The Renewable Energy Home Handbook

Introduction & acknowledgements

Since the early 1980s, I’ve been writing and publishing technical books – and I hope they’ve been helpful and friendly technical books – on motor vehicle and associated subjects. Over the same period (and longer) my wife, Shan, and I have designed, built and continuously modified our own house. And always with more than half an eye on conservation and sustainability.

In fact, our first designs for the house where we still live were produced in the 1970s, during which time I spent many hours in Dudley Library, researching building regulations and finding, by chance, the then-current Swedish standards of house insulation. I was amazed, at the time, to discover that the additional cost of building a house to those Scandinavian standards of insulation – roughly equivalent to the UK’s requirements for houses built from about 2012 – was scarcely greater than that of building the almost universal ‘gas-guzzling’ houses. So, we built our house the Swedish way, with not just loft insulation but also floor and foam wall insulation (with a wider cavity between the courses than was normally used); insulating wall blocks and wall boards instead of brick and plasterboard; double-glazing, of course; insulated pipes and lots more. It was so radical then, but so obvious now.

So, while writing about cars (and I included the relatively eco-friendly fuels we used ourselves such as bio-diesel, LPG power and straight vegetable oil conversions), we were actively thinking and living an earlier version of energy saving.

In recent years, we’ve gone much further, with a large, solar electricity-generating, photo-voltaic (PV) array, solar water heating, a ground-source heat pump and vegetable oil-powered emergency generator, along with all-LED lighting a range of energy-conserving heat controls ... so, what could be more sensible than to write a book about it all?

Until I started on this book, I thought I knew quite a lot about renewable energy. But when all the research began, I discovered just how much I didn’t know. I learned long ago to follow the advice of Robert Persig (author of Zen and the Art of Motorcycle Maintenance) – and to encourage others, particularly children, to do so – which is: don’t feel bad when you find you don’t know something. Be pleased, instead! It’s not a sign of failure or inadequacy; it’s a great opening; something to celebrate; a golden opportunity. And so, I’d like to thank the following people for helping me to make the most of my golden opportunity to learn stuff, some of which I didn’t even know that I didn’t know – if you see what I mean ...

We live near the border between Worcestershire and Herefordshire in central England, and it’s been a delight to find several of the top ‘renewable’ gurus within these two counties. All of them are passionate about their areas of saving CO, saving money, and saving the planet. In order of nearest to furthest from where we live, Simon Holden and Euroheat (HBS) Ltd brings an impressive range of business and educational skills to the field of biomass heating. Paul Hutchens and the crew at Eco2Solar have developed similarly high standards, with special reference to PV electricity generation, as well as solar water heating: installing systems from small-scale domestic right through to large-scale commercial premises. Simon Watts at Eco-Nomical concentrates on domestic installations, including those with a more hands-on approach. The Matthews family at the Efficient Energy Centre is an expanding company, concentrating on bio-fuel and air source heat pump installations, and last, but not least, Leading Edge Turbines combine high standards of engineering with a refreshing honesty about the limitations as well as the advantages of domestic wind turbines. There are three special features that link all of these guys, as well as all the other specialists I mention here. They’re passionate about renewables. They’re incredibly well informed. And they’re as honest as they come!

Moving further afield from chez nous, Newark Copper Cylinders was a mine of information on what is a specialised subject. Mitsubishi Electric Europe BV was wonderfully knowledgeable and helpful about the whole subject of air source heat pumps, while Mike Freeman of Ice Energy is a really helpful bloke who provided much invaluable advice about the installation of ground-source heat pump systems.

The German companies ATAG and Renusol GmbH, along with Ubbink UK Ltd (founded in the Netherlands), displayed technical virtuosity in their respective fields of solar PV and solar thermal systems and fixings, while, from California, Charles Landau – with his website www.solarpaneltilt.com – has provided an almost consummate combination of theoretical calculations and practical measurements with regard to how best to harness solar insolation for PV arrays.

The extraordinary range and depth of practical knowledge exhibited by the Energy Saving Trust can’t be overstated while, at the hands-on level, Screwfix Direct produced an amazing range of fittings and materials on a same-day or next-day basis; Makita UK reinforced my already firmly held belief that its hand power tools are the best in the world, while the same status for consumables undoubtedly goes to Würth, whose products I have sworn by for many years.

In the fields of energy-saving, StormDry, Simply LED and Eco-eye wireless electricity monitors have all proven themselves with top quality products.

I’d also like to thank Rod Grainger and everyone at Veloce Publishing. Rod commissioned my first book right at the start of the ’80s (and Rod also built his own house with business partner Jude Brooks – so they know what it’s like!), and this book has been honed, developed and produced with great professionalism by the Veloce team. And more than anything, I’d like to thank my wife, Shan. She’s been my ‘through thick and thin’ partner in everything we’ve done over the decades, and this book is a tribute to her in every way imaginable.

Finally, following the approach of PG Wodehouse, who thanked his step-daughter, Leonora, in similar vein at the start of one of his books, I’d like to thank our five ‘rescue’ dogs and eight cats, without whose unceasing support and attention this book would have been finished in half the time.

Lindsay Porter

Chapter 1

Introduction to home renewable energy

So, like me, you’re interested in renewable energy. What does that make us? Tree-huggers? Fruit cakes? Hippies? Or could it be that we’re just smarter than those who still don’t ‘get’ it? And if that sounds just a touch too self-congratulatory – oh, who cares! – and here’s why ...

• You can actually make money by installing renewables. You’re future-proofing your fuel costs in a world where fuel prices are almost certain to rise. And in many countries, you’ll actually be paid by the government to generate power. (Well, we already subsidise other fossil fuel and nuclear power systems via our taxes, so why not? It’s a great deal for the taxpayer!)

• Because it’s the right thing to do! You’re cutting your output of greenhouse gases and helping to make life more bearable – even possible – for generations to come.

• You’re investing in energy that has none of the enormous risks associated with nuclear power.

• You’re creating energy that can and will be renewed. Oil, coal and gas will run out one day. The wind, the sun, growing plants, human waste, heat in the ground: none of these is likely to cease before Hell freezes over!

Our own house on the day the very first of the renewable energy installations that were to be carried out there began. It’s now equipped with a biomass log burner and water heater; solar PV electricity generation; solar thermal hot water; a ground-source heat pump, and a vegetable oil-powered generator. It’s still connected to the grid, and electricity is sold back to the electricity company.

The great thing is: renewable energy exists freely in nature and will never run out, unlike fossil fuels. But not only that, there’s also the problem that burning fossil fuels creates greenhouse gases. Fossil fuels were formed in prehistoric times, incorporating unimaginably large amounts of greenhouse gases at the same time. As the fuels are burned, these gases are returned to the atmosphere for the first time in millions of years. When those fossil fuels are gone, they’re gone. For all time. And maybe we, the human race, will be, too. Climate Change Deniers say it might not be true. They could, against nearly all the evidence, be right, but it’s a chance I’m not prepared to take ...

WHAT’S INSIDE THIS MANUAL

In this manual, you’ll read about all the major, currently available, renewable technologies and how they are installed by the experts. For health and safety reasons, we advise that almost all of this work be carried out by qualified professionals. And in order to qualify for some government grants and payback tariffs, you’ll have to have the work professionally carried out and certified, in any case. But seeing how the work is carried out provides a unique insight into how these systems are installed and how they work in detail.

You’ll get a much better idea which, if any, of these technologies are suitable for your property and for your personal circumstances. For instance, a central heating system run by a heat pump requires no more involvement, once installed, than any gas-powered system; perhaps less. However, a ground-source air pump system can require a lot of garden area and a huge amount of disruption, which you may not be prepared to tolerate. On the other hand, a wood-burning central heating system need not require a great deal more than swapping (say) an oil-fired boiler for a biomass one, with some provision for storage of wood pellets, for instance, and it will involve some stocking, moving and lifting of sacks of pellets. And traditional log wood burners involve even more – a lot more – work, as I well know! You’ll see it all laid out in this manual.

DOWNSIDES

I recently saw an American online advert claiming, ‘Install renewables and get your money back in three years!’ That’s simply not possible in the vast majority of cases, and while – in Europe at least – it’s against the law to tell blatant lies in advertising, advertisers are naturally keener on the upsides than any downsides attached to ‘their’ technology. In this manual, I’ve tried to point out the ‘Againsts’ as well as the ‘Fors’ and I hope that showing how the work is carried out helps provide a better all-round picture.

BE A CLEVER CUSTOMER

Dave Samuels at Leading Edge Turbines tells me that his aim is to have ‘clever customers’: those who understand enough about the subject to be able to contribute to the decisions that have to be made. It’s a great aim for any specialist to have – and you should beware the ones who would rather you were kept in the dark!

Some installers seem to find renewable technology difficult to understand – though that certainly doesn’t apply to any of the specialists featured here. Some technologies are inherently more complex than others; solar water heating and electricity generation (PV) are among the simpler systems to design. Wind turbines are not inherently complex, but you do need an adviser who is honest and realistic about the potential for your site. Some have been installed in locations where it is impossible for them to work effectively. Technologies that heat the house, whether heat pumps or biomass burning boilers, have the greatest scope for mistakes to be made by the ill-informed: possibly something to do with the fact that these technologies, while by no means new, have only been used large-scale in very recent times, so installers and designers have less accumulated knowledge, while statistical, factual information on what works and what doesn’t is still being compiled. So it’s essential that you choose your installer well. Don’t just go on company size or whether or not they are accredited. Try to find and speak to others who have used the company previously. Do your own homework; find out as much as you can about the technology you have chosen, and, if you find you know more than your potential installer, look elsewhere!

• The better informed you are the more chance you will spot a less able installer.

• When your building is surveyed pre-quote, find out if the surveyor is an engineer (ask for qualifications) or a sales person. If it’s the latter, politely ask them to go away again. As you will see from this manual, there’s a lot of technical ‘stuff’ that has to be understood, calculated and assessed. Unless you’re a qualified engineer, you can’t do it. All most sales people can do is tick boxes.

• Try to buy from an installer who is local or who has a network local to you. If your renewable central heating system goes wrong, or your electricity generation system fails and you’re told, We won’t have an engineer in your area for another three weeks, understandably, you won’t be too happy.

In the UK, the Energy Saving Trust, a body set up by the government, is enormously influential, and produces invaluable information on all aspects of energy saving and renewable energy choice and installation. Its ‘recommended’ logo is applied to a wide range of goods and technologies approved by the organisation. It’s a mark you really can trust, and the website is full of excellent general advice on energy saving of all kinds.

UPSIDES

None of the foregoing is intended to sound too negative – it’s there so that you, the potential customer, can plan for the enjoyment and satisfaction, as well as the cost-savings, that a well-planned and well-installed renewable system can bring. In fact, make this manual one of your upsides! It can’t cover every single facet of every conceivable technology, not within the confines of a single, useful book, but it’s intended to give you more than enough to be able to make informed choices.

PAYBACK

In most cases, financial incentives are available for the installation of domestic renewable energy systems. In some parts of the world, all of the major systems covered in this manual can qualify for government assistance, usually in the form of payments made over a period of years and connected with the amount of electricity generated or the amount of heat produced. This can actually make the money spent on a renewable energy system a worthwhile investment in itself.

However, the levels of these payments and the steps you have to take in order to qualify for them can change on a regular basis, in recent years, making it unrealistic to try and provide that information here. Those most keen to provide you with the correct information will be the companies who want to sell you their equipment, and there are websites set up by governments and their agencies around the world where you can find out current and detailed information for yourself.

In order to assess the amount of energy being sold back to the grid, as well as the energy consumed, the electricity supplier has to change the traditional meter for a two-way version. You may have to pay for this.

The quickest, most cost-effective and often least disruptive way to save money and cut down carbon dioxide production is to reduce heat loss from your house. We touch on a few ideas in this book, but more details and information on saving energy can be found at the American Council for an Energy-Efficient Economy (aceee.org), and in the UK, the more hands-on Energy Saving Trust (est.org.uk).

There is an enormous amount of researched information out there to help select the best type of technology. This graph from the UK government’s Department of Trade and Industry (DTI) shows the average amount of energy available from sunshine (insolation) in (for example) Manchester, England ...

... while this graph shows the average amount by month and by season for the same area.

Chapter 2

Energy saving, insulation and monitoring

ENERGY SAVING

Spending loads of money on renewable technology is not wise if you’re not going to make the most of the energy you generate – and it’s amazing just how much can be wasted. In fact, saving energy and reducing CO2 is great for the planet, but it’s also great for your bank account. You can save a lot, not just by reducing the amount of energy you use, but also by using it in a smarter way.

Following are some figures that might make you raise your eyebrows in surprise! They have been verified by The Energy Saving Trust (June 2013) (please note: all percentages are per year and costs are subject to change).

Where the heat goes (% of your heat loss)

Doors – up to 3%

Floor – 8%

Ventilation and draughts – 12%

Single glazed windows – up to 18%

Roof – up to 26%

Uninsulated walls – up to 33%

Conclusion: insulation saves a packet!

You can save 6.4kWh a year (on average) just by turning down the central heating thermostat by 1°C. (Illustration: Energy Saving Trust)

Easy energy saving

Not all energy-saving measures are expensive to put in place: some cost very little, and most are relatively quick and easy to do –

Measure: Potential savings in kWh

Turning down central heating thermostat by 1°C (1°F): 6.4 (3.5)

Avoid leaving electrical devices on standby: 5 to 9

Full load in washing machine before use; use the most

water and energy efficient settings (wash at 30°C): 1.2

Four-person family replaces one bath a week with

a 5 minute shower: 1.4. (plus a saving on metered water/sewerage bills)

Insulate water tank: 4.2

Switch off lights in rooms not in use: 0.7 (average household)

Turn off TV instead of leaving on standby: 0.9

Draught-proof doors, windows and letterboxes: 2.8

Don’t overfill kettle: 0.7

Fit radiator reflector panels: 0.5

Install chimney draught excluder (open fireplace): 1.8

Insulate water tank and exposed pipes: 4.2

Replace halogen spotlights with LED equivalent: 2.8

Dry clothes outside when you can: 1.8

(Information supplied by the British Co-op, which states: ‘In the spirit of always being honest with our customers, we’d like to point out that all savings mentioned in this document are approximate figures, and should only be used as broad guide’).

• An energy-saving monitor will increase awareness of electricity use – and save you money!

• Appliance monitors could save up to 15%.

• A smart meter or energy-saving monitor with in-home display can save at least 5%.

• You could recoup the cost within the first few months of use.

Insulation savings (assuming none in place beforehand)

Measure: Potential savings in kWh

Install loft insulation to 270mm (10.62in): 17

Install cavity wall insulation: 13

Insulating inside or outside of solid walls: 44 to 48

Fit double glazing (secondary glazing): 16.5 (10)

Replacing appliances

In the UK, appliances that carry the Energy Saving Trust or Energy Recommendation logos – A, A+ and A++ – are the most energy efficient choices, while those that are G-rated are the most inefficient. Other countries will have similar organisations/rating systems.

• D-rated fridge/freezer – costs around 9 kWh a year to run.

• Replace G-rated gas central heating boiler with new condensing boiler with heating controls – save up to 30 kWh

• Install a living room thermostat – save around 7 kWh.

Smart heating and hot water tips

• Recommended room temperatures are between 18°C and 21°C (64°F and 70°F).

• Turn down hot water to 60°C (140°F).

• Bleed radiators once a year.

• Set central heating to come on no more than 30 minutes before you return home.

• Close doors and draw curtains/blinds at night.

• Don't cover/block radiators with furniture or curtains.

Fridge freezer savings

• Set your fridge at 0-4°C and freezer at -6°C to -18°C.

• Vacuum your fridge’s coils (at the back) twice a year.

• Check door seals aren’t broken or filled with food debris.

• Keep frost build-up at less than 6mm (1⁄4 inch).

DON’T WASTE YOUR TIME! Not everything in your home is a major drain on energy. Some things are generally pretty energy efficient, and you’d be better off concentrating on things that matter most. With each of these appliances, 1kWh provides you with this much usage time –

TVs

CRT (old tube-type), 32 inch, 165W: 6 hrs

LED, 42 inch, 64W: 16 hrs

LCD 42 inch 107W: 10 hrs

Plasma 42 inch 195W: 5 hrs

Other appliances

Fluorescent strip light (40W): 25 hrs

Stereo: 89 hrs

Games console: 24 hrs

Laptop: 31 hrs

DAB radio: 145 hrs

Internet router: 159 hrs

LED bulb (6W): 165 hrs

Mobile phone/MP3 charger: 286 hrs

For more information on the topics covered here, visit www.cooperativeenergy.coop

Home efficiency

There’s a lot you’ll need to assess about your home’s energy consumption and insulation before embarking on the installation of any renewable energy system. Indeed, it is a requirement in some countries that, before the approval of any grant or other financial assistance, a house or building has to comply with a certain standard of insulation and energy-saving. Regardless of whether or not this applies to you, it makes sense, in terms of reducing your expenditure and your carbon footprint, not to waste energy.

INSULATION

The most commonly used forms of home insulation are loft insulation and cavity wall insulation. The UK’s Energy Saving Trust has invaluable advice in this respect –

"Heat rises and, in an uninsulated house, a quarter of your heat is lost through the roof. Insulating your loft, attic or flat roof is a simple and effective way to save that waste and reduce your heating bills – you can even do it yourself. Loft insulation is effective for at least 40 years, and it will pay for itself over and over again in that time.

Insulating between the joists of your loft will keep your house warmer but make the roof space above colder. Pipes and water tanks will be more likely to freeze, so you will need to insulate them. If your water tanks are some distance from the loft hatch, you will also need something to walk on for safe access. The cooler air in your insulated loft could mean that cold draughts come through the loft hatch. To prevent this, you can fit an insulated loft hatch and put strips of draught-excluding material around the edges of the frame.

Cavity walls were built into most – though by no means all – homes from around 1900. The cavity brick-built wall forms an insulating air gap, and, although it’s not a very efficient one, it’s a lot better than a solid wall. The Energy Saving Trust once again states, ‘Did you know that around a third of all the heat lost in an uninsulated home goes through the walls? Heat will always flow from a warm area to a cold one. In winter, the colder it is outside, the faster the heat from your home will escape into the surrounding air [through the walls].’

There are several insulation options for buildings with solid walls, including –

• Fitting a new, foil-backed, plasterboard wall surface on all external walls, mounting the plasterboard on battens to provide a narrow air gap.

• Fitting a new, secondary wall made from insulating materials and finished with weatherproof panelling on the whole of the outside of the building.

• Adding insulation to the inside of an outside wall, as shown in the accompanying images.

The 18 inches thick walls in the original, stone-built part of our house consisted of two courses of random-sized stone filled with rubble. We decided to use rigid foam insulation, and builder Matthew began by cutting the foam to shape, then placing plaster dabs on the wall in order to hold the insulation in place.

So that the sheets lay continuously, without gaps and also in order to increase strength, we used Würth Bond and Seal, a PU sealant that works particularly well with PUR/PIR rigid foam insulation.

With the plaster dab still soft and sticky, Matthew placed the pre-cut sheet of foam in position ...

... and used a straight, relatively heavy piece of timber to tap it down onto the plaster dab, ensuring that it was completely level with the sheet or sheets already fitted.

Both of the outside-facing bathroom walls were covered in this way, with the foil side facing inward to reflect heat back into the room. Later, we used plastic tongue-and-groove board to finish the wall, but you could use almost any finishing material of your choice.

The other major problem with solid walls is that they allow driven rain and dampness to penetrate from the outside. This causes several problems: some obvious; some less so. For example, when wet brick, stone or concrete freezes, the surface of the wall breaks away in a natural process of erosion. What also happens is that, as the moisture in the wall evaporates, the wall itself and the building inside it are naturally cooled – it’s a process by which a simple, non-energy consuming coolbox can be made to work, by the way. So, what’s to be done?

Well, the first step is to repair and re-point the wall, as necessary. Once again, there are many technical matters to go into, particularly when replacing lime mortars, that there isn’t room to go into here, but suffice to say that the wall needs to be sound to start with.

If you need to check the porosity of your wall, you can buy a simple gauge which is stuck to the wall and topped up with water …

… with several of these gauges placed on the surface of the wall, the amount of fluid absorbed can be observed and compared with the acceptable or expected absorption levels described in the data sheet supplied with the gauges. (Illustrations courtesy StormDry)

Silicone is frequently used for attempting to make absorbent walls waterproof but this is a strictly temporary measure which may last no more than 12 months at most. StormDry wall treatment, while very much more expensive, lasts for many years. We found it to be extremely beneficial – so much so that it has also completely stopped water penetration around several exposed windows. It allows moisture from within the wall to evaporate, but does not allow water to penetrate from the outside-in. In fact, it can be seen to work quite clearly by the water that beads on the surface of the wall before running off.

ENERGY SAVING

As the Centre for Sustainable Energy, which serves people living in the Bristol and Somerset area states, ‘Some electrical items use a lot of electricity. Others don’t. As a rule, those with moving parts or which produce heat use much more than those producing light or sound. So if you want to save electricity and money, there’s no point worrying about a digital clock or an electric razor, since these use so little power you would hardly notice the difference. The big savings lie elsewhere.’

And if you want to know how much electricity you’re consuming, ‘Every electrical appliance has a power rating which tells you how much electricity it needs to work. This is usually given in watts (W) or kilowatts (kW). Of course, the amount of electricity it uses depends on how long it’s on for, and this is measured in kilowatt-hours (kWh).’

In a typical house, 10 to 20% of energy consumption goes into room lighting. CFL bulbs, which are in effect mini, twisted versions of striplights, are great for saving money on lighting, and you can even buy efficient outdoor lights that cost a fraction of the price of halogen floodlights to run.

We have fitted LED (light-emitting diode) lights throughout our house. LEDs are simple, solid-state electronic devices that produce a small amount of light. Domestic LED bulbs contain lots of LEDs so that a bright enough light is emitted.

LED like-for-like replacements are still, at the time of writing, expensive, but they are the most efficient type of bulb and pay for themselves several times over before they need replacing – provided you don’t buy cheap and nasty bulbs to start off with.