Please Note: This project is not currently active. The content on this site is provided for reference and is not actively maintained.

Posts Tagged ‘energy’

What Are Ecosystem Services?

by March 26, 2012

If you would like to see a high-quality infographic developed for this question, please share it with your network using the sharing icons above—these actions will increase the question’s priority. Please look at the example answers here. Also, if you would value a high-quality answer being available on the Web, please consider a small donation ($0.99) to support our research team.

More »

Why Does Sea Level Rise When the Planet Warms?

by March 26, 2012

If you would like to see a high-quality infographic developed for this question, please share it with your network using the sharing icons above—these actions will increase the question’s priority. Please look at the example answers here. Also, if you would value a high-quality answer being available on the Web, please consider a small donation ($0.99) to support our research team.

More »

What Is Ocean Acidification?

by March 26, 2012

ANSWER (CURRENTLY UNDER REVIEW): A gradual yet steady change of ocean chemistry marked by a decrease in pH that is caused by increasing concentrations of carbon dioxide in the atmosphere. This answer is focused on changes to the ocean over recent decades. In addition to the infographic below, check out several videos on our YouTube channel that we produced through a video contest.
Q001 what is ocean acidification v0289

More »

How Do Greenhouse Gases Trap Heat in the Atmosphere?

by February 26, 2012

If you would like to see a high-quality infographic developed for this question, please share it with your network using the sharing icons above—these actions will increase the question’s priority. Please look at the example answers here. Also, if you would value a high-quality answer being available on the Web, please consider a small donation ($0.99) to support our research team.

More »

From Toilet to Treatment to Treatment to Tap in San Diego

by February 10, 2012

dog-drinking-from-toilet_sm2 My first reaction to hearing at the breakfast table about today’s piece in the NY Times about water reuse in San Diego was that it isn’t all that different from what we have been doing for years: discharging treated waste water into streams and rivers and then drawing out drinking water downstream, counting on bacterial decomposition, dilution, and other processes to treat further the discharged water. I was pleased to see that this point was discussed in the article.

Drinking water that recently was flushed down a neighbor’s drain is a tough concept, pardon the pun, to swallow. However, as the piece in the Times correctly points out, we are headed into times in which resources like water are likely to be scarcer. To my mind, this community is a shining example of people—who rightly had very strong feelings on an issue—being willing to accept what the science community had to offer. Jerry Sanders, the mayor of this San Diego community, put it this way: “If science is behind you and you can prove that, I think people are willing to listen.” Here, here!

Image in post from Climate Watch. Thumbnail image on home page from the NY Times article.

More »

Tracking the Mood About Gas Prices on Twitter: A Case Study

by January 25, 2012

As another test of our strategy for teasing out public opinion from social media, we explored measuring mood about gas prices on Twitter. This post summarizes the findings from this case study. Incidentally, we are set up to measure mood from Twitter on an ongoing basis, although we would need to find a partner to help defray the ongoing costs of crowdsourcing the sentiment judgments. (See this post to read more about our decision to examine the discussion about gas prices on Twitter.)

The sentiment we mapped was culled from tweets gathered from four weeks’ worth of data starting on May 22nd, 2011. This time period was chosen to coincide with Memorial Day, a holiday during which many Americans travel by car. Our team was curious to see whether there would be an uptick in either the volume of tweets about gas prices during this period or a noticeable change in sentiment about these prices. (more…)

More »

A Billion Dollars Flowing Down the Mississippi Annually

by December 20, 2011

In a recent post, I did a bit of research to update the picture of nutrient flows down the Mississippi due to runoff and other sources in its watershed. There’s been an ongoing debate about the source of the nutrients in the river that are directly linked to low-oxygen conditions in the Gulf of Mexico.

For a taste of the debate, check out the controversy a year ago surrounding the premier of Troubled Waters, A Mississippi River Story (link to view on Twin Cities Public TV). Among other activity, there was a heated back-and-forth on the opinion pages of the Minneapolis Star Tribune (first piece arguing that research for film was dubious, counter piece by producers about the research behind the film). The flare up nearly squelched the premier, although it ultimately took place.

Personally, I experienced how difficult it can be to establish a “consensus view” of how to describe nitrogen flows for the report on ecosystem indicators described in my previous post. There was a constant tension throughout the report process to “tell readers what to do with the information” rather than just “giving them the facts.” I believe we ultimately struck a good balance, however, we nearly had resignations of participants when we unintentionally pushed the line on the indicator dealing with the movement of nitrogen and got too close to pointing fingers. (more…)

More »

Bringing the Global Carbon Cycle to Quora

by December 3, 2011

In a recent post about building a knowledge base for general consumption on the topic of ocean acidification, I suggested that it would be wise to step back and address questions-and-answers about the carbon cycle. This is a cross-posting of a post I just put up on Quora: The Carbon Cycle, Starting in.

And, the first question is also up on Quora: What are the compartments in which carbon is stored on Earth? Do you have the credentials to answer this, or do you know someone who does? Please help out—I believe it will be a rewarding way to bridge the gap between the science community and the rest of society. Also, keep in mind that “upvoting,” adding comments for the author, or suggesting edits,  as soon as there is one or more answers will be a really great way to participate.

For anyone new to Quora, I’d encourage you to take a look at a new infographic and video that helps explain how to have a winning strategy within the Quora community.

Any and all feedback is welcome!

carbon-cycle-01_lower_res More »

Making Decisions About Purchasing Alternative Vehicles

by November 28, 2011

In a recent post, I discussed Why Hybrid Cars Are Tough To Justify On Fuel Savings Alone and how Gallons per Mile (GPM) would be a better metric than Miles per Gallon (MPG) to use to compare vehicles. The gist of it is that we save a lot more fuel replacing a 15 MPG vehicle with one that gets 20 MPG compared to replacing a 30 MPG vehicle with one that gets 35 MPG. The GPM metric makes this intuitively obvious, whereas MPG does not.

A few weeks back when I dipped my cup into the Twitter river, which I need to do more often, I happened upon a press release from the U of Minnesota Extension having to do with a new spreadsheet tool designed by energy economist Doug Tiffany to help those considering an alternative vehicle purchase.

Tiffany’s tool allows the user to customize the data input, adjusting things like purchase price, down payments, expected cost of fuel, one’s personal opportunity cost (the cost to me for tying up cash for down payment and monthly car payments). The tool then produces several graphs, the first of which is a 15-year cumulative cost projection comparing several vehicle types. For the graph below, I used the default values in the tool, which can be downloaded here.


So, what this means, is that for the input parameters, the 15-year cumulative cost of ownership of the extended range vehicle, such as a Chevy Volt, comes out the highest, whereas the electric vehicle, like the Nissan Leaf, comes in with the lowest cost. The following graph shows the breakdown between car types at year 15.


Cost may not be the only motivator, however, at a time when many are concerned about greenhouse gas (GHG) emissions. Thus, it may be important for many to compare the estimated emissions of greenhouse gases from the different vehicle types. Tiffany’s tool produces this graph based on various inputs.


As would be expected, the conventional gasoline-powered vehicle has the highest emissions. There’s not as much difference between the other types, with the hybrid having somewhat higher GHG emissions than the all-electric, both of which do somewhat better than the extended range electric.

Tiffany’s tool reminded me of a widget available from my colleagues over at Climate Central, which is embedded below. It allows you to get a good sense of potential fuel and GHG emission savings between two different vehicles. It dynamically updates fuel costs for your state, which is a nice feature.

Together, these tools provide a great resource to anyone considering an alternative car purchase. Perhaps these groups could team up to create a tool that blends together both annual costs / savings and economics over the vehicle’s lifetime.

More »

The Role of Storage with Variable Energy Sources Like Wind and Solar

by November 8, 2011

In a recent post, I asked What’s Going To Happen To Your Vehicle’s Lithium Battery At the End Of Its Life? One of the options discussed in the NY Times article about the fate of batteries that sparked my post was as a means for storing electricity generated by wind turbines. A couple of other recent articles about energy storage caught my eye—both related to wind energy.

Why might storage play a key role in a grid that has a lot of wind turbines?

In early October, Mark Ahlstrom, the CEO of WindLogics, gave an excellent presentation as part of Frontiers in the Environment series at the U of MN’s Institute on the Environment (view the video here). He explained how our variable demand for electricity over the course of a typical day is met by a range of generation sources, from base load to “peakers.” Base load is met by nuclear, coal, and hyrdo—depending on location. Base load plants are meant to run 24/7, and adjustments to their output need to be scheduled well in advance. On the other end of the spectrum are peakers, which are small electrical generators that can be turned on with little notice and do not need to run for a minimum period of, say, a day. The figure below is based on a slide from Ahlstrom’s slides.


Ahlstrom went on to explain how things get interesting when a substantial amount of wind generators are added to the mix. In the figure below, the bright green line represents the reduced daily load that results by adding a number of wind turbines to this hypothetical typical energy demand. He goes on to explain how the rest of the electricity generators need to adapt to this new load curve, which can have more spikes and other challenges, such as a faster ramp-up in the early morning hours—challenges that the current energy system wasn’t set up to tackle.


Here’s a good piece by the ClimateWire group that landed in the NY Times: Fickle Winds, Intermittent Sunshine Start to Stress U.S. Power System. It dives into detail about the policy challenges that blending intermittent energy sources with our traditional electrical generation system.

Back to storage. A recent piece in the NY Times described how Batteries at a Wind Farm Help Control Output. In the largest battery installation connected to the grid in the U.S., they’ll use over a million batteries to provide storage for a few minutes of generated electricity from a large wind farm in West Virginia. The idea is that this stored electricity can be fed into the grid to help smooth things out when output from the wind turbines drops off momentarily. It is not designed to even out longer periods when the wind is calm. Significant storage on the time scale of hours and possibly days would most likely require a solution such as pumping water uphill or compressing air when the wind blows, and then using this stored energy to run a generator when the wind is quiet (here’s a project underway to study pumped hydro in conjunction with wind farms in northern Minnesota). There may also be options to store electricity in electric vehicles integrated with a smart grid of the future.

Finally, another NY Times piece that gave me some pause had to do using water heaters and electrical space heaters to store excess electricity brought about in part from excessive winds in the Pacific Northwest. The idea is that automated, shorter-term storage of excess electricity in homes that already have electric hot water heaters and heat with electricity could bleed off excess electricity pouring into the grid during storms when wind generators are running at maximum output (note that the situation was further complicated because hydropower operators were unable to reduce output from their generators for fear of creating conditions that might kill fish).

At a gut level, this strikes me as a good way to avert disaster, but probably not a great strategy from an energy efficiency standpoint. My sense is that using electricity for water heating and space heating is not nearly as efficient as, say, natural gas. The standard reason for arguing this point is that the efficiency of traditional energy plants is much less than 50%, whereas a high-efficiency hot water tank can exceed 90%. However, maybe this standard reasoning needs to be updated in a situation where electricity comes from wind or solar. This is a topic that merits further consideration.

More »

MinutePhysics: Short Videos Demystify Physics

by October 25, 2011

If you haven’t seen the videos produced by Henry at MinutePhysics, they are definitely worth a look. Here’s his latest, tackling two very different questions: Why does light speed up after leaving glass or water? What does this have to do with the President of the US?

Incidentally, Henry placed second in our energy video contest, with his “Uncle Sam’s Dinner” video, where the guy playing Uncle Sam literally eats his way through the U.S. energy diet to demonstrate our various sources of energy.

More »

Putting Candidates and Others on the Spot About Global Warming

by September 29, 2011

This opinion piece, written in response to a recent Star Tribune op-ed, was published on Yale’s Forum for Climate Change and the Media on September 29, 2011.

The presence, or perhaps more so the absence, of serious climate change dialogue in the run-up to the presidential elections could make the issue a volatile unknown: Few politicians in the national spotlight want to be caught holding strong opinions in favor of aggressive policies to slow, curb, or reverse anticipated climate change.

James Lenfestey, a former Star Tribune editorial writer on climate and education, recently argued in Minneapolis Star Tribune (op-ed 9/17) that journalists should drill presidential candidates on six questions related to climate change, presumably to highlight those who are silent, or openly hostile, toward taking action in the face of this global threat.


The media clearly can do a better job in raising serious issues like global warming with those leading, or aspiring to lead, our country. BUT putting candidates on the spot is unlikely to yield what our country desperately needs: a serious, ongoing dialogue about this global issue, which has connections to nearly every aspect of our society. Such a dialogue MUST be built on a foundation of trust and respect for political and ideological differences, as well as different scientific backgrounds.

Lenfestey’s six questions can be boiled down to these two: Do you believe global warming is occurring? And, do you believe we should have aggressive policies to counter this threat?

Lumping together opinions about how persuaded one is by the underlying science with questions about the appropriateness of a policy response is a recipe for an unproductive dialogue. Having spent a number of years working with experts drawn from across society to describe the condition and use of our ecosystems, I learned that it is essential to separate these aspects of the conversation—especially for the more contentious issues. In other words, we collectively need to find some common ground before arguing about appropriate policy responses.

We need to build an initiative that is viewed as trustworthy to all of us, no matter our ideological and political positions, or our understanding of science. WE can do that. We can run a transparent process—open to full scrutiny and input from anyone—that develops a series of questions and broadly accepted answers relevant to the issue of climate change. Not 100 questions, but rather more like 10. Each answer would be endorsed by experts drawn from across society and viewed as trustworthy by citizens and politicians from across the spectrum, both politically and ideologically.

As an example, these answers would undoubtedly include:

  • Carbon dioxide, a colorless gas present in tiny concentrations in the atmosphere, can trap radiation from the Earth that would otherwise dissipate into space.
  • There is strong evidence of a marked increase in carbon dioxide directly linked with the growth of industrialized societies across the globe.
  • Our “fingerprints” are detectable in the altered chemical nature of atmospheric carbon dioxide.
  • Long-term temperature trends indicate significant increases in recent decades.

These would be the first building blocks to a serious national dialogue.

Let’s take on this challenge. Let’s develop a robust, multimedia Web presence that brings to life the science behind the questions-and-answers for general audiences. Ideally, this effort would have its foundation on a public Q&A site, like Quora (

Circling back to Lenfestey’s questions, let’s ask each candidate if he or she would support such an open, transparent process to create robust common ground across society. Global warming, which has the potential to irreversibly alter our world, demands a serious dialogue, and now is the time for to initiate it. Time is short, and there is a lot to do. Let’s make it happen.

Kent Cavender-Bares is an environmental scientist and the founder of Dialogue Earth, a nonprofit media project that has received major seed funding from the University of Minnesota’s Institute on the Environment and the Foundation for Environmental Research. The views represented are his alone and do not represent those of the University of Minnesota.

More »

What’s Going To Happen To Your Vehicle’s Lithium Battery At the End Of Its Life?

by September 12, 2011

Energy consumed in transportation has been the focus of a number of recent posts here, including one contemplating the use of smiley faces to help drivers understand the impact of their behavioral choices, and one exploring why the cost-benefit balance is tipped against the purchase of a hybrid car based on fuel savings alone. Another big issue to consider with either a hybrid or an all-electric vehicle is the battery, which necessarily needs to pack a lot of charge, both by being large and, increasingly, by using metals like lithium.


How a lithium-ion battery works: This illustration shows the inner workings of a lithium-ion battery. When delivering energy to a device, the lithium ion moves from the anode to the cathode. The ion moves in reverse when recharging. Compared to other rechargeable batteries, lithium-ion batteries can store more energy in smaller, lighter packages. This unsurpassed energy-to-weight ratio make them the battery of choice for consumer electronics like cell phones and laptops, but also a great fit for electrified vehicles. Illustration and text courtesy Argonne National Laboratory and was accessed on Flickr.

A recent post about the prevalence of rare earth metals highlighted how much there is to know about the components used to make current vehicles based on new technologies, like hybrid drive trains. Massive supplies of elements like lithium are going to be key to permit scale-up of hybrid and all-electric vehicles requiring lithium batteries. Supply can come from mining operations, as well as recycling. An article a few days ago in the NY Times Business section highlighted the reality that there is no consensus on how electric car batteries should be recycled or reused. (more…)

More »

World Food Production: Don’t Delude Yourself; Population Will Grow

by August 31, 2011

The following letter-to-the-Editor, a follow-up to my post about global population growth that is essentially a foregone conclusion, appeared in the Aug. 31, 2011 issue of the Minneapolis St. Paul Star Tribune:

In response to Prof. Allen Levine’s commentary about world hunger (“It’s world hunger (and it’s our world,)” Aug. 21), one letter writer and several readers who commented online argue for population control as an essential part of the equation.

In reality, fertility rates have dropped markedly over past decades. Demographers understand that, even at today’s relatively low rates, today’s children will have children of their own faster than older generations will die off.

An aggressive program to lower fertility rates will not alter that reality.

For those concerned about feeding, clothing and fueling the world’s population, accepting that we will have another 3 billion residents on the planet by 2050 is essential.

More »

In Terms of Indoor Air Conditioning, How Cool is Too Cool?

by August 30, 2011

An article in Sunday’s New York Times by Elisabeth Rosenthal (Oh, to Be Warm in Summer’s Heat) reinforced the notion that some not-so-painful behavioral changes might lead to significant energy (and cost) savings. Yet, we may not be empowered with good information to help us connect the dots. Rosenthal zeros in on our exuberance to crank up the air conditioning in stores and other public spaces like airports. It does seem rather silly that we often need to grab a sweatshirt before heading out, knowing that we’re libel to run into chilly indoor environments.

I’m reminded of an NPR story from yesterday (Summer Sounds: Air Conditioning). It is a story by Teller (of the stage duo Penn & Teller) recounting his solution to the noisy air conditioning unit in his room. His parents had bestowed the unit to him because they knew that his upstairs room would be hotter than their downstairs bedroom. Even though his parents’ sleep was fitful, he solved the on-and-off noise of the A/C unit by turning on the “constant cool” feature, meaning that his room turned into the Arctic, and he needed to bundle up like on a winter’s night…

Back to Rosenthal’s story. She highlights an experience many have no doubt had: the rush of cool air that pours out the open front doors of many retailers. I often joke that they’re fighting a losing battle if their goal is to cool off outside. Of course, their goal is to lure us into the cool indoors, where we’ll want to stay and buy their merchandise.

I wonder if retailers have the information they need to weigh the benefit (extra business) against the cost (inefficient cooling system). Maybe they’d get a boost in consumer traffic if they kept the doors closed and used a marketing campaign advertising their responsible energy plan. Perhaps they could add some low-energy cooling fans near doorways to give pedestrians a sample of the coolness that awaits just inside the (closed) doors. This is clearly a ripe issue for attention, as a quick online search reveals considerable space devoted to this “open door policy” of retailers (here’s a Washington Post article about how the energy-conscious are upset by open doors, and another NY Times post about an informal survey of open doors after NY City banned the policy, albeit with plenty of loop holes for cool air to pour through!).

As discussed in a previous post, we do not do very well estimating the relative energy use of different appliances, such as window versus central A/C units. Similarly, we do not do a good job at predicting the energy savings from various behavioral changes, like adjusting our home thermostat to make it a bit cooler during the winter and a bit warmer during the summer. This blurb and accompanying graph of the typical energy usage in a home from the Energy Star website sums up why we should all pay attention in this time of ever-increasing energy costs:

As much as half of the energy used in your home goes to heating and cooling. So making smart decisions about your home’s heating, ventilating, and air conditioning (HVAC) system can have a big effect on your utility bills – and your comfort.


A final note has to do with a statistic that Rosenthal cited in her article:

Many energy experts recommend setting thermostats at 78 degrees in summer, to conserve energy and to combat rising greenhouse gas emissions. The exact energy savings depends on numerous factors, including the type of air-conditioning and the temperature outside. But turning up the programmable thermostat of a central air-conditioning system 1 degree can yield a 6 percent savings in energy used for cooling, according to the United States Energy Star program.

We’ll need to get to the bottom of the potential savings, which undoubtedly vary regionally and across different types of home construction. The 6-percent-savings is higher than I’ve seen elsewhere, and it seems like a lot for adjusting the thermostat by only a single degree.

More »

GPM Sheds Light On Why Hybrid Cars Are Tough To Justify On Fuel Savings Alone

by August 23, 2011

Hybrid car parking only

Photo credit, Chris Bloke on Flickr

Have you ever considered buying a hybrid car and gone through the calculations to compare the fuel cost savings to the higher price over comparable non-hybrid models? Chances are good that the math is not on the side of purchasing a hybrid, as pointed out in this USA Today opinion piece questioning the recently-announced, aggressive fuel efficiency standards. Most likely, it is our choice of metrics for evaluating fuel efficiency that help to make such calculations turn out to be less intuitive than we might expect, as discussed in this previous post on fuel economy metrics.

Hybrid cars are those that combine a large battery with an engine that generally runs on gasoline, although diesel hybrids are possible. In city driving with lots of starts and stops, the energy normally lost through braking is used to incrementally charge the battery—through a technology known as regenerative braking. If you’re looking for a 2-minute diversion, check out this video below featuring Maxwell von Stein, whose video was featured on Science Friday last week. He created a bike that uses a flywheel to store energy from braking to provide a boost literally down-the-road. He sees this as a great test case for creating a new type of hybrid car…

Because we need to brake less on highways, hybrids lose much of their advantage during highway driving. You can check out the EPA city/highway ratings for hybrids and compare them to non-hybrids side-by-side at

Following up on the previous post on MPG v. GPM (that is, miles per gallon v. gallons per mile), here are some quick calculations showing the fuel savings for two models from Toyota (Camry) and Ford (Fusion) that are available as hybrids. As in the previous post, the orange bar shows the fuel savings in gallons for 5000 miles of city driving.


The Fusion Hybrid driver could anticipate saving about $1000 on fuel over three years if she/he drove 5000 city miles, and the Camry Hybrid driver could expect about $700 in savings for three years of 5000 city miles—these calculations assume a gas price of $3.50 per gallon.

Grabbing some rough prices from Motor Trend’s site, it would cost about $6800 more for a Fusion Hybrid and about $4400 for a Camry Hybrid (these comparisons are very rough and are based on models that are one step up from the base offering for the non-hybrids; they also do not include any applicable rebates, deals, etc.).

Baring any government subsidy to help offset the purchase price, we immediately see the quandary facing a potential purchaser of a hybrid car: it is very tough to imagine recovering the extra purchase price through fuel cost savings. Plus, as mentioned above, if the hybrid was to be used for a good bit of highway driving, the potential fuel savings would diminish considerably.

I argued in the aforementioned post that GPM is a better way to get an intuitive feel for fuel savings. Interestingly the site offers vehicle stats in GPM rather than MPG. I have to wonder if many people click on that option. Here are the side-by-side comparisons of the hybrid and non-hybrid Fusion and Camry models. First, using MPG as the comparison point, then with gallons per hundred miles (GPM). The cost savings tables at the bottom provide the same type of thought experiment as described above, though it is a bit more complex blending highway and city mileage.

fueleconomy_gov_mpg fueleconomy_gov_gpm

It would be a little like getting a nation to think metric, but one gets a sense that the second comparison provides information that is more instructive about cost savings from fuel usage.

More »

How Would Smiley Faces Change My Driving Behavior?

by August 12, 2011

xcelenergyreport1 Having just spent a bunch of time working on a pre-proposal for the National Science Foundation, I’m excited about an idea to create more feedback for drivers about their energy use. This project concept is motivated by recent research that many of us have a tough time judging the relative energy savings from a variety of behavior changes.

For example, the researchers found that many Americans estimate that a central air conditioning system uses about the same amount of energy as a window unit, when in fact a window unit typically uses several times less energy (link to abstract of article by Shahzeen Z. Attari and colleagues in the Proceedings of the National Academy of Sciences here).

Perhaps you are an Xcel Energy customer, or you’re with another utility that is taking advantage of OPOWER’s innovative approach to giving feedback to utility customers. As a residential customer of Xcel’s, we receive a monthly statement showing our use of energy compared to similarly-sized homes in our neighborhood. Thus, we receive a chart with our use of electricity and natural gas over the past 12 months, comparing our usage to that of our “efficient neighbors” and “all neighbors.” Here is our household usage over the past year from Xcel’s Energy Report website, which provides all of the data digitally after registering. (more…)

More »

Do Electric Cars and Nuclear Power Really Have Zero Carbon Emissions?

by August 8, 2011

The Nissan Leaf

Photo credit, Tom Raftery on Flickr

A piece about incentives to promote electric cars in Europe published in the Star Tribune a few days caught my eye. The author, who actually wrote the piece for the New York Times, discusses how the size of incentives are linked with reductions in carbon emissions and stated “Logically, electric cars with zero carbon emissions qualify for the largest incentives.”

Unless the electric vehicle (EV) was manufactured in world that uses no carbon-based fuels and the electricity that charges the EV’s batteries is devoid of carbon emissions, then this is not possible.

My guess is that the author confused direct and indirect emissions from EVs. Yes, there are no carbon emissions from EVs directly. However, electricity is needed to charge an EV’s battery, and even wind and solar have small carbon emissions. Electric vehicles also need to be manufactured and maintained, both of which will contribute to lifecycle emissions of carbon. Here’s one recent study that digs into the the energy use, cost, and carbon dioxide emissions of electric cars.

The statement about EVs reminded me of similar statements I’ve heard recently on the radio about nuclear energy. True, the plume that is characteristic of a nuclear plant’s cooling towers is water vapor. Yet, there are considerable lifecycle emissions of carbon connected to facility construction, uranium mining and processing, and waste disposal. Here’s a recent paper that evaluates the lifecycle emissions associated with nuclear energy, including estimates of how nuclear compares to other energy sources—on average about twice that of solar photovoltaic (PV) and about seven times less than natural gas.

More »

Using Miles Per Gallon Ratings To Reduce A Nation’s Oil Consumption Is An Indirect Approach

by August 2, 2011


AP Video Coverage of President Obama's Announcement

The new agreement between President Obama and automakers, nearly doubling fuel efficiency for automobiles by 2025, will have a direct impact on oil consumption by the U.S. automobile fleet. Yet, if this aggressive goal is fueled by a desire to maximize reductions in oil consumption, then it would be more useful to measure our performance with a direct indicator of oil consumption: gallons per mile (GPM), the inverse of our standard metric, miles per gallon (MPG). (more…)

More »

Which Energy Questions To Answer?

by July 28, 2011

2540266946_df7114d8fa The memory of our frustration during our last car purchase, more than 10 years ago, is still strong. Fuel economy was central to our decision, and we ended up opting for a turbo diesel Volkswagon. Soon after our purchase, I certainly engaged in some second guessing. This was the older generation turbo diesel, which means the dirtier version. We were in Washington, D.C., so we had to carry with us the reality that we were contributing to lowering the air quality. A more nuanced issue—and one that I’ve not fully researched—is that fuel mileage for a diesel is not directly comparable to that of a gasoline powered car, especially if one is interested in their transportation carbon foot print. I’d forgotten about this for a while, but it is very relevant now that we at Dialogue Earth are working on a project proposal to supply information to support consumer decisions that are connected to energy use.

Over the coming weeks and months, we’ll be exploring how people get their information about energy use when they’re pondering a purchase, be it a new car or a clothes dryer. Is there the proverbial “low hanging fruit” in terms of information that would be relatively easy to provide, but is not readily accessible currently? No doubt consumers will span the spectrum from knowing very little about energy to having a deep knowledge. What do consumers with different energy knowledge want to know?

Have you thought about your personal energy use recently? Did you seek out new information? If so, was it easy to find? What sources did you tap? If not, why?

More »