Inventos

Energy USA
What are the major sources and users of energy in the United States?
The major energy sources in the United States are petroleum (oil), natural gas, coal, nuclear, and renewable energy. The major users are residential and commercial buildings, industry, transportation, and electric power generators. The pattern of fuel use varies widely by sector. For example, oil provides 94% ofthe energy used for transportation, but only 1% of the energy used to generate electric power. Understanding the relationships between the different energy sources and their uses provides insights into many important energy issues.
The electric power sector has seen large changes in the fuel mix. A little over 50 years ago, nuclear energy played no role in electric power generation, but in 2010,nuclear energy provided 21% of the energy used to generate U.S. electricity. Oil provided a growing share of energy for electric generation through the 1960s, but its share has declined to 1% in 2010 since peaking at 18% in 1973
http://www.eia.gov/energy_in_brief/major_energy_sources_and_users.cfm
Energy UK

Electricity network and supply
Electricity is carried across the country from powerstations into our homes by the grid, a network of cables and wires. Electricity direct from the grid is too powerful to use in homes and businesses. This is why high voltage wires carry electricity to grid supply  substations. There, it is changed to a lower voltage and enters local distribution networks which carry it into homes and businesses.
The grid plays a key role in the electricity system.Keeping the balance between supply and demand is an important task. This is vital because unlike gas, it is very difficult to store electricity.
National Grid runs the grid system across Great Britain. They manage the flow of electricity across the entire network.National Grid also owns the England and Wales transmission system. Other operators are:
* Scottish Power Transmission
* ScottishHydro Electric Transmission Limited
* Northern Ireland Electricity.
Similar to electricity, gas is taken from the high pressure transmission system and distributed through low pressure networks of pipes to properties across the country.

Covering separate regions of Britain, there are eight gas distribution networks. There are also a number of smaller networks owned and operated byIndependent Gas Transporter.
http://www.energy-uk.org.uk/energy/electricity-network-and-supply.html
Nuclear Power USA
* The USA is the world's largest producer of nuclear power, accounting for more than 30% of worldwide nuclear generation of electricity. 
* The country's 104 nuclear reactors produced 807 billion kWh in 2010, over 20% of total electrical output. 
* Following a 30-year periodin which few new reactors were built, it is expected that 4-6 new units may come on line by 2020, the first of those resulting from 16 licence applications made since mid-2007 to build 24 new nuclear reactors. 
* However, lower gas prices since 2009 have put the economic viability of some of these projects in doubt.
* Government policy changes since the late 1990s have helped pave the wayfor significant growth in nuclear capacity. Government and industry are working closely on expedited approval for construction and new plant designs. 
In 2009, the USA generated 3950 billion kWh net of electricity, 45% of it from coal-fired plant, 24% from gas and 7% from hydro. Annual electricity demand is projected to increase to 5,000 billion kWh in 2030, though in the short term it isdepressed and is not expected to recover to the 2007 level until about 2015. Annual per capita electricity consumption is currently around 12,400 kWh. Total capacity is 1025 GWe, less than one tenth of which is nuclear.The USA has 104 nuclear power reactors in 31 states, operated by 30 different power companies. In 2009 these plants achieved a capacity factor of 91.1%, generating 799 billion kWh and...