How China is affecting the world’s photovoltaic industry.

Workers at a Suntech factory in China. Due to the glut in PV, Suntech has closed a quarter of it's manufacturing capacity.
Photo Credit: Peter Parks, Getty Images for the New York Times

When China dives into a technology, it does so in a big way. Nowhere is this more the case than in photovoltaic (PV) panel manufacturing, where dramatic growth has not only taken a toll on other manufacturers around the world, but also now threatens its own PV industry through rampant oversupply.

This has significant implications for us here in the U.S.—both good and bad.

What happened?

China learned how to manufacture PV modules from leading-edge manufacturers in the U.S., Germany, and elsewhere, then figured out how to do it better and much cheaper than anyone else. In just a few years China came to dominate world PV manufacturing, leaving a trail of bankrupt Western manufacturers in its wake.

Introducing the Resilient Design Institute: a new nonprofit organization that has been created in Brattleboro.

A massive ice storm, in which up to four inches of ice were deposited in early January, 1998, destroyed over 100 power distribution towers and tens of thousands of wooden utility poles, leaving millions without power for up to three weeks in Eastern Canada.
Photo Credit: Hydro Quebec

Some 27 years ago, following a five-year stint as director of the Northeast Sustainable Energy Association (which was then based in Brattleboro), I launched my own company focusing on information about environmentally responsible design and construction. That company, now called BuildingGreen and with a staff of 18, remains a leading player in the green building world—a trusted source of information on green building products, the place to find objective news on happenings in the green building world, an independent voice on the U.S. Green Building Council’s LEED Rating System.

It’s a great place to work and I’m thrilled to serve as executive editor at BuildingGreen and be able to research and write about all the cool stuff that our subscribers need to know. Nadav Malin has been doing a superb job at running the company since I handed the reins to him several years ago.

My shift away from company management at BuildingGreen has given me the space to focus on where we’re heading in the building industry and what sort of changes will be needed to solve the many challenges we face, led by climate change. My sabbatical last year, which I began with a contemplative 1,900-mile bicycle trip through the Southwest, provided an opportunity to delve deeply into this thinking.

This simple system for recovering heat from wastewater makes a lot of sense—especially for families and commercial buildings that produce a lot of hot water.

Power-Pipe drainline heat exchanger. Heat from the hot water going down the drain pipe is transferred to water passing through the smaller-diameter pipes. Click to enlarge
Photo Credit: RenewABILITY Energy

Over the past few weeks I’ve written about various strategies to produce hot water efficiently. We’ve seen that tankless water heaters are more efficient than storage water heaters (though are not without their drawbacks), and we’ve learned that heat-pump water heaters produce two to three times as much heat per unit of electricity consumed as electric water heaters that rely on electric resistance heat.

But the unfortunate reality is that even with the most efficient methods of generating hot water, we still lose the vast majority of that heat down the drain. Domestic hot water is a once-through product. I’ve seen estimates that 90% of the heat in hot water is lost down the drain. Dan Cautley, an energy engineer with the Energy Center of Wisconsin, says that drain water “may be one of our largest untapped resources.”

It turns out that we can do something about that. Im the right application, drainline heat exchangers allow a significant portion of the heat from hot water going down the drain to be recovered.

New federal regulations beginning in mid-April 2015 will require that larger electric water heaters be heat-pump models. It’s time to pay attention to this option.

The GE GeoSpring heat-pump water heater is the quietest model I could find and the only one that's made in America.
Photo Credit: GE Appliances

Last week I wrote about “hybrid” water heaters, a relatively new type of water heater that includes features of both storage and tankless models. This week I’ll cover another type of water heater that is also (confusingly) referred to as “hybrid”: heat pump water heaters. These produce over twice as much hot water for each unit of electricity consumed as any other type of electric water heater (storage or tankless).

You’re going to be hearing a lot about heat-pump water heaters over the next few years, because new federal regulations that take effect in 2015 will require heat pump functionality for larger electric water heaters—more on that below.

A relatively new type of water heater combines features of both tankless and storage water heaters.

A.O. Smith's NEXT Hybrid water heater.Click to enlarge.
Photo Credit: A.O. Smith

In last week’s blog I compared tankless and storage water heaters and explained why tankless water heaters often don’t make that much sense.

This week I’ll describe a newer type of water heater that has some features of both storage and tankless designs and solves several problems that are common with tankless models. While these are referred to as hybrid water heaters, they are quite different from heat-pump water heaters, which are also often referred to as hybrid. I’ll cover heat-pump water heaters next week.

While they have higher efficiency, for most applications tankless water heaters don’t make sense.

Rheem's Prestige condensing tankless water heater has an efficiency of 94%, 11,000 to 199,000 Btu/hour gas input, a maximum hot water delivery (at a 45°F temperature rise) of 8.4 gpm, and a minimum flow rate of 0.26 gpm. Click to enlarge.
Photo Credit: Rheem Water Heating

There are two primary types of water heaters: storage and tankless. In this column I’ll try to explain the differences between these two approaches and offer some guidance on choosing between them. (There are also “hybrid” water heaters with features of both that I’ll cover in a future blog post.)

Storage water heaters

Most water heaters are storage models. These are insulated tanks holding 20 to 120 gallons with either electric heating elements or gas burners. The storage tank stratifies with hot water at the top and cold incoming water at the bottom, so that as you draw off hot water (from the top), you get consistently hot water until the hot water is nearly depleted. The “first-hour rating” tells you how many gallons of hot water can be delivered in an hour. 

Those ubiquitous exit signs use a huge amount of electricity; a little-known alternative to conventional LED products offers surprising savings.

An exit sign at Yale's LEED-Platinum Kroon Hall. Click to enlarge.
Photo Credit: Alex Wilson

In the years that I’ve been writing about energy and energy conservation (longer than I really want to admit), I’ve reported on several dramatic transitions in how we illuminate the exit signs in commercial buildings. For an energy geek, it’s been an exciting technology to watch.

Why care about exit signs?

Why do we even pay attention to exit signs—those ubiquitous red or green illuminated signs that direct our escape from a building should the need arise? They can’t use very much energy, can they?

Each one uses relatively little electricity, but they are on all the time. And we have a lot of them in our schools, factories, and office buildings. The U.S. Environmental Protection Agency estimates that there are more than 100 million exit signs in use today in the U.S., consuming 30–35 billion kilowatt-hours (kWh) of electricity annually.

An update on getting the global warming potential (GWP) out of insulation materials.

Today's closed-cell SPF has a global warming potential of 1,430, but if producers adopt new HFO blowing agents, it will drop to close to zero. Click to enlarge.
Photo Credit: John Straube

I’ve been pretty vocal about a big problem with some of our most common insulation materials: that they are made using blowing agents that are highly potent greenhouse gases.

All extruded polystyrene (XPS) and most closed-cell spray polyurethane foams (SPF) are made with HFC (hydrofluorocarbon) blowing agents that have global warming potentials (GWPs) many hundreds of times greater than that of carbon dioxide. (My apologies for contaminating this column with so many acronyms!)

Insulation: good news, bad news

With new oil discoveries and more effective extraction methods, the world is probably many decades away from peak oil.

A "Hubbert Curve" of world oil production, showing the peak in this decade, which was widely predicted just a few years ago. Click to enlarge.
Photo Credit: Energy Watch Group, UK.

I first wrote about “peak oil” in 1998, reporting on an in-depth article in Scientific American by petroleum geologists Colin Campbell, Ph.D. and Jean Laherrère. Campbell and Laherrère believed that up to that time the world had consumed about 800 billion barrels of oil (BBO), and the known reserves of conventional crude oil totaled about 850 bbl in 1996 and another 200 BBO of conventional oil was yet to be discovered.

The result, they argued, was that the world would reach the half-way point—or the peak—in (conventional) world oil production within the first decade of the 21^st century. That peak would occur, they argued, when cumulative world oil consumption reached about 925 BBO. (At that time the world was consuming 23.6 BBO per year.)

The significance of peak oil is that once that point is reached, so the proponents argue, annual oil production will begin an inexorable decline with a concomitant rise in cost. It would become too expensive to use oil for many uses and the “end of the oil age” would be in sight.

Finally fixing the basement drainage problems that have plagued my house for 30 years

I tried fixing the drainage years ago, but my fix failed at the basement window wells, including the one shown here on the back of the house after digging it out, exposing the EPDM drainage layer. Click to enlarge.
Photo Credit: Alex Wilson

When I bought the house in West Dummerston, Vermont, where my wife and I have lived for the past thirty years, one of the first things I did was fix the drainage problems that were dumping water into our basement….

Or so I thought. Let me explain.

When I moved into the 1780s house there was a hill on the west side that channeled runoff right into the dry-stone foundation. During rainstorms rivulets of water would flow into the basement with abandon. The house had only survived so long because the soil is very sandy. Moisture that got into the basement would quickly soak into the ground and disappear.

Step one was to change the topography. I hired an excavation contractor to move several hundred yards of earth from the west side of the house, creating a bit of a swale to direct runoff away from the house.