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PHOTO VOLTAIC
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PV Power Introduction
If we could harness Solar PV generated power we could produce thousands of times more energy than the world currently uses today. A small fraction of the Mohave Desert covered with PV could generate all! the world's electricity requirements. Over 34 tonnes of greenhouse gas emissions could be saved from a single Households PV clad rood during its lifetime. PV powers TV and communication satellites because in the heavens there is no mains power and the earth shares this power input from the sun of 2 x 1017 Watts which dwarfs the capabilities of fossil fuels or nuclear fission. Billions of people on earth have no electricity and derive their energy comes from high cost alternatives whose are greater than the cost of a quality solar home system. Many buildings use cladding materials that cost £1000 per square metre. By contrast, solar PV cladding - which can look every bit as attractive as marble or bronze - costs as little as £500 per square metre.
Why solar for the Home user?
It is a great selling point for a house because it is equivalent to having your very own power source. It is helping the world to conserve energy and provider a cleaner safer world for you and your family
Benefits
The benefits of a solar roof are: ·
- A clean power source that helps reduce global warming ·
- Reduction in your electricity bills ·
- Increases the desirability of your property
- Very low maintenance and lifetime of 30 years plus ·
- Noiseless and unobtrusive
The word photovoltaic is a marriage of the words 'photo', which means light, and 'voltaic', which refers to the production of electricity. Photovoltaic technology generates electricity from light. Electricity is the existence (either static or flowing) of negatively charged particles called electrons. Certain materials, called semi-conductors, can be adapted to release electrons when they are exposed to light. Silicon is the most common of these materials with 98% of solar PV cells made today from it. All PV cells have at least two layers of such semiconductors: one that is positively charged and one that is negatively charged. When light shines on the semi-conductor, the electric field across the junction between these two layers causes electricity to flow - the greater the intensity of the light, the greater the flow of electricity.
Types of PV System
These are shown in order of common installations found today.
Off-Grid
Completely independent of the grid, the solar system is directly connected to a battery, which stores the electricity generated, and acts as the main power supply. An inverter can be used to provide AC power, enabling the use of normal appliances without mains power.
Grid Connected
The most popular type of solar PV system for homes and businesses. The solar system is connected to the local electricity network allowing any excess solar electricity produced to be sold to the utility. Electricity is taken back from the network outside daylight hours. An inverter is used to convert the DC power produced by the solar system to AC power needed to run normal electrical equipment.
Hybrid System
A solar system can be combined with another source of power - a biomass generator, a wind turbine or diesel generator - to ensure a consistent supply of electricity. A hybrid system can be grid connect, stand-alone or grid support.
Roof Suitability
A guide to assessing the solar potential of your home.
Location:
Shaded locations by objects like trees or buildings should be minimised.
Orientation:
PV is most effective on those facing south but can work on any roof. A north-facing PV roof will generate about 40% less than a south-facing one.
Inclination:
PV products are suitable for pitched, flat and curved roofs with roof angles from 25o - 40o.
Area Installed:
The greater the surface area the greater the power potential. For a grid-connected system the minimum required area is approximately 10 m2.
Planning permission:
PV roofs do not usually require planning permission unless the building is listed or in a conservation area. However you should always call your council to check on local policy. Selling your electricity Grid connect systems allows you to take part in net metering. This means that any electricity you generate but don't use is sold back to your electricity supplier and when you are not generating enough (e.g. at night) you buy it back at the same price.
Planning guidance
Who needs to apply for planning permission? The majority of solar panels installations typically fall within what are known as "permitted development rights". This means that, if a solar panel or system is more or less flush with an existing roof, the council will not ask for a planning application. However, if you live in a listed building, a National Park, an Area of Outstanding Natural Beauty, a conservation area, or an area covered by an "Article 4" direction from the local council, you may need to put in a planning application.
We advise you to check with your local council before installing a solar system. Planning permission may be required If the installation project significantly beyond the roof plane where it faces a public right of way or the solar array is so large the roof or house exceeds that house's permitted development limit. Solar arrays that face away from roads and footpaths are unlikely to need a planning application.
Building Control
Building Control will need to be informed of the proposed changes. Unlike Planning, Building Control may charge if they decide to make a site visit. This charge varies from council to council.
Social Housing
PV panels can play a significant role in assisting the social housing market in providing affordable homes for the less well off in our society.
Benefits
"No other energy technology has the scope to help in the regeneration of our cities." Richard Rogers, 'Towards Urban Renaissance' Solar PV shows a Councils vision and your commitment to progressive community development and develops Agenda 21 proposals for their community. A high visibility, low risk innovative project becomes more appealing to residents, employees and investors both in the public and private sector. It demonstrates commitment to building a sustainable Britain for all our citizens. Funding "I want to see thousands, rising to tens of thousands of roof covered in solar panels every year over the next ten years." Brian Wilson, Energy Minister, 2001 A solar support programme started on May 1st 2002, the Major Development Programme (MPD1). Housing Associations and Housing Developers are eligible this particular phase of the support programme is due to run until June 2004. With a high visibility, low risk innovative project your association becomes more appealing to residents, employees and investors
Schools and Colleges
Solar PV is already being installed in UK, an obvious benefit is that during the long summer break and other holidays the schools can actually capitalise on the energy being produced by selling it back to the national grid. By doing this the schools can offset the cost of their electricity consumption during the rest of the year. Many schools are fitted with architectural standing seam roofs, which lend themselves perfectly to PV standing seams. In addition, schools normally have high levels of flat roof space, which can be easily adapted to energy generation with no structural interference.
There are numerous environmental benefits, which include:
- · The non-fossil fuel contribution to electricity use leads to the displacement of one or more tonnes of carbon dioxide per year (depending on system size) - a positive solution in combating climate change ·
- No emissions or noise of any kind are produced over 30+ years of use - combating air pollution (and hence asthma incidence) and acid rain.
- Solar cells are recyclable and have usually been produced from recycled silicon from the computer industry ·
- Silicon-based solar cells have no toxic parts and present no hazard to students during installation, use or disposal ·
- Well-installed solar arrays require little or no maintenance during their lifetime and are usually guaranteed for up to 20 years
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