"Assume a spherical cow"
OK, please forgive me my ignorance here, but let's try to talk about this in stages.
First, let's "assume a spherical cow", as the joke goes (link below).
For three dryers (Pat's, Chris' and Sam's) connected to the utilities, if we consider *just* the point of view of the users and ignore everything that happens prior to the hookups, do we agree that:
All dryers have a timer and an electric motor that turns the fan and the tumbling drum, so we can ignore that as being "equal" in the three dryers?
That if Pat's dryer has a gas burner that consumes say, 22,000 BTU/h, there will *always* be pollutants associated with the burning of that fossil fuel (carbon dioxide, some carbon monoxide [in case of a misadjusted burner], nitrous oxide/dioxide etc)?
That if Chris' dryer is a standard electric dryer, ignoring everything that happens before the hookups, Chris' dryer produces *no* pollutants? That is, an electric dryer is as clean as the electricity provided to it, going, from worst to best, coal, fuel oil, gasoline, propane/natural gas, wind/solar/hydroelectric?
That if Sam's dryer is a heat-pump dryer, not only it moves heat at the rate of 3 to 4 times the electricity it used, but this dryer is also as clean as the electricity it is being provided to it, like Chris' dryer?
Can we agree that what is more energy efficient is sometimes at odds to what is less expensive?
For example, if we consider what happens *before* the hookups, let's say that Alex has solar panels on the roof and can get electricity for free or sell it back to the utility. Say it costs $0.80/load to run an electric dryer and $0.40/load to run a gas dryer. Alex can either run his electric dryer for free, or run a gas dryer and *get paid* 40 cents by selling the electricity from the panels back to the utility. But an electric dryer would generate no emissions in this case, and the gas dryer would generate emissions *despite* the fact that Alex got 40 cents/load back. Alex could run a heat-pump dryer for less energy (25%-33%) than a conventional dryer, still get money back from the utility and generate no emissions.
If we start considering the whole system, and I think we should, it seems to me that people in lots of areas in Canada, the Pacific Northwest, the Tennessee Valley Authority area, etc can safely use an electric dryer and cause way less greenhouse gasses to be released than people like me in the Northeast where more power plants still use coal or gas.
Anyplace where electricity comes mostly from wind, solar or hydroelectric will provide clean or almost clean electricity.
The petroleum companies have always vilified electricity to the point where we know mostly old rules of thumb (one burns 3 times the amount of energy to produce electricity, for example), but we know next to nothing about the Natural Gas industry.
Those values come mostly from electric power plants that used coal and steam, and also the smaller plants that used internal combustion engines (also less than 33% efficient, there are plenty of buildings that used co-generation in the early 1900's to produce *heat* for the building and sold the electricity back to the utilities). Modern gas turbines are over 60% efficient.
Wind, solar and hydroelectric produce no emissions and yet, all we hear is about the "transmission losses", despite the fact no fossil fuel was burned to get the energy.
It should be easy for anyone who has used and/or seen an air compressor (building sites, workshops etc) to agree that compressing gases takes a lot of energy and that transporting said gas produces losses along the transportation hoses, pipes, ducts etc, which can be witnessed by drops in pressure and/or flow rates.
Some people have experienced the loss of both natural gas pressure and flow during the worst parts of winter, when demand is highest -- sometimes water heaters, furnaces and even stovetop burners or oven burners fail to light or maintain a flame.
Like Louis mentioned, obtaining natural gas has environmental consequences -- some people in US have demonstrated on TV that they can open the kitchen faucet and light a flame above the faucet due to their well getting contaminated by volatile organic compounds (methane, propane etc) that leaked from fracking nearby.
From Scientific American (
https://www.scientificamerican.com/article/how-much-natural-gas-leaks/):
"Because methane, which makes up about 95 percent of the natural gas in pipelines, is about 25 times more potent as a greenhouse gas than carbon dioxide, the leakage raises a troubling climate question: How clean is natural gas?"
"For its part, AGA is quick to highlight U.S. EPA's estimates of methane emissions from natural gas. EPA has said that, from the gas well to your stovetop, the industry leaks 1.4 percent of the gas it produces."
From (
http://www.eng-tips.com/viewthread.cfm?qid=76881), about transmission losses for NG and the need for compressors:
One engineer mentions a pressure drop of 300 psi per 100 miles (700 psi to 1,000 psi compressors). That is for level parts of the pipelines, in severe grade they need compressors every 40-50 miles.
Another points out that compressors on the gas distribution lines go from 500 HP to 35,000 HP.
One particular gas company has 840,000 HP in total installed compressors.
From (
http://www.sourcewatch.org/index.php/Natural_gas_transmission_leakage_rates):
"Methane concentrations in the atmosphere have more than doubled over the last 150 years, and may account for a third of the climate warming from greenhouse gases."
In any case, most of my point(s) is that the vast majority of what we heard in the past 80 years has more to do with economics than with environmental point of view. Natural gas and fossil fuels have been so cheap that no one bothered to get electricity in USA from wind, solar or hydroelectric all this time, with few exceptions, and those had more to do with the fact that people often wanted a cheap/clean source of electricity to power the Steel and Aluminum industries and/or flood control than anything else.
On the other hand, the evidence that the *price* of the fossil fuel is more important than the efficiency of power generation is made more obvious by the fact that propane and methane have the *same* statistics, that is, they both work nearly identically when generating electric power in that you still get from 30-60% of the energy you burned (in BTUs) back. The problem is that propane is way more expensive than natural gas when your home is piped to natural gas, so people in rural America who are dependent on propane for heating their homes often find that an electric dryer is cheaper to operate.
We also like to ignore the many places in America (or Canada) where proximity to hydroelectric power generation makes some people have all-electric homes, including heat.
So, if I'm being a moron here and spouting gibberish, I'd love to be corrected, given that just by looking up some of these facts I've already learned that in remote areas far from electric grids, the compressors used to send natural gas to us are indeed powered by burning some of the gas in jet turbines (about 60% efficiency) or older internal combustion engines (less than 33% efficiency).
In case what I've been talking about makes sense to you, I'd love it if the next time someone asks, you'd respond with something along the lines of "electric dryers/stoves/furnaces/cars/etc are as clean as the electricity supplied to them -- you need to do some research to see if a gas dryer/stoves/furnaces/cars/etc pollutes more or less than the electric version."
And whether or not any of you agrees with me, thank you for reading and considering what I've posted.
Cheers,
-- Paulo.
