How it works
A solar panel system comprises of photovoltaic (PV) panels and one or more inverters. The panels are mounted on framework connected to the roof structure; alternatively they can be mounted on the ground.
Solar panels comprise of many, smaller units called PV cells. The cell is made up of two layers of semi-conducting material, usually silicon. The panels generate power by allowing photons, or particles of light, to knock electrons free from atoms, generating a flow of electricity. To generate electricity PV cells need to establish an electric field.
To construct a field, manufacturers “dope” silicon with other materials, giving each side of the cell a positive or negative electrical charge. Specifically, they seed phosphorous into the top layer of silicon, which adds extra electrons with a negative charge to that layer. The bottom layer uses boron, which results in fewer electrons, or a positive charge. This makes an electric field at the junction between the silicon layers. When a photon of sunlight knocks an electron free, the electric field will push that electron out of the silicon junction. Metal conductive plates on the sides of the cell collect the electrons which then flow through cables connecting the panels together in an array.
The cells don’t need direct sunlight to work – they can still generate electricity on a cloudy day, albeit not as much. When daylight hits the cells it creates the electric field – the brighter the sunlight, the more electricity is produced. This direct-current (DC) electricity then flows to the inverter(s), which converts it into alternating-current (AC) electricity to be used within the connected building(s).
During the day when solar panels are generating electricity, the power will automatically feed anything connected to your fuse board including machinery, appliances, lighting, etc. When the property’s power consumption is greater than the PV system is generating, i.e. peak demands or after sunset, you will purchase from the grid in the traditional way. Similarly, as solar panels produce electricity when the sun is shining – which does not necessarily correlate with the building’s usage – it is sometimes necessary to export the excess power back to the grid. Alternatively, a battery system can be utilised to store the excess energy and use it later in the day or at night.
The Feed-in Tariff (FIT) scheme is a government programme designed to promote the uptake of a range of small-scale renewable and low-carbon electricity generation technologies.
FITs were introduced on 1 April 2010 and replaced UK government grants as the main financial incentive to encourage uptake of renewable electricity-generating technologies. The tariffs were introduced by the Government to help increase the level of renewable energy in the UK towards the legally binding target of 15% of total energy from renewables by 2020 (up from under 2% in 2009). The UK Government’s Department for Energy and Climate Change (DECC) makes the key decisions on FITs in terms of government policy. The energy regulator Ofgem administers the scheme.
Your energy supplier will make the FITs payments to you. The large energy suppliers are required by law to provide them; smaller suppliers are not, but many have opted to offer them anyway. Applications can usually be made through your current electricity supplier but are not linked to your current purchase contract. You do not need to use the same supplier and you can switch your electricity tariff in line with your current contract in the future. All suppliers offer the same payments and you would therefore expect to keep the FIT scheme with the same supplier for the duration of the payments (20 years).
Once you are receiving FIT payments, the rate you receive will increase in line with inflation in accordance with the Retail Price Index (RPI). There are two aspects to the scheme;
Generation Tariff – this is paid for every unit of electricity produced, irrespective of whether you use it or export it back to the grid. The tariff level is determined by the size of the system, the larger the system the lower the tariff. This reflects the economies of scale achieved by installing the biggest system you can fit or afford within your budget.
Export Tariff – any electricity sent back to the grid receives an additional payment on top of the generation tariff.
In addition to the two above payments, any electricity you consume that has been generated by the PV system is free of charge.
Solar Panels can be mounted either on or within the roof structure; in-roof would generally only be utilised during new construction as the PV system can replace the requirement to purchase roof covering. It is however advisable to mount the panels on framework above the roof, this keeps the panels cooler by improving air flow underneath the panels – therefore aiding efficiency. There are many different types of roof i.e. tiles, corrugated sheets (metal or fibre cement) etc. and consequently there are many different types of fixing methods. Before any installation work is undertaken structural surveys and wind loading calculations are conducted to ensure integrity. Alternatively, the PV system can be ground mounted; multiple panels are mounted on posts secured into the ground at predetermined intervals.
Types of Panel & Comparisons
There are three types of panels to consider, polycrystalline, monocrystalline and thin film. They all have slightly different characteristics and perform better in different scenarios. If space is no issue then the thin film are the ideal choice, they perform better in low light conditions (cloud cover or towards the beginning or end of the day), this results in more kWhs and higher payments through FITs and increased savings. They are also more tolerant to higher temperatures which aids production in the summer months. Poly and Mono require less space resulting in more kWp if the roof space is restricted.
The price per watt does not vary hugely between in the middle range of each type of panel, i.e. 10kW of poly, mono or thin film will cost a similar amount. Albeit, the high end mono panels, which offer the most wattage in the smallest area do carry a premium; usually only worth paying in the space is limited and the main driving factor is to install as much capacity as possible. A bigger price range can be found between different manufacturers, depending on their size, origin and brand power.
To find out which type of panel will suit your building and arrange an initial meeting and/or survey please use our contact form.
Regensys offer a complete turnkey service, meaning you do not need additional trades or contractors on site. We will organise the scaffolding for roof mounted systems and the digging for ground mounted systems. This approach ensures complete transparency on the project cost and ensures we are responsible for the entire PV installation giving you one point of contact in the event of any questions.
Regensys is an established company and provides a complete service for the installation, but also for the lifetime of the system. We offer scheduled and reactive maintenance to ensure your system performs at the optimum level. Please see more detail within the Operations & Maintenance (O&M) section of our website.
Purchase or Funded?
Funding Options for Solar Installations;
Capital Investment – Purchase via reinvesting profits or raising finance. Benefit from payments and savings on utility bill.
Power Purchase Agreement (PPA) – Lease roof space with zero capital outlay. Benefit from savings on utility bill.
Regensys conduct free no obligation assessments to establish the suitability of the property. The preliminary investigation will include generate a site specific report including financial analysis. We will assess your building and the energy requirements through a detailed survey and analysis of the current utility usage, we then cross-reference the data with your objectives to ascertain the best solution to meet your goals. Whether you need to meet a target reduction in CO2 to meet regulations, or have capital to reinvest within the business, or simply want to become less reliant on the grid – we will propose the most suitable options based on our assessments. If you would like to discuss your requirements please give us a call or arrange an initial meeting and/or survey via our contact form.
Operations & Maintenance (O&M)
Our goal is to build long term relationships with our clients, we are not an installer looking to install and forget. We will discuss maintenance options during the design phase and by ensuring we think about these aspects we can reduce future maintenance costs. For example, one area we can explore is future access; by installing a permanent safety system on the roof as opposed to a temporary solution decreases access costs, not only for cleaning and maintenance of panels, but also roof lights, gutters or various mechanical equipment installed on the roof. Please visit our ‘Services’ section.
Monitoring plays a major and important role in O&M and can save money in various ways. Please visit our ‘Monitoring’ tab at the top of this page.
Energy Storage (Battery/Thermal)
Standalone without a Renewable Energy Source
Battery systems are becoming more and more popular now the technology can be delivered at a economical rate. Using low rate electricity at night to charge the battery for daytime usage is the most common application. Equally, off-grid sites can use battery power in conjunction with a generator, the battery can be charged when convenient and the generator can work at maximum output and therefore perform most efficiently.
Complimenting a Renewable Energy Source
During the day when solar panels are generating electricity, the power will automatically feed anything connected to the fuse board including machinery, appliances, lighting, etc. When the property’s power consumption is greater than the PV system is generating, i.e. peak demands or after sunset, the grid will provide the power in the traditional way. Similarly, as solar panels produce electricity when the sun is shining – which does not necessarily correlate with the building’s usage – it is sometimes necessary to ex-port the excess power back to the grid. Alternatively, a battery system can be utilised to store the excess energy and use it later in the day or at night.
It is always better to use the power on site if possible as it has more value. This assumes the electricity tariff is at least 30% higher than the export tariff (it is usually at least 200-300% higher). The reason you need this gap is that storage is not 100% efficient; you will lose 20-30% through the process and therefore the extra saving will pay for the cost of the batteries.
You can potentially improve the financial case for the battery system by charging it overnight on a lower tariff, again assuming the 20-30% rule mentioned above.
There are three types of battery storage solutions to consider:
Back Up ‘Island’ – is the best solution as it allows the PV system to completely separate itself from the grid, thus ensuring you store the maximum amount of power possible. The best percentage return on in-vestment is likely to be found with this option as you utilise all/most of the power. Before considering any battery option ensure it will physically disconnect from the grid; if you are charging the battery from a solar array and it is still connected to the grid there is no way of ensuring all ‘free’ electricity goes to the battery and not the grid.
Grid Assisted – means you are still permanently connected to the grid. The downside is the electricity generated will always take the path of least resistance and may end up exporting more energy when in fact it would still be beneficial to store it by charging the battery. This type of battery system is currently more common in production and therefore a wider variety and increased competition may make it economically attractive in the short term.
Off Grid – is utilised when there is no access to the national grid and allows the end users to be completely off grid. However, depending on the energy demand there may need to be additional power sources to charge the batteries to complement the solar panels i.e. a generator.
Working within the renewable industry has given Regensys a lot of exposure to other renewable energy companies. We have worked with many heat pumps specialists while installing our solar PV systems. This has allowed us to develop relationships with credible, high quality partners. If you would like one point of contact for all of your renewable energy needs, Regensys are happy to oblige and provide a total package using our carefully selected partners; please use our Contact Form to get in touch. Alternatively, you can contact our ground source heat pump partners directly via their website. Please mention Regensys when you speak to them as they will liaise with us to ensure continuity and harmony throughout the design process; although there is no ’direct’ integration of the two systems they do complement each other and certain aspects such as the electrical supply can be looked at simultaneously if required, saving on possible application fees. The Renewable Design Company (http://www.therenewabledesigncompany.com/home/).
Working within the renewable industry has given Regensys a lot of exposure to other renewable companies. We have worked with many solar thermal specialists while installing solar PV. This has allowed us to develop relationships with credible, high quality partners. If you would like one point of contact for all of your renewable energy needs we are happy to oblige and provide a total package using these carefully selected partners.
With payback periods of under one year possible, LED lighting offers a great opportunity to save on the building running costs. It also ensures any solar power generated at the same time covers a higher proportion of the demand.
- Much lower energy consumption, saving money and the environment.
- Much longer life – 20 years – saving on additional outlay further down the line.
- Instant light, they are flicker free and require no warm up time.
- Run at a much lower temperature, improving safety and allowing your more efficient heating system perform the task it is designed to do.