Onshore wind FAQs

The facts of onshore wind energy

BACKGROUND

Intermittent supply and demand

Wind energy is intermittent. Electricity is only generated when the wind is blowing so it can never provide a secure supply. There may be a surplus during the night when demand is low or none at all during the day when demand is high. A further problem with intermittency is that our consumption of electricity varies through each hour of the day as well as seasonally (we use more electricity in winter than summer). Electricity cannot easily be stored, (see ‘storage’ below) - it has to be used instantly so the amount of electricity generated has to match our use of electricity.

Wind speeds

Turbines only operate given the ‘right’ wind. As well as not operating when the wind isn’t blowing, they turn off when it gets too windy. Turbines typically start producing electricity at wind speeds of around 10mph, but need to be shut down above 55mph. They are most efficient at wind speed of around 20mph. Above this their efficiency declines as the wind increases. Onshore wind turbines have an average annual efficiency of around 27% (the capacity or load factor). Offshore wind turbines where the wind is more constant and reliable have a capacity factor of 40-50%

Land mass

Wind farms need to cover large areas to give a significant output. Wind may be free but it is a very weak source of energy compared to fossil, nuclear or even hydro-power. Large areas of land need to be covered with turbines with a visual impact on the landscapes for miles around. A typical gas fired power station (which is available to operate all years round) can produce around 13,000 megawatts of electricity for each square kilometre of land they use. To produce the same amount of electricity annually wind farms would need to take up 3,400 square kilometres of land.

FREQUENTLY ASKED QUESTIONS

Is it cheap?

No it isn’t. This myth arises from electricity ‘strike prices’ for MW generated that are bid by developers to secure the option to build.. These are notional prices for wind farms not yet built and do not include hidden costs such as constraint payments (payments to wind farms to shut down when their output is not needed), backup costs (typically the provision and operation of fossil fuel generators running inefficiently on standby) or the costs of transmission (typically by pylons over long distance to where the energy is required) or the costs of decommissioning.

What is the lifespan of turbines?

Wind turbines have a much shorter life than conventional generating plant. Gas and coal stations operate for 40 years or more and can be refurbished or upgraded component by component. Nuclear stations have an operational life of 50 years or more. In contrast, wind turbines only last for around 20-25 years before having to be scrapped. In addition, recent research shows that their efficiency and output deteriorates significantly after only ten years.

What about backup?

Because of its intermittent nature, wind energy needs constantly available backup from conventional generation and as a result displaces only a modest amount of conventional electricity. At present this backup is typically provided on standby by relatively inefficient OCGT (open cycle gas turbines) generation rather than more efficient and environmentally friendly CCGT generation because of the former’s ability to respond quickly to changes in demand.

What about storage?

Battery Energy Storage Systems (BESS), based on lithium batteries, are now increasingly being built both alongside new wind farm developments and separately as stand alone installations. The problem with BESS is that not only are they only ever likely to be able to provide a few hours of electricity at best, but that like lithium batteries in phones and laptops they have a limited lifespan of 8 to 10 years. Rapid charging and discharging of BESS also causes them to heat up which requires additional electricity for air conditioning units to keep the batteries cool. Like other lithium batteries there have been numerous serious incidents across the world where these BESS have spontaneously caught fire or exploded with fires that are difficult to get under control.

For more information see: https://www.thegwpf.org/content/uploads/2019/07/GridStorageWeb.pdf

Are transmission lines required?

Wind energy requires long transmission lines. Onshore wind farms are mostly built in remote areas far away from centres of population where the electricity is needed. This requires longer, more expensive and more intrusive transmission lines than power from conventional sources which are located much nearer to the large cities. Such long transmission lines also lead to greater power loss through the length of the transmission lines themselves. This can be a substantial loss - estimated as about 4% over 100 miles for a high kilo voltage transmission line. Generators get paid for the amount of electricity they produce from the wind.farm, not for the amount that actually arrives at the point of use.

Are claims of CO2 emissions reduction true?

The wind energy industry claims that a unit of wind-produced electricity displaces one generated from coal or gas, so reducing CO2 emissions. The wind farm developers show this information in their proposals. However this fails to take into account the CO2 emissions of the standby generators.

What about the CO2 emissions from construction?

Turbines may never pay off their ‘carbon debt’. The renewables industry claim the carbon emissions from construction is paid back within the first year of operation. This is patent nonsense as it fails to take into account the construction cost and environmental impact of the turbine components or the manufacture and installation of the associated cables and transmission lines. It also assumes that damage to peatland is successfully addressed by restoration efforts.

What about local jobs?

The industry claim wind farms create local jobs, but in reality wind energy creates few local jobs. The majority of the firms manufacturing wind turbines are located outside the UK - predominately in China, Denmark and Germany.  Most employment arising from wind farm developments in Wales would come only during the planning and construction stage. After construction wind farm site supervisors can look after several wind farms in an area, consequently the number of permanent local jobs arising is economically insignificant, even in remote rural areas

What are effects on the environment?

Communities near wind farms experience several local environmental effects. The most obvious effect is the visual impact of a group of wind turbines on the landscape. Whilst wind turbines were typically up to 100m high into past, recent proposals are for 200 to 250m high turbines. A view of large moving industrial structures is out of context in a natural landscape with a devastating effect on the the wellbeing of settled human and wildlife communities in the area   An additional  nuisance is noise. Wind turbines create various sounds, such as swishing and thumping (amplitude modulation) and tonal fluctuations. Turbine noise varies and may cause stress for anyone suffering the noise effect. Finally shadow flicker, where the rotation of the turbine blades causes the sunlight shadow to flash on and off rapidly. This can also happen at night if the turbines have aviation safeguarding lights. Apart from the irritation this effect is a significant health risk to some people.

The industrialisation and major earthworks to construct on-shore wind farms have the potential to disrupt or pollute private water supplies and nearby rivers. This is of particular concern in Wales where the hills favoured by developers are catchments for the environmentally important rivers of the Wye, Severn, Usk and Towy.

Other problems can arise with construction traffic, new transmission lines and the potentially adverse effects on birds, bats and wildlife in general.

What about Community benefit payments?

Enhanced incentives are now being offered by wind farm developers to local communities to accept wind farms in their areas. In Wales these vary between £5,000 and £7,500 per MW of capacity depending on the developer and location.

Community benefit payments are not a material matter in a planning application although they are often referred to and may influence local Councillors. Community benefit is distributed in various ways. What is increasingly obvious is that little or no money reaches those properties which directly suffer from the adverse effects of ‘hosting’ an industrial neighbour in their rural environment.

For communities receiving community benefit, there remains some uncertainties because there is no formal monitoring or reporting of payments. Since they are discretionary payments by wind farm operators, payments can be withdrawn or reduced at any time and payment of such benefit cannot be enforced by local authorities. They are not normally underwritten so would cease should the developer be unable to meet its commitments due to financial difficulties

CONCLUSIONS

Wind energy can make a potentially valuable contribution to addressing climate change as it can provide energy without burning fossil fuels. However, as with most technology there are adverse issues which need to be balanced honestly against the positive benefits. Onshore wind farms can have adverse local environmental impacts, including significant release of carbon by being sited on precious peatlands which counter their aims to produce carbon savings from generated electricity. In addition predictable adverse effects and risks for local communities, the environment and ecology require to be put into the balance of whether projects should be approved..

There  will always be underlying problems with wind farms. The unavoidable intermittency of wind energy, only producing electricity when the wind blows, means that it can never be the sole source of electricity generation. The short life expectancy of wind farms requires that after 25 to 30 years, infrastructure will require to be replaced, with more environmental damage and use of precious resources. Other sources of electricity, including from fossil fuel generators, are required on permanent standby to provide back up for when the wind is not blowing. Reducing demand and encouraging alternative sources of renewable energy represent better options for the future.

Adapted from original work by Scotland against Spin and posted with their kind permission