Norfolk Solar - PhotoVoltaic Systems

PhotoVoltaic panels Since the start of the government’s Clean Energy Cashback scheme (also known as Feed In Tariff scheme or FITs), we have been installing grid connected solar PV systems.

The FITs rewards households that generate some of their electricity from small scale PV systems. The exact tariffs paid on electricity generated by such systems varies depending on system size, building type and when the system is installed, but the tariffs available until the end of March 2012 are widely regarded as a generous financial incentive.

Every April (beginning 2012) the tariff rates will be revised, according to how much financial support the government considers PV technology will require, in order to meet targets relating to its uptake by UK consumers.

converting sunshine to electricity

Solar PV modules mounted on a roof are connected to cables and a power inverter. When the light shines on the solar PV modules, a DC electrical current is created which flows through the cables to the inverter. The Inverter alters the DC voltage and current to AC voltage and current, which can be passed to the household consumer unit (fuseboard) for consumption by electrical appliances in the usual way.

There is a meter which measures all electricity generated by the PV system (the generation meter) and this meter reading is used to calculate the main part of the feed-in tariff payable to the household (the generation tariff).

Where there is a surplus of electricity from the PV system (that is not consumed within the building), electricity is automatically exported to the electricity distribution network and a further payment is due to the PV system owner (the export tariff).

In this case, either an export meter would be installed by the electricity supply company (not very common) or the electricity company would estimate the percentage of PV generated electricity that is exported (known as deemed rate; assumed to be 50% of the total electricity generated by the PV system).

If the PV system is generating electricity at the same time as appliances in the building are consuming electricity, energy is automatically supplied from the PV system to the appliances being used.

Each unit of electricity supplied by the PV system and consumed within the building is a unit that does not need to be purchased from the electricity company (a typical saving of 12-14p per unit: prices vary depending on energy supplier and tariff rate).

solar pv circuit

system durability

PV Systems often have no moving parts and so are expected to last for many years. There are two main components; PV modules (the solar panels) and Inverters. Both have typical product warranties of 5 to 10 years depending on the brand, though there are occasional exceptions, and extended warranties can be purchased for some models.

PV modules also typically have a performance warranty for 25 years, which normally guarantees 90% of original output after 10-12 years, and 80% after 25 years.

The worldwide PV industry is very dynamic and there are many new manufacturers offering us products with guarantees longer than their trading history.

Whilst this may not necessarily be bad, Norfolk Solar has built a reputation on quality and this means that our components are sourced from reputable suppliers and established manufacturers.

choosing the right system

As with all technologies there are good and not so good solar PV systems. When choosing a solar PV system there are a number of points to consider

The two main factors affecting the size of a system on most projects are:

initial cost; In almost all cases, PV systems are more expensive than Solar Hot Water systems. Contact us for the latest prices
available roof space; as Solar PV modules are less efficient than Solar Hot Water Collectors, more are needed to deliver a useful energy contribution. A rule of thumb is 7-8 square metres of roof space per one kiloWatt peak (kWp) of modules. KiloWatt peak is a common measure of PV module size, eg: 5 modules with an output of 200 Watts peak is a 1 kWp system

PV modules

We use PV modules from many different manufacturers and make recommendations that are appropriate for each project (most roofs are different!).

PV modules vary in several ways. The main differences are:

Efficiency; this essentially describes the area of roof occupied by a module for a given peak electrical output
Cell composition; there are four main groups – thin film, poly crystalline, mono crystalline and hybrid
Yield; this is the electricity produced over time, in kilowatt hours
Build quality / durability and warranties
Shape and appearance; modules are available in a variety of sizes (some long & narrow rectangles, some short & wide rectangles) and sometimes frame colours can be specified in plain alloy or painted black.

inverters

We use Inverters from proven manufacturers such as SMA, Diehl, Fronius and Mastervolt.

By working with more than one inverter manufacturer, we can choose from a wider range of products in order to get a good match for each project.

To ensure best value and efficiency from the inverter, we check every system design using a sophisticated German computer simulator.

mounting systems

We use a variety of mounting systems to install PV modules; most are designed in Germany and feature a combination of stainless steel and aluminium alloy components to ensure strength and long service life.

typical system output

An array of PV modules facing approximately South at an angle between 30 – 45 degrees from horizontal would be expected to deliver around 800 kiloWatt hours of electricity per year, providing there is little or no shading.

It is possible in many cases to install PV modules onto one or more roofs facing other directions, but less light on average will fall on these roofs compared to South, which will reduce the annual yield and therefore the financial return.

what to do next?

Contact us on 01603 734851 or email: lee@norfolksolar.co.uk to book a technical survey of the property. We will assess whether PV technology is suitable and can discuss the latest information on feed-in tariffs, products etc.

Be assured, we don’t use pressure selling tactics. In fact, we don’t even employ sales staff.

A technical survey is exactly that, so we would need to have a good look around the building, and we won’t outstay our welcome.

To find out more about how we do business, have a look at the why us pages on our website.

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