Aren’t wind turbines inefficient?

Modern wind turbines are extremely efficient at converting the available kinetic energy of the wind into electrical power, with none of the thermal losses inherent in fossil fuel plants. Wind power is therefore an efficient and clean way to generate electricity, using an energy source that will never run out.

Over the course of a year, a turbine will typically generate about 25-40% of its theoretical maximum output (depending on the site wind characteristics and turbine type installed). This is the turbine’s ‘capacity factor’, NOT a measure of the efficiency of the turbine. For example, a car almost never runs at its maximum power output; and if you drove it in this way for any length of time, the engine would soon break down.

In the same way, the capacity factor of fossil fuel power stations is around 50% because of stoppages for maintenance or breakdowns, or because the power from that plant simply isn’t needed all of the time. In short, no electricity generating plant generates power 100% of the time.

Wind turbines are very efficient at what they do, converting a very high proportion of the available wind resource into electricity, in a clean, sustainable way.

Are wind turbines noisy?

The noise emitted from wind turbines has been reduced significantly over the last 20 years. Improved design has greatly reduced the noise of mechanical components so that the most audible sound is that of the wind interacting with the rotor blades. Even in quiet rural areas, the sound of the wind is often louder than the turbines.

Noise effects from wind turbines are rated by a standard recognised in National Planning Guidance called ETSU-R97. Under this standard, it is accepted that the higher the wind speed, the greater the noise emissions from a wind turbine (because it is working harder). However, the background noise will generally also be higher, from the wind moving around obstacles such as trees and buildings. Background noise levels will be measured at properties that are relatively close to proposed wind turbines. These background noise levels are then used to establish how the windfarm design should adapt to the noise environment in the area, to ensure that these properties do not receive noise levels significantly in excess of the background noise that they already experience.

These background noise levels are used by local authorities to set noise limits for the project. The limits are set out in planning conditions which are attached to almost every wind farm planning consent. The noise conditions are strictly monitored by the planning authorities, to ensure that wind farms do not cause unacceptable noise impacts upon nearby houses.

Do wind turbines affect wildlife and birds?

RSPB has indicated that, as long as a wind farm is situated appropriately, it will not pose a significant hazard to birds. The RSPB has stated on record that, “Climate change poses the single greatest long-term threat to birds and other wildlife, and the RSPB recognises the essential role of renewable energy in addressing this problem.” They further state that, “Wind power is the most advanced renewable technology, available at a large scale, over this time period. For this reason, the RSPB supports a significant growth in offshore and onshore wind power generation in the UK.” (Source: http://www.rspb.org.uk/forprofessionals/policy/windfarms/).

As part of the comprehensive environmental impact assessment which is carried out on all of our wind turbine developments, Force 9 consults with Scottish Natural Heritage and RSPB and, where appropriate, other environmental bodies. This helps ensure that any negative effects upon wildlife are avoided and/or mitigated. Wherever possible, we look for opportunities to actively enhance the environment for protected birds and other wildlife, eg through the creation of habitats that are attractive for rare species of birds and animals.

Do wind farms affect tourism?

There is no evidence that tourism numbers have been damaged by the growth of renewable energy projects in Scotland. A study by BIGGAR Economics in October 2017 considered 28 wind farms which had been constructed between 2009 and 2015 and found that, “in the majority of cases, sustainable tourism employment performed better in areas surrounding wind farms than in the wider local authority area”.

Research by Visit Scotland concluded that, “the presence of wind farms had no influence on decision making of the vast majority of tourists” (source: Revised Oct 12 Insights Wind Farm Topic Paper).

Some wind farms have even become tourist attractions themselves, such as Whitelee, south of Glasgow and Scroby Sands in Norfolk. Wind farms also have the potential to encourage tourism by improving infrastructure; for example, by funding improvements to path networks, signage and other tourist facilities.

Why not put all wind turbines offshore?

Ultimately, if the UK is to maintain progress towards its carbon neutral targets, substantial deployment of both offshore and onshore wind projects will be needed: it is not a case of choosing between them. The Climate Change Committee (the UK Parliament’s independent advisory body) stated in March 2020 that, “Total UK electricity supply will need to double by 2050, and electricity from low-carbon sources will need to quadruple, in order to deliver the UK’s commitment to become a Net Zero emissions economy by that year”.

Whilst well sited offshore wind projects have a strong role to play in our energy mix, it would be impractical to rely wholly on offshore wind for our renewable energy requirements, given the extent of predicted need for renewable electricity if we are to meet UK Government targets.

Doesn’t the wind industry get large subsidies from the government?

Onshore wind power received UK government price support from the latter part of the 1990s but the level of that support was reduced over time and, after the 2015 general election, onshore wind farms were not eligible to receive any government support (subsidies) at all. A major challenge for developers and funders is the volatility of the open market energy price. What is required is a mechanism that stabilises the sale price of electricity that is produced by wind power projects. Contracts for Difference (CfDs) are just such a mechanism and are used in many countries throughout the world to support renewable power production, whilst also offering value for money for electricity bill payers.

From 2021 onshore wind will be allowed to compete, for the first time since 2015, for UK Government-backed CfDs. CfDs provide electricity sale price stability for the contract period of 15 years, and thus make investment in renewable projects more attractive. Developers must bid at auction for a CfD, offering to produce electricity over a 15 year period at a supported price (the ‘Strike Price’) which is proposed by the Developer. A Government agency, the Low Carbon Contracts Company (LCCC) will only award CfD contracts to those developers who bid low enough, thus incentivising low cost production of renewable electricity. Further protection for bill payers comes through the CfD obligation to repay any excess above the Strike Price back to the LCCC.

The Climate Change Committee (The UK Parliament’s independent advisory body) welcomed the announcement that, from 2021, onshore wind farm developers will be permitted to bid for CfD contracts for the first time since 2015: “I am delighted that the Government is recommitting to onshore wind and solar; amongst the cheapest forms of low-carbon electricity. We’ll now find out how cheap these technologies can really be. Reaching Net Zero emissions by 2050 means pulling out all the stops – we have called for a quadrupling of low-carbon electricity from current levels” (Chris Stark, Chief Executive of the Climate Change Committee).

Why do wind turbines sometimes not turn when it’s windy?

Wind turbines start operating at wind speeds of 3 to 4 metres per second (7-9 mph) and reach maximum power output at around 15 metres/second (33 mph). At very high wind speeds, i.e. storm force winds, (25 metres/second or 55mph) wind turbines are shut down. However, these are the sort of extreme wind speeds that cause damage to buildings and typically cause schools and businesses to close; and this only happens on a very few days in the year. Also, all forms of generating plant must be shut down sometimes, for routine or indeed emergency maintenance, or for health and safety reasons.

Turbines are sometimes switched off for short periods at times of ‘overcapacity’ on the national grid, ie when there is too much generation in relation to demand at that specific moment. See more on this under the ‘Pointless?’ FAQ.

Why build wind farms when we always need 100% back up when the wind isn’t blowing?

Our national electricity grid is designed to have some limited overcapacity at all times. All generation plant needs backup in case another part of the system goes offline – e.g. the major fire at Didcot gas Power Station in October 2014 or the shutdown of the Little Barford gas-fired plant in Bedfordshire in August 2019.

The National Grid constantly balances supply and demand for electricity. They liaise with large electricity users and monitor and predict industrial and domestic electricity use, based on patterns established over several years. They can ask most generators to increase or decrease output at any time to maintain a steady supply on the grid. When wind farms are generating (and this can be predicted with sufficient accuracy for the National grid at about 12 hours’ notice) they can ask other generators, typically gas plants, to reduce their electricity production. Wind farms thus help National Grid balance and fine tune supply and demand in a much more flexible and cost-effective way than other forms of generation. Overall, wind farms help us to use less fossil fuels, reducing emissions, improving air quality and conserving resources for future generations.

Why do windfarms sometimes get paid money NOT to operate?

National Grid sometimes asks wind farms to switch off for short periods of time because it is the cheapest and most flexible way of balancing overall electricity supply and demand: and quicker and more cost effective than shutting down other forms of electricity generation such as gas-fired plants or nuclear stations.

National Grid has explained the issue like this: “A constraint arises when power cannot be transmitted to where it is needed, usually due to congestion at one or more points on the transmission network. When this happens, we need to take action to ‘balance’ the network. This is similar to occasionally using traffic lights to manage the flow of cars joining a motorway during a busy period. It wouldn’t be economic or sensible to build another parallel motorway so that there was never a traffic jam.

These constraint payments are not new. National Grid has been paying coal and gas generators – and for other types of generation – to reduce output on occasion for some time now”.