Solar Electricity Handbook

212 Pages·2017·4.18 MB·English

by  Michael Boxwell

Greenstream Publishing Limited
70 Olton Boulevard East
Birmingham
B27 7NG
United Kingdom
www.greenstreampublishing.com
Published by Greenstream Publishing Ltd, 2017.
Copyright © 2009–2017 Michael Boxwell.
All rights reserved.
Kindle eBook edition: ISBN 978-1-907670-67-1
First Edition published April 2009
Second Edition published November 2009
Third Edition published March 2010
Fourth Edition published January 2011
Fifth Edition published October 2011
Sixth Edition published February 2012
Seventh Edition published December 2012
Eigth Edition published December 2013
Ninth Edition published January 2015
Tenth Edition published April 2016
Eleventh Edition published January 2017

Michael Boxwell asserts the moral right to be identified as the author of this work.
A catalogue record for this book is available from the British Library.
While we have tried to ensure the accuracy of the contents of this book, the author or publishers cannot be held
responsible for any errors or omissions found therein.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any
form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of
the publishers.
Table of Contents
Table of Contents
Introducing Solar Energy
Who this book is aimed at
The rapidly changing world of solar energy
Solar electricity and solar heating
The source of solar power
The principles of solar electricity
Understanding the terminology
Setting expectations for solar electricity
Why choose a solar electric system?
Cost-justifying solar
Solar power and wind power
Fuel cells
Solar electricity and the environment
In conclusion
Making and saving money with solar
The ever rising cost of energy
Installing electricity to a new building
Subsidies, grants and other financial incentives
In Conclusion
A Brief Introduction to Electricity
Don’t panic
A brief introduction to electricity
How to measure electricity
The relationship between volts, amps, ohms, watts and watt-hours
Low current and high current systems
A word for non-electricians
In conclusion
The Four Configurations for Solar Power
Stand-alone/off-grid
Grid-tie
Grid-tie with power backup (grid interactive)
Grid fallback
How grid-tie systems differ from stand-alone
In conclusion
Components of a Solar Electric System
Solar panels
Batteries
Controller
Inverter
Electrical devices
Connecting everything together
In conclusion
The Design Process
Short-cutting the design work
Solar energy and emotions
In conclusion
Scoping the Project
Designing grid-tie or grid fallback systems
Fleshing out the scope
Producing a power analysis
When you are ready to proceed
Calculating inefficiencies
When do you need to use the solar system?
Keeping it simple
Improving the scope
In conclusion
Calculating Solar Energy
What is solar energy?
Solar panels and shade
Solar array power point efficiencies
The effects of temperature on solar panels
Working out an approximate cost
Working out dimensions
In conclusion
Surveying Your Site
What we want to achieve
First impressions
Positioning the solar array
Identifying the path of the sun across the sky
Shading
Positioning batteries, controllers and inverters
Cabling
Site survey for the holiday home
In conclusion
Understanding the Components
Common components for all systems
Solar panels
Solar panel mountings
Solar array cables
Solar array connectors
Fuses and isolation switches
The importance of using the correct cables, connectors and isolation switches
Ground fault protection
Components for Grid-Tie systems
Grid-tie solar panels
Grid-tie inverters
Components for Stand-Alone Systems
Calculate your optimum voltage
How to calculate your current
Calculating cable thicknesses
Mixing and matching solar panels
Batteries
Solar controller
Inverters
Cables
Plugs and sockets
Appliances
Reputable brand names
Shopping list for the holiday home
In conclusion
Planning, regulations and approvals
National and international standards for solar components
Installation regulations
Getting your electricity supplier involved
In conclusion
Detailed Design
Safety is designed in
Solar array design
Batteries
Specifics for a grid fallback system
Circuit protection
Cable sizing and selection
Some sample wiring diagrams
The next step
Solar frame mounting
Positioning batteries
Planning the installation
In conclusion
Installation
Safety
Assembling your toolkit
Preparing your site
Testing your solar panels
Installing the solar array
Installing the batteries
Installing the control equipment
Installing a grid-tie system
Commissioning the system
Charging up your batteries
Connecting your devices
In conclusion
Troubleshooting
Keep safe
Common faults
Excessive power usage
Insufficient power generation
Damaged wiring/ poor connections
Weak battery
Inverter issues
Maintaining Your System
Internet Support
Tools available on the website
Appendix A – Typical Power Requirements
Household and office
Garden and DIY
Caravans, boats and recreational vehicles
Appendix B – Living Off-Grid
A solar electric system in conjunction with grid electricity
Grid Fallback and Grid Failover systems
A Final Word
Introducing Solar Energy
Ninety-three million miles from Earth, our sun is 333,000 times the size of our planet.
With a diameter of 865,000 miles, a surface temperature of 5,600°C (over 10,000°F)
and a core temperature of 15,000,000°C, it is a huge mass of constant nuclear activity.
Directly or indirectly, our sun provides all the power we need to exist and supports all
life forms. The sun drives our climate and our weather. It’s a huge energy source.
Without it, our world would be a frozen wasteland of ice-covered rock.
So harnessing that power from the sun and using it to power electrical equipment is a
terrific idea. There are no ongoing electricity bills, no reliance on a power socket,
simply a free and everlasting source of energy that does not harm the planet!
Of course, the reality is a little different from that. Yet generating electricity from
sunlight alone is a powerful resource, with applications and benefits throughout the
world.
So how does it work? For what is it suitable? What are the limitations? How much does
it cost? How do you install it? This book answers all these questions and shows you
how to use the power of the sun to generate electricity yourself.
Along the way, I will also expose a few myths about some of the wilder claims made
about solar energy and I will show you where solar power may only be part of the
solution.
I will keep the descriptions as straightforward as possible. There is some simple
mathematics and science involved. This is essential to allow you to plan a solar electric
installation successfully. However, none of it is complicated and there are plenty of
short-cuts and online calculators at www.SolarElectricityHandbook.com available to
keep things simple.
The book includes a number of example projects to show how you can use solar
electricity. Some of these are very straightforward, such as providing electrical light for
a shed or garage, for example, or fitting a solar panel to the roof of a caravan or boat.
Others are more complicated, such as installing photovoltaic solar panels to a house.
I also show some rather more unusual examples, such as the possibilities for solar
electric motorbikes and cars. These are examples of what can be achieved using solar
power alone, along with a little ingenuity and determination.
I have used one main example throughout the book: providing solar-generated electricity
for a holiday home which does not have access to an electricity supply from the grid. I
have created this example to show the issues and pitfalls that you may encounter along
the way, based on real life issues and practical experience.
A website accompanies this book. It has lots of useful information, along with a suite of
online solar energy calculators that will simplify the cost analysis and design processes.
The website is at www.SolarElectricityHandbook.com.
Who this book is aimed at
If you simply want to gain an understanding about how solar electricity works, then this
handbook will provide you with everything you need to know.
If you are planning to install your own stand-alone solar power system, this handbook is
a comprehensive source of information that will help you understand solar and guide
you in the design and installation of your own solar electric system.
Solar has a big application for integrating into electrical products such as mobile
phones, laptop computers and portable radios. Even light electric cars can use solar
energy to provide some or all of their power requirements, depending on the
application. If you are a designer, looking to see how you can integrate solar into your
product, this book will give you a grounding in the technology that you will need to get
you started.
If you are specifically looking to install a grid-tie system, i.e. a solar energy system that
will feed electricity back into your local power grid, this book will provide you with a
good foundation and will allow you to carry out the design of your system. You will still
need to check the local planning laws and any other local legislation surrounding the
installation of solar energy systems, and you will have to understand the building of
electrical systems. In some countries, you need to be certified in order to carry out the
physical installation of a grid-tie system.
If you are planning to install larger, commercial–size systems, or hoping to install grid-
tie solar systems professionally, then this book will serve as a good introduction, but
you will need to grow your knowledge further. This book gives you the foundations you
need to get started, but there are special skills required when designing and
implementing larger scale solar systems that go far beyond what is required for smaller
systems and are beyond the scope of this book.
If you are planning your own solar installation, it will help if you have some DIY skills.
Whilst I include a chapter that explains the basics of electricity, a familiarity with
wiring is also of benefit for smaller projects and you will require a thorough
understanding of electrical systems if you are planning a larger project such as powering
a house with solar.
The rapidly changing world of solar energy
I implemented my first solar energy system in 1997. Back then, the largest panels I could
buy were 100Wp panels. Each panel was around 9% efficient. The cost for the ten
panels I needed to create my 1kWp array was almost £10,000 (around $13,000).
Today, solar panels can be up to 24% efficient. They have a far higher capacity, a longer
life expectancy and they are far cheaper. If I were to recreate my first 1kWp array today
using larger, modern solar panels, the panel price would be around £400 ($530).
Ignoring twenty years of inflation, that is a 96% drop in the ticket price for a solar
panel!
Of course, there is more to the installation cost than just the solar panels alone. Cabling,
inverters, batteries, mounting brackets and time all cost money, and most of those prices
have increased in the past twenty years, but the fact remains that solar has been
transformed from an obscure niche product to mainstream energy generation because of
incredible leaps in the technology that has made solar more efficient and more
affordable.
I wrote the first edition of this book early in 2009. This 2017 issue is the eleventh
edition. Most editions have included significant rewrites in order to keep up with the
rapid pace of change, and this edition is no exception.
The rapid improvement in the technology and the freefall in costs since early 2009 have
transformed the industry. Systems that were completely unaffordable or impractical just
two or three years ago are now cost-effective and achievable.
Solar panels available today are smaller, more robust and better value for money than
ever before. Battery storage has become more reliable and far cheaper. For many more
applications, solar is now the most cost-effective way to generate electricity.
Government incentives to promote renewable energy sources have also changed why
people install solar. In countries like Germany, the United Kingdom, Spain and in the
southern states of the United States, residential solar is becoming a common sight. Solar
is making a big impact in the way that countries generate electricity. In the past two
years, solar panels have produced over 50% of the nations electricity during peak
production periods in summer. The United Kingdom is not far behind, with over 35% of
the nations electricity coming from solar power on sunny days in summer.
Over the coming years, all the signs are that the technology and the industry will
continue to evolve at a similar pace. In the 2012 edition I claimed that solar will be the
cheapest form of electricity generator by 2015, undercutting traditionally low-cost
electricity generators such as coal-fired power stations. I was wrong. In reality, we
reached that cross-over point in many parts of the world by the middle of 2013. Huge
solar farms are becoming a common sight, not just in wealthy parts of the world with
hot, sunny climates such as in California and the southern parts of Europe, but in Canada
and northern Europe where weather is less predictable and also in India and China,
where solar was an unaffordable luxury only two or three years ago.
Between 2009 and early 2014, prices of solar panels were in freefall, dropping by as
much as one-third each year. Since then solar panel prices have continued to fall by
around 10% per year. As a consequence, the cost of a solar panel today is less than one
sixth of its price eight years ago.
As prices have fallen and efficiencies improved, we have seen solar energy