Undertaking aspects in this section means that you have done all you can with the cheaper options discussed in previous articles. This is the big one! This is where, in some aspects of bigger cost improvements, you will begin to really see your energy bills being reduced, and even making a lot of money! With making money comes a big investment, there’s no two ways about in. Later chapters will go into detail on Renewable Energy Technologies (RET’s) describing how they work, what to expect in terms of planning permission (if there is any), grants available and most importantly the cost! This chapter will address a few last improvements, and then give a brief outline into RET’s, considering suitability, cost and grants to installing it to your home or business dwelling if applicable.
Approximately 18% of heat loss in a house is through windows. According to the Energy Saving Trust you could save £135 per year if you upgraded from single to double glazed windows.
To put technical figures on this, it is important to understand what certain values represent.
- U-Values represent the rate of heat transferred over an area. The lower this value the better a material is at not exchanging heat.
- R-Values represent the thermal resistance of a material, the larger the number, the better the materials effectiveness in insulating.
These two values look quite similar. They are. One is the reciprocal of the other. One or both values should be displayed as part of the information of a material that you are buying (whether its windows or loft insulation).
- ‘Low-e’, meaning low emissivity, shows that a material entitled with this on has a low e coating between glass layers. It is a coating of metal onto glass within a glass panes air space. This reflects thermal/heat radiation from the sun or inhibits its emission through the glass therefore reducing heat transfer through the glass.
- SHGC – stands for Solar Heat Gain Coefficient. This basically describes how a material allows heat through itself. In terms of building, such as a trombe wall, you may require a high SHGC to heat your home. In terms of glazing, you will require a low SHGC as this will mean that heat is not readily transferring between the interior and exterior of your house. In terms of windows, single glazing has the highest SHGC, and triple glazing the lowest.
Double or Triple Glazing is better than single glazing in terms of insulating your house, however double and triple are not necessarily better than each other. Triple is more costly for obvious reasons, however if you were to have double glazing with low-e coating in it then there would be only a little difference in U, R and SHGC values in comparison with normal triple glazing, and therefore still cheaper than triple glazing.
Cost
Double and Triple glazing is in the ‘high improvement’ section as it will cost a few thousand pounds to replace your existing single glazing. However, it is expected to last 20 years plus according to the Energy Saving Trust (EST). With this in mind and a quick calculation using the £135 saving per year and say 25 years, only gives you £3375 saved so far. It is recommended that you get quotes from a variety of double and triple glazing installers to get the cheapest. But at best for 10 to 15 windows plus doors you should be paying between £5000 and £6000.
So what are you getting for all this money? Well as for saving money, in the short space of time of 25 years, you’ll probably be in deficit by around £2000. However, you do save according to the EST, 720kg/CO2, or 18 Tonnes (25 years) of CO2 based on an average home! You also have the benefit of comfort and security in your home, and in theory a reduction in condensation. Retaining heat in the winter and keeping your house cool in the summer will mean your house is more comfortable to occupy.
So a further option could be of fitting the windows yourself, which may save you that couple of thousand pounds. Fingers crossed your windows will last for at least 44 years if you want to recuperate you money.
The cost figures I have given are based on my own guess/estimation from reading a vast number of blogs about double glazing installations over the internet. It has been useful as it has put into perspective not just the cost of double glazing, but also the companies that are out there and some genuine public opinions of them. This is why it is recommended to research heavily into replacing your windows before undertaking an installation.
You will have noticed that when you step inside a greenhouse, it tends to be a lot warmer than the outside. This is because of the sun’s ‘heat’ radiating through the glass and becoming trapped. Passive solar heating is all about this and can come within 3 general builds; direct gain, conservatories and trombe walls.
- Direct gain is what it says on the tin. The suns radiation travels through windows or is absorbed by a thermal mass such as a wall and heats the inside. This can be particularly helpful if the building is large, however, being small you will notice your dwelling overheating.
- Conservatories. It is in effect a greenhouse but with ventilation aspects built in. Air within the conservatory heats up, this warm air rises and travels through gaps and holes around your house, eventually leaking outside. This is designed to generally heat up the northern side of your dwelling.
- Trombe Walls. These are in effect a squashed conservatory. They have an air space which is enclosed by double glazing and a thermal mass (such as a specially designed wall in front of your house). When the sun is out, vents can be opened within the wall to allow warm air to circulate around the house. As heat rises the cooler air from your house is sucked into the trombe wall to be reheated. Obviously at night, when there is no chance of solar gain, these vents will be closed to retain heat.
These are useful builds to develop as they provide you with heating, reducing your day heating bill during winter months.
It is difficult to show a cost on conservatory and trombe wall builds as it will all depend on a builder’s quote and the design of your house.
Renewable Energy Technologies (RET)
The big ones! This is in essence, the final stage of cutting down your carbon emissions, saving energy and saving money. At present, no doubt you will have heard about renewable energy both globally and nationally. Buzz words such as sustainability have been used, sometimes in the wrong context. Sustainability or sustainable development means ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs (United Nations 1987). Renewable Energy is defined as an energy resource that can never run out. Fossil fuels such as coal, gas and oil, are limited resources, and so are not renewable. In the case of biomass; as long as the fuel is ‘sustainably managed’ then this too, is a renewable resource.
Under the Climate Change Act, the UK has to reduce its CO2 emissions by at least 26% by 2020. To do this, RET’s will form a substantial percentage of this 26%.
10% of the UK’s electricity generation is to come from Renewable sources by 2020. So, out of this 2% of UK electricity generation is intended to come from micro-scale RET’s, or in other words, from you the householder or small business. This is being done by incentives (such as the Feed-In-Tariff), the usual way of encouragement if the government want and need you to do something. Other percentages may come from the Renewable Heat Incentive, destined to be in place by April 2011 which will cover the thermal side of energy generation, and is expected to cover wood stoves and geothermal energy for example.
This section of the article will briefly outline most types of Renewable Energy Technologies with some food for thought on suitability, incentives and grants, and typical costing. Later articles will go into the overall types of RET’s on a macro (large) and micro (small) scale.
Photo comes from the Greek word for light and voltaic transpires from volt (the driving force in electricity). This is one of the types of solar panels available. This one generates electricity by radiation from the sun. This technology is the highest ‘earning’ in terms of the feed-in-tariff, basically the pence per kilowatt hour an energy company will pay you that you generate.
As the UK is in the Northern Hemisphere of the world then the sun is in a position south of the UK. This means, that to gain maximum radiation for a day, a panel must be installed, south facing. This is where suitability comes into it, and you will need to have a look if you have any space (normally on your roof as this is the least interrupted part of a dwelling as it is not blocked by trees and other buildings etc) available to you that you can install this on.
Also, is your roof built strongly enough? Certain roofs will not be able to hold a panel’s weight, so you may have to have the roof re-strengthened.
Cost – Typical installations range between £8,000 and £12,000. Larger arrays will obviously cost a lot more than this!
F-I-T – The feed- in-tariff, between Apr 2009 and Mar 2012 will give a price of 41.6p/kWh for an installation built onto an existing dwelling, or 36.1p/kWh for an installation built onto a new build. The lifespan however for PV feed-in-tariff is set to last until 2035!
The map shows average irradiation (or intensity of the sun) in Europe [1].
The other solar panel! This panel involves heating a fluid within the pipe workings of the panel which then in turn heat water or air. These tend to be cheaper than the PV panels. There are two types of solar thermal panels; evacuated tubes and flat plate collectors. There are also ‘point’ and ‘line’ focus collectors which involve dishes and curved troughs which aim the suns radiation to one focus point which then heats water; however the technologies are not so commonplace domestically.
Cost –Typical costs of a solar thermal panel are anywhere between £3,000 and £5,000, depending on the rating in kW.
F-I-T – The feed-in-tariff for solar thermal, between Apr 2009 and Mar 2012 is 18p/kWh, and is valid until 2030.
Biomass is a collective term for materials that are or have been a living organism and are biodegradable. Biomass ranges from food waste to crops and wood. Biomass is generally used on a micro scale for heating purposes. However, on macro scale, both electricity and heat are generated. Biomass technologies on a macro scale range from straw fired power stations to anaerobic digesters. On a micro scale they are generally wood pellet stoves to wood burners.
Cost – A wood stove is likely to cost around £3,000, whereas a gravity or automatically fed wood pellet stove is around £8,500 -£9,500.S
F-I-T – There is no feed-in-tariff for Biomass. This is likely to come under the new Renewable Heat Incentive (RHI) to be implemented in 2011.
Wind
The UK has one of the best wind resources in the world. There has been much controversy surrounding wind generation, ranging from bird deaths to noise and the actual storage and supply of the electricity. This will be discussed in a later article. The name windmill and wind turbine often get confused. A wind mill uses wind to ‘mill’ a material, most notably corn and wheat to make flour. A wind turbine uses wind to generate electricity through a ‘turbine’ and generator.
There are many different sizes of wind turbine, on a micro scale, domestic roof mounted turbines tend to be rated at no larger than 2kW. Free standing micro scale turbines rate between 6 and 15kW and on a macro scale, usually built as a ‘wind farm’ turbines at present are rated 0.5 to 3MW. There are some turbines being developed that are rated as a whopping 6.5MW!
The suitability for a wind turbine depends on many things. Wind speed is of the most important. Turbines are generally built where an average wind speed for a year is around 5.5 metres per second and higher. Free standing turbines need to be above the ground in such a way that the surrounding area does not block or inhibit the wind causing turbulence. Therefore, a turbine should definitely not be sited near trees and buildings. The turbulence affects the turbines efficiency to generate electricity effectively.
Turbines can be built in conservational areas providing they meet the correct criteria. This can involve ensuring that the turbines do not suppress a view or inhibit the lives of endangered species.
Turbines should also be built as near as possible to the electricity grid due to the large cost that comes with building a connection.
Cost –Typical cost of a roof mounted turbine is around £1,500 to £2,000, whereas larger turbines are around £3,000 to £20,000, depending on the rating.
F-I-T –The feed-in-tariff between Apr 2009 and Mar 2012 is 34.5p/kWh for turbines rated below 1.5kW, and 26.7p/kWh for turbines rated between 1.5 and 15kW
Bio-fuels
Bio-fuels are not a relatively new idea. Rudolph Diesel invented the diesel engine originally to run on vegetable oil. Bio-fuels can be made from a variety of ‘energy crops’. There are two main types of bio-fuel, bio-diesel and bio-ethanol. Bio-diesel is manufactured to be the fuel in a diesel engine and is predominantly made from the oils of plants and other organisms. Bio-ethanol is the fuel substitute in a petrol engine and is made by turning plants sugars into alcohol.
You may see in fuel stations ‘blends’ of diesel and petrol. Such as E85 or E80, meaning 80 or 85% of the fuel volume is made up of the bio-fuel and the remaining 10 or 15% is the fossil fuel.
The cost of biodiesel at this present time (11th June 2010) is around £1.04 – £1.05/litre for E100 biodiesel [2].
The cost of bio ethanol at this present time (11th June 2010) is around £1.12 for E85 [3].
‘Hydroelectricity’ in essence means ‘water electricity generation’. On a micro scale a hydro project could be built where there is a substantial enough flow of running water (that flows all year round). There are many variations of hydro turbines that are designed to work efficiently in a specific water condition. However, to get more power out of a body of water will really depend on how fast the water is flowing. The amount of energy that you could get out of a flow of water is quite amazing, which could mean a small payback period. I have visited a project that literally only took a couple of years for the owners to get their money back because they were selling what they didn’t use to the grid.
Some draw backs;
- The capital needed to be raised for the project is often quite large.
- You will need to consult the Environment Agency about the water course. Often there are fish or newts living in the water, and this may inhibit the project.
Cost – A micro hydro project could range anywhere between £20,000 and £40,000, depending on circumstances
F-I-T – The feed-in-tariff between Apr 2009 and Mar 2012 is 19.9p/kWh and lasts for 20 years.
Geothermal
‘Geothermal’, comes from the Greek Geo – meaning earth, and thermos – meaning heat. Geothermal technology is defined as a renewable resource.
Heat can be extracted from the ground anywhere in the world. However, for large scale needs a geothermal heat pump would have to be drilled to a deeper depth or be situated near a hot source. Hot springs, geysers and aquifers are examples of hot fluid sources. Drilling into deep rock where no fluid is present is known as ‘hot dry rock geothermal energy’. Fluid in this case is manually pumped down a bore hole to be heated up.
However, over extraction of heat from hot fluid sources too quickly can cause a cold spot.
Ground and Air Source Heat Pumps (GSHP and ASHP)
Ground and air source heat pumps are similar to air conditioning units. What ground source heat pumps do, is to extract heat from the ground during the winter, and put heat into the ground during the summer. It works because the earth remains at a pretty constant temperature during the entire year. Air source heat pumps work very similarly to this as well. Air and ground source heat pumps work like a refrigerator; however unlike a refrigerator, they can reverse between cooling and heating!
Cost- Anywhere between £7,000 and £13,000 for GSHP, and between £5,000 and £9,000 for ASHP.
F-I-T – Feed-in-tariff, from Apr-2009 to Mar 2012, around 7p/kWh. The lifespan for this particular price is until 2028 for ASHP and 2033 for GHSP.
For any more information on any large scale energy saving change you are considering for your home feel free to make an enquiry with Energy Saving Warehouse.
[1] http://re.jrc.ec.europa.eu/pvgis/cmaps/eu_opt/pvgis_Europe-solar_opt_presentation.png
[2] Taken from an online source; http://www.swbiofuels.co.uk/pricing.php
[3] Taken from a Taunton Morrison’s Fuel Station
