconductor structure...   ...looks like...   ...works like...

1018 kilowatt-hours of sunlight reaches the earth’s surface every year, which is 6,000 times greater than the world’s annual energy demand. This means that the Sun provides world’s annual energy to the earth in one hour! In another metric, on a clear day, sunlight measures a power density of 1 kilowatt per square-meter or area.

A. The power generated by a solar cell depends on the amount of sunlight it receives, area of the solar cell and its efficiency. For example, on a clear day, a 15% efficient solar cell of area 15 x 15 cm2 will produce 3.4 watts of power.

A. A solar cell is a single semiconductor device, while a photovoltaic module consists of multiple solar cells connected together into a single unit to protect the solar cells and increase the voltage and power above that of a single solar cell. “Photovoltaic panels” and “Photovoltaic arrays” are sometimes used interchangeably, but they refer to the collective system of photovoltaic modules connected together in the system.

Solar or PV cell.   PV module.   PV array.

A. Just as individual batteries can be interconnected, solar cells too can be connected in series and parallel connections and encapsulated into a module to output desired power.

PV module circuit.   Equivalent battery circuit.

PV panels produce DC power, which is the same type of power produced by batteries. An inverter is used to convert this DC into AC power in order to run typical household appliances.

A. Due to its versatility, photovoltaic energy can be used in a wide range of applications requiring power from a couple of milliwatts for small electronics to a couple of megawatts to support entire communities. Traditionally, the most common application of photovoltaics has been for electrical loads that cannot be easily plugged into the electricity grid, either because they should be transportable – such as solar calculators, watches, etc. – or because the electricity grid does not exist at a particular location. Where the grid is located far away from a particular application, photovoltaics is being used to provide “remote power”. Examples of these applications are houses not connected to grid power, telecommunications, remote villages, water pumping and space applications. However, a recent and rapidly growing application for photovoltaics is for residential or building-integrated which are connected to the electricity grid. During the day, power is used from photovoltaics, and at night power is used from the electricity grid. A final application is utility-scale photovoltaics, in which a utility company installs a large amount of photovoltaic power. These larger systems, which are far less common than other applications, are typically installed to achieve a specific technical goal.


A. A photovoltaic system mainly consists of:

  1. Solar panels, which directly convert sunlight into DC electricity,
  2. Charge controller, which interfaces the solar panels to the rest of the photovoltaic system and ensures maximum power extraction from the solar panels,
  3. Batteries, if the system is designed to store energy,
  4. Inverter, to convert DC electricity into AC if required,
  5. Net-metering equipment, if the generated power is fed back into the electricity grid, and
  6. Monitoring equipment, if it is intended to monitor the photovoltaic system.
Typical grid-connected home PV system.   Typical stand-alone PV water pump system.


Solar cells do not directly work at night; however, typical solar systems are designed to store power generated during the day into batteries, and power can be extracted from batteries at night.

A. Photovoltaic systems are very robust and reliable, since there are no moving parts. A photovoltaic system would be expected to last in excess of 20 years. Many manufacturers have 20-year warranties on the photovoltaic modules. The electronic components can also be made reliable, since again there are no moving parts, but the warranties on these systems tend to be lower, about 5 years. If the photovoltaic system contains batteries (most stand-alone systems do and residential grid-connected do not), then the batteries will need to be replaced every 5 to 10 years.

Advantages: Photovoltaics has several technical advantages that make it the best choice for electricity generation...

The fuel for photovoltaics, sunlight, is practically infinite, free, and easily accessible. In fact, the earth receives enough energy from the sun in one hour to fulfill the global energy demand for one year!

2. Photovoltaic panels are extremely reliable and require low maintenance even in harsh conditions.
Photovoltaic systems are very versatile as they are suitable for loads of any size; they can provide a couple of watts for small loads like lanterns or electronic gadgets, a couple of kilowatts for loads like heavy machinery and households, or a couple of megawatts for solar power stations.

Photovoltaic systems are versatile also in the sense that they can be stand-alone, local grid, central grid-connected or even hybrid (in conjunction with other technologies like wind or hydro) systems.
Photovoltaic systems are an ideal choice and turn out to be cheaper for remote applications away from the grid as infrastructure costs of electricity transmission can be avoided.
Photovoltaic systems work best when we need energy the most, i.e. during peak energy demand period of the day. This reduces infrastructure costs for fossil-based generation plants as they have to be designed to meet peak demands, while they run to meet that demand only for a short period of time.

7. Photovoltaic systems are modular, where additional power generating capacity can readily be added.
Photovoltaic systems last at least thirty years as typically there are no moving parts involved in electricity generation; consequently, they don’t create any noise pollution.
Photovoltaic conversion does not involve any polluting emissions, combustion, radioactivity, high temperature and pressure process or disposal or raw materials.
10. Photovoltaic systems have a very short lead time for installation.
11. Photovoltaics has a high rate of public acceptance and an excellent safety record.
12. Photovoltaics is a green technology and has the potential to play a major role in controlling greenhouse gases and global warming.
13. Photovoltaic industries create jobs in addition to energy, and help the economic development of societies.
14. Thus, photovoltaics is a proven technology and a practical solution to energy crisis and security.

Disadvantages: There is tremendous research thrust to overcome the challenges that photovoltaics is currently facing...

The main disadvantage of photovoltaics is its relatively high cost compared to many other large-scale electricity generating sources. However, the cost of solar electricity has dramatically reduced over the last couple of years with advances in technology. Moreover, the cost of photovoltaics will further reduce as more and more systems will be deployed (economies of scale) and an infrastructure starts revolving around it.

Even though the sunlight reaching earth carries 6,000 times greater energy than the global requirement, the power density of sunlight is relatively low. This means that photovoltaics tends to be less suited for applications that are physically small compared to the energy they require.

The output of photovoltaic systems is variable depending on the availability of solar radiation. Areas with greater cloud cover and shorter days will experience lower power generations, and such systems have to be designed accordingly.

Photovoltaic energy is typically stored in batteries, which increases the costs and maintenance of such systems. However, there is a tremendous thrust to improve energy storage technologies such as solar-hydrogen systems.

Photovoltaic modules are typically only 13-18% efficient; this low efficiency is one of the dominant causes for the high cost. Again, this technology is aggressively pursued to further photovoltaic cell and system efficiency.

In spite of the popularity of the concept of photovoltaics, there is a vast lack of knowledge, and hence, faith in this technology. Confidence in this technology will be gained with education and examples.

Solar cells are often characterized by the percentage of the incident power that they convert into power, called the power conversion efficiency or just efficiency. The efficiency is given by a percentage. The efficiency of a solar cell is determined by the material from which it is made and by the production technology used to make the solar cell. Efficiencies for commercially available solar cells range from about 5% to about 20%. The bulk of the commercial market consists of bulk silicon solar cells, and the research or laboratory efficiency of these is close to 25%. Space applications, where efficiency is more important, often use a different solar cell technology and may consist of solar cells made from different materials stacked on top of one another. The efficiency of these solar cells is up to 40%. The theoretical efficiency limit of solar energy conversion given completely idealized conditions and materials is 86%, but given present technology, solar cells that can potentially be made have theoretical conversion efficiency closer to 50%.


In addition to the power conversion efficiency, other methods to characterize solar cells also contain the word efficiency and are also given by a percentage. For example, the quantum efficiency measures, at a given wavelength of light, how much of the incident light is turned into current – not power. Quantum efficiency is a chiefly a method of analyzing devices used by specialists in the area and does not simply or directly relate its power conversion efficiency. For solar cells that have power conversion efficiencies of 15%, the quantum efficiencies may routinely reach over 90%. For newer or experimental solar cells, the quantum efficiency is often much lower, about 30%, and the power conversion efficiency is often less than 10%. The quantum efficiency and power conversion efficiency are sometimes confused in press or non-specialist articles, leading to apparent claims of very high solar cell efficiencies.

Solar cell technologies differ from one another based firstly on the material used to make the solar cell and secondly based on the processing technology used to fabricate the solar cells. The material used to make the solar cell determines the basic properties of the solar cell, including the typical range of efficiencies.


Most commercial solar cells for use in terrestrial applications (i.e., for use on earth) are made from wafers of silicon. Silicon wafer solar cells account for about 85% of the photovoltaic market. Silicon is a semiconductor used extensively to make computer chips. The silicon wafers can either consist of one large singe crystal, in which case they called single- or mono-crystalline wafers, or can consist of multiple crystals in a single wafer, in which case they are called multi-crystalline silicon wafers. Single crystalline wafers will in general have a higher efficiency than multi-crystalline wafers. Silicon wafers used in commercial production allow power conversion efficiencies of close to 22%, although the fabrication technologies at present limit them to about 17 to 18%. Multi-crystalline silicon wafers allow power conversion efficiencies of up to 18%, with present fabrication achieving between 13 to 15%.

The PERL cell developed by University of New South Wales holds the silicon single junction efficiency record of 24.7%.

The efficiency achieved by a solar cell depends on the processing technology used to make the solar cell. The most commonly used technology to make wafer-based silicon solar cells is screen-printed technology, which achieves efficiencies of 11-15%. Higher efficiency technologies are the buried contact or buried grid technology, which achieves efficiencies op up to 18% and has been in production for about a decade.

Typical screen-printed solar cells.

Although silicon solar cells are the dominant material, some applications – particularly space applications – require higher efficiency than is possible from silicon or other solar cell technologies. Solar cells made from GaAs or related materials (called III-V materials since they are generally made from groups III and V elements of the periodic table) have a higher efficiency than silicon solar cells, particularly for the spectrum of light that exists in space. GaAs solar cells have efficiencies of up to 25% measured under terrestrial conditions. To further increase these efficiencies, solar cells made from different kinds of materials are stacked on top of one another. Such devices are called tandem or multijunction solar cells (the term multijunction applies to other types of structures as well). Such solar cells have efficiencies of up to 40% under concentration.

Space solar cell application. World-record 40.7% efficiency triple-junction solar cell developed by Spectrolab.

A final class of solar cell materials is called thin film solar cells. These solar cells can be made from a variety of materials, with the key characteristic being that the thickness of the devices is a fraction of typical single or multi-crystalline solar cells. Thin film solar cells may be made either from amorphous silicon, cadmium telluride, copper indium diselenide or thin layers of silicon. The efficiencies of thin film solar cells tend to be lower than those of other devices; but to compensate for lower efficiencies, the production cost can also be significantly lower. Of these technologies, amorphous silicon is the best developed, and laboratory efficiencies are between 10 to 12%, with commercial efficiencies just over half these efficiencies. The other thin film technologies are still the subject of development, although commercial products exist. The efficiency of these devices is about 6% to 10% efficient.

CdTe module developed by First Solar. Power plastic developed by Konarka.

Most solar cells will theoretically operate with a higher efficiency under intense sunlight than under the conditions encountered on earth. Concentrator solar systems exploit this effect, by focusing sunlight into a concentrated spot or line. Concentrator systems exist for both silicon and III-V solar cells. Silicon concentrator systems have reached efficiencies of 28% while III-V based systems have reached about 41%.

Solar concentrator developed by SolFocus. A typical solar concentrator array.

Any capital-intensive disruptive technology or industry, in its infancy stages, faces challenges to sustain itself. Typically, the costs involved for such products are high while markets are undeveloped, and hence, such ventures prove to be non-profitable. However, such industries have to potential to sustain themselves in the long term by overcoming the learning curve, scaling up their economy, and developing a suitable infrastructure. Typical examples of such industries are those concerned with renewable energy.

On the other hand, governments foresee challenges that they would face in the future, and identify the significance of such industries. Hence, it becomes important for the government to develop such industries and support them till they become self-sustaining. Governments use policy as their primary driver, which has a substantial influence on the growth and shape of such industries. Growth of renewables is strongest where and when the policy-makers in charge have established favorable conditions.

With the current challenges based on fossil energy and climate change, is imperative to invest in renewable energy for long-term energy sustainability and security, economic development as well as control environmental pollution. Hence, it becomes important for governments to frame the right policies for renewable energy.

Any capital-intensive disruptive technology or industry, in its infancy stages, faces challenges to sustain itself. Typically, the costs involved for such products are high while markets are undeveloped, and hence, such ventures prove to be non-profitable. However, such industries have to potential to sustain themselves in the long term by overcoming the learning curve, scaling up their economy, and developing a suitable infrastructure. Typical examples of such industries are those concerned with renewable energy.

On the other hand, governments foresee challenges that they would face in the future, and identify the significance of such industries. Hence, it becomes important for the government to develop such industries and support them till they become self-sustaining. Governments use policy as their primary driver, which has a substantial influence on the growth and shape of such industries. Growth of renewables is strongest where and when the policy-makers in charge have established favorable conditions.

With the current challenges based on fossil energy and climate change, is imperative to invest in renewable energy for long-term energy sustainability and security, economic development as well as control environmental pollution. Hence, it becomes important for governments to frame the right policies for renewable energy.

Clearly, each country faces different barriers to mainstreaming renewable energy. Developing nations' priority is increasing energy access to all people, while encouraging economic development and sustainable lifestyles. Economies in transition must encourage competition in their energy markets in order to draw investment. Industrialized countries have established oil dependencies maintained by subsidies, corporate power and the public's reluctance to change. However, encouraging competitive energy markets in all nations around the world will accelerate the use of renewables.

Developing Nations: The unstable markets in developing nations lack competition because investors do not want to put money into weak economies. These nations can focus their policy on attracting domestic and foreign investment and possibly restructuring publicly owned energy entities. However, privatizing the energy industry is tricky and may have unwanted side-effects such as social unrest and political instability.

For developing and transitional countries, it is increasingly evident that reducing fossil fuel subsidies will improve their energy problems. Reducing or eliminating subsidies provides internal revenues for investment, improves the prospects of attracting direct foreign investment, and improves the financial capacity of governments to pursue other development objectives. Subsidies that underprice electricity have cost developing nations $130 billion a year for the past decade.

The United Nations Development Program (UNDP) suggests a better solution for developing nations would be to reform subsidy programs by focusing them on financial, social and environmental sustainability. In addition, fundamental legal, institutional and social reforms will help attract energy sector investment. Also, local renewable projects, such as Barcelona's Solar Law have been successful because they combine government action with enough individual control to stimulate market competition.

Industrialized Nations: In industrialized nations, which already have sufficient investors and well-functioning markets, policies can concentrate on leveling the playing field for all competitors. Both removing subsidies and internalizing the social costs of burning fossil fuels will help eliminate market price distortions. Societies that want to account for external costs can create emission taxes, fiscal incentives (investment grants, tax credits, guaranteed prices for renewables), use ethical persuasion by educating the public on social costs of using energy sources and can implement certificate trading programs.

Other ways for industrialized countries to accelerate the use of renewables include setting targets, implementing renewable portfolio standards and certificate and emissions trading programs. All of these options allow flexibility for companies to choose the manner in which they increase the percentage of total renewables they produce and consume. Setting technology standards, such as vehicle emissions standards, ensure that companies develop cleaner technology, but also provide flexibility for their R&D.

Research and development of new energy technologies is important for all countries. In industrialized countries, current pricing systems provide few incentives for private investment; private companies also tend to invest in short term R&D, so public money should be spent on long-term development and demonstration. Developing nations must dedicate public funds to renewable R&D because technologies most adaptable to their communities (e.g., decentralized rural electrification) tend to be under-funded in industrialized nations. To complement the R&D, capacity building must be implemented to ensure the energy technology will be used effectively and maintained properly.

The relatively short history of renewable energy policy has already produced a vast variety of political measures intended to promote renewables. Various categories of policies can be classified as follows:

Most forceful are mandated market policies, which set mandatory quantities in the form of quotas (renewable portfolio standards (RPS), blending,...) or mandatory prices such as feed-in tariffs. They are applied in order to give renewable energy a considerable role in the electricity generation and transport fuel markets, and create a critical mass for the development of the industry. In segregated partial-markets, competitive bidding for renewable energy concessions and renewable energy or green energy tradable certificates also constitute mandated market policies. In some cases (e.g. off-grid areas where previously no market exist) policy must actually organize markets and the necessary institutional development.

Financial incentives constitute another category of policies, which is focussed more on cost reductions and improving the relative competitiveness of renewable energy technologies (RET) in given markets: capital grants, third-party finance, investment tax credits, property tax exemptions, production tax credits, sales tax rebates, excise tax exemptions, etc. Some of these measures can be well applied to RET invested by the users themselves. Taxes on fossil fuels also improve the competitive position of renewable energy and are particularly appropriate to internalize negative external effects on environmental or energy security.

Public investments giving RET preference in government procurement, infrastructure projects and use of public benefits funds etc. are another way of increasing the market share of renewables. This is also an area where renewable energy growth stimulation can be combined with development programmes.

RET can only occupy the markets if respective industry standards, permits, and building codes exist, as well as the respective environmental guidelines. This must therefore be an area of utmost concern for a meaningful renewable energy policy, especially as RET typically are new technologies that are constantly evolving.

Policy should also contribute and assure basic functions with regard to information, awareness building, education and capacity building.

As RETs are typically new technologies, research and development should also be an important element of renewable energy policy.

The electricity feed-in laws in Germany, and similar policies in other European countries in the 1990s, set a fixed price for utility purchases of renewable energy. For example, in Germany starting in 1991, renewable energy producers could sell their power to utilities at 90% of the retail market price. The utilities were obligated to purchase the power. The German feed-in law led to a rapid increase in installed capacity and development of commercial renewable energy markets. Wind power purchase prices were highly favorable, amounting to about DM 0.17/kWh (US 10 cents/kWh), and applied over the entire life of the plant. Total wind power installed went from near zero in the early 1990s to over 8500 MW by 2001, making Germany the global leader in renewable energy investment.

An RPS requires that a minimum percentage of generation sold or capacity installed be provided by renewable energy. Obligated utilities are required to ensure that the target is met, either through their own generation, power purchases from other producers, or direct sales from third-parties to the utility’s customers. Typically, RPS obligations are placed on the final retailers of power, who must purchase either a portion of renewable power or the equivalent amount of green certificates.

Renewable energy (green) certificates are emerging as a way for utilities and customers to trade renewable energy production and/or consumption credits in order to meet obligations under RPS and similar policies. Standardized certificates provide evidence of renewable energy production, and are coupled with institutions and rules for trading that separate renewable attributes from the associated physical energy. This enables a “paper” market for renewable energy to be created independent of actual electricity sales and flows.

Distributed generation avoids some of the costs of transmission and distribution infrastructure and power losses, which together can total up to half of delivered power costs. Policies to promote distributed generation—including net metering, real-time pricing, and interconnection regulations—do not apply only to renewable energy, but nevertheless can strongly influence renewable energy investments.

Net Metering: Net metering allows a two-way flow of electricity between the electricity distribution grid and customers with their own generation. When a customer consumes more power than it generates, power flows from the grid and the meter runs forward. When a customer installation generates more power than it consumes, power flows into the grid and the meter runs backward. The customer pays only for the net amount of electricity used in each billing period, and is sometimes allowed to carryover net electricity generated from month to month. Net metering allows customers to receive retail prices for the excess electricity they generate at any given time. This encourages customers to invest in renewable energy because the retail price received for power is usually much greater than it would be if net metering were not allowed and customers had to sell excess power to the utility at wholesale rates or avoided costs. Electricity providers may also benefit from net metering programs, particularly with customer-sited PV which produces electricity during peak periods. Such peak power can offset the need for new central generation and improve system load factors.

Real-Time Pricing: Real-time pricing, also known as dynamic pricing, is a utility rate structure in which the per-kWh charge varies each hour based on the utility’s real-time production costs. Because peaking plants are more expensive to run than base-load plants, retail electricity rates are higher during peak times than during shoulder and off-peak times under real-time pricing. When used in conjunction with net metering, customers receive higher peak rates when selling power into the grid at peak times. At off-peak times the customer is likely purchasing power from the grid, but at the lower off-peak rate. Photovoltaic power is often a good candidate for real-time pricing, especially if maximum solar radiation occurs at peak-demand times of day when power purchase prices are higher. Real-time metering equipment is necessary, which adds complexity and expense to metering hardware and administration.

Interconnection Regulations: Non-discriminatory interconnection laws and regulations are needed to address a number of crucial barriers to interconnection of renewable energy with the grid. Interconnection regulations often apply to both distributed generation and “remote” generation with renewable energy that requires transmission access, such as wind power. Interconnection regulations include Access Laws, Dynamic Generation and Transmission Scheduling, Elimination of Rate ‘Pancaking’ (remote-transmission costs and fees), Capacity Allocation, and Standard Interconnection Agreements.

Historically, renewable energy in developing countries has come from direct donor assistance and grants for equipment purchases and demonstrations. In recent years a number of new approaches have emerged for promoting renewable energy in off-grid rural areas, including energy service concessions, private entrepreneurship, microcredit, and comparative line extension analysis.

Rural Electrification Policy and Energy Service Concessions: Many developing countries have explicit policies to extend electric networks to large shares of rural populations that remain unconnected to power grids (globally, an estimated 1.7 billion people). However, in many areas, full grid extension is too costly and unrealistic. Policies and rural electrification planning frameworks have recently started to emerge that designate certain geographic areas as targets for off-grid renewable energy development. These policies may also provide explicit government financial support for renewable energy in these areas. Such financial support is starting to be recognized as a competitive alternative to government subsidies for conventional grid extensions.

Rural Business Development and Microcredit: Private entrepreneurship is increasingly recognized as an important strategy to fulfill rural energy goals. Thus, rural electrification policies have begun to promote entrepreneurship. Promising approaches are emerging that support rural entrepreneurs with training, marketing, feasibility studies, business planning, management, financing, and connections to banks and community organizations. These approaches include “bundling” renewable energy with existing products. Bundling can reduce costs if vendors of existing products and services add renewable energy to their activities—and use their existing networks of sales outlets, dealers, and service personnel. In conjunction with entrepreneurship, consumer microcredit has emerged as an important tool for facilitating individual household purchases of renewable energy systems like solar home systems. Credit may be provided either by the system vendors themselves, by rural development banks, or by dedicated microcredit organizations. Notable examples of consumer microcredit for solar home systems have emerged in some developing countries.

Comparative Line Extension Analyses: Economic comparisons of line extension versus distributed renewable energy investment are also emerging in developed countries. Some power line extension policies require that, in cases where utility customers must pay a portion of construction costs for utility power line extension to a remote location, the utility must provide information about on-site renewable energy technology options. Some of these policies require the utility to perform a cost/benefit analysis comparing line extension with off-grid renewable energy. Renewable energy options may be less expensive for rural customers, but without line extension policies, many customers would not be aware of this.

Subsidies and Rebates: Reduction in the initial capital outlay by consumers for renewable energy systems is accomplished through direct subsidies, or rebates. These subsidies are used to “buy down” the initial capital cost of the system, so that the consumer sees a lower price.
Investment Tax Credits: Investment tax credits for renewable energy have been offered for businesses and residences.

Accelerated Depreciation: Accelerated depreciation allows renewable energy investors to receive the tax benefits sooner than under standard depreciation rules. The effect of accelerated depreciation is similar to that of investment tax credits.

Production Tax Credits: A production tax credit provides the investor or owner of qualifying property with an annual tax credit based on the amount of electricity generated by that facility. By rewarding production, these tax credits encourage improved operating performance.

Grants and Loans: Grant and loan programs offer financing for the purchase of renewable energy equipment. Loans can be market-rate, low-interest (below market rate), or forgivable, and available to virtually all sectors—residential, commercial, industrial, transportation, public, and nonprofit. Repayment schedules vary, with terms of up to 10 years common. Interest rates for renewable energy investments can often be 1% or more higher than those for conventional power projects because of the higher perceived risks involved, so government-subsidized loans that offer below-market interest rates are also common.

Government procurement policies aim to promote sustained and orderly commercial development of renewable energy. Governmental purchase agreements can reduce uncertainty and spur market development through long-term contracts, pre-approved purchasing agreements, and volume purchases. Government purchases of renewable energy technologies in early market stages can help overcome institutional barriers to commercialization, encourage the development of appropriate infrastructure, and provide a “market path” for technologies that require integrated technical, infrastructure, and regulatory changes.

Power sector restructuring is having a profound effect on electric power technologies, costs, prices, institutions, and regulatory frameworks. Restructuring trends are changing the traditional mission and mandates of electric utilities in complex ways, and affecting environmental, social, and political conditions. There are five key trends underway that continue to influence renewable energy development as discussed below:

Competitive Wholesale Power Markets and Removal of Price Regulation on Generation: Power generation is usually one of the first aspects of utility systems to be deregulated. The trend is away from utilities monopolies towards open competition, where power contracts are signed between buyers and sellers in wholesale “power markets.” Distribution utilities and industrial customers gain more choices in obtaining wholesale power. Such markets may often begin with independent-power-producer (IPP) frameworks. As wholesale electricity becomes more of a competitive market commodity, price becomes relatively more important than other factors in determining a buyer’s choice of electricity supplier.

Self-Generation By End-Users and Distributed Generation Technologies: Independent power producers may be the end-users themselves rather than just dedicated generation companies. With the advent of IPP frameworks, utility buy-back schemes (including net metering), and cogeneration technology options, more and more end-users, from large industrial customers to small residential users, are generating their own electricity. Their self-generation offsets purchased power and they may even sell surplus power back to the grid. Traditionally, regulated monopoly utilities have enjoyed economic advantages from large power plants and increasing economies of scale. These advantages are eroding due to new distributed generation technologies that are cost-competitive and even more efficient at increasingly smaller scales. In fact, newer technologies reduce investment risks and costs at smaller scales by providing modular and rapid capacity increments.

Privatization and/or Commercialization of Utilities: In many countries, utilities, historically government-owned and operated, are becoming private for-profit entities that must act like commercial corporations. Even if utilities remain state-owned, they are becoming “commercialized”—losing state subsidies and becoming subject to the same tax laws and accounting rules as private firms. In both cases, staffing may be reduced and management must make independent decisions on the basis of profitability.

Unbundling of Generation, Transmission and Distribution: Utilities have traditionally been vertically integrated, including generation, transmission and distribution functions. Under some restructuring programs, each of these functions is being “unbundled” into different commercial entities, some retaining a regulated monopoly status (particularly distribution utilities) and others starting to face competition (particularly generators).

Competitive Retail Power Markets and “Green Power” Sales: Competition at the retail level, the newest phenomena in power sector restructuring, means that individual consumers are free to select their power supplier from among all those operating in a given market. Competitive retail power markets have allowed the emergence of “green power” suppliers who offer to sell renewable energy, usually at a premium. As green power sales grow, these suppliers are forced to invest in new renewable energy capacity to meet demand, or buy power from other renewable energy producers. Green power markets have begun to flourish where retail competition is allowed, but often only in conjunction with other renewable energy promotion policies.

EERE (Energy Efficiency and Renewable Energy) Newsletters of the U.S. Department of Energy (D.O.E.) provide information on various projects, news, and activities within EERE.

Homepower Magazine
features comprehensive, technical coverage of solar, wind, and microhydro electricity, energy efficiency, solar hot water systems, space heating and cooling, energy-efficient building materials and home design, and clean transportation options.

by Solarbuzz™ summarizes the most important solar energy news items of the week and is issued free by e-mail on Mondays.

New Energy
is a monthly magazine covering policy to business and ground-breaking technologies in the regenerative energy sector.

NREL (National Renewable Energy Laboratory) News Releases provides news stories about the laboratory and renewable energy and energy efficiency technologies.

Solar Progress
published by the Australian and New Zealand Solar Energy Society (ANZSE) provides news and articles about renewable energy applications, ideas and new directions.

Solar Today
published by the American Solar Energy Society is a bi-monthly magazine that covers all solar technologies, from photovoltaics to climate-responsive building to wind power.

Photon International
is your global navigation throughout the PV Industry.

PV News
is the photovoltaic industry’s oldest and one of the most respected newsletters.

PV Power, a newsletter intended to provide information on the activities of the IEA-PVPS Programme.

PV Tech aims to provide up-to-date independent news coverage of developments within the photovoltaics industry in an easily accessible and navigable format.

Renewable Energy World Magazine
is a bi-monthly that features industry, technology, policy, finance and news important to the renewables sectors.

The ARC Photovoltaics Center of Excellence at the University of New South Wales (UNSW) focuses on the key challenges facing the field of photovoltaics over the next 20 years as well as "spin-off" applications in microelectronics and optoelectronics including focuses on the key challenges facing the field of photovoltaics over the next 20 years as well as "spin-off" applications in microelectronics and optoelectronics.

The Center for Energy and Environmental Policy (CEEP) at the University of Delaware is a leading institution for interdisciplinary graduate education, research, and advocacy in energy and environmental policy.

Florida Solar Energy Center (FSEC)
was created by the Florida Legislature in 1975 to serve as the state’s energy research institute. The main responsibilities of the center are to conduct research, test and certify solar systems and develop education programs.

The Fraunhofer Institute for Solar Energy Systems ISE conducts research on the technology needed to supply energy efficiently and on an environmentally sound basis in industrialized, threshold and developing countries.

The Institute of Energy Conversion (IEC) established at the University of Delaware in 1972, and designated a University Center of Excellence for Photovoltaic Research and Education by the Department of Energy and the National Renewable Energy Laboratory in 1992, is a laboratory devoted to research and development of thin-film and crystalline silicon photovoltaic solar cells, and other photonic devices.

The National Center for Photovoltaics (NCPV) at the National Renewable Energy Laboratory (NREL) performs fundamental research in PV-related materials; develops PV cells in several material systems; characterizes and improves performance and reliability of PV cells, modules and systems; assists industry with standardized tests and performance models for PV devices; and helps the PV industry accelerate manufacturing capacity and commercialization of various PV technologies.

The Photovoltaic Systems Program at Sandia National Laboratories collaboratively works with the U.S. photovoltaic industry, the U.S. Department of Energy (D.O.E.) , the National Renewable Energy Laboratory, other government agencies, and international organizations to increase the world-wide use of photovoltaic power systems by reducing cost, improving reliability, increasing performance, removing barriers, and growing markets.

The Solar Energy Technologies Program at the U.S. Department of Energy (D.O.E.) focuses on developing cost-effective solar-energy technologies that have the greatest potential to benefit U.S.A. and the world.

The Solar Power Program at the University of Delaware collaborates with many universities, laboratories and industry to develop high-performance, affordable solar electric power (photovoltaic) systems.

University Center of Excellence for Photovoltaics (UCEP)
at the Georgia Institute of Technology is established by the U.S. Department of Energy (D.O.E.) to improve the fundamental understanding of the science and technology of advanced PV devices, fabricate record high efficiency solar cells, provide training and enrich the educational experience of students in this field, and provide guidelines to industry and government agencies for achieving cost-effective and high-efficiency PV devices.

The Australian and New Zealand Solar Energy Society (ANZSE) promotes the understanding and use of solar energy in all its forms and applications.

The British Photovoltaic Association advances the development and use of photovoltaic (PV) technology. Since 1992, it has actively promoted the use of PV within the UK as well as for export. PV-UK has working-groups on market strategy, grid connected issues, and training. The Association has 53 members, who represent the wide cross-section of expertise in the UK. Members are drawn from industry, universities and consultancy practices, and many are world leaders in their field(s). Expertise includes product manufacture, systems design and installation, R&D, consultancy and project management.

The European Photovoltaic Industry Association (EPIA) is the world's largest industry association devoted to the solar electricity market. The association aims to promote photovoltaics at the national, European and worldwide levels and to assist its members in the development of their businesses in both the European Union and in export markets.

The North American Board of Certified Energy Practitioners (NABCEP) is a volunteer board of renewable energy stakeholder representatives that includes representatives of the solar industry, NABCEP certificants, renewable energy organizations, state policy makers, educational institutions, and the trades.

The Solar Alliance is a state-focused alliance of solar manufacturers, integrators and financiers dedicated to accelerating the promise of photovoltaic (PV) energy in the United States.

Solar Electric Power Association (SEPA) is a nonprofit organization, formed in 1992 as the Utility Photovoltaic Group. From national events to one-on-one assistance, SEPA is the go-to resource for unbiased and actionable solar intelligence. SEPA is comprised of 300 utility and solar industry members. Breaking down information overload into business reality, SEPA takes the time and risk out of implementing solar business plans and helps turn new technologies into new opportunities

Solar Energy Industries Association (SEIA)
is the U.S. national trade association for the solar industry. We work to expand markets, strengthen research and development, remove market barriers, and improve education and outreach for solar.

DSIRE (Database of State Incentives for Renewables & Efficiency) is a comprehensive source of information on state, local, utility, and federal incentives that promote renewable energy and energy efficiency in U.S.A.

gives consumers a place to estimate costs and output of solar systems for hot water, electricity, and pool or spa heating. It also provides an online directory linking thousands of home and small business owners around the country to qualified solar energy system installers serving their area.

International Electrotechnical Commission (IEC) is the world's leading organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as ‘eletrotechnology’.

Global Approval Program for Photovoltaics (PV GAP), non-profit international organization, is dedicated to the sustained growth of global photovoltaics (PV) markets to meet energy needs world-wide in an environmentally sound manner. Their mission is to promote and encourage the use of internationally accepted standards, quality management processes and organizational training in the design, fabrication, installation, sales and services of PV systems.

The Solar and Wind Energy Resource Assessment (SWERA) Programme provides easy access to high quality renewable energy resource information and data to users all around the world.

Underwriters Laboratories (UL) is a trusted source across the globe for product compliance. Benefiting a range of customers – from manufacturers and retailers to consumers and regulating bodies – UL has tested products for public safety for more than a century.