I called Norway Savings Bank and was referred to Brian Shibles, Executive VP and Treasurer.

He said that NSB loans to the community, in the form of residential mortgages, construction, commercial, real estate, equipment, and of course, personal loans. This makes up about 80% of their investment.

Less than 10% of their investment portfolio is in bonds and the stock market.

(I wonder about the remaining 10-15%...)

This is when I asked about green investments vs fossil fuels.

He said they don’t invest in tobacco, and they do take environmental considerations into account. Utilities and energy stocks are a shrinking part of the portfolio.

NSB is a Mutual Savings Bank, not a Stock Bank, so optimizing profits is not necessarily their primary focus. They focus on their customers first, their employees, and the communities they serve, through lending, reinvestment (eg low and moderate income housing, and start-ups).

I encouraged him to take climate into account when thinking about new investments.

Then I researched Mutual Savings Banks:

The first ones were established in 1816, to “teach the lower classes the virtues of thrift, and self-reliance by allowing them the security to save their money….

“The difference is that a Mutual Savings Bank is chartered in a way that the Depositors Own the Bank! In other words, the bank does not have shareholders that keep the profits, in the likes of the Citigroups and the JP Morgans of the world. The profits, if any, are somehow passed on to the Depositors….

“Mutual savings banks were designed to stimulate savings by individuals; the exclusive function of these banks is to protect deposits, make limited, secure investments, and provide depositors with interest. Unlike commercial banks , savings banks have no stockholders; the entirety of profits beyond the upkeep of the bank belongs to the depositors of the mutual savings bank. Mutual savings banks prioritize security, and as a result, have historically been characteristically conservative in their investments. This conservativism is what allowed mutual savings banks to remain stable throughout the turbulent period of the Great Depression, despite the failing of commercial banks and savings and loan associations.”

http://www.marketplacelists.com/mutual_savings_bank_stock.htm

To: Sandy Matheson, Maine PERS Executive Director

cc: Michael Morrell, President of Oxford Hills Education Association

Dear Ms Matheson,

I am a public school teacher, expecting to have my retirement financed at least partially by my Maine PERS pension. As such, I consider myself a stockholder in, as well as a beneficiary of, Maine PERS. I am extremely concerned about Climate Change, and think everyone should be doing everything possible to reduce its growing impact. I strongly urge you to divest my portfolio from fossil fuel production, and from other industries that support or cause greenhouse gas emissions. I understand that you are legally required to focus on strictly financial profit. I would like to point out how acting against climate change is in our financial interest.

There are two ways fossil fuel divestment will benefit your portfolio, and thus my retirement:

1. Both the production/extraction of coal, petroleum and natural gas, and their use as fuel, add huge amounts of carbon to the atmosphere. This is a double-whammy. Carbon emissions are causing increasing climate stress on the general economy, including infrastructure, agriculture, health care, insurance, and hospitality sectors. The sooner anmore completely we stop putting carbon into the atmosphere, the less severe the economic impacts of this climate stress will be.

2. Fossil fuel companies and others that support them are becoming less and less profitable,* while renewable energy technologies are becoming increasingly more competitive. Investments should be proactive and move toward more profitable industries while they are young.

When you make the commitment to divest from fossil fuels, you will be joining a growing group of smart investors, including the cities of New York and London, and the country of Ireland. Two huge retirement funds in California, CalPERS and CalSTRS, are now required to report on “climate-related financial risk of its public market portfolio” every three years because “climate change presents an array of material financial risks, including transition risk, physical risk and litigation risk, that reasonable investors must take into account when making investment decisions.” (California Senate Bill No. 964 Chapter 731)

On a more personal note, your divestment from fossil fuels will be a contribution to the stability of the natural environment, which supports humans in every way. It will be an investment in the health and well being of our children; physically, spiritually, and economically.

Thank you for your consideration,

Andrea AskenDunn

askendunn@gmail.com

* Sanzillo and Hipple, “Fossil Fuel Investments: Looking Backwards May Prove Costly to Investors in Today’s Market,” Institute for Energy Economics and Financial Analysis. Feb 2019

Dear Editor,

Recently, the USDA declared much of Maine a Primary Natural Disaster Area due to drought. Of course, weather fluctuations are normal, but since the mid-2000s climate-related disasters have been declared in every county in Maine.

We can’t let these disasters become routine.

Climate disruptions also bring economic disruptions, and both eat away—literally—at the health and stability of everyday life. Before the pandemic, Maine had the highest rate of food insecurity in New England: with middle-class jobs being replaced by low-wage jobs, or disappearing altogether, Maine is increasingly sandwiched between climate-driven and economic hardships. This is why we call upon our legislators to support the bipartisan Energy Innovation and Carbon Dividend Act (H.R. 763). Currently supported by eighty two representatives, the Act will reduce the human-caused carbon pollution behind global warming and re-allocate the collected carbon fee in direct monthly payments to American households

This summer’s extensive drought should make us thirsty for climate legislation: instead of waiting for things to get worse, let’s take preventive action.

Price carbon, pay families.

Sorrel Dunn and Andrea AskenDunn

Harrison, Maine

I have been writing every day to my elected officials during Lent. Recently I sent this one:

There are a lot of products and services that I would not like my savings to be invested in: fossil fuels, nuclear weapons, war paraphernalia, privatized prisons, casinos, toxic chemicals, factory farms, alcohol, tobacco, etc. Traditional places to put one’s money (banks, stocks, mutual funds) invest in many of the above. That’s why I’m in favor of The Clean Energy Victory Bonds Act of 2019 introduced by Senator Tom Udall. If enacted, this law would allow the federal government to sell bonds totaling $50 billion a year to jumpstart the research, development and sales of renewable energy such as wind, solar, geothermal, small-scale hydropower and hydrokinetic forms of energy. Organizations supporting this program are: American Sustainable Business Council, Green America, Union of Concerned Scientists and the National Wildlife Federation. Bonds for the purpose of winning World War II generated $185 billion (worth over $2 trillion today). We are in a crisis far worse than World War II. Spending money to encourage us to use up our finite supply of fossil fuels as quickly as possible will only bring on economic and ecologic disaster for the world. I’d love to invest my savings in something that will attempt to heal the ravages that humans have inflicted on the earth. https://www.tomudall.senate.gov/news/press-releases/udall-lofgren-and-matsui-introduce-legislation-to-give-all-americans-an-opportunity-to-invest-in-building-our-clean-energy-future

On March 5th, Bill McKibben and youth climate activists from Maine spoke to a standing room only audience at the Oxford Hills Comprehensive High School in western Maine, kicking off the 2020 Vision: Finding Hope in Climate Action Climate Convergence—two days of intense climate activist training in which hundreds participated.

Such a community “convergence” is pretty much unthinkable roughly two weeks later as we each seek, in our own ways, to prevent a public health catastrophe by sheltering in place and practicing the odd new skill: social distancing.

Snippets of the Convergence are still swirling around in my mind. For example, in each of the workshops I led, we concluded with a group visioning session, going around the circle, unleashing our imaginations to offer ‘glimpses’ into the year 2030, when the transition to net-zero carbon emissions is well underway, ecosystems are being restored, and we are successfully conserving biodiversity in our backyards and across the planet. After a couple of times of going around the circle (each new addition to the vision beginning with the unifying and affirming words ‘Yes, and’ . . .) a truly beautiful picture of the near-future began to take shape. Many of the ideas put forth were marvelous and ingenious, others thoughtfully simple and elegant. Others, it must be said, were heart-piercingly poignant, such as when 15-year old climate activist Anna Siegel said, “Yes, and in this new world children like me will not have to do what I am doing. They can just be children.”

The bottom line is, that despite the current urgency of the global pandemic, the climate crisis that brought us all together continues unabated. Indeed, scientists warn that the kind of global disruption we are now experiencing so keenly, will become increasingly common in the years to come unless we act now to sharply curb our CO2 emissions. And while the COVID-19 challenge before us seems more than enough to handle, if one takes a deep breath and wades into our current predicament for a while, it also becomes apparent that here, in the midst of all the chaos and uncertainty, new unprecedented pathways to meaningful, positive change are also opening up.

For example . . .

‘Social distancing’ and ‘sheltering in place’ are causing us to find, devise, and become adept at new ways of communicating authentically with one another through technology. These are precisely the tools that we are going to need to become better global citizens, to learn from each other, to share what we have learned, to provide encouragement and make meaningful connection across borders and boundaries, to work together in new ways to bring down our carbon emissions and help those whose lives are being upended by climate chaos.

Our increased awareness of shortfalls of current global supply chains has the potential to encourage widespread movement toward locally-produced goods and services, to create and enliven new local markets, to provide new incentives for growing and processing our own food, building materials and fiber. In other words, new ways are opening up for communities to become more vibrant, connected, resourceful, and resilient.

It is hard to imagine that an economic system that favors profits over people, or a health care system that leaves so many at risk, will ever be viewed again in the same light. Sweeping, systemic change is precisely what is needed if we are to achieve a more sustainable civilization within the time demanded, and these systems will surely be part of the mix.

Despite what we may have believed prior to this crisis, we are learning that we can indeed change old patterns of living overnight, mobilize with great speed to address the emergency at hand, and make personal sacrifices in order to protect not just our own families, but also our unknown neighbors, our communities, our fellow Mainers, our species.

As we work collectively to tamp down a deadly global pandemic, old divisions between neighbors and nations seem less meaningful, habitual ways of doing things seem less useful, past assumptions seem less inevitable, all of which make this moment ripe with possibility.

Yes of course, the priorities have shifted. Yes of course we will have to put many of our climate action plans on the rear burner for a while. But as we work to negotiate the current public health emergency and find new ways of truly taking care of one other, we would also do very well to stay attuned to the pathways to a brighter future that are uniquely opening right now, so when the day comes to fully seize them and work to realize their full potential we will be ready. I believe this is what Winston Churchill was referring to when he said, “Never let a good crisis go to waste.”

In the meantime keep up the social distancing and stay well everyone.

Roberta's article was published by the Post Cabon Institute's Resilience on March 20, 2020

https://www.resilience.org/stories/2020-03-20/a-climate-activists-message-from-the-front-lines-of-a-global-pandemic/

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 have to do a full circle in 3 seconds. If the rotor diameter is 300 feet the circumference is a little over 900 feet. 900 ft in 3 seconds translates to 200 mph. If you stand directly below one of these you can really sense how fast they are moving as they pass over you.

In optimal conditions, these blades are extracting over 40% of the energy of the wind passing through them. The reason the blades are so far apart is that at the high speed that the blades move they leave a wake in their path. If the blades are too close together the wake created by one blade affects the efficiency of the next. Careful theoretical and experimental work has shown that the familiar three blade turbines you see on hilltops in our area are the most efficient design.

Similarly, each individual turbine leaves a wake downwind. If the turbines are too close together their wakes will interfere with each other. Typically they need to be separated by 3 to 10 times the diameter of the rotors. The actual layout depends on the prevailing wind direction in a specific location.

So, the blades are going much faster than you might think, and there’s a good reason they are thin and sparse-looking. Now how about height and location?

The two factors that most affect wind speed are location and height above the ground. Wind speed actually increases fairly predictably with height off the ground due to decreasing friction with the ground. Separately, wind speed is always higher on top of a hill because it is not blocked by nearby features.

It should be obvious that where the wind speed is greater you will get more power. But what is not so obvious is HOW MUCH more. The power available in the wind increases with the cube of the wind speed. That means if you double the wind speed, the available power isn’t doubled - it increases by a factor of eight. (2x2x2).

So, say you have a small, 30 foot tall turbine in your yard, where it receives wind at 8 mph. If the tower were instead 350 ft. high, it might receive wind of 16 mph, and having doubled the speed you increase the power by a factor of eight, as above.

Meanwhile at the top of the mountain the wind speed might be 1.5 times faster (24 mph) than down below. Now the speed is 3 times the original 8 mph. 3x3x3 is 27 so the power there will be 27 times as much as the original location with a 30 foot tower. The power in the wind is also dependent on the area swept out by the blades of the turbine. In sum, one 300 foot diameter wind turbine on the ridge in a 24 mph wind can produce the power of more than 60,000 six-foot diameter turbines in the 8 mph wind in your backyard.

Though our last column touted the footprint and payback time of photovoltaic panels (PVs), it turns out that wind power has an even better profile, according to the latest Life Cycle Analyses (LCAs), which you will remember take into account all of the energy inputs for the manufacture, installation, operation, and decommissioning of the turbine. The LCAs indicate that a wind turbine will compensate for all those energy costs in less than eight months. Given the expected lifetime of 20 years or more, a turbine will generate more than 30 times the energy it uses.

One interesting way to compare different renewable energy sources is by considering how much land area is required to produce a given amount of power. Let’s compare electricity from wind to that from biomass. At best, biomass can grow at a rate of 6 tons per acre per year. If this acre of biomass is harvested and used to generate electricity, it could produce around 5000 kWh per year. The Kibby Mountain wind farm in Franklin County covers around 3000 acres and produces around 300 million kWh each year. That amounts to 100,000 kWh per acre, or twenty times as much power as biomass.

We don’t know about “THE answer,” but turbines are part of the answer, and they’re definitely blowin’ in the wind.

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. (Click the down arrow continue reading.)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 you might need for the same work.

Let’s take solar panels, or photovoltaics (PVs). Some criticize PVs for requiring lots of energy to produce, for involving the mining of silicon sources, for posing a waste disposal problem. But let’s examine these criticisms with quantitative tools.

First: Some claim that more energy is needed to produce a PV than it will generate in its lifetime. This can be addressed with a “life cycle analysis,” or LCA, which calculates how much energy it takes to produce, operate, and dispose of the item in question. It includes such things as the energy required to extract and transport all of the necessary materials, to refine the materials and assemble the panels, to transport and install the arrays, and finally to dispose of or recycle the materials involved.

According to the most recently published LCAs on photovoltaics that we’ve found, a typical 1000W solar array requires about 4000 kWh of energy to produce, install, and decommission. So we need to compare this with the amount of energy that PVs produce here in Maine (among the toughest testing grounds!) in order to tell whether they in fact produce more energy than they consume.

Here in Maine, the 1000W array mentioned above will produce around 1450 kWh of energy in one year, so its energy payback time is a little less than 3 years. If the panel continues to produce electricity for 30 years, it will have produced more than ten times the energy invested in it. (By the way, that same panel in the sunny southwest US would have an energy payback of about 20 months.)

So we’re clearly producing more energy than we’ve used, and in fact can demonstrate a very respectable payback time. But another critique is hastily advanced: “It takes fossil fuels to produce those panels, and therefore the energy they produce is actually “dirty!”

OK, yes, fossil fuels are currently involved in PV manufacture, but let’s look at it quantitatively before we draw conclusions.

To start with, a measure of the impact of an energy source on greenhouse gas production is how much CO2 is released in the production of one kilowatt hour of electrical energy. For a coal fired power plant that number is about 1000 grams of CO2 for every kWh of electricity produced. For a natural gas plant it is about 400 grams per kWh.

For the solar panel, obviously no CO2 is generated while producing energy--nearly all the CO2 production occurs during its manufacture and installation. We average this over its useful life and find that it involves between 30 and 90 grams of CO2 per kWh of power. Note that this is somewhere between 11 and 30 times less than coal. Some projections for the future of PVs estimate their CO2 to decrease to between 8 and 14 grams per kWh.

So what about the silicon in the PVs? Quartz is mined to produce the silicon wafers that make up PVs. To produce a 1000W array, around 17 kg of quartz is required to produce the 4 kg of refined silicon used in the 1000W array.

In Maine this array, with its use of 17 kg of quartz, will produce about 44,000 kWh of electricity over its lifetime. To produce that much energy from coal would require about 16,000 kg of coal; from oil about 5,000 gallons.

But quartz shouldn’t even be an issue, as the relative abundance of quartz in the earth’s crust is orders of magnitude greater than coal or oil. Silicon is the second most abundant element (second only to oxygen) in the earth’s crust, so there’s no shortage!

We’ve all heard the adage that “there is no free lunch.” But in truth, the benefits of photovoltaics in terms of energy production and CO2 avoidance currently outweigh their costs by a long shot. Moreover, ongoing advances in the technology are reducing the cost of solar electricity ever faster.

Let’s face it - the only free energy is the energy you don’t use. So maybe there is no free lunch - but maybe a “reduced” lunch? And hopefully, one day soon, a CARBON-free lunch!

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, you lose heat at one rate, but if the heat is turned down to 60°F and it is 30°F out, the heat escapes at a rate about one quarter slower, so less heat escapes during the period it is turned down.

Of course it’s true that your heating system will work harder during the time it takes to bring it back up to 70 in the morning, but that extra heat will ALWAYS be less than what you saved by having the temperature turned down during the night because you were losing less heat during the night.

Another way of thinking of it is: Suppose you have a container of water that has some small leaks at the bottom. The higher the water level, the greater the pressure, and the faster the water leaks.

To maintain a constant level you need to add water at the same rate that it’s leaking. If you allow the water level to drop for a while the leak rate will decrease, because the pressure decreases. To bring the level back up you need to increase the incoming water flow for some time.

However, by the time the water gets back up to its original level the total amount of water that has leaked out will be less than if the level had been kept high. Since the total water coming in has to equal the total water leaking out, you use less water overall.

So it is with the leaking heat. Less heat will leak at the lower temperature than at the higher, so less heat will be used!

You will definitely have some savings, but you may ask, “How much?” Well, here in central Maine turning down your heat by 10°F for 8 hours can account for between 8% and 10% of your heating bill, a noticeable difference. If your oil bill is $1000 dollars in a given year this can save you $80 to $100 per year. In very leaky old Maine homes it will make an even bigger difference.

It should be noted, though, that if you have a super-insulated newer home you might not even notice the difference since you are using relatively little energy to begin with and it takes a longer time for the temperature inside of the house to go down. It also is not a good practice to change your thermostat setting over short time periods as there is not enough time for the temperature to respond. This is especially true for heat pump systems which should not cycle on and off frequently.

Some people can have trouble remembering to turn the thermostat down before going to bed. A simple solution is to invest in a programmable thermostat. For under $50 you can get a “5-2” thermostat which allows you to change the setting four times per day with separate settings on weekdays and weekends. This allows additional savings because you can turn the heat down during the day when people are out of the house. These thermostats are easily overridden if you want to turn the heat up or down at different times.

Given the savings mentioned above, the payback time for this investment in a programmable thermostat is less than one heating season.

So - Next time someone tries to tell you it’s a waste of heat to turn your thermostat down overnight or for long stretches of the day, you can patiently explain that, actually, NOT doing so is a wasted opportunity to save on heating bills.

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 (such as light bulbs and sealing leaks around windows and doors), but sometimes even a big purchase can pay for itself quickly, and subsidies or rebates can ramp up the payback dynamic considerably at times.

One such example would be a heat-pump water heater, right now, in Maine.

In most households the water heater is the most energy intensive appliance. If you have a standard electric water heater (resistance heater) and you use 40 gallons of hot water per day (slightly less than national 3-person average), the cost is about $32 per month or about $390 per year. If you are about to replace your water heater, should you consider a heat pump water heater? The payback on a heat pump water heater might guide your decision.

A heat-pump water heater uses the same technology as a heat-pump you use to heat a home. Heat is taken from the air and used to heat the water. The advantage is that you can get the same amount of heat for less than one-third of the electricity. In other words, about 30% of the energy comes from electricity and 70% from the surrounding air. In terms of cost that means you pay less than one third as much. Using the example above, that means you would pay only around $10 per month or $120 per year for hot water. That is a savings of $270 per year.

So what is the payback time? That will depend on the cost of the heater and the installation cost. An electric heater is the least expensive and easiest to install. So it might be tempting to simply go with that. The average water heater installation cost is estimated by ConsumerAffairs.com at $750. The electric heater itself will run between $400 and $600. So your total cost should be somewhere between $1,150 and $1,750. (You should check with your local installers as these costs may vary.)

The heat pump water heater is quite a bit more expensive. They start at around $1,100 and the installation, according to ConsumerAffairs.com, would be $700-$900. So normally the installed cost could be in the vicinity of $1800 to $2400. But right now in Maine, you can get a $750 rebate for a heat pump water heater. (see efficiencymaine.com for details.) This means the cost of the two will be virtually the same.

Since the heat pump heater and electric heater are almost the same in cost, installing a heat pump water heater rather than a regular resistance water heater right now with the rebate will provide more or less an “instant payback”: You will save ⅔ of your water heating costs (typically around $20 per month) from then on!

We welcome any questions on this or other Energy Matters columns. Please contact us at the email in the heading.

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 carbon dioxide, believe it or not! Multiplying 750 by 19.6 pounds you get 14,700 pounds (7.6 tons) of CO2 per year that you are adding to the atmosphere just from driving a car getting 20 mpg.

If you have a car that gets 40 mpg, obviously you are burning half as much gas - producing around 3.8 tons of CO2. Since the average American is responsible for 18 tons of carbon dioxide emissions per year, your choice of a vehicle and its “carbon tire track” can make an impressive difference in your overall carbon footprint. In this example, switching from 20 to 40 mpg will likely reduce your total CO2 output by 20%.

Electric cars do still have a “carbon tire track,” since they use plenty of energy - it’s just in the form of electricity. Electricity involves less waste and no by-products in using it as an energy source, so it is generally a good idea in terms of emissions. But the electricity that most of us buy is generated by a variety of sources, including fossil fuels. In Maine, we have a fairly high contribution of renewables like hydro and wind, but the CO2 is not nothing.

There is a cool website called fueleconomy.gov operated by the U.S. Department of Energy that allows you to see the estimated greenhouse gas emissions associated with driving any model or year of electric vehicle, specially targeted to your zip code’s electricity sources. For instance, it tells us that if we were driving a 2019 Chevy Bolt our CO2 emissions rate would be 80 grams per mile. That would translate, in our 15,000 miles of annual driving, to 2,600 pounds of CO2, or 1.3 tons, about a third of what our 40mpg Honda Fit produces.

There are other issues involved in looking at the total footprint of electric cars because of their batteries and other manufacturing issues, but CO2 emissions are definitely minimized.

In future columns we will examine other areas of potential impact for average individuals trying to do practical things to limit their contribution to our greenhouse gas emissions. There are many things people do, hoping to make a difference - but you might be surprised at the comparisons among various measures when you take a quantitative approach using established values for emissions.

Meanwhile, we hope this analysis of “carbon tire track” is useful to you in planning your next vehicle purchase!

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.

People often refer to ground source heat pumps as “geothermal,” conjuring images of hot springs, geysers, molten layers in the earth, and other very hot things. Actually the temperature of the “source” of ground source heat is about 40 - 45 degrees Fahrenheit.

The thing that probably confuses people is that you can extract heat from things like 45 degree ground and 25 degree air. It is not, as they say, “intuitive!” Nevertheless, you can extract heat from a substance of pretty much any temperature by using a little physics and engineering.

Heat pumps work essentially like refrigerators, using a refrigerant to take heat out of somewhere and put it somewhere else. You know how the coils at the back of the refrigerator are hot - it is because the refrigerant in the coils cools the inside of the fridge by extracting the heat from it. Similarly, a heat pump cools its source (the ground, the outside air) by extracting heat, which it then pumps into your house. The process is reversible, and so in the summer you can use the heat pump for air conditioning.

Now, it is true that with outside temperatures like those we have in Maine, it is not possible to provide all of our heat with air source heat pumps. Heat pumps combine very well with other automatic heating systems - automatic stoves, furnaces, and boilers, whether oil or gas or pellet. When the temperatures outside are below a certain level another automatic source of heat can supplement the heat pump as needed.

Meanwhile heat pumps can easily provide for ⅔ of your heating needs, and so thereby significantly lower your need for fuels. Heat pumps do use electricity, which is generated from various sources including fossil fuels, but the magic is in the numbers.

One gallon of fuel oil contains about 140,000 Btu (British thermal units) of energy. When you burn it to heat your house it delivers about 125,000 Btu of heat if you have a high efficiency furnace or boiler.

Electricity, of course, also contains energy. The 125,000 Btu you are getting from your furnace is equal to 37 kWh (kilowatt-hours) of electricity. But using electricity to run a heat pump, 37kWh can deliver as much heat as between 3 to 5 gallons of fuel oil, due to the heat you are getting from the air or ground. In other words you can get a gallon’s worth of heat for less than 12 kWh of electricity. Comparing prices, that gallon of oil is around $2.60 right now while those 12kWh will cost you less than $1.80.

Incidentally you also reduce your carbon footprint significantly with the heat pump. Burning a gallon of fuel oil produces about 20lbs of CO2, while generating those 12 kWh of electricity produces about 5lbs of CO2. That’s a 75% reduction!!

The installation cost of heat pumps will vary depending on the construction of your home and the size of the space to be heated. A typical installation is around $2500 for an 18,000 Btu-per-hour unit. Right now, Maine has a program that will provide rebates of $1,000 for installing your first high-efficiency heat pump, and $500 for the second one (https://www.efficiencymaine.com/at-home/ductless-heat-pumps/) - so it is a good time to act if you are considering it. With this rebate program your energy savings will generally pay for the system in 3 to 5 years.

Efficiency Maine is running the rebate program. You can call them at 866-376-2463 to learn more about the program, which heat pumps qualify, and how to find a contractor.

We hope this article has helped you feel more up-to-speed on heat pumps, and that you will feel more able to evaluate how they can help with your heating (and cooling) future!