Energy Matters

Is the Answer Blowin’ in the Wind? To some, industrial wind power is as puzzling as the Bob Dylan song proclaiming that “the answer is blowin’ in the wind,” an answer which basically inspires more questions - such as, does it even make sense? Likewise, why do they build these giant towers hundreds of feet tall and then stick thin, sparse blades up there that seem to turn sluggishly?  Why are wind turbines so different from those little windmills on the miniature golf course that spin busily in the breeze?  How is it worth it to spread them out on scenic hilltops when you could put them in less noticeable places? Why don’t they at least put them closer together?  The answers, my friend…Well, here are a few of them anyway. First, those blades. Why are there only three seemingly thin blades rotating so slowly? Actually the tips of the blades are moving quite fast.  They seem slow because they are so large.  Their typical rotation is about 20 revolutions per minute (rpm’s), so the tips hav

Ever get the impression that everything is more complicated than it seems?  It’s true! There seems to be some controversy these days about  “green energy” sources such as wind, solar, and hydro, in terms of whether their net impact is in fact “green.”  The thesis seems to be: “If you dig up the dirty laundry behind green renewables, you’ll see that they are just as bad for the environment as fossil fuels.”  In fact, although it is true there is some dirty laundry with any approach to sustaining our modern energy demands, we don’t need to throw out the baby with the bathwater, and belief in a fossil fuel-free future is indeed justified. An apt analogy might be using rags instead of paper towels to clean things.  True, re-using rags involves laundry detergent and running a washing machine, perhaps even a dryer; but you’ve avoided the tree harvesting, pulp processing, chemical treatments, resultant hazardous waste, packaging, shipping, disposal etc. involved in the many, many paper towels

So What About Solar? Maybe you’ve already heard this, but it’s a fun fact to ponder:  The amount of solar energy hitting the earth in one hour is equal to the amount of energy consumed by all of humanity in a year.   Of course harnessing the sun’s energy is another story, since it turns out to require the help of technology. But it’s actually a rather exciting story, given the speed with which that technology is evolving: The cost of photovoltaics has dropped by almost 70% in the past 10 years, making it competitive with any fossil fuel energy source today (at least, up until the pandemic-induced, likely temporary, oil pricing chaos).    If you are considering solar panels for your household, there are websites that can help you with rough estimates.  A good one is www.solar-estimate.org.  But here is some background to help you understand the basics of home photovoltaics, including the interaction of the solar energy available in your location with the efficiency of solar panels, and

Turning Down the Heat - Is It Worthwhile? We’ve heard people say that it does no good to turn your heat down at night because it takes more energy to bring the house back up to temperature in the morning than you save by turning the heat down.  One person even quoted her heating contractor making this assertion. It’s simply not true, and a couple of basic laws of physics can explain why.   The first law, usually called “The Law of Conservation of Energy,” states that the energy going into a system (in this case, your house) equals the energy coming out of that system.  The total amount of heat put out by your heating system equals the total heat lost through the envelope. You heat the house, and eventually that exact same amount of heat escapes! The second law relates to how heat flows from warmer to colder regions. The heat flows at a rate that depends on the temperature difference between those regions. For example if you keep your indoor temperature at 70°F and it is 30°F outside, y

What do they mean by “payback period” when it comes to deciding on energy-saving measures or purchases? Payback period is the time it will take for your energy savings to pay for the cost of the energy-saving thing you bought.  Say you spend $2 on switching to a 9 watt LED light bulb from a 60 watt incandescent bulb that is used for 4 hours/day. The LED bulb will save you about $1 per month in electricity cost, so its payback period will be 2 months.  After that, you simply have an extra dollar in your pocket every month compared to your old bill (and incidentally, LED bulbs last 10 years or so, believe it or not!). You always want to consider the “useful life” of the thing you are purchasing, and bear it in mind when looking at the payback period. It does no good if something saves $50 per year and costs $1,000 (20-year payback) but lasts only 10 years, because it will have to be replaced before it pays for itself.  The shortest payback will usually be for the least expensive things (

Carbon Tire Tracks            These days, many individuals are trying to come up with ways to reduce their “carbon footprint.”  How much does your car matter to your “carbon footprint?” Maybe we should be asking, “What is your car’s “carbon tire track?”            About 29% of the 6 billion tons of carbon dioxide Americans send into the atmosphere every year come from transportation.  About two thirds of U.S. transportation emissions are by passenger vehicles, if you include light and medium-duty trucks (EPA.gov).  So yes, transportation is an important part of the problem.             To assess the carbon output of your car, all you need is a few numbers.  How many miles to the gallon do you get?  How many miles do you drive per year?  Say you get 20 miles per gallon and you drive 15,000 miles per year, as an average Mainer.  You divide the miles you drive by the mpg and get 750, the number of gallons of gas you use in a year. So every gallon of gas burned produces 19.6 pounds of carb

Wow!! Rebates on Heat Pumps!! Cool! Wait. What’s a heat pump?             Many people are confused about heat pumps:  how they work, what they do.  Don’t feel bad if you are confused, because very few people seem to understand them at all.  Still, they are worth understanding, because they can make a big difference in your heating bill - and in your “carbon footprint.” And there are big rebates for installing them in Maine right now. There are ground source heat pumps and air source heat pumps.  There are even water source heat pumps for a home adjacent to a pond or lake. The basic mechanism at work is that we take heat out of the source, be it air, ground, or water, and put it into your house with the heat pump.              Most household heat pumps in Maine are air-source heat pumps, also known as “mini-splits.” The cost of air source heat pumps is quite a bit less than ground source heat pumps, so they pay for themselves much faster and they require a lot less capital outlay. P