Home Efficiency Blog

Best Way to Boil Water

2009-08-17T20:43:00.010-04:00

When it comes to home energy use, we often find that conventional wisdom is wrong, uselessly vague, or outdated. So, we recently set out to put a bit of experimental rigor into the question of making our morning cup of tea.

Here are some questions we wanted to answer:

What’s the best (i.e. least energy intensive) way to boil water?
Is the answer different for 1 cup of water vs. 4 cups? What about 2 quarts?
Most importantly, if I’m doing it wrong, is it worth changing the way I do things already?

We carried out 13 tests on a typical microwave (1.3 kw), a popular electric stove (1.5 kw element), and a standard electric kettle (1.5 kw). The results were a bit surprising. The electric kettle (unsurprisingly) performed great. The microwave, on the other hand, was shockingly inefficient while the stove performed surprisingly well (considering all of the wasted heat it dumps into the kitchen).

Question 1: What’s the best way to boil water?
Answer: The electric kettle won hands down. The real advantage with the kettle is on the first cup. It boils in half the time as the first cup boiled in either the microwave or the stove. Since (at 1450 Watts) it uses about the same amount of power as the others, halving the time halves the energy. Thereafter, the energy requirement for boiling larger volumes of water is nicely predicted by a linear function. Each additional cup requires an additional 25 Watt-hours of energy and about a minute of additional time. The stove had similar performance except that the first cup required twice the energy (and time) of the kettle’s first cup.

Question 2: Does the answer change based on the volume of water boiled?
Answer: For the first quart of water, the answer is surprisingly unchanged. The only thing that really changes is that the microwave performance degrades much more rapidly than the other two. So, while the decision to boil one cup of water in the microwave isn’t much worse than using the stove top, using the microwave to heat up 4 cups of water is a bad choice (from the energy and time perspective).

Question 3: Is it worth changing my behavior?
Answer: In the grand scheme of home energy usage, it turns out the savings you could gain by changing your habits on this one aren’t huge. In fact, even if you boiled a quart of water every day, the cost difference between the best performer (the electric kettle) and the worst performer (the microwave) would only be about $4 per year. But, what if we extend this lesson into other realms? We might consider reheating our soup in the kettle rather than the microwave or adding an electric kettle to the office kitchen for all of those cup-o-noodles (after all, the kettle is faster too). Furthermore, this is one of those rare energy decisions that can save time, money, and energy. Electric kettles are cheap, fast and efficient. Microwave ovens are expensive, slow and inefficient (for heating water).
The relative strength of the stove can also be seen as great news. If you size your pot appropriately the stove can almost rival the kettle… not bad.

*- To heat 8 cups in the microwave or electric kettle would take two batches. You can therefore approximate the time (and energy) by doubling the time it takes for 4 cups. The savings are small enough though that you might as well just use the stove for volumes greater than your electric kettle capacity.

How to Be an Energy Efficiency Hero

2009-08-05T16:54:00.020-04:00

Some truths transcend their original context. In Jim Collins' modern classic, Good to Great, he classifies the qualities of businesses with exceptionally high growth rates over sustained periods of time. The findings sound a lot like timeless common sense, and one quality struck me as particularly applicable to energy consumption.

If you’ve read our blog before, you know our mantra, “You can’t manage what you don’t measure.” But sometimes measurement feels uncomfortable and painful. Fear of the unknown thwarts us from wanting to discover what ugly truth may lie behind door #1. Maybe it’s a test result that will have implications for our health or an auto tune-up that reveals this may be a more expensive bill than we’d planned on. That feeling of unknowing can be terrible.

And yet, Collins finds that truly excellent businesses, the ones that have gone from mediocre to awesome, share the quality of confronting the brutal facts. They don’t stop there, though. They possess the rare combination of confronting the facts while also having an unwavering faith that they will prevail in the end, regardless of the difficulties. Collins calls it the “Stockdale Paradox,” but for the purposes of this post, I’ll call it the heroic combination.

The second element, unwavering faith that you’ll prevail, can be difficult. The challenges of global warming or even the thought of having to change our behavior can make us want to throw up our hands. “This is too hard, too tedious, too hopeless,” we say. “I don’t want to know how bad it is.” But our greatest heroes are those who face the facts and press on with the faith that they will prevail.

Our goal at PlotWatt is to give you rich information about what’s happening in your home… which appliances are consuming the most energy and how much energy you’re consuming on a day-to-day basis. Sound scary? It may be, at first. Remember the heroic combination though. Armed with the facts, you can prevail to make far-reaching, sustainable reductions to save you money and prevent tons of energy from being generated. Then, you’ll be an energy efficiency hero. And who knows, maybe tomorrow you’ll fly around the planet so fast that you reverse time to save the world. With heroism, you’ve got to start somewhere.

http://www.flickr.com/photos/bohman/ / CC BY 2.0

Upstream Watt Multiplier (1 Watt Saved > 1 Watt Generated)

2009-07-30T15:52:00.022-04:00

In the world of “clean energy,” projects fall into one of two categories: increasing clean energy generation (supply) or decreasing energy consumption (demand). The energy generation side is developing technologies aimed at displacing the power plants we already have and building additional capacity for our ever-increasing energy appetites. Cool. On the other side, there are those of us focusing on more efficiently using the energy produced, no matter what the source. In this post, I’ll describe why these aren’t just two sides of the same coin.

This is really important: energy saved can have multiplicative upstream impacts. A unit of energy (e.g. a kilowatt-hour) consumed by your television has much more impact than the same unit of energy produced by your local power plant. This is a consequence both of inefficiencies in our system and of the laws and limitations of physics.

Inefficiency in the Home
Let’s look at the power it takes to illuminate a light bulb. We’ll start with a new term, the lumen. A lumen is a unit of measurement used to express the amount of useful (visible) light produced by a light bulb. It is important that we start there because lumens (not Watts) are what we want from our light bulbs. We’ll begin at the lumens and follow the electricity back to the power plant where we’ll discover just how much energy a light bulb wastes along the way.
Let’s say we want to create 1700 lumens of visible light. If we had a perfectly efficient light bulb, it would take about 2 Watts of electricity to produce 1700 lumens. Incandescent bulbs are far from being perfectly efficient. They are about 2% efficient at producing useful light. That means for every 1 Watt worth of useful light produced, 50 Watts are wasted on things like heat and invisible light. For incandescent light 1700 lumens requires a 100W bulb (i.e. 98% of the energy is wasted).

Transmission Inefficiency
Next up, we have transmission losses. This is energy lost between the power plant and our homes (usually the loss takes the form of heat). In the US, our average transmission losses are about 7%. So, a 100W bulb, which makes 2 Watts worth of light, requires 107W of power from the power plant.

Power Generation Inefficiency
Finally, we have power plant losses. Extracting energy from just about any fuel source is an inefficient business. We generally burn a fuel and then use the heat generated to turn a turbine. In the US, across all electricity sources, we’re about 32% efficient (i.e. 68% wasted). So 107W requires 334W of input. All-in-all, it takes 334 W to make 2 W worth of useful light. From coal mine to illuminated living room, we are wasting 99.4% of the energy. Yikes.

So what?
The repercussions of our gross inefficiencies are oft-neglected when it comes to clean energy thinking. We think that adding generation to the grid has the same impact as removing demand from the grid. In reality though, doing without the 2W worth of light is equivalent to removing the upstream need for 334 W worth of input or 107 W worth of generation. Similarly, increasing the end-use efficiency from 2% to 8% like we can do with CFLs, has huge upstream repercussions. Now, we’re still creating 1700 lumens of light, but it only takes a 25 W bulb, 27W of generation, and 84W of input.

Adopt a Home and Live Net Zero

2009-07-08T10:51:00.009-04:00

A lot of the readers of this blog are energy-savvy “ecogeeks.” Most of you share our enthusiasm for energy efficient, conservation-oriented living. We love you for that. In this post I’m going to frame our individual efforts in the big picture and encourage you to spread the energy-saving love.

We humans are a self-serving species. There are few places where this is more apparent than environmentally-oriented purchasing. We will go to great lengths to make our individual lives eco-pristine. Photovoltaic solar anyone? We will squeeze every ounce of energy waste out of our homes and we often do so at great monetary expense. The first 10, 20, even 50% might be easy, and then it starts to get costly. We start to rationalize things like 20-30 year payback periods.

At the point where we start looking at home improvements that take a decade or more to pay for themselves, we should all ask ourselves a question: “Why am I doing this?” Your answer to that question is important. If your goal is to stimulate innovation by pumping money into bleeding edge technologies, that’s awesome. If your goal is to have the most eco-bling on the block, that’s fine too (I guess). But, if your goal is to reduce the need for dirty power plants, fight climate change, end mountain top removal, pursue energy independence, or take up any other clean energy goal requiring collective improvement, I’d like to suggest an alternative to the big capital investments. The alternative is to adopt a friend or family member’s house. Help them save 10% and then adopt another.

Keep in mind, 10% of a serious consumer’s energy might amount to your home’s entire energy bill. When it comes to overall energy reduction, personal percentage reductions really aren’t important. This is a bit like the MPG Illusion. Our friends live in homes that burn energy like a Hummer with flat tires. Meanwhile we are giving ourselves a pat on the back for upgrading from a Toyota Corolla to a Prius. We are unplugging cell phone chargers to save watt-hours when we could be helping others to save kilowatt-hours. We need to reduce the total number of kilowatt hours used. For that McMansion your brother-in-law lives in with the landscape lighting running at all hours, a simple timer might be worth a thousand times its weight in coal. So, let’s get off of our high horses, stop trying to get our own electric bills to zero and start going after the big opportunities.
Please don’t mistake my plea as presentation of a false dilemma. There is lots of room for a “both and” approach rather than an “either or” approach. Often, you can shave the watt-hours from your bill AND help your neighbor with the kilowatt-hours. If you’re thinking about spending the big bucks though, please do so with your eyes wide-open, acknowledging that you could almost certainly achieve the same end with much less capital and bit of friendly outreach.

Want to see how we tackle energy waste? Sign up for our mailing list at plotwatt.com to learn about becoming a pilot home.

Images from:

http://www.flickr.com/photos/auntylaurie/ / CC BY 2.0 & http://www.flickr.com/photos/landschaft/ / CC BY 2.0

1 Watt Rule of Thumb

2009-06-24T17:29:00.006-04:00

In the spirit of sanity checking my energy saving decisions, I like to keep simple technical estimations in mind. In this post, I’ll discuss one of the most useful. If you’re not in the mood for math, here’s the bottom line: 1 Watt of energy reduction equates to approximately $1 of electric bill savings per year. So, eliminating 10 Watts of phantom load from your house will save you about $10 per year, 100 Watts produces $100 of annual savings…
Disclaimer:
This is a gross estimation. As such, this rule should only be used for getting a ballpark idea of savings potential.
Let’s Practice:
If 1 Watt of energy reduction produces $1 of savings per year, replacing a 60 Watt incandescent bulb with an equivalent 13 W compact fluorescent could provide as much as $47 (60-13=47) of annual electricity bill savings. BUT, most of us don’t keep our lights turned on 24/7. So, instead let’s say that that same bulb is turned on only 2.5 hours per day. Since 2.5 hours is about 1/10th of a day, our savings have dwindled to $4.70 per year. If it’s on just 15 min per day (1/100th of a day), the annual savings fall to 47 cents per year. (More on CFL's here and here.)
Let’s look at another example. A typical cell phone charger has a phantom load of about 2 Watts. If you leave it plugged in all the time the charger will waste $2 per year. S0, religiously unplugging it after charging your phone will save you about $2 per year. Cool. But if you forget to plug the charger back in just once you might find yourself with a dead cell phone (and that might cause > $2 of frustration). For that reason, I prefer to target the less risky phantom loads, like that TV in the guest room. A TV might use as much as 15 Watts of energy when it is turned off but in standby mode. Unplug the TV’s you seldom use (or learn a slick new use for a holiday light timer here) and save as much as $15 per year per TV.
Here’s the math:
As you might recall from a previous post, one kilowatt-hour is the amount of energy used by 1000 Watts running for one hour or 1 Watt running for 1000 hours. There are 8760 hours in a year (24 hours per day x 365 days = 8760). So, if an appliance uses 1 Watt of electricity constantly (24 x 7 x 365) it uses a total of 8760 Watt-hours or 8.76 kilowatt-hours of electricity in a year. With me?
The average cost of a kilowatt hour in the US is between 9 and 10 cents. We’ll round up and call it 10 cents. So, if one watt burns up 8.76 kwh in a year, it will cost you 87.6 cents on your electric bill every year. In the spirit of gross estimation (and in anticipation of rising electricity costs), I round that up to $1.
The graphic shows the approximate distribution of electricity rates around the country. The 1 Watt rule of thumb is close enough for most of us. If you’re in Hawaii though, where electricity is more than 20 cents per kwh, this estimation should be closer to $2 per Watt.
Happy energy saving!

Vocab Lesson: On-Peak, Off-Peak

2009-02-24T16:28:00.013-05:00

Through recent industry events and conversations with consumers it has come to my attention that there are some electricity grid fundamentals that the industry insiders take for granted and we consumers never even consider. One such fundamental is that of baseload generation and its counterpart, peaking generation. In this post I’ll outline these principles and touch on what they mean to you, as a consumer of electricity.

First, the basics:
When we look at energy consumption curves, they reveal particular times of the day when we tend to use lots of energy, and other times of the day when we use very little energy. For instance, in the winter months here in South, where lots of people have electric furnaces, there is a spike in energy use at around 7 or 8 AM when lots of the furnaces come on to warm up homes and offices after a cool night. Then, as the day warms, energy use subsides as the furnaces are used less. Again in the evening, as it gets cold there might be another spike. The periods of high energy demand are called “on-peak hours” and the low-energy use periods are “off-peak.” As you might imagine there are lots of different ways to characterize these periods. Some utility companies have off-peak, medium-peak, and high-peak periods for instance. The basic premise remains the same: our collective energy use over any given day is not a flat line. And the peak and off-peak hours change with the seasons and even with the day of the week (weekends being different than weekdays).

Why does it matter?
It turns out that certain sources of energy are best suited to meet certain types of demand.

If we are painting with a fat brush, our electricity generation pie looks like this:

What the pie fails to represent is the temporal characteristics of various fuels’ usage. It turns out that coal plants are very difficult to start and stop. Furthermore, they are happiest when plugging along at a constant output. Think of a coal power plant as a campfire. Keep shoveling in the coal, and it keeps pumping out the power. Like a campfire though, it’s tough to quickly turn down, turn off or crank up a coal plant. For that reason, coal power plants are best suited to meet the minimum, mostly constant, baseline power needs of the grid, aka baseload power. Nuclear plants are similarly suited to baseload generation. Hydroelectric is also usually considered a baseload.

Natural Gas plants, on the other hand, run like a car engine. In the case of a gas plant, when you turn on an electric appliance, the power plant instantly responds by pumping out more energy. Turning on an appliance is like stepping on a car’s accelerator, the power plant just works a little harder and burns more fuel to power the appliance. This relative nimbleness makes natural gas plants ideal for on-peak generation. Such power plants are called peaking or peaker plants. As you can probably imagine, these peaking power plants tend to be much more expensive to operate than the baseload plants so they are only used when needed. This cost discrepancy is the basis for utilities offering time of use billing plans… more on that in a future post.

What does this mean for you?
The implications for you depend in part on your goals. If you want to save money on your electric bills, shifting your energy usage to off-peak hours can save you serious cash. This gets into time of use billing plans (once again the subject of a future post) but I can hit the key points here. Time of use billing is already available in some parts of the country. If you can handle the inconvenience of shifting your demand to your utility’s off-peak hours, opting in to time-of-use billing can be great. In my case, by shifting my demand to off-peak hours I pay about 30% less per kwh than I would if I were on a standard billing plan. If TOU billing isn’t available to you, shifting your demand to off-peak hours still helps your utility to run more efficiently and theoretically keep your bills low.

If you’re more interested in environmental concerns, simply shifting demand to off-peak hours may not help the cause. In fact, if such a shift means more coal and less natural gas you may actually be doing more harm than good! Natural gas plants after all emit about half the CO2, one-third the NOx and almost no SOx and Mercury. I suspect there is a win-win opportunity here to shift our demand to those off-peak hours that are best met by renewable sources. Does your area have lots of solar power? If so, consuming in the few hours on both sides of noon makes good environmental sense. Do you live near wind turbines? Perhaps you should try and run your dishwasher when it’s windy. In truth, this type of demand shift might encourage renewable generation as much as paying extra for it on your electric bill.

In theory, if we all shift demand properly, utilities will run more efficiently, and we’ll all get lower rates and maybe some cleaner power too!

A Letter to Dr. Steven Chu (the next Secretary of Energy):

2008-12-23T17:07:00.008-05:00

My faithful blog readers, I apologize for the lapse. If you are not already using an RSS reader or the “Subscribe via Email” feature on this blog, please consider doing so. It will obviate the need to check in on the blog to see if there is a new post. And now, back to our irregularly scheduled post…

Dear Dr. Chu,

As a “cleantech” entrepreneur, I’m really excited by President Elect Obama’s decision to appoint you the next Energy Secretary. Based on the tremendous breadth of energy research that you have overseen in your time at Lawrence Berkeley National Labs, I believe that you may be one of the best equipped scientist-administrators to take on the challenge of American energy policy. It has been my experience that this sector needs a healthy dose of perspective. We all get lost in the weeds of our particular technology and become myopic. Those who can afford it hire lobbyists to spread their myopia in Washington where any and all things nominally pro-environment are seemingly being promoted with reckless abandon. If your project Helios lecture is any indicator, I think you will be able to help Washington to get out of the weeds and properly prioritize our research and short-term energy priorities.

However, I do have some warnings and observations to share. The rest of this post will be devoted to the critical observation that when it comes to energy policy, California (your home state) may not be the shining example of sustainable consumption success that its politicians like to claim. You rightly have pointed out that while America’s average per capita energy consumption has been rising since the industrial revolution, California’s per capita consumption leveled off around 1970 and has remained the same since. Way to go California! But wait a second… Is “per capita energy consumption” really the right metric?

At VisibleEnergy we are big fans of using meaningful metrics (see the Cheeseburger Calculator and the Gallons per Mile posts). When it comes to metrics that are intended to assess our energy sustainability, “per capita use” isn’t very helpful. This metric fails to consider some very important characteristics like population growth and energy source. If the population is growing and the per capita energy consumption is flat, the total energy use still grows. When it comes to resource sustainability, our finite resources don’t care whether our average consumption is low. Sustainability is much more a concern of aggregate or total consumption. So what does California’s total energy use look like? Not so great. That is not to say that per capita consumption is a useless metric altogether, just not an adequate measure of sustainability.

The following series of graphs illustrate different ways to look at the same data. You tell me, where should we be investing our attention? Making the country more like California or figuring out what on earth is going on in Alaska?

This first graph shows a zoomed-in picture of the per capita energy consumption in all 50 states and the total per capita energy consumption for the US. I've highlighted some stand-outs. Nice work Rhode Island!To make things comparable in this second plot I scaled all of the values to be a percentage of the total consumption in 1970. So, you can see for instance that America's energy use is now about 150% of what it was in 1970.This plot reveals that California doesn't look so great when compared to the US if total consumption is the metric of choice. Since the per capita consumption is relatively flat, the population must have grown.The following graph shows the zoomed-out perspective on the first graph. From this perspective the worst offenders are Alaska, Wyoming, Lousiana, and North Dakota.And finally, a zoomed out picture of total consumption for Alaska, California and the US.Thoreau wrote: “In the long run, men hit only what they aim at." (Walden)
Let's find something good to aim at.

Best of Luck Dr. Chu!

- The data for all of these charts can be found through the Energy Information Administration (eia.doe.gov) -

Backfire: A Case for Thoughtful Energy Consumption

2008-09-30T17:57:00.008-04:00

Let me start by saying, the occurrence of the Jevons Paradox in our modern use of energy is difficult to prove outright. However, the more broadly defined big brother of the Jevons Paradox, known as the rebound effect, irrefutably occurs in a major may. The contents of this post are applicable even if we are only thinking about rebound.

The Jevons Paradox asserts that as technology allows us to more efficiently consume a given resource we tend to use more of that resource rather than less. If you’re a student of economics this relationship might not seem so paradoxical when viewed as a question of supply and demand. As efficiency increases, we can get more work done for less, lowering the price of work. This makes for an increase in the demand for work. If the relationship is elastic the increase in demand makes up for the decrease in price and the aggregate amount spent actually increases. In the world of energy efficiency, when the increased demand rebounds so far that the total increased usage of a resource outweighs the reduction from the efficiency, it’s called backfire. If I’ve lost you, don’t sweat it. The next part is the important stuff.

At the micro level, consider your electric bill. If you found a way to cut your electric bill in half, what would you do with the extra money in your checking account? If you spent it on buying a new big screen TV, your savings would be paying for the energy to build and operate that TV… new energy that would not have been expended if not for your reduced electric bill.

On the macro level increased energy efficiency can bring luxury items to more and more homes. So, things like hot tubs that used to be prohibitively expensive to operate find their way into thousands of homes. Yes, the new hot tubs are more efficient, but if that efficiency makes them super popular the net result could be more energy used. Let me be clear, I love hot tubs. I’m merely pointing out that more efficient hot tubs might result in a hot tub adoption craze that makes for more total energy use. I don’t love that.

The repercussions for the individual, the policy maker, and of course our precious resources are enormous. Here we are trying to live greener by reducing our energy use and the net effect can be an increase in energy use! What to do?

Micro strategy: If instead of buying another TV with the savings from your electric bill, you spend it on replacing old appliances with more efficient ones or your buy less energy intensive alternatives to the stuff you already purchase, like local groceries, your savings could actually further encourage resource conservation. Everybody wins.

Macro strategy: This is where policy might come in. Most of the efficiency wonks use rebound to justify things like a carbon tax that prevents resources from being deployed on more energy use. They claim that the only way to prevent rebound is to tax energy so that the perceived cost stays high. Keep in mind that this will only succeed if those tax dollars are intelligently deployed. I’m unconvinced that this is the only answer. Have ideas? Please share in the comments.

If you are really into this stuff and have a high tolerance for technical jargon and generally boring writing, pick up The Jevons Paradox and the Myth of Resource Efficiency from your local library. The book contains some great nuggets of insight and a pretty thorough examination of the magnitude / existence of the paradox around the world.

Comparing Energy and Water – Why Recirculation Pumps are Over Rated

2008-08-22T19:29:00.008-04:00

When a hot water recirculation pump in my home recently stopped working, it challenged me to figure out whether this seemingly water-saving idea really made sense. In this post I’ll present my logic for not fixing it.

To get us all on the same page, a little background education: a recirculation pump is a pretty common way to produce instant (or nearly instant) hot water throughout a home. It tends to be used for larger homes where the water heater might be a long way from a shower or sink. This pump continuously pushes water from the water heater throughout the hot water lines in the home and then back into the water heater tank. It prevents the water in the pipes from ever cooling down, making for quicker hot water at the shower and tap. These pumps are marketed as water saving devices because they prevent homeowners from needing to run the water for a long time before hopping in the shower or using the sink. While I can’t argue with the convenience they provide, it turns out they might not score so high on water conservation.

My recirculation pump used a constant 150Watts of electricity 24/7. That’s the same as 3.6 kilowatt hours per day (150W * 24hrs / 1000 = 3.6 kwh). It takes a lot of water to make electricity. On average across all of our electricity sources it takes about 2 gallons of water for every kilowatt hour of electricity produced. This is mostly water lost to evaporative cooling. So, without even factoring in all of the energy it takes to keep that water warm, it already takes 7.2 gallons of water per day just to power the pump. Let me be clear, this 7.2 gallons of water does not show up on your water bill, it is used during the generation of the electricity to power your pump. For more info on this, check out the "2 gallons of water" link above.

Now, if I unplug the pump it takes 45 seconds longer for the water in my shower to get warm when the shower is at full tilt (around 2 gallons per minute). So I use an extra 1.5 gallons of water every time I shower. To justify my recirculation pump as a water-saving device I would have to shower (or do other similar hot water things) 5 times every day… and that’s not even considering the energy expended to heat that recirculated water.

Just to run this to ground, let’s do a quick estimation on the extra energy used to heat all of that recirculated water. In the previous test we figured there was about 1.5 gallons of water in the pipe between my shower and the heater. So we’re talking about 3 gallons or so of total water that had to be constantly warm (water lines to and from the shower). Even in insulated pipes it’s probably reasonable to assume that the water had to be cycled through every hour or so to keep it hot enough. Since the water that is re-introduced to the hot water heater isn’t exactly cold, let’s put a fudge factor in and say we only have to heat the equivalent of 1 extra gallon every hour, or 24 extra gallons per day. At 24 extra gallons of hot water every day, that recirculation pump may have been doubling my hot water bill! Wow! Too bad I don't have real-time gas monitoring to check the savings...

If you do have a recirculation pump and can’t live without the convenience it affords, at least consider putting it on a timer so that it’s not running at all hours… after all do you really need instant hot water available at 3AM or while you’re at work? A simple holiday light timer will do the trick.

Vocab Lesson: Utility Deregulation

2008-07-31T17:32:00.010-04:00

In this post I’ll discuss what deregulation is, why you might care, and present some stats.

What is Deregulation?

Deregulation is the removal of government controls over an industry. The goal of removing these controls is to create a more competitive free market for things like electricity. Utility deregulation came into vogue around 1996. Today there are 14 states that are deregulated. 8 others have either tried and rescinded or suspended plans to try it altogether. See the map.

Does it work?

The simple answer appears to be “not really.” In the graph I’ve presented the average cost of electricity per person in regulated states, deregulated states, and states that suspended deregulation efforts. On the surface it looks like deregulation makes for expensive electricity. But remember that deregulation did not begin happening until 1996. So, in reality states with expensive electricity to start with were the most likely to pursue deregulation in the first place. Unfortunately for them, any effect it may have had appears to have been a negative one, as rates in those states appear to be growing faster than those of regulated states.

So what?

At VisibleEnergy we try to maintain a laser focus on helping people to save money. Yes, we love the idea of reducing energy consumption and working toward making the planet a happier, greener place. But in our experience the best lever for making that happen is saving cash. In that vein, another look at the graph shows us that regulated or not, the future of cheap energy is not looking so hot. All prices are climbing and the predictions from folks like the Energy Information Administration indicate that trend will continue. If we are going to save money in the future, it looks like efforts toward making utilities more competitive probably won’t help much. We simply need to use less energy.

So Many Metrics, So Little Cents

2008-06-23T16:03:00.006-04:00

Continuing on the theme of the inadequacy of units of measurement, a couple of Duke professors recently revealed in their paper, "The MPG Illusion," a very powerful misconception in the way we Americans look at fuel efficiency. In this post I'll discuss their conclusions and discuss the repercussions for the bigger efficient energy usage picture.

To summarize the study, Professors Richard Larrick and Jack Soll conducted surveys that asked folks to choose the better option between:

1. replacing a highly inefficient vehicle with a slightly more efficient vehicle
OR
2. replacing a typical vehicle with a highly efficient one.

For instance they might ask "Is it better to replace an SUV that gets 10 Miles Per Gallon (MPG) with a 15 MPG Minivan or to replace a 25 MPG sedan with a 60 MPG hybrid?" The mere asking of the question probably tells you that the answer is the less intuitive former case. Here's why: 10 MPG is the same as 1000 gallons of gas per year for the average American car owner (10,000 miles of driving per year). The 15 MPG minivan uses 670 gallons for that same average year of driving. This means that replacing the SUV with the minivan results in 330 gallons of saved gas. The 25 MPG sedan, on the other hand, uses 400 gallons per year whereas the 60MPG hybrid uses 170 gallons per year, resulting in only 230 gallons of saved gas. Are you with me? The important metric here is the amount of gas saved, not the number of miles traveled on a single gallon. When viewed through the proper lens we can see increased miles per gallon leading to diminishing returns in a more important metric like gallons (or dollars) per 10,000 miles. The chart at right presents gallons of gas used when driving 10,000 miles in vehicles of various fuel economies.

So, what does this have to do with home energy efficiency? Most of us are "driving" really inefficient homes and furthermore when we try to improve our home's efficiency we tackle the wrong things. For instance, we find ourselves focused on 10 or 20 Watts of phantom load when we could be eliminating thousands of Watts of useless air conditioning load! The SUV of your home electricity consumption is probably not your cell phone charger (if it is, you deserve a pat on the back). Focus your efforts on the big stuff like heating, air conditioning, large appliances, and jacuzzis. If you can cut the usage of the big energy hogs by a small percentage it will make a world of difference.

update: The Duke professors mentioned in this post have launched a site with a super cool GPM calculator. Here's the site: http://www.mpgillusion.com/

My Beef with the Watt

2008-06-14T13:19:00.006-04:00

This week's post comes from Sarah Kate of the VisibleEnergy team.

Second Congress of the British Association for the Advancement of Science, I have a bone to pick with you. What's my beef? The unit of measurement known as the “Watt.”

A Watt is another way of saying joules per second. A joule is a unit of energy measuring heat, electricity, and mechanical work. So what’s the big deal? Well, for starters, we’re defining a unit of measurement I don’t intuitively understand using another unit of measurement that I don’t intuitively understand. When was the last time you described something in terms of joules? Physics class in high school, perhaps? So to understand what a Watt is, we have to figure out what a joule is. A joule is the amount of work done by a force of one Newton moving one meter along the direction of the force. Now we’re in Newtons, and blimey, the metric system! A Newton is equal to the amount of force required to give a mass of one kilogram an acceleration of one meter per second squared. Are you kidding me? This is not productive; the farther away we get from the original unit of measurement, the less capable we are of conceptualizing it.

But wait, I’m just getting warmed up. What more could be wrong with a Watt? How about the fact that a Watt is a rate? That doesn’t seem so bad, does it? It doesn’t until you remember the terms used to express nearly all other rates… miles per hour, beats per minute, megabytes per second… are units per time. But Watts are already in joules per second, so at any one time, the building you’re in is using energy at a rate of X Watts rather than something like Watts per hour. That means that Watt-hours, a related unit of measurement, are actually a measurement of energy, not a rate of energy (one Watt-hour is equivalent to 3600 joules). Egad!

So here’s the analogy, building off of one of Luke's previous posts:

A car driving 100 miles per hour (rate) for 2 hours (time) travels 200 miles (distance).

A house using 100 Watts (rate) of electricity for 2 hours (time) uses 200 Watt-hours (energy used).

It’s embarrassing that this nuance took me months to finally grasp. Might I suggest switching to a new universal standard of measurement? I propose the Cheeseburger (a quarter pounder). The Cheeseburger represents 500 Calories (kcal) of consumption. My home consumes energy at a rate of 60 Cheeseburgers per day. I can picture this, and the rate is stated the way rates should be – in units per time. Stated this way, I can internalize my consumption, I can picture the mound of hamburgers. With Watts, I must rely on comparison in order to know anything about my personal consumption, and as the wise John Fortescue once said, “comparisons are odious.” And they’re even more odious when you have no frame of reference for comparison. Congress of the British Association for the Advancement of Science, please consider my proposal. If we’re going to help people understand their daily impact, meaningful, digestible units are a must.

At VisibleEnergy, we want to help people intuitively understand their consumption, so thankfully we don’t have to wait for the Congress of the British Association for the Advancement of Science to act. How many Cheeseburgers does your home use? Find out using our Cheeseburger calculator:

Cooling (and Heating) Lesson #1: Programmable Thermostat Selection

2008-06-05T14:59:00.012-04:00

In this post I will cover the logistics of selecting and choosing to install a programmable thermostat. If you live in a place with air-conditioning and/or heating a programmable thermostat can save you buckets of money and reduce your carbon footprint by a whole lot. I will devote a future post to quantifying these savings, but with summer upon us the installation cannot wait. In my own house, I installed a programmable thermostat and the thermostat paid for itself (in electricity savings) in the first month.

Definition:
A programmable thermostat is a simple to install replacement for your old thermostat that allows your heating and air-conditioning (HVAC) to automatically accommodate your schedule. It prevents your HVAC system from working really hard when no one is home to enjoy the comfort. It does this by allowing you to program time spans when you don't need the house to be comfortable, like when you are at work.

If you already have one of these, good work. Now you just need to program it! Studies have revealed that 70-90% of installed programmable thermostats are not programmed. This won’t save any energy.

Can I install one of these things myself?
A "tinkerer" capable of hooking up a home entertainment system will find the installation of a programmable thermostats to be pretty easy. I would not recommend it to technophobic folks. Your need of a handyman depends on your own comfort with wires and the complexity of your existing system. In my experience, the phone support from the thermostat manufacturer made the process pretty easy to do myself with even a complex system (total install took less than 30 min and nothing more than a screw driver). Since you will cut off the power at the breaker box and since thermostats are very low power, the risk of electric shock is very low.*

Which one should I get?
Short Answer: I am pretty happy with these two models carried by Lowes: Hunter 44360 (simple and intuitive, here's a link) and Hunter 44860 (more complex and cool looking, here's a link). Honeywell and others offer similar models that tend to cost a little more.

Long Answer:
1- How much customization do you need? If you get a programmable thermostat from Home Deport or Lowes you will be confronted by LOTS of choices. You can simplify the decision making process by answering the customization question first.
This will tell you if you need a thermostat that you can program differently for every day of the week ("7 day"), or if it is ok to have a weekday schedule and a weekend schedule ("5+2"), or if you need a weekday schedule and separate sat and sun schedules ("5+1+1". Personally I like maximum flexibility so I spent the extra $10 or so on a thermostat that allows me to have a different schedule for every day. These 7 day thermostats can be just as easy to program as the more limited "5+..." versions, but it also means that there will be more buttons.
2- Make sure you get something that is Energy Star compliant. This should be advertised on the packaging. That way if you decide to try and get your house Energy Star certified one day, you might be one step closer.
3- An energy monitor feature is a nice bonus. This will allow you, at the press of a button, to see how many hours your system was running over the last day, week, and month. It is a great way to get some quick feedback. When you can see that this week your system only ran a couple hours, it makes you feel good and tells you that you're saving money.
4- At a bare minimum use default Energy Star settings on the thermostat. Most of these thermostats will come with a default Energy Star mode. You can start there and then tweak the schedule and temperature settings to increase comfort and/or increase savings.
5- "Home Today" button is a nice feature as is "Away" or "Vacation." The 44860 model I mentioned will allow you to program the length of your vacation which means that you can come back to a cozy house. These features are only as useful as the likelihood of your using them!
6- If you happen to know whether you have multi-stage heating or cooling, make sure you get a thermostat that accommodates. The two I recommended will work with most systems (the 44860 being the most accommodating and most likely to be overkill).
7- If you are really into technology, you can get thermostats that allow you to do things like call from your cell phone to tell your house to warm up or use a portable thermostat that ensures the room you are in is the desired temperature. I have not used any of these products though and you would probably have to order them online.

Here's a thermostat installation video for a super simple system to get you motivated.

Other things to keep in mind:

Your old thermostat may have lots of mercury inside. Handle it with care and dispose of it properly. You should be able to find local disposal options here.

Getting the settings right on your new thermostat might take a couple of tries, so be prepared to set the thermostat and then tweak it. Keep in mind that the closer the settings are to the outside temperature, the more energy you will save.

* Disclaimer: I am neither an electrician nor an HVAC repair person. Please do not take my recommendations as an excuse to electrocute yourself.

Vocab Lesson #3: Carbon

2008-04-26T18:15:00.008-04:00

VisibleEnergy is all about cost-effective ways to live greener. Because of this goal for cost-effectiveness we often frame our recommendations in dollars and cents. In this post, I'll get away from the monetary benefits of greener living to instead touch on a word oft-used but seldom explained in the environmental community, carbon.

The media, politicians and environmentalists throw around terms like "carbon footprint," "CO2 emissions," and "carbon tax" as if we all know what they mean. Fact of the matter is, very few people who use those words even know what they mean.

Carbon is the fourth most common element on earth (behind hydrogen, helium, and oxygen). We are, as you may remember from high school biology, carbon-based life forms. The amount of carbon on earth is pretty much constant. So what's all the fuss about?

Carbon occurs in lots of different forms. When it is acting as the second most abundant part of our human bodies (behind oxygen), we need it. When it is in diamonds, we covet it. When it is in coal or oil, we burn it. When it is the carbon in carbon dioxide (CO2) or the carbon in methane (CH4) that is where the discussion of carbon footprints comes in.

Carbon changes between its various manifestations through a biogeochemical cycle. This means that the chemical element called carbon moves through both the living (bio-) and non-living (geo) parts of earth's ecosystem. There are some "sinks" along the way that hold carbon for a period of time before it returns to the cycle, at which point the sink becomes a "source." A growing tree for example is a sink while it is taking carbon dioxide out of the atmosphere and converting the carbon into tree matter. Once the tree dies or is cut down it becomes a source of carbon. If it naturally decays, some of the decay becomes methane gas for instance. If the tree is burned, some of it becomes carbon dioxide. This is all part of the carbon cycle.

Another sink is fossil fuel. When carbon-based life forms decompose and eventually (over millions of years) turn into oil wells, all of that carbon is stored up in the oil. When the oil is burned, the carbon bonds with oxygen and creates gaseous carbon dioxide. This is where the cycle gets out of balance. It took millions of years to slowly collect the concentrated carbon in the fossil fuels. Burning them releases the carbon much faster than it was created. So, until we can figure out how to push the carbon back into a sink as fast as we source the carbon through burning, the cycle will continue to be out of whack.

This line of thought provides a nice sanity check on our greener living decisions. For instance, this shows us that planting trees should not be viewed as a one-to-one offset for burning fossil fuels because when trees die they ultimately produce just as much carbon as they removed. So what does make sense? Reducing our energy use! Perhaps technology will eventually bring us a carbon sink that allows us to remove or sequester the greenhouse gases as fast as we source them, but until then let's focus on doing what we can to slow down the unbalancing.

Does this make sense? Was it valuable to you? Did I miss anything? Please let me know in the comments. I'll dive into the actual math behind the "pounds of CO2" that make up our carbon footprint in a later post.

The Case for Line-Drying (Sometimes)

2008-04-06T18:25:00.012-04:00

How often do you run your clothes dryer? Do you live somewhere where you could line dry? Line drying costs almost nothing and saves lots of energy. So why aren't we all doing it? In this post I'll quantify the energy and cost savings in an attempt to encourage you to consider line drying, if only on occasion. I'll also provide some helpful effort-saving tips.

the math:
There will be some variety due to characteristics like the size of the load, the wetness of the clothes, and the efficiency of your dryer. No matter how efficient your dryer though, it can't beat the efficiency of line drying.
At VisibleEnergy we are all about learning from actual data (as opposed the advertised data in this case). So, based on actual sample cases in which we dried large loads of laundry after they had been run on a "max extract" cycle in the wash, we found that our test dryer used around 3.5 kwh per load. That's about 35 cents of electricity. If we do two loads of laundry every week for a year, we're consuming 365 kwh ($36.50) annually for drying our clothes. This shakes out to between 1-2% of typical residential energy consumption. You might prefer these metrics:

It takes about 300 pounds of coal to deliver 365 kwh of electricity to your house.
365 kwh is the same amount of energy contained in 10 gallons of gasoline.

the hardware:
If you have some string you can start now. If you want to get fancy, here are some fun tools:

I'm a fan of the retractable clotheslines like the pictured one that they sell at Home Depot.
The picture at the top of this post features another cool retractable line that I use for indoor line drying.
If you want to impress the neighbors, you can go high-tech with something like this (kind of pricey for marginal benefit though in my opinion): http://www.cordoclip.com/
Plastic clothespins will generally stay prettier and last longer than the wooden ones. For indoor line drying I find that the lack of wind negates the need for any clothespins.
Outdoor patio umbrellas can provide a nice frame in which to hang clothes.

some tips:

Occasionally wipe the line with a damp cloth to keep it clean. This will seldom be necessary if you use a retractable line.
Generally hang things upside down to keep any clothespin or line marks in the less noticeable places.
If drying outdoors, hang colors inside-out to avoid sun bleaching.
Shake the items out really well before putting them on the line and then smooth them out with your hands to reduce wrinkles.
If you want faster drying, run your washer on "Maximum Extract" or similar fast-spinning cycle to get them as dry as possible before drying. Yes, this does use a little more energy, but nowhere close to the amount your dryer would take for the same effect. Using "Maximum Extract" is even more important when using the dryer to reduce drying time and energy use.
If clothes are left feeling stiff, pop them in the dryer for just a couple minutes.
If your Home Owners Association or other authority forbids outdoor drying consider using a well-ventilated room in the house and starting a dialogue about changing this policy.
If you don't have space consider an indoor rack.

references:
more tips on line drying
NY Times article on the topic

A Practical Guide to Fighting Phantom Loads (plus Vocab Lesson 2)

2008-03-21T17:21:00.009-04:00

“Phantom loads” (aka Vampire loads) have been getting a lot of press in the green world lately. In this post I'll discuss what they are and whether they are worth your attention. To get straight to the point, for most folks they are not worth much attention. There are some free and painless things we can do though to reduce phantom loads and save a little energy. And every little bit helps right?*

Definition:
A phantom load is the power consumed by appliances that are plugged in but doing nothing useful. I'm talking about the 10-15 W your television uses when it is turned off and the 2-4 W consumed by your cell phone charger when it is not attached to or charging a cell phone. These little loads all add up. The phantom load of a typical American home is between 5-10% of total home consumption. I know that sounds like a lot. So, let's break it down.

Discussion:
Typical American home electricity consumption per month is around 1500 kwh (about $150). If 10% were phantom loads, that would be 150 kwh (or about $15 per month). 150 kwh is the same as 210 Watts of phantom load running 24/7. If you're lost, please review my previous post about kilowatts and kilowatt hours or just skip to the end. Based on measurements around some of our test homes, the largest sources of phantom loads tend to be in entertainment systems and home offices. Other phantom loads are scattered in tiny energy burning pieces around your home.

Solutions:
At VisibleEnergy we're all about the easy steps that make a big difference. So, here are the easiest and most cost -effective phantom load fighting options we've found.

1- Unplug the stuff you never use! In my house I just found a radio plugged in that was using 16 W ($1.15 per month... that's enough for 4 gum balls ;-) ) to sit there. I have not used it in months. This tip generally applies to things that have digital clocks, lights or displays that are always on, remote controls, or AC/DC converters, those little black boxes that plug into the wall (pictured on right). Things like lamps and fans can stay plugged in because they don't have phantom loads.

2- Creatively use those holiday light timers. If you have a large phantom load like a TV, sound system or cable box that you only use during certain hours, put a $3 timer on it (pictured left) that will kill the power to it during the unlikely use part of the day. For instance, we never watch TV between 2AM-7AM nor from 10AM-4PM. If I put my entertainment system on a timer that cuts it off during those hours, I'll save 200 kwh ($20) in a year. Beware, those little timers do use 2 W themselves, so don't use this solution for small phantom loads.

3- Centralize your portable device chargers on one power strip (surge protector) and turn it off when you're not charging anything. Each one of those little AC/DC converters is sucking up 2-4 W when it is doing nothing for you. So, create a charging station. Whenever you plug the cell phone in to be recharged, make sure you flip the surge protector on. When nothing is being charged, flip the surge protector off. 6 chargers on one surge protector could save you another 25 W of phantom load (that's like $1.75 / month... 7 more gum balls!)

4- Plug the seldom used office appliances into a common power strip and only turn it on when needed. If you seldom use your fax machine, scanner, or copier plug it into a power strip and keep the strip turned off. Some of these appliance might use up to 20 W.

5- If you hate convenience, get crazy and unplug the TV. Your entertainment center could be sucking more than 50 W. Warning: If you unplug your Tivo it will not record! If you unplug your TV, the remote control will not turn it on! 50 W costs about $3.60 per month. I'm willing to pay that to avoid inconvenience. At least consider unplugging this stuff (or turning off the power strip) when you go on vacation.

Do not buy a fancy phantom load-fighting surge protector unless you have a really good reason! These things cost about $50, introduce one more remote control into your life and are only slightly more convenient than a regular surge protector.

* Before you tackle phantom loads, please please please heed my CFL advice.

Energy Efficiency Vocabulary Lesson 1: Kilowatts and Kilowatt Hours

2008-03-12T16:08:00.009-04:00

In general at VisibleEnergy we try to explain efficiency concepts in the most relatable terms like dollars, but on occasion it is helpful to talk more specifically about energy usage with the proper vocab. In this first terminology lesson I will cover the language used on your electricity bill, namely kilowatts (kw) and kilowatt hours (kwh).

A kilowatt is a unit of power. This means that it is an instantaneous measure of consumption rate. To be specific, a kilowatt is a thousand watts. A watt is a joule per second. And a joule is a unit of energy. So, kilowatts are a measure of energy used per time. To use a familiar simile, kilowatts are like miles per hour in your car. Kilowatts tell you how fast you are using energy.

Kilowatt hours are a unit of energy (like calories). One kilowatt hour is the amount of energy used when something consumes one kilowatt of power for one hour, or when something uses 2 kilowatts for a half hour, 500 watts for two hours, etc. If kilowatts were shown on your homes “speedometer,” kilowatt hours would appear on the odometer. Kilowatt hours tell you how much total energy you have used, like the odometer shows you how many miles you've traveled.

Most utility companies charge a fixed rate for each kilowatt hour of energy used. On average in America, we pay about 11 cents per kilowatt hour of electricity. So, when you use 1500 kwh in a month, the utility company charges you 1500 x $0.11 = $165. Got it? If not, please tell me in the comments.

What about the non-monetary value of CFLs?

2008-03-01T17:48:00.003-05:00

In response to some great feedback on previous posts, I’d like to address the non-monetary aspect of energy efficiency steps like CFL replacement. There are compelling non-monetary cases for pursuing energy efficiency. Efficiency can be justified by any number of valid reasons like: combating climate change, increasing energy independence, protecting land from mining or drilling, human / plant / animal health, etc. While I believe whole-heartedly in the good intentions of these justifications, I find them difficult to quantify and objectively assess. For that reason I have chosen to evaluate home efficiency improvements in dollars and cents, with the understanding that these dollars and cents will continue to align more and more with positive environmental impact (as energy prices rise, technology advances, carbon markets discourage waste…).

In the case of Compact Fluorescent Light bulbs (CFLs), for instance, one can quantify cost and energy usage pretty easily. Total environmental impact, however, is not so straightforward. One question for which I have yet to find a satisfactory answer is: “How much energy does it take to make and deliver a CFL when compared to an incandescent bulb?” Based on the complexity of the CFL, I’m willing to bet that the fabrication is much more energy intensive. But maybe CFL factories, by virtue of their newness, are more efficient factories. What’s more, how about disposal? We can throw our incandescent bulbs in the garbage. CFLs require special disposal treatment (due to mercury content). This special disposal suggests that further energy must be expended to transport and properly disassemble CFLs… granted, since they last so long this disposal is infrequent.

What’s a consumer to do? To the disposal question, we can take some comfort in the fact that CFL makers include disposal cost in their bulb pricing. To the fabrication and transportation energy questions, CFL makers must account for these costs in the price too. This brings me back to dollars and cents. In my opinion, technology, market and political forces will continue to drive us toward a future in which environmental thinking and smart financial thinking align. If not, we will never see green become mainstream. In this blog I intend to present the areas of technology where the “green” in green living means fiscally responsible AND environmentally friendly energy use.

Which Bulbs to Replace with CFLs

2008-02-26T11:54:00.020-05:00

In the previous post I compared the long term costs of buying and operating a Compact Fluorescent Light bulb (CFL) with the same costs for a traditional incandescent light bulb. I showed that it makes good sense to install CFLs in light fixtures that are on at least 4 hours per day. But what about all of the lights we only turn on for a few minutes or a couple hours every day? In this post I'll present a straight forward recommendation for which incandescent bulbs you should replace with CFLs immediately, which ones you should replace when the existing bulbs burn out, and which ones don't make sense to upgrade at all (from a cost perspective).

In order to make my recommendation table below I modeled the payback period of each light bulb. This means that I computed the amount of time it would take for the electricity bill savings to make up with difference in price between a new CFL, a new incandescent, and operating an existing incandescent. For instance, I discovered that the savings in electricity from replacing a working 100 Watt incandescent bulb that is on for 3 hours every day with an equivalent CFL bulb pays for the cost of the new bulb in 4 months. After that 4 months, the future savings are like money in the bank. Don't worry if this is confusing, the table should make things clear.

To use this table first print it out by click on it to open a large printable version. Print in landscape. Then use it to take an inventory of the incandescent lighting fixtures in your house. If you have, for instance, a lamp with standard 60 W incandescent bulb that is on for 3 hours every day, put a mark in the appropriate box (the intersection of 3 hours and 60 Watt "normal"). Once you've filled out the chart for your whole house follow the color coded recommendations to start saving immediately. Or, if you're not that motivated, just take a look at this chart next time a bulb burns out or you're planning a trip to the hardware store. Keep in mind that 5 minutes per day is the same as 30 hours per year... maybe appropriate for those dining room lights that only come on for holidays.

You can also use this guide to make sure the CFLs you already have are installed in the best places. If you have some CFLs in the red zone, consider moving them to lighting fixtures in the green zone.

To give you an idea of the savings we're talking about, using this table I spent a one-time amount of $75 to buy the bulbs that will save me $16 every month for the next several years (giving me a payback period of less than 5 months).

Some important elements of this model are the cost data and assumptions used. Most importantly, the model is built using the average cost of electricity in the US of $0.08/kwh. For light bulb prices I tried to find the best prices from national hardware stores and online lighting stores. I've included the CFL prices in the table.

My recommendations are based on an observation that lighting technology is advancing fast enough that it may not be prudent to upgrade to CFLs wherever the payback period is longer than 2 years. In some cases in the above table the payback period is more than 200 years!

Are CFLs Worth Their Price?

2008-02-21T12:01:00.010-05:00

Compact Fluorescent Light bulbs (CFLs) are presently being pushed pretty aggressively by energy efficiency organizations, retailers, and even governments. When we go to the hardware store to buy some new light bulbs, though, we find that CFLs often cost 10 times as much as the good old-fashioned incandescent bulbs. In order to see if CFLs are worth their price tag, I compared the total cost of purchase and operation for CFLs and standard incandescent light bulbs over a long period of time. The results show that CFLs will pay for themselves in savings on your electric bill in a matter of months. Keep in mind that the costs shown below are for just one light fixture operated 4 hours per day.

Let’s do a little math. At your local hardware store you can probably find 40, 60, 75, and 100W incandescent bulbs for as little as 25 cents apiece. At the same store, it will likely cost you about $2.50 per comparable CFL. The average life on the incandescent will be about 750 hours, whereas you can expect around 8000 hours out of the CFL. So, when we look at the cost, it only makes sense to do so over a nice long period of time. Otherwise we would neglect the cost of replacing the incandescent several times over the life time of the CFL.

In the graph below I’ve shown the total cost of buying and operating the light bulbs for one light fixture for 8 different scenarios. In this case the light is turned on for 4 hours every day. I intend to delve a little more into this data in a subsequent post, but I hope this plot makes it clear that over a reasonable time horizon (a few months), the CFL will save way more than the purchase cost.

* To get the same amount of light as a 40W incandescent, it only takes 10W for a CFL. For 60W, it takes 13W; for 75W it takes 20W; and for 100W it takes 26W.

To the quality point, there are some CFLs on the market that offer nice, soft lighting. The dimming capability may still need a little work though. The NY Times put together a decent energy efficient bulb comparison table here.

Electricity Metering Today and Tomorrow

2008-02-05T09:42:00.001-05:00

In this world of wireless, web-enabled digital devices there remain a few aspects of our lives that haven't yet caught up with the times. One of these holdouts is our electricity metering. The most common type of meter in the U.S. is called an electromechanical induction or Thomson meter. It was invented in 1888 by Elihu Thomson.

Imagine this: Instead of every house having an electricity meter with a tiny digital display or little dials moving imperceptibly around and around, the utility companies instead put a jar with two zinc plates immersed in zinc sulfate connected across a shunt in each home circuit. Are you with me? I didn't think so.

In my world of zinc plates in a jar, current flowing through the jar causes metal to dissolve off of the positive plate and deposit onto the negative plate. Every month, the power company could weigh each plate and bill customers based on the change. Bills might be tougher to dispute if the evidence of consumption were dependent on something so physically observable rather than some crazy contraption like the Thomson meter. Right?

In reality, the zinc plate scheme was Thomas Edison's. It was used for the first power bills, sent out only 5 years before the invention of the Thomson meter. So, there was the first power bill in 1883, followed by another metering innovation in 1888, then 120 years of very little progress.

In my opinion, the lack of progress is due in part to incentives. The utility companies historically have lacked a compelling incentive to update their metering technology. With energy shortages looming, this may change. But why wait? We, as consumers, can embrace technology and monitor our own consumption more effectively today... or least in the very near future. That's what we're working on every day at VisibleEnergy -- giving consumers real-time feedback on their energy consumption so that they can live more sustainable and informed lives.

Energy Reduction as a Coal Power Alternative

2008-02-01T09:20:00.000-05:00

Recently several coal power generation stories have been in the headlines. Some have discussed the slew of advertisements we've seen, particularly during the Presidential debates, about "Clean Coal." More recently there has been lots of coverage in the cleantech and energy worlds about the DOE's pulling the plug on a project called FutureGen. Here in North Carolina, final approval has been granted for Duke Energy to construct an 800 megawatt coal plant called Cliffside.

There are plenty of more informed and opinionated folks talking about the need for or alleged evils of coal power. I would like to avoid that fight and make a different point.

The 800 MW of electricity generated by Cliffside will shake out to around 4 Million megawatt hours of energy over the course of a year. It takes about 10 megawatt hours of electrical energy to power the average home in America for one year. So, 4,000,000/10 tells us that Cliffside will power about 400,000 average American homes... fewer homes in North Carolina though since we consume more energy than average. Using the real numbers, Cliffside will generate about 7% of the residential demand of North Carolina.

You know what else could accommodate 7% of our residential demand? Energy efficiency! If North Carolinians discover how easy it is to shave 7% off of their energy use, we can eliminate the need for the next Cliffside altogether. Everybody wins. Duke Energy doesn't have to fight the environmentalists to stay alive, nor do they have to increase our rates to pay for new construction. Rate payers get smaller bills and an opportunity to make a difference.

If we run the numbers on FutureGen and replace the $1B of DOE money invested with $1B of installed programmable thermostats, we find that energy efficiency (in the form of programmable thermostats) could make up for 24 times as much energy as FutureGen would have generated. Here are the numbers:

FutureGen was planned to generate 275 MW or 1.4M megawatt hours
$1B buys 33M thermostats at $30 each
33M homes x 10 MWh x 10% energy reduction = 33M megawatt hours
33 / 1.4 = 24

I understand that distributing, programming and installing that many thermostats might be a crazy proposition. It's a fun thought experiment though.

State of the Union & Energy

2008-01-29T11:17:00.001-05:00

In case you missed it, here's what President Bush had to say last night about Energy in his State of the Union Address:

"To build a future of energy security, we must trust in the creative genius of American researchers and entrepreneurs and empower them to pioneer a new generation of clean energy technology.
Our security, our prosperity and our environment all require reducing our dependence on oil consumption over the next decade… Together, we should take the next steps. Let us fund new technologies that can generate coal power while capturing carbon emissions.
Let us increase the use of renewable power and emissions- free nuclear power.
Let us continue investing in advanced battery technology and renewable fuels to power the cars and trucks of the future.
Let us create a new international clean technology fund which will help developing nations like India and China make greater use of clean energy sources.
And let us complete an international agreement that has the potential to slow, stop, and eventually reverse the growth of greenhouse gases.
…The United States is committed to strengthening our energy security and confronting global climate change, and the best way to meet these goals is for America to continue leading the way toward the development of cleaner and more energy-efficient technology.
To keep America competitive into the future, we must trust in the skill of our scientists and engineers and empower them to pursue the breakthroughs of tomorrow.
Last year, Congress passed legislation supporting the American Competitiveness Initiative, but never followed through with the funding. This funding is essential to keeping our scientific edge.
So I ask Congress to double federal support for critical basic research in the physical sciences and ensure America remains the most dynamic nation on earth."

I post this only as a reference point of where we stand with respect to our energy attitude as a nation. I am not particularly concerned with legislation pertaining to investments in cleantech. The good capitalist in me believes that the best ideas (those ideas that are both environmentally and financially sustainable) will prosper one way or the other... as long as legislation isn't overtly in the way of progress.

What I find interesting in the President's remarks are what I see to be a common misconception of where we should focus our attention. In the above, there is one passing remark about energy efficiency. In my opinion, we have the technology today to make great progress on the energy reduction and independence front. The question is one of deployment.

If the President instead challenged Americans to replace some light bulbs with CFLs or turn down their thermostats a couple of degrees, today would be a more energy independent day than yesterday.

newsobserver.com | For Duke Energy CEO, forum is tech fest

2008-01-25T18:04:00.000-05:00

The News and Observer (a Raleigh-Durham newspaper) posted a story that alludes to the importance of smart power networks in the future. Apparently Jim Rogers (CEO of Duke Energy) has talked to Google about smart network opportunities.
newsobserver.com | For Duke Energy CEO, forum is tech fest

Fresh from the Pan: The Startling Effect of Feedback

2008-01-24T12:28:00.000-05:00

Fresh from the Pan: The Startling Effect of Feedback
This is a great anecdotal post on the effect of real-time monitoring for some folks in the UK.