General Questions
If you had to put in one sentence what buying a Solar
PV or Thermal Energy System would do, what would you write?
We
would probably say that a Solar Power Station, whether PV or Thermal, converts
free Solar Energy into power, paying for itself with money you would only be
going to pay your Energy Supplier, and once the savings equal the cost you get
free power forever, whilst helping to save the Planet.
Apart from saving money what are the mains reasons
why I should buy a Solar Energy System, what would it be?
If you
have seen the Film by Al Gore, An Inconvenient Truth, or just listened to the
news, day after day, Global Warming is the biggest danger all of us face. The
CO2 level in the atmosphere was 280ppm in 1780 and now is 382ppm. Up to the
year 2000, it was rising at less than a 1% increase per year, but since then,
has been rising at over 3% a year. The CO2 level is rising because we are
burning fossil fuel, and although it isn’t the only dangerous gas, it is the
most important.
If we do not stop this continuing, and CO2 levels rise
even faster, there will be a climatic disaster, affecting every one of us, and
more importantly, the future generations. Our children, and grandchildren, will
be greatly affected by what we do or don’t do. Solar Power Stations stop the
emission of many tons of CO2 during their lifetime, even small domestic Systems,
so buying one will help prevent global warming.
PRESERVATION OF
CRUDE OIL:
Apart from saving money and the environment, there is
another good reason for seeking alternative energy sources. Solar, Wind and
Nuclear will only give electricity, however by products of crude oil is
omnipresent and cannot be easily replaced. Examples of the by products are
tarmac, plastic, pesticides to name a few. This is a good reason why we should
preserve the reserves of crude oil and seek alternate sources for power
generation.
What do Solar PV and Thermal Systems do?
Solar Thermal Systems - These Heat Water and are used to provide up to 70% of your domestic Hot Water requirements, and is ideal for under floor space heating. They can be used to heat indoor, and outdoor swimming pools, and can provide Hot Water and heat swimming pools at the same time. For indoor pools up to 70% of the energy can be provided and for outside pools, used in summer only this can be 100% of the energy required.
Solar PV (photovoltaic) Systems – These produce Electricity and Govt Grants pay for up to £2500 of the cost. The amount of Electricity produced, is directly related to the number of Solar Panels installed. If you use under 5000 Units of Electricity, and have a sufficient space to place the PV Panels on your property, all your Electricity needs may be met, so you can have Free Electricity for life. Indeed, some people install PV Systems that produces more energy than they use, and make a profit from selling it to their Energy Supplier
What sort of Return on Investment will I get?
A very good article was written by Ashley Seager for the Guardian, on Sept 11th 2006, stating the current rates of return on PV and Thermal Systems. For PV there was about a 5% Return On Capital Employed, due to the Saving on the Energy produced, Monies back from the Suppliers for the Energy sold to them and for the £30 a Kilowatt received from the sale of Renewable Obligations Certificates (ROC’s). On Solar Thermal, a return of 4.25% was calculated for mains Gas, and 8% for other Fuels.
His concluding sentence was: - So why wait? The returns already justify the outlay and, if you are worried about Global Warming this is a concrete step you can take with tried and tested technology. Just do it.
We could not put it better ourselves, and this is at Today’s price of Energy. How much more will it save in the Future.
How much have energy prices risen?
Energy bills have risen steadily and from 1974 to 1999 Gas prices rose 411% and Electricity 717%. From then until 2003 they were rising at over 14% per annum.
From Jan 2003 to Nov 2006 Gas rose by 97%, an increase of over 20% a year. Electricity prices have risen by 60% from Jan 2003 to Nov 2006.
We all know that even if wholesale price of Gas comes down, it will not be reflected in lower prices. The Carbon Offset Tax for each EU Country, and the need to invest in the infrastructure, ensures Energy prices are only going up.
What are future energy bills going to cost me in?
That we don’t know but prices rise as in compound interest, by percentage loaded onto percentage so if prices only rose 10% a year :-
| Today’s bill | £ 950 |
| Year 5 | £1550 |
| Year 10 | £2450 |
| Year 15 | £3950 |
| Year 20 | £6400 |
Over 20 years the total you will have paid is £61,000
If the % rise stays at much higher levels than above, the money you may pay out over 20 years could be double the £61,000, or worse. So how does that make the investment seem now? Pretty good we would have thought.
Who pays for a Solar System ?
Once a System is installed, you immediately start saving the Money you would normally be paying your Energy Supplier, and for PV the extra income from ROC’s, so in effect it is your Energy Supplier who is paying for your System. If you do not purchase a System, you just carry on paying their bills, and are left with nothing whatsoever, to show for your money.
When will I get Free Energy?
Once the money you would have given your Energy Supplier is equal to the price of the Solar System you bought then all the Energy you generate is Totally Free.
Do PV and Thermal Systems depreciate ?
Not for a very long time - As if just saving money is not good enough, PV and Thermal Systems will retain their Value for many Years, so if you sell up you can add the price you paid for the Solar System to your House price, or if not just take it with you. PV systems are very easy to move, and it is not that difficult to move Thermal, although you would leave the Solar Hot Water Cylinder.
Just compare that to a the value of a Car for the same money. A Thermal System costs about the same as a 6 years old runabout, which, when 10 years old, is worthless. The same Car, when new, may cost a similar amount to the biggest PV system available, yet worth only 30% after 6 Years, and worthless after 10, when we expect the PV or Thermal Systems to be worth about what you paid initially.
How do PV and Thermal work?
Both PV and Thermal work by absorbing light, plus Infrared and ultraviolet radiation, which they convert into energy we can use. Each works in a different way, the end result being Heated Water for Solar Thermal, or Electricity for PV, and many people have both installed at the same time. They are not interchangeable, although a PV System can power an immersion heater to heat water, but that isn’t the best use for it.
Does Britain receive enough energy to make these systems work?
The answer is yes. We receive about 60% of the radiation that lands on the equator, and although there is a variance between the North of Scotland and the South West, there is more than enough energy to power Solar Energy Systems. In the South of England each year, we get about 1300 Kilowatt Hours of energy striking every square metre of the ground, or roof
Approx 70% of all energy falls between March to September, with the remaining 30% from October to February
Do they require direct sunshine to work?
No - Diffuse light, through cloud, is fine, which is prevalent in Britain.
Indeed, the Solar Thermal Vacuum Tube Systems can work in temperatures as low as - 30C, and even in mid-winter, on a cloudy day, the water in the Collectors can reach 30/40 degrees C.
The PV Systems work all the year as well, although producing less power in winter. However, PV Systems often produce more power in summer than is usually used by a household, even on some of the smaller Systems, so the excess Energy is sold to the Energy Supplier. Obviously, strong direct sun does increase the output, so the more sunshine we get, the more power the Systems produce, and this year there has been higher outputs than ever before.
Do the PV and Thermal Panels have to point South?
No – Actually, the most energy gain is to be had from tracking the sun daily, so the Panels would rotate from North East to North West at 10 degrees pitch in June, and South East to South West at 50 degrees pitch, in December. However, although there are systems for PV doing just that, for practical purposes almost all PV and Thermal Panels are fixed in a stationary position.
For fixed Panels, facing South tilted at 30/40 degrees is the best compromise, but you only lose 4% of available power if the Panels face between South East and South West, and 86% if placed facing due East or West. Even if you laid a Panel flat, you would still get 90% of the total power available,
If a roof has a North/South ridge, we place half the Panels on the East side, and half on the West, which gets over 90% of the total again. Panels placed in these positions start power production earlier, and continue later, than South facing Panels. Panels can also be placed in arrays, in Gardens, or on outbuildings or sheds.
Can shading decrease the power output?
Yes - Trees or buildings casting shadows on the Panels (particularly PV) can decrease power outputs. However, when the sun is strongest in summer, the sun is very high in the sky and rarely casts much of a shadow. Therefore, unless the buildings or trees are very close it may not be a problem. Also, for a large part of the year we have diffuse light, not direct sunshine, and the power output is not affected in diffuse light. In winter, the sun is low in the sky, increasing shading but deciduous trees drop their leaves, so most of the light can still get through, and as most of the light is diffuse in winter, no reduction of power.
Is Planning permission required?
Normally no – Planning Permission is not required, for either PV or Thermal, even in Conservation Areas, under The Town and Country Planning (General Permitted Development) Order 1995 Schedule 2 Part One Class B. We have a number of replies confirming this, from local authorities, National Parks and the Office of the Deputy Prime Minister. However, if the property is in the curtilage of a Grade1 or 2 listed building, Listed Building Consent is required.
Any temporary structure, such as an array of PV Panels placed in a garden, will not require Planning Permission. Customers should ensure that no special restrictions apply to their properties.
Is Building Control Permission Required?
No – The Panels (both PV and Thermal) are not heavy enough to affect the structure of a roof, and of course all plumbing and electrical work has to meet the appropriate new Building Regulations, but as the works are carried by qualified people who can self certificates the works no applications are required.
Do we have to Clean the PV panels or Thermal Collectors?
Under normal circumstances, rain will wash off any dirt landing on PV or Thermal Panels. We know of Thermal Collectors, installed for nearly 20 years, that have never been cleaned.
Solar Thermal Systems
How do Thermal systems produce Hot Water?
By converting the suns energy into heat energy, and using that heat to warm
water. Thermal Systems can absorb about 80% of the radiation striking it, and of
that energy over 96% is converted to Hot Water, so only 2/3 Square metres of
Collector is required, to provide up to 70% of all your Hot Water needs.
There are two main types of Collecting Panels - Flat Plate and Vacuum Tubes,
heating the water in the Solar Hot Water Tank directly, or indirectly.
Vacuum Tube Collectors, are the best ones for our northern climate. The Tubes
are between 35mm to 60mm in diameter, 1.4m to 2m long and made from very strong
Borosilicate glass. The air inside is extracted, as the vacuum acts as an
insulator, so the energy collected can’t escape, aided by dark blue selective
absorbing coatings which help retain 96% of the energy landing on it.
The typical Thermal System consists of a Collector Panel, which has a number of
Collecting Tubes connected to a Manifold. Solar4us use Schott Glass Panels,
which has 16 Tubes per Panel. We usually we use 2 Collector Panels on a
property.
A water/antifreeze mixture circulates though the Thermal Panel, collecting heat,
which circulates via copper pipes, through a Solar coil in a Solar Hot Water
Cylinder, where it loses that heat to heat the hot water and returns to the
Thermal panel to get reheated. The heating fluid circulates via a pump,
controlled by a mini computer, using information supplied by sensors on the
Collectors and Solar Hot Water Tank. The System is under 6 bar pressure, so an
expansion vessel, pressure safety valves and air bleeders are also installed.
Solar Heat Stores can replace Solar Hot Water Tanks. These are vented Systems,
holding a fixed static amount of water in them. They have 3 coils, one for the
boiler, the second for the solar that heat up the water, and then mains pressure
water circulates through another coil to pick up the heat. More heat is stored
than in a standard Solar Hot Water Cylinder, and all taps are at mains pressure,
so you don’t need Cold Water Storage Tanks. They are more expensive than
Standard Systems, and only of worth installing if you use if a lot of hot water
in a short time.
All types of Thermal Systems usually allow the Boiler to be turned off in March,
and not be required again until September, so savings can be made in 2 year
servicing intervals, rather than one.
Can you install a Thermal System if we have a Combi boiler?
Yes, we can. If the Boiler is fairly new, and will accept preheated water,
either a Mains Pressure Cylinder or a Heat Store is required.
If the Boiler does not accept pre heated water it can be modified to take a
Standard Solar Twin Coil Tank, but the taps will not be at mains pressure, nor
showers, and you need to have Cold Water Tanks installed. The better
alternative is to use a vented Thermal Store, so no Cold Water Tanks are
required and you have mains pressure on taps and showers.
Obviously, either of the above is a more expensive installation than connection
to a Standard Boiler.
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What sort of Savings can be made by using a Thermal System?
You will save up to 70% of your Hot Water needs.
What that is in real terms depends on the type of Fuel you normally use. Oil or
Calor Gas is twice as expensive as Mains Gas. The following assumes one Fuel,
only, is used for Space Heating, Hot Water production and cooking.
Although we know of people with 50% savings on their bill, we would normally
expect around 30/40%. Less if one person lives in a big house, more if a lot of
people live in a small terraced house. The more insulated the house, the
greater the % saved. Mains Gas usually has a dual tariff at around 3.5p for the
first 1500 KWh per quarter, and 2p thereafter. In the later part of spring,
summer and early autumn, most of the first expensive units are used for Hot
Water, so the savings will be a higher % of the total bill than the actual % of
physical energy saving.
Most people underestimate their usage of energy for Hot Water. Even if you
don’t use any Hot Water, 35 galls is being heated, usually twice a day, and you
can tell why when you open your airing cupboard, because it’s hot from heat
escaping from the HWT. Baths use around 20 galls, a shower maybe 12 galls, but
if you have teenagers who stand there for 20 mins, even more than a bath. Water
coming into the house is very cold, using a lot of energy to warm it. A family
with two children may heat over 150 galls a day.
Can Thermal Systems provide Space Heating?
Both Yes and No – In fact properly designed and insulated homes hardly need
heating at all, but even the latest properties, designed to this years Building
Regs, are nowhere near as insulated as they should be and older properties
hopeless, so to minimise heating requirements all methods of insulating and
draught proofing should be the first consideration.
In houses built to the latest Building Regs up to 50% of your Space Heating
needs can be met, if you link a Thermal System to an Under-floor Heating System,
which only needs water temperatures of 35/45 degrees C, but you need many Solar
Collector Panels, say 10/12 and a very large Heat Store. Using Solar Thermal
with low temperature skirting radiator systems is a good option.
Most installers will say radiators cannot be powered by Solar Thermal Systems
because the water temperature required, (75 degrees), cannot be generated by
Solar Thermal in Winter, which is true as in Dec and Jan anything over 30
degrees is unlikely. However, some of the latest Thermal Stores can preheat
water going into the boiler, which may provide heating for Spring and Autumn
when the temperature of the water required for background heating is similar to
that required for under-floor heating. Any Company that suggests they can just
add an extra panel, link it to the radiators to provide Space Heating and charge
several thousands of pounds is knowingly fraudulent.
The best way to get green Space heating is with biomass boilers (woodburners)
having back boilers linked to radiators and also linked to the Solar Hot Water
Cylinder via a third heating coil provide the remainder of the winter hot water.
Can you save electricity With Solar Thermal Systems?
You can also plumb the hot feed into your dishwasher and washing machine, even
when they are cold feed only, to save a lot of electricity.
Why don’t you link Vacuum Tube Collectors directly to Hot Water Tank Systems?
We only install indirectly Solar Heated Hot Water Tanks as they are the only
ones that you can ensure the water in the Hot Water Tank remains above 50
Degrees C, heated either by Solar power or through the boiler coil. This stops
any chance of bacteria growing in the Tank.
What is the Guarantee on the Tubes?
The Tubes have a 5 year Guarantee, but we expect many, many decades of life, in
reality. If a Tube becomes damaged it can be replaced individually. Each Tube
would cost approx £45 plus fitting.
We have heard that Vacuum Tubes can fail - Is this true?
The Tubes Solar4us use, should never fail, as we use Schott Glass Tubes, the
evacuated part of the Tube being solely glass.
Most of our competitors Tubes have a metal pipe running through the glass, so
due to different expansion rates between metal and glass, the seal can be
broken, hence the vacuum lost. Although the quality manufacturers, such as
Thermomax (a British Co), have very clever joining methods, and made millions of
tubes, without many failures (and we know of some 20 years old as good as new),
some of the cheaper Chinese imports can, and do, fail.
Photovoltaic Systems
How does a PV (photovoltaic) System work?
When the sun strikes the PV panels, which are typically 1.5m x 1m in size,
direct current (DC) is produced, and converted into alternating current (AC), by
an Inverter at 230 volts, which is sent to your fusebox, to power your home.
PV Panels consist of a number of Cells. Each Cell has two layers of Silicon,
one doped with Boron, the negative layer (n), the other with Phosphorous, the
positive layer (p). When joined together and light strikes them, the (p) layer
attracts electrons from the (n) layer, hence electricity flows, and a watt or
two of energy is produced. Cells vary in size from 100mm sq to 150mm sq.
50 to 70 Cells per Panel are imbedded in resin, topped by glass, and placed in
aluminium frames. The average Panel produces about 200 watts at 30/40volts.
Various switches isolate each part of the system and an output meter supplied.
Your Supplier may install a meter to measure the energy you export to the Grid
in summer.
The best Solar PV System available is close to 20% efficiency so about 6 sq
metres (5/6 panels) generate approx 1 Kilowatt of power at peak power (Kwp). 1
Kwp produces approx 1000 Kilowatt hours per year Kwh/y (Units as per your bill)
from the best Panels (Sanyo).
What is a typical usage of electricity?
A single person living in a small property can use as little as 1500 Units. A
couple, in a small bungalow, typically use 3500 Units, and a 4 person family, in
a detached House, rarely use less than 4000 Units, and typically use 5/7000
units. We do come across properties where 18,000 to 30,000 Units are being
consumed, if there is air conditioning or electric heating. Even underfloor
electric heating uses a lot of power, but high usage can be caused by 3 Kilowatt
fires left on all the time, or the immersion heater on and thermostat not in
place, etc. Lots of recessed Halogen lights can significantly increase usage,
as can garden or security lighting. Tumble dryers use lots of energy, plasma
screens TV ‘s are big users of electricity and American style fridges can use a
lot.
What size of System do you usually install?
We install PV Systems from 8 panels (1.5 Kwp) upwards, with 3 to 4 Kwp very
popular (16/20 Panels). The Govt will pay up to 50% of the costs for domestic
Systems, to a max of a 5 KWp System (24/26 Panels), producing up to 5000 Kwh/y
(Units).
Guarantees
PV panels have power guarantees for 20/25 years, and expected to last a Century.
What Sort of savings can I make with PV?
If you install a PV System producing all the power you normally use, you will
save all the money you would ever need to spend on electricity, forever. You
can of course choose to buy a smaller System, powering a % of your needs, or
even install a System which produces more than you need, and sell the power to
your Supplier, at an ever increasing rate of return.
Are there any other reasons I might benefit from having a Solar PV or Thermal System?
Yes we can think of a few more:-
Oil and Gas Depletion - Oil and Gas will get more difficult to extract and more than half of all the Oil and Gas reserves may have gone already, and with ever increasing demand for energy, there may only be a 2/3 decades of steady supply left.
After all, we have used up nearly all the North Sea Gas and most of the Oil, and are now net importers of Gas. There is a couple of centuries of Coal left, but that is costly to make into a clean CO2 free fuel.
Buying a Solar System will help make those reserves last longer, and to some extent make you independent of that energy source. If you also use biomass boilers in the winter, you may become totally independent!
Continuity of Supply - Unless new Nuclear Power stations are brought on stream quickly, and then we use nothing but electricity, we are dependent on foreign Gas and we have seen what Russia is capable of. In fact there is limited Uranium for Nuclear Power as well.
As 40% of our Mains Electricity is generated by Gas to have independent Hot
Water and a supply of electricity, independent of the Grid, even if limited for
a couple of winter months, it has to be good. Many people have electricity cut
off for periods, and PV is a boon for them. The comments re biomass boilers
apply, as above.
What are your thoughts on other types of alternative energy?
Biomass Boilers
We love wood-burning stoves or wood-fired boilers, because you can use the Solar Thermal in the summer for Hot water, then switch to the wood-burner or boilers in winter, which can provide all your Heating as well. The wood-burner can have a back-boiler added to it, and you can buy log or pellet wood-fired boilers. You also need to have a third coil in the Hot Water Tank. This makes your total Heating and Hot water Carbon neutral.
Wind Turbines
Small House mounted
Most of these are a waste of time,
as in urban areas there is not a consistent flow of wind, and it takes a
significant wind speed to get them to produce much power. The really cheap ones
may well be worn out before they save the money they cost. There is a danger to
houses from the pressure against a chimney, and can shake a house in windy
weather which could result in the chimney coming down on older houses.
Free Standing Turbines
If positioned where sufficient wind flow and
speed they compliment PV very well, as when there is sun, there usually is no
wind, and conversely, in winter, when there is less sun there is often wind.
Freestanding Turbines are more expensive than PV, for similar power outputs unless in a very windy position, but if you are in a Community, where 5/6 households can share the costs of a really big Turbine, then it is a good idea, as long as you have consistent wind. Similarly, for Schools or Commercial Buildings, large Turbines can provide a significant amount of energy. They should last for 30 years or so. We can arrange for the installation of good British made freestanding Turbines. Planning Permission is required.
NB - Vertical Rotating Turbine System
We are expecting to become the
UK Agent for a Japanese Vertical Axis Turbine, soon. They work much better in
urban situations, at lower wind speeds, and should last much longer. Watch this
space!
Ground Source Heat Pumps
You can extract heat from the ground using a heat pump, which works well, except they use Electricity to power them. This is twice the cost of Gas so only a good idea if you only have Oil or Calor Gas, so the claims need to be halved for those on mains Gas. It still uses fossil fuel to work, so it is definitely not as Carbon Saving as PV or Thermal.
The Sunday Mirror Dec 3 2006 rated them as 2/10 as a useful alternative energy source, which is a bit harsh, but they may have a point.
Are there any people I should not get a Solar System from?
Solar Energy has taken off in a big way, and just as happened in Double Glazing, there are Cowboy Companies who want to overcharge you.
This mostly relates to Solar Thermal, with some Companies wanting to charge you £6300/10,000 for a System. If you asked to pay over £4500 for a Standard Thermal System, it is too much. Any Company that won’t tell you the price, until the end of a presentation, and for which they offer a subsidy on the night, for you to help promote their product in your postcode area, are not the people you should deal with.
There are 4/5 well known Cowboys Companies, often appearing on Watchdog etc! They usually send mail shots offering a subsidy, or stating they are Govt supported. They may suggest that if you help them get sales, they will pay you money, and if you sell six Systems, you will get your system free. At the end of the presentation, they say a System costs between £8500 and £10000 and up to £13000 for a radiator heating assist system, with a £2000 subsidy if you sign up now.
As we have already commented, there is no Solar System that can heat radiators,
just by adding a few extra Tubes. 1 sq m of extra Tubes cannot produce more
than a few watts of power in Dec or Jan, when you need the heat most, and you
can’t get the radiators to the temperature they need to be to work anyway,
however many extra Tubes are installed.
Finally, a few comments on Climate Change and why preventing it is important?
We have been warned, for over thirty years, about global warming and what will happen, but it has only recently been finally being accepted by just about everybody now. Indeed, it has taken the melting of the ice caps and rise in global temperatures to convince some people it is actually happening, now! If you still have any doubts, get the Al Gore DVD, An Inconvenient Truth, which spells out what will happen. We are at a tipping point and all of us need to start to change to a more sustainable way of living.
We managed to halt the Ozone layer from going and that is stabilising now, so we can do it.
If everyone of us made small changes to our carbon footprint, and one way, of course, is to buy one of the available Solar technologies, the problem would be solved. We know we all can also help by turning off the TV at night, putting in low energy bulbs or better insulating our houses, amongst a raft of other things.
The Stern Report, published in Nov 06, gives perhaps the most dramatic case for what will happen if we do not stop this rise in CO2. The CO2 level was 280ppm in 1780, today is at 382 and if not stabilised at no more than 550, total disaster will take place.
The findings
- Climate change could shrink global economies by 20%
- World temp would rise by 2 degrees C by 2050 or sooner and could rise by 5
- Up to 200 million people could become refugees through flooding or drought
- A 2 degree rise in temp would cause extinction of 40% of species
- Rich nations have caused global warming but the main sufferers will be the poor nations
- Remedial action will cost 1% of global GDP but will save £1.32 trillion
- Govts must use tax and regulation to reduce carbon emissions and double research into low carbon technology
- The worst impacts of climate change can still be avoided – but delay would be costly
The Solution
Lead individuals and businesses to switch away from high carbon goods, energy sources and services and to invest in low carbon alternatives.
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