Human and animal impacts: safety and health risks
What about safety risks? People do fall off rooftops when installing solar arrays and there have been installation and maintenance deaths associated with wind turbines, around 150 so far globally (CWIF, 2014). However, it is hard to put these risks in the same category as the risk associated with, for example, major nuclear accidents. There are disputes over the final public death toll from the Chernobyl nuclear disaster in Ukraine, but the estimates run into tens of thousands (Fairlie and Sumner, 2006). By contrast, for wind or solar, even the most catastrophic accident (a fire or a blade throw) will be unlikely to pose much of a threat to the general public. Indeed no member of the public has so far been injured by a wind farm accident, although one small light aircraft did crash into one in the United States, killing its crew. In the case of PV, while operationally there should be few problems, the manufacture of solar cells can involve the use of toxic materials and so presents an occupation health risk. Some cells also contain toxic materials and so have to be carefully disposed of when no longer used. However, these chemical risks are similar to those with the production and use/disposal of many consumer products.
The exception to the low-risk potential of renewables is hydro. Big dams can and do fail, and large numbers of people can be killed. For example, the Banqiao/Simantan dam failure in China in 1975 claimed 30,000 lives and around the world there have been many other hydro accidents with loss of life. On this basis, large hydro is sometimes put in the same category as nuclear, with similar direct death rates per kWh of electricity generated.
However, while tragically, in the case of hydro accidents, it is relatively simple to estimate the death rate (counting drowned people), with nuclear, there are disagreements not only about the death tolls from major accident, but also about the long-term impacts of smaller leaks and even the regulated emissions, for example, given that the health effects may not show up for many years and may not be attributed to radiation exposure. Similarly with fossil fuel burning and deaths from lung disease. And it is even harder to produce estimates of health impacts from climate change and air pollution in the future, and to make sensible comparisons, especially given the relatively short period for which modern (non-hydro) renewables have been used. For example, there is as yet little experience with working with offshore wave and tidal stream technology, in what is inevitably a potentially hazardous environment.
Overall, making realistic and reliable quantitative long-term comparisons across the various technologies is hard, so the reliability of some estimates is uncertain (Wang, 2011). For example, in the study mentioned earlier by Brook and Bradshaw (2014), on-land wind is seen as having much higher fatalities due to accidents (0.15/TWh) than nuclear (0.04/ TWh), and solar is even worse (0.44/TWh). However, the wind and solar figures are based on relatively limited operational experience (large capacities have only recently been installed) and for nuclear there are divergent views on the long-term impacts of radiation, including low- level radiation exposure (Fairlie, 2014). Certainly, some very different rankings have emerged from other studies. For example, the EU’s long- running Externe study tried to estimate the extra social and health costs of all energy systems, renewables, fossil and nuclear, but it excluded the costs of long-term climate change impacts, since they were seen as hard to estimate accurately at that time.
On that basis it ranked coal as imposing the highest extra cost, €57/ MWh (more than its generation cost), then gas, tying with biomass at €16/MWh, followed by PV solar at €6/MWh. Next came hydro, tying with nuclear at €4/MWh. And finally wind was seen as imposing the lowest extra cost, €1/MWh (Externe, 2006). A recent study by Ecofys for the European Commission included estimates for climate change costs, and put nuclear external costs higher at €i8-22/MWh, more than for any renewable (Ecofys, 2014).
No technology is totally benign, and clearly some renewables do have impacts, but they are generally much lower than those associated with fossil fuels, especially when the potentially large long-term impacts of climate change are taken into account. As for nuclear, while it might avoid some of that, it is arguably a little perverse, in health terms, to promote a radiation-based technology which has significant potential for long-term damage to cellular and possibly genetic material and to the health of ecosystems.
What about lower-level social impacts? Some say that wind turbines impose unacceptable noise impacts on local residents (Windbyte, 2015). There are strict controls of permitted separation distances from habitations and of noise levels, and modern wind turbines are much quieter than earlier models. On wind farm sites it is rare to hear more than a swish sound even close up, often hard to hear over the sound of wind in trees or bushes, or the noise from any nearby road. However, noise, especially at very low levels, is a subjective issue. Some people cannot sleep in a room with fridge in it. And once you are sensitised to it, a noise, however low, can become annoying. It has been argued that people who are unhappy with wind farms for other reasons (e.g., visual intrusion) may well become hyper-sensitised to noise that would otherwise not worry most people. For example, Simon Chapman, a professor of public health at the University of Sydney, says that studies have concluded that ‘pre-existing negative attitudes to wind farms are generally stronger predictors of annoyance than residential distance to the turbines or recorded levels of noise’ (Chapman, 2012).
However, complaints persist, with some claiming that low-frequency infrasound is produced and can have significant health impacts. Many machines create ultrasound, often at much higher levels than would be possibly experienced at a distance from wind turbines. Several studies have been carried out, including major ones covering the United States, European Union and Australia, to see if anything really was amiss (Murray, 2014; NHMRC, 2015). So far they have not found any serious problems. Nevertheless, given that some people clearly do feel they have problems, a precautionary approach seems wise. Wind farm developers may sometimes get exasperated at what can seem like unjustified complaints, but they do seek to be good neighbours (Cummings, 2012).
Visual intrusion is a more general problem. Again it is subjective. Some people love the look of wind farms, seeing them as inspiring symbols of progress to a clean energy future. Others hate them, seeing them as gross, ugly industrial intrusions, ruining treasured views, and allegedly undermining the value of nearby properties. There is the ‘shock of the new’ effect. Some studies have indicated that, while initially, when at planning stage, a proportion of local people oppose wind projects, they become acclimatized to them once built. Even so, some residual opposition to wind farms often remains, and that has slowed deployment in some countries. There has also been opposition to solar farms on the grounds of visual intrusion and land use conflict issues.
Clearly, there is a need for sensitive local consultation over projects like this, taking local perceptions on board (Devine-Wright, 2011). It is understandable that people who have chosen to live in rural areas may resent what they perceive as intrusions (even if in some cases these are city people with second homes), while some who are visitors may see rural areas as leisure resources. Certainly, there can be underlying rural- urban conflicts, with cities relying on rural areas for power generation, and rural areas having to accept the physical impact, although all do benefit from the energy produced. It is notable that, if local residents are given an opportunity to share directly in the economic benefits of a local project, then opposition reduces significantly. Most of the wind projects in Denmark, and many in Germany, are locally owned, for example, by local wind co-ops, and opposition is usually minimal. An old Danish proverb is sometimes used as an explanation: ‘Your own pigs don’t smell’ (Elliott, 2003). In some cases, however, opposition to wind or solar is less about visual intrusion and location than about the technologies’ costs and efficiency and more general energy policy issues, which are looked at later in this book.
Impacts on animals are also often seen as an important issue. For example, poorly sited wind turbines located in seasonal bird flocking/ migration paths have in some cases proved to be particularly problematic in the past. That can be easily dealt with by avoiding wind farm location in such areas. Most birds in normal flight avoid moving objects, and modern large wind turbine blades move relatively slowly, allowing birds plenty of time to avoid them. However, some birds clearly do not, but the numbers are usually small, as many studies have found (Kraemer, 2014a). If the problem remains, then acoustic bird scarers are available. And it’s worth noting that, although all animal deaths should be avoided, cats kill very many times more birds than wind turbines (Milius, 2013).
Wind turbine infrasound noise has been suggested as one explanation for the large number of miscarriages and deaths reported for minks in a farm near a new wind project in Denmark, but minks, especially in captivity in pelt farms, are prone to illness and this case seems inconclusive, although much commented on by the opponents of wind farms (Dunchamp, 2014). More substantially, wind turbine impacts have been reported on bat populations. Their lungs are especially sensitive to the pressure drop that occurs near moving turbine blades (Baerwald et al., 2008). Evidently, they are attracted to stationary or slow-moving wind turbines since they think they are trees, and are injured if they start up fully. There are ideas for resolving that, including ultra sound bat scarers (Gosden, 2014).
All offshore systems have the potential for significant effects on marine wildlife, such as dolphins, porpoise, grey seals, and wildfowl. However, studies of the impacts of the technologies used for the extraction of energy from offshore wind, wave and tidal flows have so far suggested this is minimal. Indeed, once built, these new structures in the sea seem to provide habitats for some species: crustaceans seem to like the wind turbine foundations, while sea mammals stay clear, as do fish (Lindeboomet, 2011). Certainly, compared with the impact on fish of the high-speed turbines used in hydro plants or tidal barrages, which can cause problems (sometimes avoided by building fish ramp/ ladder routes, e.g., for spawning Salmon), the relatively slowly rotating free-standing tidal rotors in tidal stream turbines represent a low hazard for fish. But the first large tidal stream project, Sea Gen in an inlet in Northern Ireland, has used a sonar system to monitor the approach of sea mammals. They seem to avoid it, but if not, the turbine can be shut down while they pass by (Phys Org, 2012).
The use of solar energy does not lead to animal impact issues, any more than do windows or other glazed areas, but in the case of concentrating solar power (CSP) there have been concerns about impact on desert wildlife and, more dramatically, about the lethal impact on birds that fly into the focused solar beams near the central power towers, as at the 392 MW Ivanpah CSP plant in California’s Mojave Desert. It may be that the bright light attracts insects (as street lights do), which then attract insect-eating birds that fly to their death in the focused beam. Dish and trough CSP designs should avoid the problem, since the heat focus is smaller and more contained. But for big sun tracking-mirror arrays, focused on power towers, acoustic bird scarers may be a possible remedy and a range of other remedial ideas has emerged (Kraemer, 2014b; Kraemer, 2014c; Kraemer, 2015).