By Dave Elliott
“There is no habitat that benefits from coal pollution”, says David Roberts, commenting on an article in New Yorker last year by Jonathan Franzen, who was worried that, in the rush to deal with climate change by using renewables, local impacts on birds would get ignored, given the argument that global climate change due to fossil fuel use would hurt them much more than wind farms or whatever: http://grist.org/living/jonathan-franzen-is-confused-about-climate-change-but-then-lots-of-people-are/
By Dave Elliott
It has been an eventful year for renewables. While progress continues apace, with renewables now supplying around 15% of electricity in the UK and 22% of global electricity, in this pre- Xmas post, rather than spelling out all the good news, I will look at some of the less good stories from the year- concerning wind power and CSP. (more…)
This past weekend on the Public Broadcasting Service (PBS) an episode, “A Murder of Crows,” of the show series Nature focused on research related to the behavior of crows. Due to the fact that crows have an equivalent brain size more closely representative of primates than other animals, crows have high levels of intelligence. Their intelligence allows them to be resilient and use multi-step problem solving skills. As noted in the documentary, crows are social animals that play, mourn death, and pick monogamous mates for life.
One interesting story form the movie with an energy slant is that the crows in Japan use wire clothes hangers for making nests. And crows nest in many places given the scarcity of good trees in the cities. One of these nesting locations is often among power lines and transformers. Put wire meshes together with electricity, and that creates an obvious recipe for disaster for the crows and reliability for electricity. So much has this become a problem that one utility has created a dedicated team of employees that travel power lines in search of crow nests to clear. This nest-clearing is not the normal task that one imagines in estimating operation and maintenance costs for operating a utility electric grid, but it shows the resiliency of nature to cause problems for humans. It seems the term “smart grid” is turned on its head in this case as a smart animal is making use of our trash to rewire the grid for us.
Wind farms can reduce local bird numbers by up to half, according to a new study by the Royal Society for the Protection of Birds in conjunction with the Scottish Natural Heritage. It looked at 12 upland wind farms in the UK during the breeding season for a dozen common species including rare species such as hen harriers and skylarks. The research, published in the Journal of Applied Ecology, found 7 species showed ‘significantly lower frequencies of occurrence close to the turbines.’ The breeding population of buzzard, hen harrier, golden plover, snipe, curlew, wheatear and meadow pipit were reduced by up to half within 500 m of the turbines. It suggested that the most likely cause of the decline is the fact that birds are less likely to live and breed near wind farms because of the noise and development. Collisions with turbines was also suggested as a possible cause, but was thought to be less likely.
The British Wind Energy Association concurred with that: “This study shows there is a potential problem with displacement, but it is not yet proved that there is a problem with bird mortality rates.” It added ‘Wind farms and turbines are the most benign form of energy generation and the industry has found that wind farms simply do not pose a threat if they are properly sited and follow procedure. The threat of global warming could be a far greater threat to the population of birds than wind farms’.
The RSPB have recently backed wind farms as long as they are properly sited, and recommended a spatial planning approach as used elsewhere in the EU.
The Daily Telegraph (26/9/09) however claimed that RSPBs pro-wind stance had caused ‘many members to leave in protest because of concern about the developments ruining the view in remote areas and contributing to the decline of birds’.
Nevertheless, James Pearce-Higgins, senior conservation scientist with RSPB Scotland and lead author of the study, told them that it still supported wind farms. But developments should not be put in the wrong area – where they can harm birds. ‘There is an urgent need to combat climate change, and renewable energy sources, such as wind farms, will play an important part in this. However, it is also important to fully understand the consequences of such development, to ensure that they are properly planned and sited. Our results emphasise the need for wind farms to avoid areas with high densities of potentially vulnerable species such as curlews and golden plover, and help offer a way forward by informing the likely extent of positive habitat management which may help to offset the impacts of development.’
It’s not just birds though, it’s also bats that can have problems and it seems in larger numbers. But researchers at Aberdeen University, funded by the People’s Trust for Endangered Species (ptes.org) are currently making good progress on using radar to deter bats from colliding with in the turbine blades.
But collisions may not actually be the problem. A study of bat deaths at a local wind farm by the University of Calgary reported by Science Daily found that the majority of migratory bats in this location were killed because a sudden drop in air pressure near the blades caused injuries to the bats’ lungs known as barotrauma. Although the respiratory systems in birds can withstand such drops, the physiology of bats’ lungs does not allow for the sudden change of pressure.
TransAlta, Canada’s largest publicly traded provider of renewable energy, initiated a follow-up study at the same site to determine what could be done. They tested a revised operating procedure slowing turbine blades to near motionless in low-wind periods significantly reduces bat mortality. Prof. Robert Barclay, who led the University of Calagary study, commented “Biologically, this makes sense as bats are more likely to fly when wind speeds are relatively low.” It was found to reduce bat deaths from wind turbines by up to 60% without significantly reducing the energy generated from the wind farm.
Ref: Baerwald et al. 2009 ‘A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities’. Journal of Wildlife Management 73 7 ; 1077 DOI: 10.2193/2008-233
It’s well known that cats kill many more birds than anything human beings have come up with, including cars and aeroplanes, but there’s an interesting survey of avian deaths from wind, fossil and nuclear plants: ‘Contextualizing avian mortality: A preliminary appraisal of bird and bat fatalities from wind, fossil-fuel, and nuclear electricity’, by Benjamin K. Sovacool in Energy Policy 37 (2009) 2241-2248.
Based on operating performance in the US and Europe, this study offers an approximate calculation for the number of birds killed per kWh generated for each systems. It estimates that wind farms and nuclear power stations are responsible each for between 0.3 – 0.4 fatalities per gigawatt-hour (GWh) of electricity, while fossil-fuelled power stations are responsible for about 5.2 fatalities/GWh. Although this is only as a preliminary assessment, the estimate means that wind farms killed approx. 7000 birds in the USA in 2006, but nuclear plants killed about 327,000 and fossil-fuelled power plants 14.5 million. However, the data is sparse, especially on bats, and the paper concludes that further study is needed.
Even so it provides a useful introduction. It notes that coal, oil, and natural gas-fired power plants induce avian deaths at various points throughout their fuel cycle: e.g. during coal mining, through collision and electrocution with operating plant equipment and transmission cables, and from poisoning and death caused by acid rain, mercury pollution and climate change. The scale of the direct impacts is quite surprising. e.g. an observation of 500m of power lines feeding a 400MW conventional power plant in Spain estimated that they electrocuted 467 birds and an additional 52 were killed in collisions with lines and towers over the course of two years. By comparison wind turbines seem quite benign (birds tend to avoid moving objects), although they too will have power grid links, and there were some early major problems with multiple bird strikes when wind farms were located in migratory paths e.g. in Southern Spain. Clearly sites like that should be avoided and we must also reduce casual impacts to the minimum possible, by sensitive location.
That is something the Royal Society for the Protection of Birds is keen to improve. It has come out with a positive approach to wind farm spatial planning, which it says can avoid problems and help ensure the development of wind power – which it backs as a response to climate change and energy security problems.
The RSPB report, ‘Positive Planning for Onshore Wind’, warns that ‘inappropriately sited wind farms can damage fragile wildlife and habitats, through habitat loss, mortality through collisions and a range of different disturbance effects’ but Ruth Davis, RSPB’s head of climate change policy, said ‘Left unchecked, climate change threatens many species with extinction. Yet, that sense of urgency is not translating into action on the ground to harness the abundant wind energy around us. This report shows that if we get it right, the UK can produce huge amounts of clean energy without time-consuming conflicts and harm to our wildlife. Get it wrong and people may reject wind power. That could be disastrous.’
It now wants to see a UK system of strategically chosen areas. That was the basis of Welsh “TAN8” planning policy introduced in 2005, which set out seven “Strategic Search Areas” that wind developers were to consider for wind farms. However, TAN8 has had mixed results so far, although the RSPB suggests there wasn’t enough consultation over the selection of the Strategic Search Areas. Scotland is now beginning to implement a “spatially explicit” new approach to onshore wind planning, via local development plans, but the RSPB report also highlights successful systems in Germany and Denmark- the RSPB commissioned a report from the Institute for European Environmental Policy, which found that wind farms were being developed rapidly on the Continent without harmful impacts on bird populations.
- A one year research programme carried out in the USA by the Bats and Wind Energy Cooperative, a partnership of the wind industry, government and conservation groups, at the Mountaineer windfarm in W. Virginia, and at the Meyersdale windfarm in Somerset County, Pennsylvania, found “substantial” mortality of bats at two U.S. windfarms, with a daily kill rate of 0.7 bats per turbine. At both windfarms, most bats were killed on nights when average wind speeds and power production were low, but while turbine blades were still moving at relatively high speeds, with fatalities increasing just before and after the passage of storm fronts and when bat activity was highest in the first two hours after sunset. Temporary close down during such periods is one possible remedial response.