Energy Consumption - Pushing Away from the Table
- Jun 9, 2010 12:00 pm GMTJun 8, 2015 10:27 pm GMT
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Energy costs are an increasing concern in a tough economy and a competitive marketplace. The common-sense solution to high energy costs is to either increase energy sources or to reduce our use of energy. Numerous barriers exist to increasing our energy sources. Environmental issues inhibit drilling for oil in new locations or building new coal-fired power plants and safety concerns discourage the use of nuclear energy. Renewable energy sources, such as solar and wind, are promising, but technology hurdles limit their capacity for the foreseeable future. New technologies, such as fuel cells, are still in development and are limited commercially. While solutions to these barriers will eventually be realized, they will not happen in the short-term. What can a concerned citizen do?
Energy Resources and Use
According to the U.S. Department of Energy, we produce 70% of our energy needs domestically. The rest is imported, mainly as crude oil. An estimated 40% of total U.S. energy consumption is in the form of liquid fuel, such as gasoline and diesel. Another 40% is split equally between natural gas and coal. Since significantly increasing these energy sources is not likely, energy conservation becomes the only viable option for decreasing costs and ensuring our energy independence. It would be helpful to take a closer look at the energy conservation opportunities for each fuel type, ignoring for the moment any cost differences or environmental impact. For each fuel, how can you get the most energy output for raw fuel input.
Gasoline and diesel fuel represent about two-thirds of our liquid fuel consumption, and the vast majority is used for cars and trucks. Motor vehicles consume 135 billion gallons of gasoline and 40 billion gallons of diesel fuel per year. Unfortunately, internal combustion engines are not very energy efficient. The efficiency of converting the energy content of liquid fuel to horsepower by combustion is only about 30% for gasoline engines and 40% for diesel engines. The rest of the energy is lost mainly as heat.
So, how do you increase motor vehicle fuel efficiency? New technologies such as fuel cells and electric vehicles are often touted as the answer. Fuel cell energy efficiency however, is roughly equivalent to diesel engines. Electric vehicles are highly efficient, but a significant amount of energy is wasted in the generation of electricity. Attempts are being made to legislate better fuel efficiency. Corporate Average Fuel Economy (CAFE) standards require an increase of 25% in fuel efficiency for passenger cars by 2020 -- that is not going to happen by increasing combustion efficiency. Rather, Americans will have to get used to driving much smaller cars.
Energy conservation, not technology, is the less expensive and more effective short-term alternative. For instance, drivers can increase fuel efficiency 20% across the board by just not driving so aggressively. Driving less through can pooling, working from home, bicycling, and public transportation can also help to significantly reduce fuel use. These are sometimes difficult options in a car-oriented society, but these kinds of changes are necessary to reduce fuel costs and increase energy independence.
While a growing amount of natural gas is used for electricity generation, the great majority of natural gas is consumed in industrial processes and in commercial and residential space and water heating. Boiler controls, steam trap maintenance, and steam system insulation are just a few of the energy saving strategies available for improving the energy efficiency of industrial process heating systems. For space heating, replacing older gas furnaces with newer, energy efficient gas furnaces or heat pumps can result in efficiency increases of 15% or more. For faster and cheaper increases in energy efficiency, consider adjusting your thermostat or sealing air leaks in doors, windows, and other building areas.
Coal is almost exclusively used for generating electric power in the US. Roughly half of electricity production comes from coal, while the rest comes from nuclear power and natural gas combined. Consumption of electricity is fairly evenly split between residential, commercial, and industrial sectors. Half of residential electricity is used for appliances, of which kitchen appliances represent the largest share. Replacing old appliances with ENERGY STAR® rated appliances will improve efficiencies between 10% and 50%, depending on the type of appliance. Unplugging "energy-hog" devices like battery chargers and "instant-on" TVs will result in small but immediate savings. Lighting represents only 10% of residential electricity consumption. However, replacing incandescent bulbs with compact fluorescent lamps (CFLs), however, will reduce lighting energy consumption by 75%.
In the commercial sector, space cooling and lighting use more than half of overall electricity consumption. Space cooling efficiency can be increased by adjusting thermostats and making sure that air leaks are properly sealed. Replacing older T12 fluorescent lamps and magnetic lighting ballasts with newer T8 fluorescent lamps with electronic ballasts can save between 15% and 30% of lighting electricity consumption. Another effective lighting strategy uses sunlight for more than just solar panels. The practice of "daylighting" uses skylights and light sensors to automatically turn off internal lighting when there is plenty of sunshine. Many big box retailers use daylighting effectively in their stores.
In the industrial sector, motors use about 50% of total electricity consumption. Replacing older motors with newer premium-efficiency motors will increase efficiency by up to 3%, but that adds up over time, because motors are often operating during two to three shifts per day. The most attractive opportunity is to replace single-speed motors with variable speed motors and drives. Reducing your motor speed by one-half can result in energy savings of over 75% for some applications such as pumps and fans.
Saving Energy and the Environment
This conservation approach has ignored the cost differences between energy sources and their environmental impacts. But sometimes a simplistic approach leads to simple answers that can be practically and quickly implemented. The bottom line is that America is wedded to fairly inefficient energy consumption practices and divorce is not an option. While it is important to focus on finding alternatives to the internal combustion engine and coal-fired power plants, taking steps to conserve our limited fossil fuel resources should not be ignored. This will not only help to reduce costs in the short-term, but it can have significant environmental benefits in lower greenhouse gas emissions.