How does a solar power system work

Solar photovoltaic (PV) panels use cells containing a semi-conductor material to capture the sun’s energy and convert solar radiation into electricity. The most commonly used semi-conductor material is silicon, which is an abundant natural resource found in sand. When light strikes the cell a certain amount of energy is absorbed within the semiconductor material, knocking electrons, the negatively charged particles that form the basis of electricity, loose.

Most PV cells have two layers of semi-conductor material, one positively charged and one negatively charged. When light shines on the semi-conductor the electric field across the junction between these two layers causes electricity to flow, generating direct current (DC). By placing metal contacts on the top and bottom of the PV cell, we can draw that current off for external use.

Solar PV electric panels do not require bright sunlight in order to operate, meaning that you can still generate electricity on cloudy days, however in general the greater the intensity of light the higher the flow of electricity. Although,  due to the reflection of sunlight, days with slight cloud can result in higher energy yields than days with a completely cloudless sky.

It is important to realise that you can only use your free solar electricity when it is being generated – so unless you also invest in batteries to store power for use in the evenings and at night, you will need to pay for your energy use as normal when the panels are not producing electric.

How the Electricity is Converted for use

Direct Current (DC) needs to be converted into alternating current (AC) so it can be used in a domestic building; this is performed by an inverter. The AC electricity then passes via the generation meter, which measures how much electricity has been created, and on to the consumer unit where it can be fed into the property for use or exported back to the national grid via the electricity meter.

A typical grid connected roof mounted system consists of a number of components, as shown in the diagram to the right.

You will be paid for every kWh of electricity that your solar PV system generates, even if you use the power yourself. You will also be paid an additional amount for any electricity that you export to the national grid. Click here to visit the feed in tariff page to find out more.

The Main Elements in a Solar PV System

Photovoltaic Solar Panels or Tiles

Solar panels form the heart of every PV system. We are able to offer a choice of industry leading solar panels made by Solarworld AG, LG, Axitec, SunForte, BenQ, Panasonic, Phonosolar REC, Kyrocera, as well as award winning traditional solar slates, manufactured in Wales by Solar Slate Ltd.

Inverters

Inverters convert the DC current produced by the solar panels into AC current which is then fed into the electricity supply for use in the home, with any surplus electricity fed back into the national grid. We supply and fit industry leading inverters from SMA, Schneider, PowerOne, Samil Solar River and Solis, Plus Enphase Micro Inverters when neccessary.

Generation Meters / Monitoring Systems

In order to conform to regulations and qualify for feed in tariff payments you need a meter or system that will accurately register the total kWh of PV electricity generated by the solar panels. We offer a range of compliant systems from industry leaders SMA.

Mounting System

We offer solar panel mounting systems from Fischer, Schletter and K2 that allow us to mount the panels in a place that suits your requirements – whether that is on top of your existing roof tiles (on roof), flush with roof tiles (in roof) or on a flat roof or the ground.

If you would like to find out how solar PV could work for you give us a call, email us or fill in our enquiry form to arrange a free on site assessment. We promise to give you honest advice on the suitability of solar pv for you and will design the optimum system to meet your requirements.

We all know that solar photovoltaic (PV) panels transform sunlight into useable electricity, but few people know the actual science behind the process. This week on the blog we are going to get into the nitty-gritty science behind solar. It can seem complicated, but it all boils down to the photovoltaic effect; the ability of matter to emit electrons when bathed in light.

Before we get to the molecular level, let’s take a high-level look at the basic flow of electric generation:

Basic Steps in Solar Energy Generation and Transmission

1. Sunlight hits the solar panels, and creates an electric field.
2. The electricity generated flows to the edge of the panel, and into a conductive wire.
3. The conductive wire brings the electricity to the inverter, where it is transformed from DC electricity to AC, which is used to power buildings.
4. Another wire transports the AC electricity from the inverter to the electric panel on the property (also called a breaker box), which distributes the electricity throughout the building as needed.
5. Any electricity not needed upon generation flows through the utility meter and into the utility electrical grid. As the electricity flows through the meter, it causes the meter to run backwards, crediting your property for excess generation.

Now that we have a basic idea of the generation and flow of solar electricity, let’s take a deeper dive into the science behind the solar photovoltaic panel.

The Science Behind Solar PV Cells

Solar PV panels are comprised of many small photovoltaic cells – photovoltaic meaning they can convert sunlight into electricity. These cells are made of semi-conductive materials, most often silicon, a material that can conduct electricity while maintaining the electrical imbalance needed to create an electric field.

As the solar panel generates an electric current, the energy flows through a series of wires to an inverter (see step 3 above). While solar panels generate direct current (DC) electricity, most electricity consumers need alternating current (AC) electricity to power their buildings. The inverter’s function is to turn the electricity from DC to AC, making it accessible for everyday use.

After the electricity is transformed into a usable state (AC power), it is sent from the inverter to the electrical panel (also called a breaker box) [step 4], and distributed throughout the building as needed. The electricity is now readily available to power lights, appliances, and other electrical devices with solar energy.

Any electricity that is not consumed via the breaker box is sent to the utility grid through the utility meter (our last step, as outlined above). The utility meter measures the flow of electricity from the grid to your property and vice versa. When your solar energy system is producing more electricity than you are using on site, this meter actually runs backwards, and you are credited for the excess electricity generated through the process of net metering. When you are using more electricity than your solar array is generating, you pull supplemental electricity from the grid through this meter, making it run normally. Unless you have gone completely off-grid through a storage solution, you will need to pull some energy from the grid, especially at night, when your solar array is not producing. However, much of this grid energy will be offset from the excess solar energy you generate throughout the day and in periods of lower usage.

While the details behind solar are highly scientific, it doesn’t take a scientist to convey the benefits a solar installation can bring to a business or property owner. An experienced solar developer can walk you through these benefits and help you explore if a solar solution is right for your business.

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