The Phoenix Works - Photovoltaic Overview V2.3

Installers of energy saving technology

Photovoltaic Overview

www.thephoenixworks.com [email protected] Tel: (+44) 01138 155366

The Phoenix Works is part of Phoenix Renewables LTD Company Registration Number: 7477370

VAT Number: GB 109 6957 79

Photovoltaic Overview V2.3 Date Authorised: 28/04/2016

Author: Thomas Newby Page 2 of 20

Registered Address: Unit 59-62R - Springfield Commercial Centre, Farsley, West Yorkshire, LS28 5LY.

Introduction We have put this document together to explain the technology, design considerations and incentive mechanism for grid-tied solar photovoltaic systems.

Contents

1. About Us

1.1. The Phoenix Works

1.2. Service

1.3. Technology

1.4. Quality

2. Financial Incentive

2.1. The Feed-in Tariff

2.2. Electricity savings

2.3. Export Tariff

2.4. Common questions

2.5. Worked example

3. Design Overview

3.1. System constraints

3.2. Planning permission

3.3. Grid connection

3.4. System performance

3.4.1. Pitch and orientation

3.4.2. Seasonal variation

3.4.3. Shading

3.4.4. Module types

3.4.4.1. Multi/Poly-crystalline

3.4.4.2. Mono-crystalline

3.4.4.3. Amorphous/Thin film

3.4.5. Inverter design

3.4.5.1. String or central inverters

3.4.5.2. Micro-inverters

3.4.5.3. DC optimised inverters

4. Installation

4.1. Workmanship warranty

5. Purchase Options

5.1. Direct purchase

5.2. Finance purchase

5.3. Free solar

6. Terms and Conditions

mailto:[email protected]








1. About us Incorporated in 2010, Phoenix Renewables Ltd trade as The Phoenix Works. Based in Leeds, West Yorkshire, we offer a range of energy saving technologies and specialise in optimised solar photovoltaic systems.

1.1 The Phoenix Works The Phoenix Works is a family business built on reputation, quality and customer service. We have our own highly-skilled workforce and have built excellent relationships with industry leading manufacturers. This enables us to offer our customers systems of the highest quality and specification, at a competitive price.

1.2 Service Customer service is our priority and our customer satisfaction record is testament to this. We deliver all projects in-house with our core team, and in addition, we have established relationships with key partners. By combining resources The Phoenix Works can complete larger projects in a timely, efficient manner, whilst maintaining the high standards by which we are renowned.

1.3 Technology The Phoenix Works have a comprehensive portfolio of specialist products and excellent working relationships with key manufacturers. Manufacturer trained, with extensive product knowledge, we search the market to provide our clients with products which are technically superior, backed by industry leading warranties. In conjunction with manufacturers, all our systems are designed in-house by our highly motivated team of engineers; we install the right technology first time.

1.4 Quality The Phoenix Works will not compromise on quality; our systems are designed to be operational for a minimum of 20-years. Understanding this, we design systems in consideration of levelised cost of ownership. Though this may require a higher initial capital investment, the overall return on investment is greater since our systems are more reliable and consistently outperform those of our competitors.









2. Financial Incentive In April 2010 the UK Government introduced the Clean Energy Cash-back scheme to encourage small scale generation of electricity from renewable sources. Owners of micro-generation systems are paid through the Feed-in Tariff for every unit of power generated by the system.

2.1 Feed-in Tariff Eligible micro-generation systems produce clean renewable electricity from sources such as solar. The output from the system is measured using an approved electricity meter, known as the generation meter. For each unit of power (kilowatt-hour – kWh) the system generates, the owner is rewarded with a payment through the Feed-in Tariff. The tariff rate is dependent on the total installed output capacity (kilowatt peak- kWp) rating of the system, and is paid by the power companies, in accordance with the following table:

System Size Generation Tariff (p/kWh)* Duration (years)

0 - 4 kWp 4.32 20

>4 - 10kWp 4.32 20

>10 - 50kWp 4.53 20

>50kWp - 150kWp 2.38 20

>150kWp - 250kWp 2.38 20

>250kWp 1.99 20

Standalone 0.74 20

*Rates for Solar PV, accurate as of Aril 2016.

Once your system is registered, the tariff is fixed at the current rate plus an annual inflationary increase for the life of the scheme. Depending on the number of systems installed nationally, the current Feed-in Tariff rate is reduced on a quarterly basis. This digression mechanism is designed to track the cost of installation and provide a consistent rate of return. Thus the sooner your system is installed and registered, the better the rate!

2.2 Electricity savings The power generated by the system is available for use on-site in preference to that supplied from the National Grid. By using this clean, free electricity you will consume less power from the grid and consequently reduce your electricity bill. Since the system works in synchronisation with the grid, if the system isn’t producing sufficient power to meet the demand (such as at night,) the extra is supplied from the Grid in the conventional manner.

2.3 Export Tariff In addition to the Feed-in Tariff, in times of high-output, surplus power generated by the system is sold back to the grid. There is a minimum rate paid for this exported power and for larger commercial systems power purchase agreements can be negotiated with utility providers. In these instances The Phoenix Works will help negotiate preferential rates on behalf of our clients. For systems less than 30.00kWp the export isn’t metered and is instead deemed to be 50% of the total power generated.









2.4 Common questions Who can claim the tariffs?

Anyone who installs a renewable energy system producing electricity is eligible to claim the tariff provided they are installed by a Micro-generation Certification Scheme (MCS) approved installer such as The Phoenix Works.

What renewable energy systems are eligible?

Most forms of renewable electricity generation are eligible, such as: hydro, wind, solar PV and micro combined heat and power (CHP) systems.

How do I claim the tariffs?

The payment of the tariff is managed by the utility providers. Though the client is responsible for claiming the tariff, The Phoenix Works will handle all the paperwork on your behalf.

How much are the tariffs?

The Feed-in Tariff rate varies depending on the size and type of system (see chapter 2.1 Feed-in Tariff). Are the tariffs guaranteed?

Yes, they were introduced through and protected by the Energy Act 2008. Also, remember that the Government is legally obliged to hit the EU’s renewable energy commitment and the tariffs are an important means of achieving that.

Who pays for the tariffs?

The tariff is funded by a levy on electricity bills which is passed on by the energy suppliers. The levy typically adds 1-2% to the cost of grid-supplied electricity.









2.5 Worked example Let’s imagine we install a 4.00kWp photovoltaic array, facing due South, on domestic house roof with 35° pitch, in York at a cost of £7,350.00 inclusive of VAT. This system will generate around 3,656 kilowatt hours (kWh) of electricity per year and for this size system the tariff is set at £0.0432 per kWh. 50% of the power generated is consumed and the rest is exported to the grid; the current rate for exporting power is £0.0491 per kWh. By using the clean, free power generated the site reduces the amount of electricity which is purchased from the grid at £0.1400 per kWh:

Example

Year-1

Income from generation tariff: 3,656kWh x £0.0432 £157.94

Income from electricity exported: 1,828kWh x £0.0491 £89.75

Savings on grid-supplied electricity: 1,828kWh x £0.1400 £255.92

Total benefit: £503.61

CO₂ Saving: 2,076.6Kg

Return on Investment: 6.85%

Points to note:

I. To be eligible for the full Feed-in Tariff (or FiT) your property must have an Energy Performance Certificate (EPC) rated “D” or above (this is a measure of how energy efficient your house is). If your property has a rating lower than “D” then the Feed-in Tariff you receive will be significantly lower. The EPC must be issued on or before the commissioning date of the installation.

II. All products and installers must be MCS certified for you to qualify for payments under the FiT scheme. You can read more about this in Renewable Energy Consumer Code (RECC) consumer guide here.

III. The exact level of the Generation Tariff cannot be guaranteed and the date the payments will start cannot be predicted with certainty because this depends on the total number of other FIT applications made by consumers during the relevant tariff period.

Deployment caps introduced in February 2016 limit the generation capacity eligible for Feed-In-Tariff (FIT) support in any given quarterly period. This means that if your FiT application is received after a deployment cap has been exceeded then it will be placed on hold in a queue for assessment for the next quarterly tariff period. Assuming there is sufficient capacity available within the next tariff period (and assuming the installation meets the eligibility criteria for the FIT scheme) then you will receive the tariff applicable for that tariff period. A place in the queue does not guarantee eligibility for a particular tariff or support under FITs.


http://www.recc.org.uk/consumers








3. Design Overview We have outlined below the key factors we consider when designing a solar photovoltaic system. Designing with these considerations in mind allows us to deliver a bespoke solution which meets the individual requirements of our clients.

3.1 System constraints There are three main factors of consideration:

Available installation space

Capacity of the electricity network

Budget

To maximise the financial returns for our clients, in addition to these factors we often size systems in consideration of the Feed-in Tariff payment bands. There is more information on the incentive mechanism in Chapter 2.

3.2 Planning permission

In many instances the installation of a solar photovoltaic system is covered by the General Permitted Development Order and thereby planning exempt. The exceptions to this are as follows:

Installations within a conservation area

Installations within an area of outstanding natural beauty

Installations within a national park

Installations on a listed building

Ground-mounted systems with a footprint over 9m²

Should permissions be required we will lend our expertise and experience to facilitate the application.









3.3 Grid connection When connected to the electricity network, all micro-generation systems which are capable of producing over 16-amps per phase require permission from the Distribution Network Operator (DNO). This is to ensure the system integrates with the electricity network without causing disturbance to other users. Domestic systems generally fall below this threshold and can therefore be installed immediately without permission. The Phoenix Works have extensive experience liaising with the various DNOs. We make the required applications on behalf of our clients and work in consultation with the DNO engineers to realise the most suitable and cost effective design specification. The process of application takes place under a pre-determined time frame. To ensure this doesn’t hold back a project we observe the following process:

a. On request of the client The Phoenix Works prepare an initial design specification Typically within 5-working days

b. The Phoenix Works request a budget quotation from the DNO Typically within 5-working days

c. The DNO replies with an estimate of network upgrade costs where required Response within 10-working days

d. The Phoenix Works produce an installation proposal in consideration of these costs Typically within 5-working days

e. On instruction by the client The Phoenix Works make a formal application for connection Response within 45-working days

f. Any grid works are undertaken and the system is installed









3.4 System performance The output from a solar photovoltaic system depends primarily on the following factors:

Geographical location

Pitch and orientation

Seasonal variation

Shading

Inverter design

Module type

The exact performance of a system is impossible to predict due to annual variations, though the average is fairly consistent. When projecting the output we consider all the above factors and make a prediction based on a worst case scenario according to the industry standard assessment procedure.

3.4.1 Pitch and orientation Generally speaking, for systems located in the United Kingdom, the highest power yield is achieved when the array is inclined at an angle of 35° - 40° facing due south. Though moving away from this optimum will reduce the output, it is often less than perceived and east/west facing arrays are still perfectly viable if un-shaded. The chart below illustrates this in terms of percentage from optimum:

You can see from the chart that an array facing due west at 30° will realise 80% of the power of a system which faces due south. In consideration of this you will often see roof mounted systems where the system is split equally between the eastern and western aspects. This has the added benefit of spreading the production of power through the day enabling a higher proportion of the power to be self-consumed.









3.4.2 Seasonal variation Given the higher solar irradiance available, solar photovoltaic systems produce more power in the summer months in comparison to the winter.

Since projections are based on an annual average, where systems are funded by a finance mechanism which requires regular repayments it is important to consider that the output, and therefore tariff payments, will vary with the seasons.









3.4.3 Shading Any objects which obscure the skyline, thereby shading the array, will significantly reduce the system output. The significance of this is often underestimated; even a small object such as an adjacent chimney, aerial, or distant tree can reduce system output by over 20% with conventional systems. As such, any obstructions should be removed wherever possible. When it isn’t possible to remove obstructions an optimised inverter solution should be specified.

The image below is a snapshot of the data-feed taken from the site shown in the photograph above. You can clearly see the reduction in output caused by the lamppost. If this system employed a conventional string inverter the output would be significantly compromised.









3.4.4 Module types A solar photovoltaic (PV) cell consists of two or more thin layers of semi-conducting material, most commonly silicon. When the material is exposed to light an electrical potential is generated between the layers which is conducted away by metallic contacts. The electrical output from a single cell is small, so multiple cells are connected together and encapsulated (usually behind glass) to form a module which is sometimes referred to as a panel. The PV module is the principle building block of a PV system and any number of modules can be connected together in an array to generate more power.

There are three common types of solar photovoltaic module commercially available:

Mono-crystalline Multi/Poly-crystalline Amorphous/Thin film









3.4.4.1 Multi/Poly-crystalline These cells are made from an ingot of melted and re-crystallised silicon. In the manufacturing process molten silicon is cast into ingots which are then cut into very thin wafers and assembled into complete cells. Poly-crystalline cells are cheaper to produce than mono-crystalline due to the simpler manufacturing process. Though slightly less efficient than mono-crystalline, at around 15%, poly-crystalline cells produce more power in diffuse, low- light conditions (overcast) and are therefore well suited to the Northern European climate.

3.4.4.2 Mono-crystalline Made from a single cylindrical crystal of silicon, the principle advantage of mono-crystalline cells are their higher efficiencies, typically 15-20%. The efficiency rating refers to the proportion of light which is converted into electricity for a given area. The manufacturing process required to produce mono-crystalline silicon is complicated, resulting in slightly higher costs than other types.

3.4.4.3 Amorphous/Thin film Composed of silicon atoms in a thin homogenous layer, rather than a crystalline structure, amorphous silicon absorbs light more effectively so the cells can be thinner. For this reason amorphous silicon is also known as a "thin film" PV technology. Amorphous silicon can be deposited on a wide range of substrates, both rigid and flexible, which makes it ideal for curved surfaces and flexible modules. Amorphous cells are less efficient than crystalline based cells, with typical efficiencies of up to 13%, but yield around 15% more power due to improved low light level performance.









3.4.5 Inverter design Solar photovoltaic (PV) modules convert daylight into DC (direct current) electricity. To integrate with the National Grid this needs to be converted into AC (alternating-current); this process is undertaken by the inverter. There are three main types of inverter:

String or central inverter Micro-inverter DC optimised inverter

The architecture and efficiency of the inverter has a very significant effect on the performance of the system. The Phoenix Works understand this implication in detail and as such specialise in systems where the output from each module is optimised and monitored. We work closely with the manufacturers of this intelligent inverter technology and have more experience than most in their application.

Micro-inverters on a factory roof DC optimisers on a church roof









3.4.5.1 String or central inverter With this design a number of PV modules are connected together in series to form a high-voltage DC string. Depending on the size of the inverter it may often have a number of strings connected to a single device. The inverter examines the output from each string and determines at what voltage and current the maximum power is available; this is known as maximum power point tracking (MPPT). The PV modules within the string act as one larger unit and as such the inverter is unable to differentiate between them.

Since the modules are all connected together in a series chain, the output is governed by the worst performing singular unit; this is often referred to as the fairy light effect. As such, string design, number of MPPTs and array layout is critical. Generally speaking, the modules within each string must be at the same pitch, orientation and un-shaded. Equally, the modules must be electrically identical since the output from each string sits within a strict design window.

The safety implications of the high voltage DC cabling which connects the array to the inverter should be a consideration. Due to the nature of high-voltage DC, a fault within the cabling, switchgear or interconnections can lead to arching, thus presenting a significant fire risk. In addition, since the modules produce power whenever they are exposed to light, there is no way of turning this off! String inverters are typically supplied with a manufacturer warranty of between 5 and 10-years. As such, if not purchasing extended warranties at point of installation, the cost of at least one replacement should be factored into financial projections. Though these systems are typically less expensive to install initially, they are inevitably compromised in real-world applications. The Phoenix Works recognise these limitations and strongly recommend the use of alternative designs.









3.4.5.2 Micro-inverters These devices apply the same principal as a string inverter but the DC to AC conversion process is independent for each module. In addition, by tracking the power-point (MPPT) of each individual module, the output is optimised, increasing the total power harnessed from the system. The system is always able to realise the maximum potential output and is no-longer governed by the worst performing module. Micro-inverters often include the provision to supply data from each unit. The collated data from each module is relayed to a central gateway then uploaded to an internet portal where it can be viewed and analysed. This data can be used to monitor the performance of each module within the array and ensure individual performance is within specification. Micro-inverters carry longer manufacturer warranties since they employ smaller, more reliable internal components. Micro-inverters are mounted underneath each module and the cumulative AC outputs from each unit are connected together; grid-compliant power is delivered directly from the array. A conventional PV module in combination with a micro-inverter is sometimes referred to as an AC module or ACM.

Since the power from each module is converted directly to AC, this configuration is inherently safer since there is no high-voltage DC cabling; the associated fire-risk is eliminated. In addition, for cases of maintenance or emergency, it is possible to shut down the power from the entire system with a single switch.









3.4.5.3 DC optimised Inverter In this configuration a DC power box mounts behind each PV module performing MPPT optimising functions. This output is then converted to a fixed string voltage which, when connect in series with other optimised module outputs, is then inverted to AC power by a simplified string inverter. This process is a hybrid of micro and string inverter systems. By performing MPPT per module it ensures the full array is optimised; by inverting a fixed DC string voltage the optimum voltage for inversion can be achieved. Since the inverter is simplified these units carry longer manufacturer warranties than the string inverters but not typically as long as micro-inverters. This system also has individual module data provision service allowing detailed monitoring of system performance.

Each DC power box requires a signal from the central inverter to operate. If the inverter is shut down for maintenance, or in case of emergency, the DC voltage of the whole system is reduced to a safe level. In addition the inverter is able to monitor the system and shut down the array if DC arc faults are detected. Together these features provide significant safety improvements over convention string inverter systems.









4. Installation The Phoenix Works have a core team of installers who we use on all of our projects. In addition to this we have built relationships with key partners who we appoint to support us on larger installations. By having a highly skilled core team, whilst maintaining relationships with a restricted and select number of others, we are able to monitor and safeguard the quality of our installations. Our core team are experienced in all aspects of installation, roof and ground mounted. We use the highest quality equipment at every stage, ensuring the project delivery is as efficient and as smooth as possible. Any works that we undertake will only be completed whilst adhering to all relevant health and safety protocols; the safety of our workforce and those around is of paramount importance.

4.1 Workmanship warranty The Phoenix Works provide a comprehensive 5-year warranty on all of our works; all hardware warranties are held with the manufacturer. Should a claim need to be made on the hardware warranty, The Phoenix Works will facilitate this on your behalf.









5. Purchase Options Though various funding solutions exist, the three main options are detailed below:

5.1 Direct purchase In this instance the client purchases the system outright. This is usually achieved either through a cash purchase, self-sourced finance or a mixture of both. Direct purchase is subject to our standard payment terms.

5.2 Finance purchase

Through our finance partners we are able to provide funding at competitive rates. The benefit from the system is still greater than the capital and interest repayments, though the breakeven point is longer than with systems purchased directly.

5.3 Free solar

Domestic – The client enters into a lease agreement effectively renting their roof space. In exchange for this rent, the homeowner is able to use the power generated by the system free of charge. The investor collects the tariff payments thereby realising a return on their investment. Commercial – The property owner enters into a lease agreement with the funder who provides the installation and maintenance of the system in exchange for providing the generated power at a reduced rate in comparison to grid supplied energy.

6. Terms and Conditions

To proceed with an installation were require the complete Contract of Sale document and deposit payment; our payment terms are as follows:

Domestic Commercial

10% deposit 10% to secure the project

Balance on completion of the project 40% on order of materials 25% when the materials are delivered to site Balance on completion of the project

Our preferred method of payment is BACS bank transfer. As described in the terms of the RECC Code, you are provided with a 14-day cooling off period from the date we receive the signed contract; unless otherwise instructed, no works will commence before this date. Upon receipt of the signed contract we will contact you to detail a timescale for the works. In line with the terms outlined in the contract quotations are valid for a period of 30-days.


Tel: 0113 8155 366

Email: [email protected] Web: www.thephoenixworks.com

Unit 59-62r – Springfield Commercial Centre, Bagley Lane, Farsley, Leeds. LS28 5LY

Documents

The Phoenix Works - Photovoltaic Overview V2.3