Sustainable Building, Eco Development Techniques

Information resouce site for GREEN sustainable building development

Solar Panel Photovoltaic Systems (PV)


What is a Solar Photovoltaic System?
Solar photovoltaic (PV) systems use free energy fron the sun and convert it into electricity using photvoltaic cells.  In fact, every minute, enough energy arrives at the Earth to meet our demands for a whole year - if only we could harness it properly.

PV produces on-site free electricity, saving hundreds of kilograms of carbon emissions per year in the process.

There are no moving parts and PV is silent in operation and highly reliable, minimising the need for maintenance. The modular nature of PV allows for system to be upgraded at any time with ease. Additionally, PV can be incorporated into the actual structure of the building at build stage, as well as being added later, either mounted on the roof, or onto a specially designed frame

How Does Photovoltaic Solar  Power Work?

Solar Power works by the action of the sun's rays on solar panels or tiles made of silicon. These solar panels create an electrical charge which is fed into your home via an inverter.

Solar PV panels can be connected to your home either directly into the national grid, or as an independent source connected to batteries).

PV cells create Direct Current (DC) electricity which needs converting to Alternating Current (AC) electricity via an inverter before being used by appliances around the home or exported to the local electricity grid (for grid connected systems).  The inverter ensures that the voltage output of the system is compatible with your household appliances.

For off-grid systems, the surplus energy produced during the day is stored in a bank of batteries for later use.   A charge controller and converter/inverter are required for charging the batteries, and for adapting the energy produced to levels required by appliances. This can be used as a backup supply during power cuts.

PV can be installed into the home in a number of ways.   You need a site with little or no shading for most of the year and a good south-eastern to south-western aspect.

You can now buy roof tiles which are already impregnated with PV cells. These look more like a conventional roof, although they work in exactly the same way.

Benefits of Solar Power

Free sustainable electricity for your home or other use 

You can sell back your spare electricity to the national grid

If you use battery storage you can have a useful source of back up solar power if the grid is unreliable in your area. 

Cost Benefits of Solar Power

If electricity prices remain static and the price you are paid by the grid remains static, then current payback is around 30 years.

If electricity prices rise by only 10% per year, but the price you are paid by the grid remains static, then payback is around 18 years.

If both prices rise by 10% per year, then payback is under 10 years.