Photovoltaic (PV) power

Plug into the sun

Solar Photovoltaic (solar PV) systems can convert the energy (radiation) from the sun directly into electrical power.

Solar PV systems generate renewable electricity producing no pollution, therefore contributing to a reduction of greenhouse gas emissions and to the improvement of local air quality. PV panels can produce electricity at the same place where it is finally consumed. In this way the energy losses from the transmission and distribution of power may be reduced.

PV systems usually supply only a share of a household’s electricity need as a large part of the consumption takes place during the evening when the sun is not shining. In many European countries consumers are allowed to feed the non-consumed electricity to the grid and receive a value for it. Buildings such as offices and schools, business, agriculture and industry largely use electricity during the day. In those cases, solar PV can be very attractive as systems can cover large parts of the electricity demand.

PV is particularly suitable for rural areas where there is often more surface available for the installation of the panels. Furthermore, PV provides a competitive and clean solution for the electrification of remote rural areas where the power grid is not available. For such areas, off-grid solutions are available. Solar PV systems may need to be complemented by energy storage equipment or auxiliary power units, potentially connected through a micro-grid, to supply electricity when the sun is not available. Buildings such as offices and schools, but also important economic sectors in rural areas including agriculture and industry, largely use electricity during the day. In those cases, solar PV can especially be attractive as systems can cover large parts of the overall electricity demand and provide electricity at the time it is needed.

Solar PV panels have seen a steep reduction of costs in recent years and this trend is expected to continue. In southern European countries, electricity generated from solar PV is often cheaper than electricity from the grid. Despite the fact that electricity from solar-PV panels is becoming increasingly competitive in a wider set of circumstances and locations, upfront investment costs may still be high and payback times relatively long. This may form a barrier for people and businesses to invest in PV systems. Lease or partial ownership schemes are offered that contribute towards or cover the investment. Some countries and regions in Europe offer investment grants.

General Info

What is it?

Solar Photovoltaic (solar PV) is a technology that converts the energy of the sun directly into electrical power.

What are the benefits?

Low carbon: Solar PV panels transform the radiation of the sun into electricity without producing greenhouse gas emissions.

As PV panels can generate electricity that can be used directly onsite, there is less need for transmission and distribution of electricity from centralised power plants. This contributes to a reduction of energy losses.

Increasingly cost-effective: Solar PV panels have seen a steep reduction of costs in recent years and this trend is expected to continue. It is expected that PV panels will become a very affordable way of producing electricity. In many countries support is available in the form of net-metering1 or self-consumption2 schemes, or other production support schemes such as feed-in tariffs and certificate schemes.

How does it work?

Photovoltaic energy is the direct conversion of sunlight into electricity (photovoltaic translates as ‘light-electricity’) by photovoltaic (PV) cells. PV cells consist of layers of semi-conducting material, commonly silicon which is also used in microchips. When the sun shines on the cell, it creates an electric current across the layers. The stronger the sunlight, the more electricity is produced. PV cells however do not require direct sunlight to work – they also generate electricity on cloudy days.

Groups of cells are placed together in panels or modules that can be fitted on roofs and building facades or ground mounted (in fields, desserts etc.). Panels are often mounted at a fixed angle facing south, but also on tracking devices that follow the sun, allowing them to produce more electricity.

Suitability/applicability

PV systems usually supply only a certain share of a household’s electricity need as a large part of the consumption takes place during the evening when the sun is not shining. In many European countries consumers are allowed to feed the non-consumed electricity to the grid and receive a value for it.

Buildings in rural areas such as offices and schools, business, agriculture and industry largely use electricity during the day. In those cases, solar PV can especially be attractive as systems can cover large parts of the electricity demand.

For remote areas where the power grid is not available, off-grid systems are available. Such systems can be more expensive as they may need to be complemented by energy storage equipment or an auxiliary power unit to supply electricity when the sun is not available. Distributed networks that combine several local sources of (renewable) electricity generation and optimise supply and demand are increasingly being developed in Europe. Solar panels are capable of producing electricity right where it is consumed. For this reason they may reduce the need for transmission and distribution of electricity from centralised power plants, particularly when combined in a distributed network with multiple users. This also reduces network losses due to long distance transmission and has the opportunity to increase the overall efficiency and may reduce infrastructural investments of a country’s or region’s energy system.

Systems can be sized and scaled according to the required power demand – large and small.

Detailed Info

Costs, Savings, Earnings

PV systems do not need any fuel to produce electricity and therefore the costs of operation are very low. PV cells and panels have a long lifetime (> 25 years) with minor efficiency losses over this lifetime. Some electric components of the system, particularly the inverter3, need replacing sometime during this period. Initial installation investment represents most of the costs for these systems. Lease or partial ownership schemes are offered that reduce or eliminate up-front investments. Costs of PV systems are expected to reduce further in the coming years due to further technological advances and in many European countries support is available.

The economic performance of PV panels depends on the following factors:

  • The solar radiation in the area and the amount suitable surfaces

(based on their orientation and angle) available for their installation

  • The electricity consumption patter of the user
  • The electricity prices in the region
  • Connectivity to the electric grid
  • Availability and type of governmental support: net-metering or self-consumption, feed-in tariffs, tax exemptions or investment subsidies.
  • Costs of capital used to finance the project (the highest this cost, the lowest the economic performance).

Environmental Impacts

Power from PV systems is considered renewable. The environmental impacts of Solar PV are very limited. During use installations do not produce any emissions or waste. A typical domestic system in Northern Europe can save over a tonne of CO2 each year. This is roughly equal to an average passenger car that drives 8,000 10,000 kilometres a year.

Efficiency

The efficiency of commercial solar panels is currently in the order of 15-20%. This means that PV panels convert 100 kWh of solar radiation in 15-20 kWh of electricity.

Commercial Maturity

PV systems are a commercially available mature technology. In several European countries, electricity from PV systems is cheaper than retail electricity prices. However, as upfront investment costs are high, payback times are relatively long. These costs are expected to come down further in the coming years. Experienced installers are widely available.

Level of Maintenance

LOW: PV panels require little maintenance, except for periodic cleaning and regularly making sure that the panels are not over shaded by objects such as trees.

Technical Details

The power of a PV cell is measured in kilowatts peak (kWp). This is the rate at which it generates energy at peak performance in full direct sunlight during summer.

PV panels require about 8m2 for every kW of installed capacity, and a typical domestic system is about 4 kWp. A system like this, if properly oriented and installed, can typically produce between 3500 kWh (Northern Europe, e.g. Berlin) and 6350 kWh (Southern Europe, e.g. Seville).

Regional variations

With the current status of the technology, PV is becoming economically attractive in a wide number of circumstances and geographic locations. In the sunny south of Europe, PV electricity generated onsite can already compete with retail electricity prices (including taxes) without the need for subsidies.

Trade associations

European Photovoltaic Industry Association

www.epia.org