Curtains or window shades may shield a residential window from heat loss, but may not be a shield against moisture migration. Under such conditions the glass temperature will fall, and the condensation rate on windows will increase. Only a sealed interior barrier will delay the onset of condensation. Read More
Sweden leads Europe in the fraction of total energy derived from renewable resources: 15 percent, mostly hydro. France and Denmark are next with 6 percent, then Germany with 4 percent and Spain with 3 percent. The Netherlands and Britain are last with about 1 percent. Renewable energy in… Read More
A traditional large residential window, with a traditional storm window, will demand about 16 gallons of oil per heating season to overcome its energy loss. A temporary plastic window added to the inside will save about 6 gallons of oil and increase the comfort of someone sitting near… Read More
Total energy use in the United States is as follows: Petroleum, 40 percent; natural gas, 24 percent; coal, 23 percent; nuclear, 8 percent; renewables, 7 percent. The renewable component (7 percent of the total) breaks down as follows: hydro, 36 percent; biomass, 53 percent; geothermal, 5 percent; wind,… Read More
Room air velocities as low as 1 foot per second will be discernable and produce discomfort to a sedentary occupant. One great source of uncomfortable air velocities is an open stairwell. If upstairs bedrooms are not heated and the doors are open or do not fit, significant convection… Read More
The thermostat may be set at 70 and produce a corresponding room air temperature, yet occupants may feel cold. A body loses heat not only to convection to the cooler air, but by radiation losses to cold surfaces. People may report “a draft” when sitting by a window,… Read More
By Dec. 8 the typical Maine household will have spent 25 percent of its annual heating fuel budget; by Jan. 21, 50 percent; and by March 5, 75 percent. These data consider only the effect of outside temperature on home heating requirements. No consideration is given to the… Read More
Indoor relative humidity of 50 percent and a temperature of 70 degrees imply a “dew point” of about 50 degrees. In many households a 50-degree temperature may well be measured in back of an electric outlet, on the floor of an upstairs closet, etc. These surfaces will be… Read More
Much has been said about insulation, alternative heating systems, etc. But the essential problem is “thermal comfort.” We tend to think of temperature alone as the condition dictating comfort, but air velocity, clothing, activity, mean radiant temperature and relative humidity also contribute to thermal comfort. The most overrated… Read More
The U.S. Department of Energy has just published (on Sept. 17) the mix of energy sources to generate U.S. electricity: coal, 49.5 percent; nuclear, 19.6 percent; natural gas, 19.2 percent; oil, 1.8 googletag.cmd.push(function () { // Define Slot var slot_sizes = [[300,250]]; var new_slot_sizes = [];… Read More
If we exclude the United States, worldwide average electric consumption is 2,200 kilowatt-hours for each person each year. The average U.S. electric consumption is 13,000 kilowatt-hours each year for each person. Read More
Don’t believe T. Boone Pickens when he claims his wind farm will supply 20 percent of U.S. electricity in 2030. The U.S. Energy Information Administration estimates that in 2030 the United States will need 1 billion kilowatts of electric generation capacity to provide about 5,000 billion kilowatt-hours of… Read More
A typical home may have a volume of 20,000 cubic feet. At least 4,000 cubic feet per hour should be exchanged with the outdoors to control odors, humidity, etc. A kitchen or bathroom exhaust fan (60 cubic feet of air per minute) may force the induction of sufficient… Read More
An oil refinery can split a barrel of crude into everything from paint thinner to road tar. The “middle distillates” include diesel fuel, jet fuel and home heating oil. Home heating oil is less than 10 percent of the total and must compete in the market place with… Read More
Do you have a brook flowing through your property? Would you like to use the flowing water to generate electricity? The flow of 1 cubic foot of water per second over a falls 10 feet high will generate about 1 kilowatt of electric power. This is the rate… Read More
Worldwide about 50 billion liters of ethanol are produced each year – about a third in the U.S. from corn and another third in Brazil from sugar cane. The energy in all this ethanol is the equivalent of about 0.25 billion barrels of oil. The annual worldwide consumption… Read More
Depending on the rhythm of the academic year, for the past several decades my household has operated with as few as four and as many as seven adults. Everything has been measured. Refrigerators, the electric dryer, the TV, etc. have separate watt-hour meters. A separate water meter tracks… Read More
The status of wind energy in Maine: Mars Hill – In production, 28 units (turbines), 42 megawatts total, 150 million kilowatt-hours per year. googletag.cmd.push(function () { // Define Slot var slot_sizes = [[300,250]]; var new_slot_sizes = []; var has_banner = false; for (var i =… Read More
While a wind turbine – a big one like those at the Mars Hill Wind Farm – will produce more than 1,000 kilowatt-hours per year for each square meter of wind disk, a photovoltaic array, for about the same output, will need to be 10 times this area. Read More
A 65-mile direct-current power line, the Neptune Project, now connects Long Island with the power grid in Pennsylvania. The cable caries 660 megawatts and passes under the ocean floor. The cost was $600 million. The offshore wind proposal of Angus King would require the transmission of 5,000 megawatts… Read More
In the very best wind locations, a modern wind turbine will generate a bit more than 1,000 kilowatt-hours each year for each square meter (10 square feet) of wind disc. A 90-meter diameter wind turbine (the blade swing area will cover about two football fields) will generate nearly… Read More
According to the Energy Information Administration, a nonpolitical arm of the U.S. Department of Energy, the use of biomass in this country will increase from the present 2.5 percent of the total to 3.1 percent in the year 2030. Other renewable energy – solar, wind and ethanol –… Read More
The “alternative energy” literature often states: “One hundred square miles of the Arizona desert, if devoted to photovoltaic electric generation, will furnish all the electricity used in the U.S.” Let’s see. A square meter (about 10 square feet) of sun energy at high noon is about 1 kilowatt. Read More
If all the fossil fuel used in Maine (oil and natural gas) were converted to the energy equivalent in oil alone, each person in Maine uses 50 barrels of oil per year. The 17 million acres of Maine forest will yield a steady harvest (both round wood and… Read More
Four-fifths of Maine households – the largest share in the nation – use oil for space heat. Maine generates a larger share of its electricity from non-hydroelectric renewable resources (mostly wood and wood-waste) than any other State. Maine is the only state in which industry is the largest… Read More
The typical monthly residential electric bill in Maine is about $100. This implies an annual electric energy use of about 7,000 kilowatt-hours per household. With about 400,000 households, the total annual residential use is a bit less than 3 billion kilowatt-hours. Maine’s total annual electric use is about… Read More
The Energy Information Administration, a nonpolitical arm of the U.S. Department of Energy, publishes an “Annual Energy Outlook.” The administration is a big operation. With a staff of nearly 400 people and a budget of nearly $100 million, it publishes endless energy-related data. For example, looking forward to… Read More