Are all transmission lines created equal?
Today's transmission system relies on a network of high-voltage lines that are capable of transporting electrical energy over long distances. These lines come in different sizes, ranging from the more common 65 kV to 345 kV to the more modern and more efficient 500 kV to 765 kV lines. The amount of power that can be sent over a transmission line is limited, so the larger lines are able to transport greater amounts of energy over longer distances while minimizing land use.
Aren't DC lines more environmentally-friendly than AC lines?
Alternating Current (AC) vs. Direct Current (DC) refers to the direction in which electrons move across our transmission lines. AC is a wave of electrons flowing back and forth across the lines, while DC is the constant flow of electrons in only one direction. The majority of today's grid uses AC lines. DC lines are often single lines and therefore some have suggested greater use to cut down on the overall footprint of transmission. However, there are some limitations to DC transmission. For example, DC lines require expensive converters to get their electrical energy onto the grid. Also, AC lines can accept power from multiple generation sources and transmit it to multiple load centers, allowing for much greater energy transfer over longer distances. DC lines do not allow for easy redirection of power in the case of a line outage. AC lines have the ability to balance power to ensure reliability and avoid a cascading effect of power failures.
Why don't we just put all the power lines underground?
Transmission lines can be either hung above ground or buried below ground. Most transmission providers site new lines above ground whenever possible for efficiency, cost, and maintenance reasons. As a general rule, underground transmission lines are five to six times more expensive to install than above ground lines. Also, underground lines are very challenging to inspect and maintain, and restoration time is usually several weeks for underground transmission if a line failure occurs. Today, there are approximately 200,000 miles of high voltage transmission lines. All but approximately 5,000 miles of those lines are sited overhead.
Why wouldn't we build more local transmission instead of regional and national?
We are all connected to our transmission system. Electrical power flows via the path of least resistance, meaning the flow of electricity cannot be routed or controlled like oil pipelines or telecommunications. Today's transmission system of 150,000 miles of high-voltage is the backbone of all the electrical energy produced at power plants across the country. The entire country is powered by an inter-connected grid that stays in perfect balance despite unpredictable and constantly changing demand fed by thousands of individual and independent power sources.
Why do we need to update the grid now?
America's transmission system is operating closer to the edge than ever before. The majority of the existing system was built more than 30 years ago and has only received incremental investment since. Today, 70% of the lines and large power transformers are more than 25 years old. Unless this is addressed, the basic reliability of the system will be increasingly at risk as electricity demand in this country is expected to rise 25% by 2030. Not only that, it doesn't connect us to the places in the country where renewable energy is most abundant. Without a modern grid, we will never be able to tap the nation's unlimited supply of renewable resources that have the power to ensure our energy security.
Would a modern grid raise the price of my electric bill?
Transmission is a relatively small part of your energy cost - generally about 7-10%. What really costs customers and American businesses is the current condition of the grid. Our electric grid has suffered from 30 years of underinvestment and we now face mounting reliability issues and increased congestion. And with increased congestion comes inefficiency. In 1970 transmission and distribution losses were about 5 percent. Since then, these losses have increased 90 percent. Inefficiencies have led to major costs for the U.S. economy. Power outages and power quality disturbances cost the economy from $100 billion annually.
How can transmission help with the development of clean energy sources?
Our nation's energy and environmental goals rely on the rapid development and deployment of domestic renewable energy like wind, solar, and geothermal. All of these sources have enormous potential for growth, but this potential will only be realized with more transmission development. We simply do connect the places where the wind blows the hardest and the sun shines the most to our towns and cities that need the electricity. According to interconnection queue databases, there is currently almost 300,000 MC of wind projects, more than 20% of our electricity needs, waiting to connect to the grid because there is inadequate capacity to carry the electricity they would produce. And based on a recent study on the economics and climate impact of renewable energy on a carbon-regulated environment by the Brattle Group, an increase in access to wind resources would make wind power economically competitive relative to conventional fossil fuels.
Would a "smart grid" remove the need for new transmission development?
New technologies that are now dubbed "smart" are part of the overall energy solution, but do not solve the underlying problem of an aging and congested electricity infrastructure. Americans are consuming more electricity than ever before and we need to build more transmission to meet this growing demand. The efficiencies that smart grid technologies would deliver are not enough to make up for a grid that suffers from poor maintenance and underinvestment.
Why should everyone pay for new transmission when it is not built in their state?
The current perception that only a limited few benefit from new transmission and therefore should be responsible for funding it is not true. The reality is that we all benefit with a modern grid, just like we all benefit from our interstate highway system. We all pay taxes to fund highway construction and repair all over the country. Even if we never drive on the stretch of highway, we very well may consume some product that was trucked over that highway. It is the same with power - we all benefit from greater reliability, efficiency and cleaner energy.
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