Science & Technology in Action

Context 

Since 1968 the world population has increased from 3.5 billion to over 7 billion. The majority of people live in undeveloped or developing countries. With increasing development comes an increasing demand for energy. There is however growing realisation that the use of fossil fuels has had undesirable consequences and that we need to reduce CO2 emissions. Alternative and more sustainable sources of energy will be increasingly required to meet agreed targets. 

Worldwide, solar and wind power are the most rapidly growing alternative energy sources. The chart shows the rapid growth in installed wind power in the past decade or so. 

Wind power has been the most rapidly growing form of energy in Ireland over the past ten years; installed capacity has risen from about 600 MW (in 2004) to 2190 MW (in 2014). Wind power is generally greatest in Ireland during winter when the demand is highest − in contrast to solar power. 

Since wind is very variable the actual capacity is, on average, about 25% of installed capacity. So although wind power sometimes accounts for over 50% of the country’s immediate electricity needs (roughly 3000 MW ± 1400 MW), wind energy currently accounts for roughly 20% of our total annual electricity (18% in 2013) and about 3.5% of our total annual energy use. The target set by Government is for 40% of the country’s electricity to be derived from renewable resources by 2020. 

Background 
In 1800 Volta invented the battery and it was an immediate sensation. Within months several discoveries were made: the heating effect of electric current, electrolysis and electroplating. However the discovery of the magnetic effect of an electric current was not made until 1820. The first practical electric motors were made in the 1830s but they still depended on batteries. 

What was needed was a practical dynamo, but that development took another thirty years (1866). Further improvements in dynamos and alternators led to the first commercial electricity distribution systems (1879) and electric public lighting (1880s). 

For over 1000 years people have been using wind power to grind grain. Its application to the generation of electricity came in 1887 when the Scottish engineer, James Blyth, built a wind-powered battery charger.