RenewableUK unveils solution to issue of Other Amplitude Modulation

This week industry trade body RenewableUK published new research on the subject of wind energy acoustics. The study was produced to explore the issue of Other Amplitude Modulation’ – this is a phenomenon which affects a small minority of wind turbine installations.

The research was carried out in partnership with  the University of Salford, the University of Southampton, the National Aerospace Laboratory of the Netherlands, Hoare Lea Acoustics, Robert Davies Associates and DTU Riso in Denmark. The aim of the research was to determine the causes behind Other Amplitude Modulation and to investigate solutions to the issue.

Firstly it should be noted that Other Amplitude Modulation is entirely different to Normal Amplitude Modulation. Normal Amplitude Modulation is the sound commonly heard from wind turbine installations – the ‘swishing’ sound generated as the turbine blades spin through the air. Other Amplitude Modulation is a  far more infrequent and uncommon sound which lasts for a few minutes.

The research reveals that Other Amplitude Modulation is caused by sudden and unexpected variations in both wind speed and direction. When this occurs the wind hits different parts of the turbine blade at different speeds causing momentary stalling of the turbine blades and a ‘whooshing noise’.

At this point it should be emphasised that the research has revealed that Other Amplitude Modulation is no louder than the more commonly occurring and accepted Normal Amplitude Modulation. Both cause noises at a level of around 35-40 decibels it is, however, the case that Other Amplitude Modulation occurs at a deeper pitch. The sound produced by these sudden variations of wind speed and direction has been likened to the noise produced by a single-carriage A-road at a distance of 1 kilometer.

Interestingly the research also revealed that Other Amplitude Modulation affects only around 3% of wind turbine installations in the UK. Very much a minority. These findings were based upon a 2007 research paper produced by the University of Salford. This paper found that only 4 of 135 turbine sites (as were installed in the UK as of 2007) were affected by Other Amplitude Modulation. From this the RenewableUK study concluded that 15 of 521 (currently operational) turbine sites would be affected by Other Amplitude Modulation. Other Amplitude Modulation could be then rightly described as affecting a very small minority of the United Kingdom’s wind turbines. However that does not stop it from being an issue that the UK’s wind industry is keen to address.

As such RenewableUK also published the solutions to the issue of Other Amplitude Modulation which were identified by their research. A software solution is sufficient to deal with the issues involved. Software systems already present in wind turbines can be adapted to change the angles of turbine blades at times when Other Amplitude Modulation could occur. This would avoid the problem of turbine blades momentarily stalling entirely.

Additionally RenewableUK has also entered into partnership with the Institute of Acoustics to produce planning conditions and guidance for the issue of Other Amplitude Modulation. This would ensure that occurrences of Other Amplitude Modulation would be minimized. It would be up to developers to measure instances of Other Amplitude Modulation and set a threshold in decibels above which they would be required to act immediately to change blade angles to minimise the noise. This would occur as part of the planning process. Given the already low level of Other Amplitude Modulation occurrences such planning procedures could virtually eliminate the issue entirely.

Speaking at the publication of the research, RenewableUK’s Deputy Chief Executive Maf Smith commented:

“It’s right that the wind industry should take the lead in investigating issues like this when they arise. As a result of the in-depth research we’ve commissioned, we’ve identified the causes of OAM, and, most importantly, the industry has identified a way to deal with it effectively.

“On the limited and infrequent occasions when OAM occurs, we can address it by using software to adjust the way turbines operate, changing the angle of the blades.

“Beyond that, the industry has worked with members of the UK’s leading acoustics institute to develop a planning condition for local authorities to use, which we’re publishing today alongside this work. This states that if OAM occurs, it’s up to the wind industry to resolve it.

“We’re proud to have commissioned this ground-breaking research as it pushes the boundaries of our knowledge of wind turbine acoustics considerably further forward. It’s a tangible example of the wind industry acting in a responsible manner, demonstrating that we’re continuing to be good neighbours to the communities who host wind farms in the UK”.

In other news this week UK company Blade Dynamics announced it’s plans to move forward development of a ‘very long’ and highly efficient turbine blade. This follows the successful completion of the design stage.

The project is receiving support from the UK Government, the industry-supported Energy Technologies Institute (ETI)  and the wind turbine manufacturer Siemens. Blade Design will now proceed to the prototype stage of the project and hopes to begin testing the new 80 metre long turbine blade before the end of 2014. The blade will be lighter, longer and more efficient than those currently in use.

News of the commencement of the next stage of the project was greeted enthusiastically.  Henrik Stiesdal, chief technology officer at Siemens Wind Power commented; “Subject to successful conclusion of the tests it is clear that the potentials of the split-blade technology of Blade Dynamics would be expected to become even more interesting as we move to even larger turbine platforms.”

Andrew Scott, program manager for offshore wind at the ETI stated:

“The ETI’s vision is to support the development of next-generation blade technology because improved rotor performance is fundamental to achieving the goal of reducing the cost of offshore wind energy.

“We greatly appreciate the ongoing commitment of Siemens to this project with Blade Dynamics. As leaders in this field, this partnership for the development of next-generation rotor technology has the potential to have a huge impact on the cost of offshore wind energy in the future.”

These two announcements indicate the progress which is being made by the UK wind industry. Whether it be the development of new and more efficient technology or the addressing of existing (if extremely infrequently occurring) issues it can be seen that the UK’s wind industry is ending 2013 as it began it; with an eye to the future.

Survey reveals farming industry’s hunger for renewables

This week industry trade body RenewableUK held a lunch event in partnership with the River Cottage food business and the online community Energyshare. The lunch was held on the Devon/Cornwall border. The Great British Wind Meal was used as an opportunity to publicize several recent items of research in regards the relationship between British farming and renewable energy.

Several of the speakers at the event suggested that a greater uptake of renewable energy generation by British farmers would help the United Kingdom to meet both it’s food and energy needs. One speaker suggested that as well as helping the UK to meet it’s renewable energy targets farmers stand to benefit from on-site generation by it allowing them to reduce the costs involved in producing food and also ensuring that their businesses are in a better position to navigate through at troubled economic climate for the farming industry.

Speaking at the event, Forum for the Future’s principal sustainability adviser Nicky Conway remarked:

“There are about 300,000 farms in the UK so if you are going to have renewable energy generation at any level of scale, farmers have the land and the capacity to install those renewable energy schemes.

“Therefore they should be a target audience because they have the land and the resources to produce the energy”.

Ms Conway went on to state that Forum for the Future was attempting to increase the uptake of renewable energy generation developments on UK farms:

“The specific way that we would like to do that is to try and build a common evidence-based vision, and [highlight] why can farm-based energy can play such a critical role in the UK’s energy system rather than being a niche activity.

“The other thing we want to do is unlock some of the key barriers. Things like grid connections and accessing finance, particularly for lower income farmers.”

Farm owner Robin Hanbury-Tenison argued against claims that renewable energy developments take land away from food production – giving the example of his own solar panels:

“A lot of people say that PV panels are taking up land, wasting land but far from it if it is done properly.

“My sheep prefer being under or around the panels than being in the open fields. The grass grows better, they also have lovely shelter and they lamb underneath them.”

Attendees at the lunch also heard the results of a new survey carried out in partnership between Nottingham Trent University, the Farmers Weekly and Forum for the Future. The survey was carried out this summer and asked nearly 700 UK farmers for their opinions on farm-based renewable energy. Interestingly 38% of the farmers surveyed revealed that they were already generating renewable energy on their farms with the two most popular technology types being solar PV and wind energy. The majority of those generating electricity from wind energy are feeding at least some proportion of their output into the National Grid. The average capacity of these developments was 176kW however it should be noted that larger scale developments are perfectly possible given the right site and the expertise and experience needed to navigate through the planning process. Furthermore 61% of those who are not already generating renewable energy specified that they would be likely to do so over the next five years. Despite that fact that the majority of those surveyed are already generating renewable energy 76% of respondents did not believe that the full potential of farm-based renewable energy generation was being realized.

The survey was also used to explore farmers perceptions  on what the benefits of renewable energy generation are. 76% of those surveyed (the most-widely held opinion) felt that farm-based renewable energy generation helped to reduce the costs of the other parts of a farm business. 73% felt that renewables provided a safe-means of generating non-fossil fuel energy. 72% felt farm-based renewables helped to contribute to the country’s energy security. 71% expressed the opinion that renewable energy generation provided a good return on investment compared to more traditional farming activities and 65% felt renewable generation helped to combat climate change by reducing a farms carbon footprint. Interestingly 81% of participants felt that family, neighbours and other farmers would approve of a decision to invest in renewable energy generation. These results would suggest that there is a widespread belief amongst the UK’s farming community that renewable energy generation represents a positive investment for the industry.

The farming industry’s opinion on the barriers to farm-based renewable energy generation were also explored in the survey with five problems emerging as the crucial barriers to completing a renewable energy development. 84% of those surveyed identified the major stumbling block as the high investment costs involved. 53% felt that red tape represented a major barrier to completing a development.52% felt the planning process to be cumbersome and costly. 45% felt that local opposition could be a stumbling block and 39% raised the issue of accessing a bank loan. At this point we at Intelligent Land Investments (Renewable Energy) would like to state that have the expertise and experience to address all these issues. We require no investment from the farmers we enter into partnership with, we have vast experience of dealing with the planning process at both a national and local level and all the red tape that may be involved. We always take steps to involve and liaise with local communities through programs such as our Community Contribution and we do not need bank loans to fund our developments.

It was left to broadcaster and campaigner Hugh Fearnley-Whittingstall, responsible for the Wind Meal’s menu, to give the final word on the role that British farmers have to play in renewable energy generation, emphasising that wind energy can be regarded as another crop:

“All farmers are in the business of renewable energy – that’s what food is,

“Farmers produce food, we consume that food for our energy, and for farmers to stay in business it has to be a renewable business.

“The idea of farmers diversifying into ‘pure energy’ as well as food energy makes a whole lot of sense.

“We know that wind is going to be an important part of our energy into the future.

“Who has got best access to wind in the country? Our farmers.”

We at Intelligent Land Investments are very pleased to be playing our part in bringing the benefits of renewable energy generation to as many farmers as possible.

 

 

New UK Wind Energy Record Set

Last week the National Grid announced that a record amount of clean energy was generated from wind power on the 29th of November. Over 6 gigawatts of renewable electricity was fed into the National Grid over the half hour period between 2:30 pm and 3:00 pm- generation levels are measured by the National Grid in half hour intervals hence why figures are not supplied in gigawatt-hours.

From 2:30 to 3:00 pm an average of 6,004 megawatts (or 6.004 gigawatts) was fed into the National Grid solely by wind power. This level of generation represents 13.5% of the electricity demand at that time. Furthermore 6 gigawatts of renewable energy is enough to power over 3.4 million UK homes. These figures demonstrate the sizable amount which wind power alone (other forms of renewable energy generation such as hydro-power also made large contributions) is contributing to the UK’s energy needs. 6 gigawatts of wind power also represents 6 gigawatts worth of fossil fuels that did not have to be burned and a sizable amount of carbon dioxide which was not emitted into the atmosphere.

The previous record for wind power generation was set on the 15th of September when 5,739 megawatts was generated in one half hour period. It should be noted, however, that this record was broken several times on the 29th of November – the 6,004 megawatt figure released by the National Grid merely represents the peak of generation. Indeed, over 13% of the UK’s energy demand was being met by wind power frequently throughout the day. This demonstrates the consistency of supply which can be produced by wind energy.

Industry trade body RenewableUK‘s Director of External Affairs Jennifer Webber commented on the setting of a new record:

“Wind energy is consistently setting new records and providing an ever-increasing amount of clean electricity for British homes and businesses. We’re generating from a home-grown source which gives us a secure supply of power at cost we can control, rather than leaving ourselves exposed to the global fluctuation in fossil fuel prices which have driven bills up. Wind gives us a way to make a smooth transition from old-fashioned fuels to a new low-carbon economy.

“We’re also generating tens of thousands of green-collar jobs for people now working in the fast-growing British wind energy industry”.

Of course it should be remembered that the figures released by the National Grid do not represent the full amount of wind energy being generated in the UK – neither on the day or within that specific half hour period. There are a large amount of wind turbines in the UK, particularly within the small to medium scale (the scale at which we at Intelligent Land Investments (Renewable Energy) specialise in) which do not feed power into the National Grid. Such turbines will be supplying power locally or on-site. The owners of such developments are not required to supply real time output data to the National Grid and as such will not have been included in their figures.

It should be noted that UK wind power breaking such records as this is set to become a regular occurrence in the near future as more turbines are consented, constructed and begin to supply power into the National Grid. We at Intelligent Land Investments (Renewable Energy) are looking forward to playing our part in this process as more of our developments are completed in the very near future.

In other news this week the UK Government announced that it is expecting around £40 billion of additional investment to be made in renewable energy generation projects by 2020. It is claimed that figure represents a large amount of progress to the country’s 2020 renewable energy generation targets.

Currently the UK has over 20 gigawatts of operational renewable energy generation capacity. Furthermore there are 11 gigawatts worth of onshore and offshore wind developments which have acquired planning consent and are awaiting construction. As of today there are also 16 renewable generation projects, representing a further 8 gigawatts of capacity if successfully developed, which have reached the next stage of the Final Investment Decision Enabling for Renewables (FIDeR) process. According to a statement released by the Department of Energy and Climate Change (DECC) these 16 projects would contribute “around 30% of the new renewables generation we need by 2020”. The statement went on to say that “the UK is now on track to meet that target”.

The level of importance that is being placed upon reforming the UK’s energy grid can be seen in the fact that 58% of the total infrastructure spending laid out in the Government’s National Infrastructure Plan is to be directed towards energy. Given that 10-12% of the UK’s current generation capacity is due to come offline over the next decade we can both the need for new generating capacity and the role that renewable energy generation, and particularly wind generation given the relative maturity of the technology, can play in meeting that need.

The level of investment being predicted by the UK Government is sufficient to generate enough renewable energy to power a further 10 million homes across the UK and reduce CO2 emissions by 20 million tonnes. Such amounts of renewable energy generation will also serve to increase the country’s energy security, reduce significantly our reliance upon international fossil fuel markets and, according to figures announced by DECC, support up to 200,000 jobs. We can see then the huge advantages that a committed push for renewable energy development will bring to the country as a whole.

Energy and Climate Change Secretary Greg Davies made the following statement at the release of these figures:

“This package will deliver record levels of investment in green energy by 2020. Our reforms are succeeding in attracting investors from around the world so Britain can replace our ageing power station and keep the lights on.

“Investors are queuing up to express their interest in these contracts. This shows that we are providing the certainty they need, our reforms are working and we are delivering ahead of schedule and to plan.

“With sixteen new major renewable projects progressing in our “go early” stage we are delivering ahead of schedule and are able to begin the move to the worlds first low carbon electricity market faster than expected.”

We at Intelligent Land Investments (Renewable Energy) are delighted to have played a part in setting new wind generation records. We also look forward to helping set new records with our already installed turbines and also those of our developments which will have completed construction in the near future.