Buying Guide
The Future Is Electric
It is now possible to become almost entirely self-sufficient in your energy requirements. Until relatively recently, solar panels have not always been the best investment as returns could not necessarily always recover the initial installation cost. With the Government-sponsored Feed-Tariff stopped and with recent increases in electricity prices, it is once again financially beneficial to install solar energy. Especially so when you also maximise opportunities for utilising your solar energy such as installing a Hot Water System and an EV (Electric Vehicle) charging point.
Solar Panels
Panel Types
There are 4 ways that commercial solar panels can be manufactured. We summarise these below.
1. Monocrystalline
These are the most common and are made from silicon wafers cut from a single crystal. They are more expensive than polycrystalline panels, albeit they produce more power and tend to maintain output better.
2. Polycrystalline
This type of panel is made up of silicon wafers pressed from crystal fragments. They are cheaper to manufacture, but do not have the durability or output of monocrystalline panels. Production techniques are constantly improving however, so it is possible that they may be more worthwhile in future.
3. Thin Film
A technique whereby a compound is coated onto a base - usually glass. They are more durable but power outputs are not so great. On the plus side, they are relatively inexpensive so may be worth considering if space is not restricted.
4. Hybrid
The Panasonic panel in particular, produces considerably more power because these panels combine two types of technology. They use the usual solar cells built from silicon wafers and combine these with a thin film of sunlight reactive material that produces extra electrical output.
Panel Efficiency
The efficiency of solar panels is solely a measure of how compact they are and has nothing to do with their electrical efficiency. Efficiency figures tell you how much power is generated per square meter, so more ‘efficient’ panels will use less roof space for a given output.
If you do not have enough roof space for a full system but you still want to maximise output, a more ’efficient’ panel will generally allow you to install more wattage. However, panels have varying dimensions and proportions. You may be able to fit more of one panel on your roof than another and thus be a better choice overall. A full solar survey will be able to best identify the ideal configuration.
Performance :
Temperature Coefficient
Another factor affecting how much power a panel can produce is its temperature coefficient. This measures how the power output reduces as the panel gets warmer. The nominal rating of a panel is calculated at 25 degrees C and for every degree warmer, the power output drops by the temperature coefficient which typically ranges from 0.3% at best to 0.38% at worst.
Power Tolerance
Power tolerance is a percentage figure showing how stated power output can vary. Usually this is around 3% so a 100W panel would be in the range 97% - 103%. This can have a considerable effect as the total power output is only as good as the weakest link in the chain. One poorer performing panel in a string of panels reduces the total available power. This is built in to the government SAP calculations.
Some are worse than others, notably the Panasonic panels have a greater variability (+10%/-5%). If you are lucky you get a really good performing array, on the down side there is a chance that a poor panel could bring the whole array down by almost 5%!
Summary
Most panels generally perform in very similar ways and the only real measure is how they perform once installed. Furthermore, we look carefully at published real data and tend to recommend JA Solar and Jinko panels for their blend of durability, performance and cost effectiveness.
Grid Tie Inverters
Grid Tie Inverters
The inverter is usually located in your loft and is responsible for converting the DC electrical power from the panels into a usable domestic AC supply.
Efficiency
Unlike panels, the efficiency of the inverter is important for power output. The higher the efficiency then the less power is wasted in the conversion process. This efficiency is measured as a percentage with the best inverters now over 98% efficient and the worst around 92% efficient. Be careful, there are often 2 figures mentioned. Maximum efficiency is often quoted but is rarely achieved, a more realistic figure is given by the Euro Efficiency measurement which calculates performance in a more realistic manner.
Life Span
Inverters will need replacing at some point. Panels can go on for a long time, early manufactured panels, made about 50 years ago are still running but with greatly reduced outputs (by about 2/3). Inverters however don't really degrade over time - instead, they suddenly fail. As many of those on sale today have not had the full test of time, their comparative reliability is unknown. Lifetimes are typically expected to be around the 12-15 year mark. There will therefore be a replacement cost at some point but it should be relatively affordable for most domestic installations.
Well Known Manufacturers
Solar Mounting System
Mounting Systems
Mostly manufactured from aluminium and zinc alloys this part of your installation will be tough and long lasting. They will probably still be stuck together long after the building beneath them has disintegrated. Once the panels active life is over, you will probably be able to replace the panels using the existing mounting system. We use the best quality on the market.
Micro-generation Certification Scheme (MCS)
To qualify for the Smart Export Guarantee, installers MUST be registered under the Micro-generation Certification Scheme (MCS) that carries detailed guidelines about the quality and specifications of any installation. The UK Government also used the opportunity of this regulation to ensure that installers operate under strict insurance, health and safety, plus fair trading standards.
Benefits of having solar energy:
Taking Care Of Your Investment
The long term nature and benefits of a solar PV installation are best realised with periodic cleaning, maintenance, monitoring and regular software updates, carried out at your convenience to ensure the optimal outputs from your system over its full life cycle. UK Solar Power Panels offers a comprehensive Solar Care Plan in a range of affordable packages tailored to your individual installation.