<P> Environmental concerns with electricity generation have led to an increased focus on generation from renewable sources, in particular from wind and hydropower . While debate can be expected to continue over the environmental impact of different means of electricity production, its final form is relatively clean . </P> <P> Electricity is a very convenient way to transfer energy, and it has been adapted to a huge, and growing, number of uses . The invention of a practical incandescent light bulb in the 1870s led to lighting becoming one of the first publicly available applications of electrical power . Although electrification brought with it its own dangers, replacing the naked flames of gas lighting greatly reduced fire hazards within homes and factories . Public utilities were set up in many cities targeting the burgeoning market for electrical lighting . In the late 20th century and in modern times, the trend has started to flow in the direction of deregulation in the electrical power sector . </P> <P> The resistive Joule heating effect employed in filament light bulbs also sees more direct use in electric heating . While this is versatile and controllable, it can be seen as wasteful, since most electrical generation has already required the production of heat at a power station . A number of countries, such as Denmark, have issued legislation restricting or banning the use of resistive electric heating in new buildings . Electricity is however still a highly practical energy source for heating and refrigeration, with air conditioning / heat pumps representing a growing sector for electricity demand for heating and cooling, the effects of which electricity utilities are increasingly obliged to accommodate . </P> <P> Electricity is used within telecommunications, and indeed the electrical telegraph, demonstrated commercially in 1837 by Cooke and Wheatstone, was one of its earliest applications . With the construction of first intercontinental, and then transatlantic, telegraph systems in the 1860s, electricity had enabled communications in minutes across the globe . Optical fibre and satellite communication have taken a share of the market for communications systems, but electricity can be expected to remain an essential part of the process . </P>

Who invented electricity and how did they do it