Archive for January, 2009

A Case Study in Community Wind: Denmark

Saturday, January 31st, 2009

With wind power jobs now outnumbering* coal mining jobs for the first time ever (probably with good reason: you never hear stories of workers getting trapped in wind-mines) we thought we’d spotlight another model for community wind.

We take you now to the land of Hamlet.

The following is an excerpt from The Citizen-Powered Energy Handbook: Community Solutions to a Global Crisis by Greg Pahl. It has been edited for the Web.


Although a number of different mechanisms to develop community wind projects have been used in Europe, they all require the participants to work together to achieve their common goal. This strategy is regularly employed in northern Europe for a wide variety of purposes, but especially in Denmark. Cooperative wind development has been a natural outgrowth of Danish cultural and agricultural interests. Around 1980, the Danish parliament provided incentives for wind cooperatives to encourage individual action toward meeting the nation’s energy and environmental policies. This program enabled virtually any household to help generate electricity with wind energy without necessitating the installation of a wind turbine in their own backyard. There were three key components to the Danish wind initiative:

  1. The right of wind power developers to connect to the electrical grid
  2. The legal requirement that utilities purchase the wind-powered electricity, and
  3. A guaranteed fair price.

As part of the legal requirements, the wind generator pays for the cost of connection to the nearest acceptable point on the grid, while the grid operator pays for any additional expenses required for grid upgrades and other improvements. These requirements removed one of the biggest hurdles to developing the wind industry in Denmark. As a result, the entire windpower initiative was spectacularly successful, and the idea caught on in Germany and the Netherlands as well.

Here’s how the strategy worked. Danish law encouraged mutual ownership of wind turbines by exempting the owners from taxes on the portion of the wind generation that offset a household’s domestic electricity consumption. A wind co-op would then purchase a wind turbine, select the best site available, sell electricity to the electric utility under favorable terms, and share the revenues among its members. This enabled the group to buy the most cost-effective turbine available, even though it may have generated far more electricity than individual co-op members needed for themselves. Although, technically speaking, many of these cooperative ventures were set up as limited liability companies owing to the vagaries of Danish law and tax policies, the cooperative nature of the organizations was clear. The Lynetten cooperative (Lynetten Vindkraft I/S) that owns four out of the seven prominent, 600-kilowatt wind turbines on a breakwater within Copenhagen’s port is a good example of the success of the cooperative wind strategy in Denmark.16With over nine hundred members, the cooperative is one of the larger wind co-ops in the world.


But perhaps the most famous Danish cooperative of all is Middelgrunden, which in March 2001 was the world’s largest offshore wind farm and is still one of the largest that is cooperatively owned. Located on a shoal about 2 kilometers outside of Copenhagen harbor, the Middelgrunden wind farm consists of twenty Bonus Energy 2-megawatt wind turbines with a hub height of 64 meters (210 feet) and a rotor diameter of 76 meters (250 feet). The twenty turbines are installed in a gentle arc with a total wind farm length of 3.4 kilometers (2 miles) and a combined generating capacity of 40 megawatts. Ten of the turbines are owned by the Middelgrunden Wind Cooperative, while the remaining ten are owned by Copenhagen Energy, the local municipal electric company. The joint relationship between the cooperative and the electric company proved to be extremely helpful throughout the planning, approval, and construction phases of the project, and provides an excellent model for North American wind initiatives as well.

The Bonus 2-megawatt units are specially designed for the harsh maritime climate in which they operate with high-grade external paint; hermetically sealed machinery; and a self-contained, internal climate-control system. The surface of the fiberglass blades is similar to fiberglass boat hulls and consequently requires no additional corrosion protection.17 A built-in crane is used for turbine maintenance. The status of the turbines and their output is monitored and regulated by an advanced, computerized control system, and the power from the wind farm is carried via an underwater cable to the mainland.18 Performance of the turbines is also publicly posted on the co-op’s Web site ( The turbines were preassembled on shore in three parts before being floated to the concrete foundations (which were also built on shore and towed into place) and erected by a barge-mounted crane.

The original idea for the wind farm was conceived in 1993. The partnership was founded in May 1997 by the Working Group for Wind Turbines on Middelgrunden, with the goal of establishing and managing a wind farm on the Middelgrunden shoal. Partners own a share in the venture corresponding to 1/40,500 of the partnership per share purchased.19 Organizers believe that the project would not have been built without the public support generated by early public involvement in the planning process and local ownership. Despite numerous obstacles, the cooperative sold 40,500 shares for €570 ($678) each, a price set as low as possible to encourage broad participation. The total investment budget for the co-op was €23 million ($27 million). All together, about 8,500 investors bought shares.20 The projected payback time on the investment was estimated at eight years, with a rate of return of 7.5 percent after depreciation. Despite some initial technical problems, overall the wind farm has performed well and met or exceeded electrical-generation projections, providing enough electricity for more than 40,000 households in Copenhagen.

*(h/t HuffPost)

5 Ways to Save Water While on the Can

Friday, January 30th, 2009

Here I sit, broken-hearted, because we’re using up too much of our supply of clean water unnecessarily.

One of the worst offenders is the way in which most of us flush away our bodily waste. We take for granted the convenience of pulling a little lever and having gallons of clear, crisp, drinkable water transport our leavings far away.

But consider this: clean water requires huge amounts of energy to be chemically treated and pumped into our homes; it uses up groundwater, which puts stress on woodlands and causes damage to wildlife habitats in wetlands and rivers; and although it may seem abundant, many regions will need to keep a substantial supply on hand to stave off water shortages and summer water rationing.

This precious resource is literally going down the crapper.

Here are some facts about water usage, from Water: Use Less—Save More by Jon Clift and Amanda Cuthbert:

  • Over a quarter of all the clean, drinkable water you use in your home is used to flush the toilets.
  • Older toilets can use 3 gallons of clean water with every flush, while new toilets use as little as 1 gallon.
  • Many people in the world exist on 3 gallons of water day or less. We can use that amount in one flush of the toilet.

Here are 5 steps you can take to reduce your water usage (also excerpted from Water):

1. Remember the rhyme: “If it’s yellow let it mellow, if it’s brown flush it down.” You will save a lot of water!
2. If you have an old toilet, you can reduce the amount of water it uses by putting a “displacement device” in the tank. Use small plastic bottles filled with water or a displacement bag designed for toilet tanks. Displacement bags may be available free from your local water department or can be purchased from a hardware store.
3. Avoid flushing anything down the toilet that has not previously passed though your digestive system, apart from toilet paper – it’s a waste of water and might block the sewer. Bag it and bin it.
4. Choose a slimline toilet rather than a full-size toilet; they use a lot less water per flush.
5. When you are buying a new toilet, look for a dual-flush toilet, or a low-flush toilet, which uses only 1.6 gallons per flush.

Staying Small and Keeping It Local: The Companies We Keep

Friday, January 30th, 2009

The following book review was originally published on

Business books on the Triple Bottom Line abound. Trust me. I speak from experience. I am an MBA student in a program focused on sustainability, and a mountain of these books stands between me and the end of each semester. Most do an adequate job of plodding through the subject matter, but I usually find myself skimming the material to extract the main points so I can move on to the next book. One down, mountain to go.

That was not my experience with John Abrams’ revised edition of Companies We Keep – Employee Ownership and the Business of Community and Place. The book is a revised and expanded version of his 2005 Company We Keep. Abrams is the cofounder of South Mountain Company, an employee-owned, custom building business based on Martha’s Vineyard that began operations in 1975. He’s written a very readable narrative that knits together a personal memoir with an examination of the employee-owned business model he has developed at South Mountain Company.

In Abrams’ words, “This is a book about a different way of doing business in today’s world — a way based on workplace democracy, shared ownership, staying small, building community, commitment to a place, and long term thinking.” He believes that building a profitable company can be compatible with serving the needs of people (employees and owners), the local community, and the environment.

We assign priority to a collection of bottom lines while consigning the traditional bottom line – profit – to its appropriate role as a vital tool that serves the others.

A worker cooperative typically uses the C or LLC corporate framework, and shares many of the same benefits. It has corporate protection from liability, earns profits, is governed by a board of directors, and is managed by one or more officers. But it differs in three aspects as Abrams explains. First, it’s a membership organization limited to employees who complete a trial period and invest through a membership fee. Second, a cooperative is democratically governed as each member gets one vote, rather than the usual one share/one vote model. And third, a portion of earnings is allocated to members based on their work investment rather than their capital investment.

Beyond the legal framework, Abrams’ vision of the worker co-op also emphasizes staying small and keeping it local. These two principles buttress the social and environmental bottom lines.

I question the lack of value placed on maintenance of those business communities we create and the communities within which our companies operate. This disregard supports unfettered allegiance to an economy whose rewards have become skewed toward the distant and the global at the expense of the local, and whose system of incentives encourages wage servitude and environmental recklessness.

Read the whole review here.

LISTEN: Matthew Stein on The Lionel Show: Technology Always Fails

Friday, January 30th, 2009

If you were tuned in to Air America earlier today, you might have heard author Matthew Stein (When Technology Fails, Revised and Expanded: A Manual for Self-Reliance, Sustainability, and Surviving the Long Emergency) talking with Lionel on The Lionel Show.

The two chatted amiably about drug-resistant super-diseases, antibiotics in our food supply, peak oil, and what impact it would have if hackers blacked out the entire internet.

(Alas, to my continuing frustration, Mat Stein again failed to tell us what we’re supposed to do in the event of a zombie apocalypse. I guess we’ll have to wait for the next revised edition of When Technology Fails.)


You, Your Apartment, and Your Chickens: Sustainable Farming at Its Best

Thursday, January 29th, 2009

As the list of salmonella-tainted peanut butter products continues to grow, let’s not forget another food known to carry the bacteria from time to time: eggs. As with so many factory-farmed products, you never really know what you’re going to get. (Forgive me for getting all Forrest Gump on you there.)

If you have sufficient yard space, why not try raising your own chickens? Aside from scoring some really delicious, fresh eggs, you’ll know for sure whether or not they have been handled, refrigerated, and prepared properly.

The following is an excerpt from R. J. Ruppenthal‘s Fresh Food from Small Spaces: The Square-Inch Gardener’s Guide to Year-Round Growing, Fermenting, and Sprouting. It has been adapted for the Web and edited for length. For the full version, see the book.

Most people who keep chickens raise them for eggs. This is sustainable farming at its best. Chickens can roam a small backyard and rid it of insects, slugs, and weed seeds. In exchange, you can get around 4 to 7 eggs per week from each chicken plus some yard fertilizer. Free-range chicken eggs are delicious and nutritious; if you’ve never had fresh eggs, you’ll be amazed at how much better they taste than the factory-farmed ones. If you have access only to a shared yard or common area in an apartment or condominium building, you might try talking your neighbors and building management into sharing some chickens. If you volunteer to take care of the birds, others might agree to share the small costs in exchange for some eggs, and this could give you access to the yard space. If allowing chickens to roam is impossible where you live, then look into buying or building a chicken tractor, which is essentially a mobile pen that you can wheel from place to place. Using a chicken tractor allows the birds to eat all the bugs, seeds, and weeds they want in one spot and then move to another. If you live in a larger building with a shared backyard, tell your building manager or homeowners’ association that your chickens can fertilize the lawn. If you don’t have any space to let chickens roam, then you can still keep them in a small coop, but you’ll have to provide all their food, and this can get more expensive.

Before deciding to get chickens, make sure that it’s legal to keep them where you live. Check local zoning ordinances by visiting the Web site for your local city or county. The good news is that even though many cities regulate chickens, most of them do permit you to keep a few chickens for personal use.

Even if it is legal to keep chickens where you live, you can still run afoul of other laws relating to public health and noise levels. Public health laws remind you to keep the pens clean and the chickens free from disease, which is a good idea anyway. Where noise ordinances are in force, residents may be cited or fined for animals that bother the neighbors. Hens are not as loud as roosters, but they can cluck enough to bother close neighbors. One way to handle this is to talk to your neighbors before getting the chickens and help them understand what you are planning. (Hint: If you offer neighbors some free eggs, they may see the logic in your plans.)

When selecting chickens, remember that you don’t need roosters for egg laying. Roosters are loud, can be obnoxious, and are illegal to keep in many jurisdictions. You’ll do better with three or four hens that can live together peacefully and lay eggs.

Chickens need basic shelter and enough space to roam a little. Their shelter need not be a formal chicken coop or animal hutch, but could be any appropriate small structure that you can either construct or commandeer. For example, an old toolshed or doghouse might work, or you could build your own shelter from some wooden crates or salvaged lumber. A small 2’ W x 4’ L x 2’ H coop could be space enough for a pair of smaller chickens. An 8’ x 12’ coop can accommodate up to 30 regular-sized chickens, but you should avoid overcrowding or else you will risk stress, disease, and unproductive hatching. Using chicken wire and a frame, you can either build in a small yard or run outside the main structure, or let them roam free when they come outside. Cover the bottom of the chicken house with some sand and a layer of bedding material (known as “litter”), which could be 3 to 4 inches of straw or untreated wood chips, or more in colder weather. For other chicken coop building plans, try an Internet search or seek out a book (there are several in print) that covers some different coop designs.

You also can purchase chicken coops ready-made from pet stores and feed stores.

Whatever structure you use for a chicken house should provide some protection from the elements and from extreme temperatures. In mild climates, the building alone should shield them from any wind and rain, but in colder winter areas, you may need to both insulate and heat the structure. Optimum temperature range for egg laying is between about 55 and 85 degrees F . There are many types of acceptable structures for this, and some are handmade. During the winter in a cold climate, if you do not want to heat or insulate, then you could consider bringing this coop into a garage or greenhouse for protection, at least during the night. Since egg laying is a function of day length, you can encourage egg laying in colder weather by installing a regular incandescent lightbulb and leaving it on.

Inside the chicken house, you also should place some nesting spots and places for chickens to roost (sit up off the ground). The roosts can be anywhere they can climb up and sit, such as a shelf or ladder made of small dowels. The nesting areas, which encourage egg laying, should be fairly tight wooden boxes measuring about 14 inches on each side and about 12 inches deep. An unused shoe rack with individual-sized boxes or a few old tool drawers may do the trick, but you could easily make some boxes yourself out of any available wood.

It’s good to protect against other dangers as well. Wild predators are not the problem in the city that they are in the country, but even dogs and cats can do great damage to an unprotected flock. Also, though I live in an urban area, we occasionally see owls, crows, raccoons, and opossums as well as plenty of squirrels. These animals can either steal eggs or harm the chickens themselves if both are not protected, particularly at night. Chicken wire or poultry wire, available at hardware stores, has a small enough mesh that it should keep out any predators. The chicken house, and perhaps the entire coop, should be surrounded by chicken wire. Ideally, you should make a “floor” of chicken wire as well to seal in the coop, which still allows the chickens to peck at the ground below if you have their pen or a lawn or bare earth. With no chicken wire base, you need to be extra careful to weight down the sides with a wooden or metal frame, so that no predator can push up the wire or dig beneath it to make an entry hole. Make one mistake and you’re bound to lose some chickens, and any survivors may be too stressed out to lay eggs for a while.

Buying commercial chicken feed is the easiest way to ensure your chickens get balanced food, and it’s a good way to start out, but you can reduce costs over time by allowing them to supplement their diet through foraging. Chickens enjoy eating your fruit and vegetable scraps as long as you avoid giving them anything strong-tasting (for example, onions or garlic), which can affect the flavor of eggs. Bread scraps and grass clippings are also good chicken food. But do not feed them any more than what they can eat in 10 to 20 minutes, or else their diets may become imbalanced. You also can feed them whole grains to cut down on costs, but limit this to 1/2 pound per ten chickens to maintain balance. Scattering these grains on the ground encourages them to scratch the litter for their food, which will aerate it and keep it in better condition. You can purchase feeders and waterers fairly cheaply online or from pet or feed stores. Finally, make sure you change the litter in the coop frequently (the bedding and manure, when aged, make great compost), gather eggs once or twice per day, and maintain the chickens’ living quarters in a sanitary condition, which often means limiting outside moisture and keeping things dry.

WATCH: Joel Salatin on Building Resilience into Agriculture

Thursday, January 29th, 2009

Joel Salatin, author of Everything I Want to Do Is Illegal, Holy Cows and Hog Heaven, and others has created a resilient organic farm that is nearly self-sustaining, with minimal inputs and “stage direction” from the farmers themselves. The system is forgiving of spiking energy prices, drought, flood, disease, and the unpredictable nature of industrial capitalism.

We talk about a food system that grows enough quantity, a food system that can be distributed to the ends of the Earth, a food system that we can produce enough of to stockpile on ports and have it rot, you know, because some warlord won’t let it cross into their land.

But how about talking about a forgiving food system, a food system that’s insulated from the vagaries of politics—the liberal left, the religious right, the multinational corporations, energy prices, natural disasters, and pathogenicity and all those things. That to me is the ultimate sustainable food system, because it’s forgiving.

And the fact is that things happen. And just like we need to be building forgiveness into our marriage relationships, our family relationships, all of these—business relationships, you know—this forgiveness aspect is, I think, severely lacking in our business models, in our farming models, and certainly our entire food system is very vulnerable to little attacks.

Thanks to filmmaker Aaron Lucich for the video. Check out his site,, which has more on sustainable food systems and healthy eating.

Chemical Companies Borrow from Tobacco Playbook to Stymie BPA Regulation

Thursday, January 29th, 2009

Bisphenol A is everywhere—in our cell phones, laptops, eyeglasses, baby bottles, and countless other products containing the plastic polycarbonate. And because of American manufacturers’ panic over “excessive regulation,” BPA and tens of thousands of other chemicals found in everyday products have undergone no government safety reviews. As investigative reporter Mark Schapiro points out in Exposed: The Toxic Chemistry of Everyday Products and What’s at Stake for American Power, the official position of federal watchdog groups in the US is “safe until proven otherwise,” a perversion of “innocent until proven guilty”—good if you’re an individual accused of a crime, not so good if you’re a multinational giving a bunch of people cancer. Or diabetes. Or autism.

In this article from business magazine Fast Company,one observation jumped out at me: “Of the more than 100 independently funded experiments on BPA, about 90% have found evidence of adverse health effects at levels similar to human exposure. On the other hand, every single industry-funded study ever conducted — 14 in all — has found no such effects.” Funny, that.

Read more:

Surely you’ve heard about BPA by now. It’s everywhere. Some 7 billion pounds of it were produced in 2007. It’s in adhesives, dental fillings, and the linings of food and drink cans. It’s a building block for polycarbonate, a near-shatterproof plastic used in cell phones, computers, eyeglasses, drinking bottles, medical devices, and CDs and DVDs. It’s also in infant-formula cans and many clear plastic baby bottles. Studies have shown that it can leach into food and drink, especially when containers are heated or damaged. More than 90% of Americans have some in their bodies.

BPA is dangerous to human health. Or it is not. That’s according to two government reports in recent months that came to opposite conclusions. The National Toxicology Program (NTP), which is part of the National Institutes of Health, reported in September 2008 “some concern” that BPA harms the human brain and reproductive system, especially in babies and fetuses. Yet less than a month earlier, the U.S. Food and Drug Administration declared that “at current levels of exposure” BPA is safe. Even after the FDA’s own science board questioned the rigor of this analysis in late October, the agency didn’t change its position.

Let’s take a moment to ponder this absurd dichotomy. How could our nation’s health watchdogs reach such divergent conclusions? Are we being unnecessarily scared by the NTP? Or could the FDA be sugarcoating things? What exactly is going on?

We went on a journey to find out. What we learned was shocking. To some degree, the BPA controversy is a story about a scientific dispute. But even more, it’s about a battle to protect a multibillion-dollar market from regulation. In the United States, industrial chemicals are presumed safe until proven otherwise. As a result, the vast majority of the 80,000 chemicals registered to be used in products have never undergone a government safety review. Companies are left largely to police themselves.

Just five companies make BPA in the United States: Bayer, Dow, Hexion Specialty Chemicals, SABIC Innovative Plastics (formerly GE Plastics), and Sunoco. Together, they bring in more than $6 billion a year from the compound. Each of them referred questions about BPA’s safety to their Arlington, Virginia — based trade association, the American Chemistry Council. “Our view would be, Well, no, there isn’t anything to be concerned about,” says Steve Hentges, the council’s point person on BPA. “In a sense, you could have ‘some concern’ about just about anything.”

Perhaps. But consider this: Of the more than 100 independently funded experiments on BPA, about 90% have found evidence of adverse health effects at levels similar to human exposure. On the other hand, every single industry-funded study ever conducted — 14 in all — has found no such effects.

Of the more than 100 independently funded experiments on BPA, about 90% have found evidence of adverse health effects. On the other hand, every single industry-funded study ever conducted — 14 in all — has found no such effects.

It is the industry-funded studies that have held sway among regulators. This is thanks largely to a small group of “product defense” consultants — also funded by the chemical industry — who have worked to sow doubt about negative effects of BPA by using a playbook that borrows from the wars over tobacco, asbestos, and other public-health controversies. A secretive Beltway public-relations consultant. A government contractor funded by the industries it was hired to assess. A Harvard research center with a history of conflicts of interest. These have been the key actors in how the science of BPA has been interpreted by the government. And it is their work, as much as the science itself, that has stymied regulation.

Read the whole article here.

Investing in Renewable Energy to Get America’s Swagger Back

Thursday, January 29th, 2009

President Obama’s stimulus bill passed in the House today, with members voting largely along party lines. (Not a single “Yea” vote from Republicans? Really? It’s a good thing we compromised on those tax cuts and cut family planning out altogether, then, eh? It really helped wrangle all those … zero votes.) So it seems we’ve staved off economic collapse, at least for a while. A good first step.

The next stimulus, says ClimateSolve’s Mindy Lubber, should be a massive green energy investment that would upgrade the efficiency of our power lines and spur the development of home-grown innovations like next-generation thin-film solar technologies.


Meredith doesn’t split hairs in her advice to U.S. CEOs and policy-makers: Stop whining about losing jobs to Asia and concentrate on restoring America’s competitiveness with new technologies that will spur new industries and jobs.

The economic stimulus legislation being debated in Congress is a golden opportunity to put Meredith’s words into action, especially in staking out America’s leadership in driving energy efficiency and the emerging clean energy global economy.

The United States’ response to date on this mega business opportunity would have guaranteed us being voted off the show Survivor. We lag embarrassingly in our inefficient use of energy, even compared to developing countries. The world’s four largest solar manufacturers are in China, Japan and England. Virtually all of the leading wind turbine manufacturers are in Asia and Europe.

“They’re surging ahead of us, poised to take the lead in these new industries,” then-President-elect Obama said earlier this month during a tour of a wind turbine plant in Ohio, outlining Europe and Asia’s current advantage over the U.S. in clean energy innovation and job creation.

A green stimulus bill that spurs innovation in energy efficiency, renewable energy and achieving a smart grid will help America get its swagger back.

Read the whole article here.

Image courtesy of

Gore: The Time Is Now for “Decisive Action” on Global Warming

Wednesday, January 28th, 2009

It seems awfully childish for the US not to have ratified the Kyoto Protocol simply because it provided exemptions to other polluters, like India and China. If India and China jump off the Brooklyn Bridge, do we follow? Bush II, Clinton, and the ’97 Senate said “yes.” Have things changed? Will we now have a saner climate change policy?

From the Huffington Post:

WASHINGTON — Former Vice President Al Gore urged lawmakers Wednesday not to let the economic crisis get in the way of addressing global warming.

Testifying before the Senate Foreign Relations Committee, the Nobel Peace Prize winner said Congress should pass President Barack Obama’s economic stimulus package as a first step to bringing greenhouse gases under control.

But Gore also pressed for “decisive action” on a bill to cap heat-trapping gases, saying that it is needed for the U.S. to take a leading role in negotiations on a new international climate treaty later this year.

The Bush administration pulled out of the last treaty, the 1997 Kyoto Protocol, because of the lack of participation by developing countries. Negotiations on a new agreement are scheduled for December in Copenhagen, Denmark.

I’m hopeful that this will accomplish something. But what would really help incentivize cutting carbon emissions is Peter Barnes’ cap-and-rebate plan: a “sky trust” with the money going directly into the bank accounts of the American people.

It makes sense, is easy to understand and explain, and stimulates the economy while cutting carbon emissions. Will Congress be crafting cap-and-rebate legislation any time soon? I’m not holding my breath. (Of course, if we don’t do something soon, we’ll all be holding our breath.)

Read the whole Gore article at the Huffington Post.

Related articles:

Natural Home Heating: Air-Source vs. Ground-Source Heat Pumps

Wednesday, January 28th, 2009

A reader comment on a previous post about home heating got my brain-hamster spinning his wheel about air-source versus ground-source (read: geothermal) heat pumps. What it boils down to is, when you’re choosing the proper heating/cooling system for your home, consider the local climate. The most energy-efficient system for one locale may not be the most energy-efficient system for another. Whereas in Orlando, Florida, an air-source system—where the heat-pump is placed outdoors—works marvelously, in a colder, wintry area—say, for example, oh, I don’t know…White River Junction, Vermont—geothermal might be where it’s at.

There are other considerations, of course, but here’s a quick overview of these systems.

The following is an excerpt from Natural Home Heating by Greg Pahl. It has been adapted for the Web.

Heat Pump Systems

On the outside, heat pumps are unexciting; they’re rectangular metal boxes with pipes and wires coming out of them. It’s what’s inside the box that creates the magic. Not all heat pumps are created equal, and there are so many choices. The analogy to a Lego toy set is particularly appropriate when you’re combining elements to create an efficient and effective heat-pump system.

Click for larger image

Air-Source Systems

The two basic types of air-source heat pumps are one piece and two piece. A one-piece heat pump is self-contained in a single unit.This type of heat pump is often found in commercial settings, such as motel rooms, or is used where a relatively small area in a house or office building is being heated and cooled. One-piece units are often mounted on the roof or in a wall.

Two-piece systems consist of two main packages of equipment. One is installed in your home, often in the basement or utility room, while the second package is located outside, normally on a concrete pad on the ground. The inside unit looks similar to a gas furnace, while the outside unit looks just like a central air-conditioning unit. These two pieces of equipment, connected by pipes and electrical controls, transfer the heat in or out of your home, depending on the season.Two-piece systems are the design most frequently used in air-source home heating applications.

Click for larger image

Ground-Source (GeoExchange) Systems

Unlike an air-source heat pump, where one heat exchanger (and frequently the compressor) is located outside, a ground-source heat pump unit is located entirely inside your home, often in the basement or utility room. This is especially important in northern climates, where extremely cold winter temperatures and snow can have an adverse impact on heat-pump equipment located outdoors. Part of the heating system is located outside, however, and that is the underground piping that contains the liquid heat exchange medium.The type and configuration of the outside piping system is the main factor that differentiates various ground-source heat pump designs.

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