While summer heat waves result from a combination of factors, global warming increases the likelihood of their occurrence and intensity. High levels of smog are formed when heat reacts with air pollutants such as nitrogen oxide to generate high levels of ground-level ozone. Particulate matter is easily airborne far downwind from the source of emission. It is an important factor aggravating respiratory diseases such as asthma. Costs for utility-scale wind energy systems have dropped dramatically.
Turbines are now much more efficient, reliable and powerful.
Compared to wind turbines built in 1981, modern turbines generate 56 times the power at only 9 times the cost. Wind farms require less capital and less construction lead time than traditional power plants. They can therefore produce low-cost clean energy quickly and conveniently. A 50 MW wind power plant can be brought on-line in about 18 months. The output of a wind turbine depends on the turbine's size and the wind speed.