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Frequently Asked Questions    Ask a Question
 Welcome to the Renewable Energy Association Online F-A-Q. Here you will find answers to common enquiries that we receive.
 General: How much CO2 will my renewable electricity generating project save?
 General/ Heat: How much CO2 will my renewable heat project save?
 Biomass: Where is my nearest wood fuel supplier?
 General: What are ROCs worth?
 General/ RO: What is the Renewables Obligation and how does it work?
 General/ Power: What qualifies for ROCs / What counts towards the Renewables Obligation?
 Biomass: Where can I find out how much woodfuel might be available for a renewable energy project?
 General: What does this mean? Is there a glossary of terms?
 Funding/ Biomass: Can I get a grant for a small biomass heat or CHP project?
 General: How do I convert between different energy units?
 General/ Power: What is the NFFO? / Non-Fossil Fuel Obligation?
 General: Why should we pay a premium for renewables?
 General: Show me a map of renewable energy projects in the UK
 General/ Power: How much electricity will this project generate each year?
 General: How many households’ electricity needs will this renewable energy project meet?
 Biofuels: Where can I buy renewable transport fuel?
 Biofuels: What are the differences between Biodiesel and Straight Vegetable Oil (SVO) or Used Cooking Oil (UCO)?
 Biofuels: Is it legal to use Biodiesel, Used Cooking Oil or Straight Vegetrable Oil to fuel my car? How is it taxed?
 Biodiesel: Can I mix biodiesel with regular diesel? Can I use 100% biodiesel straight away?
 Biofuels/ Biomass: Can I use biodiesel or vegetable oil in my oil-fired central heating boiler/AGA/stove etc?
 General: What is the future potential for renewables in the UK? How can the Renewables Obligation be met?
 Micro: How can I sell the electricity from my solar PV/ mini wind system?
 Funding: How can I get funding for a biodiesel/ bioethanol/ transport biogas plant?
 Funding/ Biomass: How can I get funding for a wood pelleting/ other renewable fuel production plant?
 Biofuels: I have a supply/ I need a supply of Used Cooking Oil
 Wind: I need some information about small scale wind energy
 Biogas: How can I generate energy from animal wastes such as cattle manure? Who develops anaerobic (methane) digestion projects?
 Solar & Micro: Please can you give me some advice on micro-renewables?
 Biomass/ Micro: I need some information on biomass/ wood heating
 General: I would like to gain a qualification/ train in renewable energy
 General: How do I contact the company responsible for my local electricity network, i need to arrange a connection? (What are the contacts for my DNO?)
 Biofuels: I need UK consumption figures for biodiesel/ bioethanol/ other transport fuel
 General: I have an invention- is it viable? I need funding for research and development, can you help?
General: How much CO2 will my renewable electricity generating project save?
Every unit of electricity that is generated from a renewable energy source results in a direct saving of greenhouse gases that would have been produced had that unit of electricity been generated by non-renewable plant. First, work out how much electricity will be generated by the plant. Multiply the capacity by the load factor, and then by 8760 (number of hours in a year). Then multiply the answer by a factor given in the table below, to give the amount of CO2 saved per year.
Emission CO2 NOx SOx Most appropriate context
Coal 910 11.8 4.3 Marginal, real-time emissions savings, or longer term view if based on premature closure of coal-fired plant
Natural Gas 360 0.5 - Longer term view, based on avoided new gas capacity
Average (Other) 500 1.2 2.4 General, non-specific scenario

Carbon Dioxide emissions figures are those used by DTI for fuel mix disclosure calculations, and represent the emissions at point of use, not the full life cycle. For more information about which figures to use, see Emissions savings for Renewable Energy

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General/ Heat: How much CO2 will my renewable heat project save?
Solar thermal used for domestic water heating usually displaces either electricity or gas, and on this basis, quantifying emissions is very straightforward. Natural gas, when used for heat production emits 224 g CO2/KWhth. If a house with a solar thermal panel otherwise heats water by electric immersion heater, then greater savings are achieved. It would be most appropriate to use the average plant mix, in this context, thus savings are 514gCO2/KWhth

Similar savings are achieved from heat production from biomass, again depending the form of heating that is being displaced. The table below can be used, to show savings.

Heating source displaced by biomass Emission saving, g/kWhth or Kg/MWth
Natural Gas 224.4
Kerosene 287
Diesel Oil 296
LPG 252
Coal 432
Indicative off-grid mix 321
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Biomass: Where is my nearest wood fuel supplier?
Visit the logpile website to see to an online database of wood fuel suppliers. It enables you to search for the nearest wood fuel supplier in your locality. It is suitable for small scale users, see the Woodfuel Resource website if you are a project developer looking for larger-scle fuel supplies.
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General: What are ROCs worth?
The further we are away from reaching the percentage of renewables required by the Renewables Obligation the more ROCs are worth.

The buy out price sets a floor price (unless the obligation is met in full - see below) but there is no ceiling price. There is a mathematical relationship between the size of the Obligation, the level of the shortfall and the theoretical value of a ROC.

To see how this works in detail see an article by Gaynor Hartnell (though written some time ago, it explains the workings.)

To see recent ROC prices.. look at the NFFO and SRO auction prices, on the NFPA website NFPA website.

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General/ RO: What is the Renewables Obligation and how does it work?
In simple terms the Renewables Obligation makes Licensed Electricity Suppliers source an increasing proportion of their electricity from renewables, or else pay a financial penalty.

See RO annual quotas & buy-out price in table below (years refer to year ending 31st March)

2003 2004 2005 2006 2007 2008 2009 2010 2011 p.a. to 2016
3.0% 4.3 4.9 5.5 6.7 7.9 9.1 9.7 10.4 +1% 15.4%
£30.00 £30.51 £31.59

the penalty is an index linked £30 for every MWh that they suppliers fall short of their target.

The buy out money is recycled back to suppliers in proportion to how much renewable electricity they supplied.

Renewable Obligation Certificates (ROCs) are the currency of the Obligation and ROCs are used as proof of compliance. Most, but not all, renewable electricity qualifies for ROCs.

see other questions on this FAQ list
What qualifies for ROCs?
What are ROCs worth?

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General/ Power: What qualifies for ROCs / What counts towards the Renewables Obligation?
The text below is a very general introduction. Refer to the legislation for detail - as it can get complicated!

In the relatively straightforward category is Wind, wave, tidal stream, PV, landfill gas, sewage gas and biogas from Anaerobic Digestion. All generating stations would qualify if built after 1990.

It is a bit more complicated, in the case of pure biomass (the fuel has to be less than 10% contaminated by fossil fuels, and various other restrictions); and hydro which qualifies whatever its size if built after 1990, and if it is refurbished and under 20MW. All micro-hydro plant, whenever it was built gets ROCs if it is 1.25MW or less.

The biomass fraction of waste gets ROCs, provided that an "advanced technology" is used, ie gasification or pyrolysis. AD of any waste qualifies for ROCs.

Where it gets complicated is in the case of Co-firing biomass with fossil fuels and for generators located on site of a NFFO project.

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Biomass: Where can I find out how much woodfuel might be available for a renewable energy project?
The Woodfuel Resource Website details the background, aims and methods used in a study of the potentially available Woodfuel Resource in Great Britain, and presents the findings in an interactive manner. This enables users to request the data they are interested in by geographic region, type of woodfuel resource and by various classes of resource.
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General: What does this mean? Is there a glossary of terms?
We have reproduced the glossary from the RPA Renewables Yearbook 2004. To look up terms starting A -D, click here, for terms starting E - N, click here, and for O - Z, click here. If we've missed something out, .

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Funding/ Biomass: Can I get a grant for a small biomass heat or CHP project?
Look on the Clear Skies website - but also, see below information on grants under the DTI’s Bioenergy Capital Grants scheme, for installing clusters of heat only or CHP units.

Project name Type of project Contact
Countryside Properties plc CHP plant up to 0.26MWe and 0.26-0.4MW th
Econergy Ltd Clusters of heating systems, to a total of 19.6MW thermal
Lignatherm Boilers totalling 7.5MW thermal in yr1, possibly increasing by 13MW per year
Nottingham Woodheat Project Cluster of heating systems, to a total of 4MW th
Rural Energy Ltd Large cluster of small scale heating systems, to a total of 27MW th
Wood Energy Ltd Clusters of heating systems, to a total of 10MW thermal
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General: How do I convert between different energy units?
Use this simple table below…..

Unit multiplied by Approximate Conversion Factor equals Unit
kilowatt hours (kWh) X 3.6 = megajoules (MJ)
tonnes of oil equivalent X 41.868 = gigajoules (GJ)
tonnes of oil equivalent X 11,630 = kilowatt hours (kWh)
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General/ Power: What is the NFFO? / Non-Fossil Fuel Obligation?
The NFFFO was a policy initiated in 1990. It raised money via the fossil fuel levy - to pay for the additional costs of nuclear power and renewables. Initially most of the levy went towards nuclear - but over time the overall size of the levy was reduced, whilst the proportion going to renewables, as opposed to nuclear, increased..

The policy resulted in contracts being awarded to renewables generators in order to "secure" a total of 1500MW dnc of renewable by 2000. (For meaning of dnc see glossary.

In all over 3600 MW dnc of renewable capacity was awarded contracts, but much of it was never commissioned. (See paper by G. Hartnell March 2000 on Planning and Renewables : Implications for meeting the targets for background on progress towards NFFO targets.

See descriptions of the NFFO policy on the DTI website

Key features of this policy were the "bankable" contracts which facilitated project financing, and the ability to stimulate renewables' deployment across a range of technologies at different stages of commercial development.

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General: Why should we pay a premium for renewables?
The first question to answer is who is doing the paying? One thing is certain; customers of today are not paying the full costs for their energy use. For example, the costs of a changing climate will fall mainly on future generations. It is clearly unfair to pollute the planet and make future generations pay - and that is why Governments across the world are attempting to combat climate change. Increasing the use of renewable energy is one of many measures being taken.

There are two ways of promoting renewables by tilting market conditions to deliver a more sustainable energy future. One is to make sure that today’s consumers pay the full price of energy. That means paying up now for climate change impacts and the costs of dealing with nuclear waste management. This would push energy costs up and there would be no need to subsidise renewables. However this is awkward politically – and it is impossible to know exactly what the true costs should be.

The other way is to subsidise sustainable energy options, to make them competitive, leaving other energy costs broadly where they are. This is politically easier to implement - and that is why we have a Renewables Obligation. (The RPA would like to see other sectors of renewables similarly incentivised, see proposals for a renewable heat obligation.

It is a price we believe is well worth paying!

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General: Show me a map of renewable energy projects in the UK
The RPA holds probably the UK’s most comprehensive database of renewable energy projects, used to provide the primary input for our Renewables Yearbook.

Following a request for data for a Government report, this has now been mapped to show the projects by location. See a consolidated map for all resources, from where you will find links to separate maps for

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General/ Power: How much electricity will this project generate each year?

To calculate this, multiply the
Capacity (in MW) x capacity factor (see table below) x 8760 (the number of hours in a year)

Typical capacity factors

Technology Typical load factor
Wind 0.25 – 0.4 depending on location (0.3 most often used)
Combustion projects, eg landfill gas, sewage gas, AD, biomass, etc 0.85
Wave 0.30
Tidal stream 0.4
Solar photovoltaics Summer, up to 0.2, winter under 0.05 and annual average, the figure to use in this context, 0.13
This will give you a MWh figure (Megawatt hours) for one year
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General: How many households’ electricity needs will this renewable energy project meet?
The number of households served is often used as a way of getting across the benefits of a proposed development. Take the output figure (MWh) and divide it by one of the figures in the table below.

MWh per year context
4.5 This is the overall average and is based on taking the total domestic electricity consumption in the UK and dividing it by the total number of households. The RPA believes this is the best number to use, but sometimes the number below is used.
3.7 This is the annual average for households connected to the gas network and that use gas for cooking and heating.
3.3 This is the figure currently accepted by Energywatch. It was also accepted by the Advertising Standards Authority in a recent rejection of a complaint about output claims.
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Biofuels: Where can I buy renewable transport fuel?
Look at Biodiesel Filling Stations. or Energy Saving Trust's cleaner fuels database.
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Biofuels: What are the differences between Biodiesel and Straight Vegetable Oil (SVO) or Used Cooking Oil (UCO)?
  • Biodiesel is usually derived from vegetable oil, with very similar properties to diesel. It is produced by combining organically derived oils with an alcohol to produce a Methyl Ester. This is called transesterification.
  • Biodiesel meeting the required EN 14214 quality standard will fuel most diesel engines. However, most engine warranties will only cover up to 5% blends of biodiesel with normal diesel, even though many reports show that biodiesel is beneficial to engines.
  • Pure vegetable oil or suitably cleaned UCO can be used as a fuel. It can be burned, without processing it into biodiesel, but only in a suitably modified engine.
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Biofuels: Is it legal to use Biodiesel, Used Cooking Oil or Straight Vegetrable Oil to fuel my car? How is it taxed?
  • Yes, it is legal, as long as you pay the correct amount of tax. If you purchase the biodiesel/ UCO/ SVO from a reputable supplier, the tax should already be included in the price. If you produce or source your own fuel, you are responsible for declaring and paying for your fuel consumption, even if you are using vegetable oil/ UCO bought from a supermarket, restaurant or a local farmer.
  • There is a duty on biodiesel of 27.1p per litre of fuel, which is 20p less than regular diesel and petrol. This helps to make biodiesel able to compete on price with fossil fuels.
  • Straight Vegetable Oil or Used Cooking Oil is taxed at the same rate as regular diesel, 47.1p per litre.
  • Click here for HM Revenue and Customs info

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Biodiesel: Can I mix biodiesel with regular diesel? Can I use 100% biodiesel straight away?
  • They can be blended in any combination. Blends of 5%-20% biodiesel are quite common, for example.
  • First check that your vehicle warranty will not be invalidated. If it’s OK, or if your vehicle is out of warranty, generally it would be recommended that you introduce biodiesel slowly over a number of refills. This is because biodiesel’s solvent properties may cause debris in your fuel system to be washed out and block your fuel filter(s). Gradual introduction allows this cleansing to happen slowly. Also some seals may have swollen slightly from using mineral diesel, and these may shrink rapidly when neat biodiesel arrives in the system, causing engine damage.
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Biofuels/ Biomass: Can I use biodiesel or vegetable oil in my oil-fired central heating boiler/AGA/stove etc?
We can find no manufacturer who has tested their products for biodiesel but in principle it burns like diesel. Switching from heating oil to diesel is often just a burner nozzle change. However, you may wish to consult your manufacturer.

You will find that biodiesel as a heating fuel is more expensive than ‘red’ diesel or heating oil.

It is possible to produce a biofuel with very similar characteristics to heating oil (as opposed to diesel), or '35 second oil', which can be used in standard oil fired boilers. At present we are unable to recommend a reliable source of this fuel, although we are looking into it.

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General: What is the future potential for renewables in the UK? How can the Renewables Obligation be met?
This Oxera/ DTI report assesses the potential contribution of different technologies to the Renewables Obligation, and breaks this down into regions of the UK. Also, our 2006 Energy Review response includes a thorough review of current analyses of the potential contribution that renewables could make to the UK energy mix.
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Micro: How can I sell the electricity from my solar PV/ mini wind system?
There are several electricity suppliers with tariffs for micro-generators. These include Good Energy, npower Juice, EDF, Green Energy and Northern Ireland Electricity. You should contact your supplier for more information.
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Funding: How can I get funding for a biodiesel/ bioethanol/ transport biogas plant?
We are not aware of any dedicated funding streams at present. Enhanced Capital Allowances for suitably efficient plants will be available from early 2007, as described in the Budget 2006-7.
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Funding/ Biomass: How can I get funding for a wood pelleting/ other renewable fuel production plant?
We are not aware of any dedicated funding streams at present. Manufacturing facilities of this kind may be eligible for European Objective Area support, for which you should contact your local authority.
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Biofuels: I have a supply/ I need a supply of Used Cooking Oil
If you have a supply of UCO that you want collected, contact A& B Oil on 023 8033 9292.

If you need to obtain UCO, you could try contacting the dept. of your local authority responsible for waste collection, or search for your local oil collection company.

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Wind: I need some information about small scale wind energy
Please consult the British Wind Energy Association. They have a website dedicated to this subject
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Biogas: How can I generate energy from animal wastes such as cattle manure? Who develops anaerobic (methane) digestion projects?
Anaerobic digestion equipment can provide you with both biogas, which can be used for heat and power generation, as well as a nutrient rich digestate fertiliser. Click here for case studies of existing AD plants. Companies that can help you set up such a facility include Greenfinch, Methanogen and Bedfordia Biogas.
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Solar & Micro: Please can you give me some advice on micro-renewables?
Unfortunately the REA is currently unable to provide advice to consumers regarding individual projects or technology choices such as solar PV, solar thermal, small wind & hydro, heat pumps and biomass boilers. We suggest you contact one of the following organsations:

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Biomass/ Micro: I need some information on biomass/ wood heating
See our page on this subject here
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General: I would like to gain a qualification/ train in renewable energy
Training providers include:

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General: How do I contact the company responsible for my local electricity network, i need to arrange a connection? (What are the contacts for my DNO?)
The ENA maintains this list: DNO Contact List
Alternatively, this is a list of DNO contacts for connecting small scale generation to the electricity transmission network, compiled by the REA.
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Biofuels: I need UK consumption figures for biodiesel/ bioethanol/ other transport fuel
Download this HM Revenue and Customs data here
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General: I have an invention- is it viable? I need funding for research and development, can you help?
Unfortunately, due to time and resource restrictions, and the need to remain impartial, the REA is unable to directly advise or assist with the development of technology. We suggest that you consult:

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