Solar Photovoltaic Systems

As with almost everyone in the country we at Morri Consult are aware of the increasing fuel costs that have resulted in higher gas, electricity and oil bills for consumers and businesses alike. This together with the increasing effect on the environment of the burning of fossil fuels has led us to focus on renewable energy sources and in particular the introduction and use of solar photovoltaic (PV) systems.

Renewable Energy – Harnessing the Sun

This map shows the total UK solar irradiation in Kilo Watt hours per square metre. So, dependent on location every square metre of your house or garden receives between 800 and 1200 kW hours per year of solar energy. This energy is completely free! And in the UK we actually receive around two-thirds of the solar irradiation experienced at the equator.

Whilst no-one can claim that the UK can benefit from solar energy to the same extent as say, Kenya, there are still significant amounts of free energy that a modern system can exploit with a high degree of efficiency.

New technologies mean that solar energy can be harnessed more effectively now than ever before. Morri Consult has an enviable track record in maximising the potential that solar energy has to offer.

Dispelling the Myths

  • All solar systems work best with direct rays of light from the sun but also work effectively with diffuse light.

  • Solar systems are able to work every day of the year in the UK to differing levels of efficiency.

  • Solar energy is free and is the most abundant energy source on the planet.

  • Against this background of new technology plus rising fuel prices and focus on renewable energy sources Morri Consult have become solar photovoltaic (PV) specialists.

The Truth About Renewable Energy Sources

The amount of energy that is contained in a litre of oil or a kilogram of coal is phenomenal. However, that energy has been concentrated in a process that has taken thousands if not millions of years. When we need energy, we can release it and generate in an instant, the product of that slow concentration. This is ideal for the way we live our lives because when we want energy, we want lots of it and we want it immediately so that we can heat a room, boil a kettle or drive a car.

Renewable energy sources are not like that, the energy is acquired relatively slowly so that we need to go through the same process of concentration until we have sufficient energy to be of use.

Solar PV – How It Works

Photovoltaic means electricity from light. Photovoltaic systems use daylight to power ordinary electrical equipment, for example, household appliances, computers and lighting. The photovoltaic (PV) process converts light directly into electricity.

A PV cell consists of two or more thin layers of semi-conducting material, most commonly silicon. When the silicon is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC). The electrical output from a single cell is fairly small so multiple cells are connected together and encapsulated (usually behind glass) to form a module (sometimes referred to as a "panel"). The PV module is the principle building block of a PV system and any number of modules can be connected together to give the desired electrical output.

PV systems can either generate electricity that is stored on your property (in batteries) and runs on a separate circuit (known as a stand alone system), or can be a Grid Connect system. The latter type of PV system is illustrated in the diagram below and involves using an inverter to change the low voltage DC generated to the higher voltage AC necessary for household electrical supply.

In-Roof PV Array

Inverter Bank

Grid Connection

Note that some inverters allow power to be fed back into the UK mains supply, therefore allowing consumers to reduce their electricity bills through “net metering”.

During the day, the electricity generated by the PV system can either be used immediately (which is normal for systems installed on offices and other commercial buildings), or can be sold to one of the electricity supply companies (which is more common for domestic systems where the occupier may be out during the day).

In the evening, when the solar system is unable to provide the electricity required, power can be bought back from the network.

In effect, the grid is acting as an energy storage system, which means the PV system does not need to include battery storage.

Typical Domestic System Size

Typical PV panels have a rated power output of around 185 - 255 Watts peak (Wp) each. A typical domestic system of 2 - 4 kWp may therefore comprise some 12 - 16 panels covering an area of between 12 - 40 m², depending on the technology used and the orientation of the array with respect to the sun.

To the end user (consumer) the benefits include:

  • Reduction of CO² emissions.

  • Use of a free energy source (the sun) reduces use of fossil fuels – coal, gas, oil.

  • Consumers enjoy more independence from utility companies.

  • Advantages over other renewable energy technologies – well suited to the urban environment and silent
  • .

Current FIT Rates

Solar PV System Size: Tariff Rates : From 01/02/2013 Tariff Lifetime:
0kWp - 4kWp 15.44p per kWh 20 years
4kWp - 10kWp 13.99 per kWh 20 years
10kWp - 50kWp 13.03p per kWh 20 years
50kWp - 100kWp 11.5p per kWh 20 years
100kWp - 150kWp 11.5p per kWh 20 years
150kWp - 250kWp 11.0p per kWh 20 years
250kWp - 5MWp 7.1p per kWh 20 years

For further information on the FIT please click here

Morri Consult can provide detailed proposals for domestic and commercial Solar PV systems.

Solar PV – Typical Costs

Installation cost is approximately £6,500 for a 4kW peak. A 1kW peak installation will generate approximately 800KWh per annum. The actual energy produced by a system will depend on the orientation of the panels, the angle of the roof and whether there is likely to be any shading on the panels.

The Government's Feed In Tariff will pay the system owner for every kWh produced by the system for 20 years. The pence paid per kWh depends on the size of the system installed.