Allen Schaeffer is the executive director of the Diesel Technology Forum. We spoke about the benefits, and surprising attributes, of clean diesel, and the role it has to play in dealing with climate change.
Treehugger: Tell us about the Diesel Technology Forum (DTF).
Allen Schaeffer: Thank you for taking the time to talk to me today. We are a not-for-profit that represents fuel refiners and companies. We define clean diesel as cleaner engines and the pieces of engines that make it clean, like turbochargers and other things within the engine. We also think about cleaner fuels--ultra low sulfur diesel as well as renewable diesels fuels. And lastly, there is the emissions control technology, the stuff that reduces emissions out of the tailpipe. Our membership happens to mirror those three components (engines, fuels and emissions controls); these include Chevron, BP, GM, VW, Caterpillar, Jon Deere, Bosch, Cummins, Delphi, to name just a few. So we've got, not the entire diesel industry, but we have the leading players.Our mission is to help people understand the value, and the progress potential, of diesel, and beyond that, we're also working with stakeholders to address issues that are important relative to diesel. For example, how do we deal with legacy products (older, higher emitting equipment)? We work with groups like the Clean Air Task Force and the NRDC (Natural Resources Defense Council), and we are part of a coalition with Environmental Defense for cleaning up school buses. So we're not just talking about clean diesel, we're also trying to walk the walk by working with stakeholders to identify and solve some of the issues that people are concerned about. One of our biggest questions is, how do you take an older diesel engine and make it run cleaner? Those are the kinds of things we work on.
TH: Walk us through some of the history of diesel, and what you see as its benefits.
AS: I am reminded that there are some parallels here between the bicycle industry and the diesel industry. The bicycle industry sprang up in the late 1800s, and Rudolph Diesel patented the diesel engine around the same time. Both were very primitive technologies, but were very insightful as well. The diesel was insightful because the engine had a 75% thermal efficiency, which is unheard of today. From a pure design perspective it was phenomenal, and the idea that people could pedal themselves around with the bike was also insightful. Of course, the first diesels were very dirty, and the first bicycles were heavy and unwieldy. But look at where these 100-year-old technologies are today — ultra light racing bikes with 20 gears, or a diesel engine that is 40 percent more energy efficient than a gasoline engine. It shows a lot of evolution that has taken place over the last 100 years in each case, a lot of iterative improvements. Certainly cycling has gone to some impressive technology, and diesel is like that as well.
And even though it's an old technology, diesel has stuck around because it has provided some unique value. The unique value is its scalability, efficiency and durability. You can get a diesel engine in a 10 hp small lawn and garden machine, on up to 10,000 hp diesel engines in huge container ships, but it's the same principle. The largest gasoline engines, the larger you make them, the more energy you lose. That's why over 90% of trucks on the road are diesel powered. That revolution took place in the late 60's; diesels won out over gasoline because of their efficiency. Diesels are also renowned for their durability because they have fewer moving parts. However, the durability can also be a problem because the new diesels are more powerful, cleaner, punchier, and less noisy. Yet we still see a lot of dirtier diesels still on the road [due in part to their durability]
That's the diesel story: it's the most efficient internal combustion engine. The largest diesel engines today are big enough to fill a conference room, but that engine is close to 50% thermally efficient, whereas a gasoline engine is half of that. Most familiar is that diesel is different from gasoline because diesels have no spark plugs. The combination of air and fuel and pressure creates the combustion process. That diesel cycle is unchanged. The 20-40% efficiency advantage of the diesel over gasoline comes from two things: 1) Diesel fuel, on a gallon-per-gallon basis, has about 10-12% more BTU's than a gallon of gasoline. Generally speaking, the fuel starts out with more carbon hydrogen bonds and more potential energy in it than gasoline. 2) The diesel engine converts more of the chemical energy in the fuel into mechanical energy, wasting less on heat loss, friction and other things.
TH: Obviously, one of the key advancements for clean diesel has been the promulgation of ultra low sulfur diesel fuel. Can you speak to the availability of clean diesel fuel?
AS: In the U.S., right now we are really in a unique position because we have the cleanest diesel in the world, but in the next few years the EU and Japan are phasing in the ultra low sulfur diesel fuel as well. So the US is a leader in this fuel policy. The ultra low sulfur fuel hit the streets in October of '06 and EPA required that at least 80% of highway diesel fuel be ultra low sulfur (defined as less than 15 parts per million), and by December 31st, 2010, 100% must be ULSD. This was a regulation that was passed in 2000, so it was 7 years before it was fully implemented. Today, over 90% of all the highway diesel fuel is ULSD, which can be used by all diesel engines, new and existing. As a result, by and large, in most parts of the country, certainly any urbanized or suburban area, it's widely available.
If you look at how many diesel stations offer diesel in general, in 1999 1/3 of the roughly 120,000 retail fuel stations in the U.S. did. Two years ago, we did a study that showed that the number had jumped to 42%. 42% means that of every ten service stations, four of those will have a diesel pump already. Converting or making one of the tanks into a diesel tank is a half a day operation; it's not a big deal. Thinking about the future, if there is growth in diesel, that seems to be a non-issue. In fact, we're already seeing that if you go to a new station, one of the things that's different is how they are marketing fuels to consumers. They are putting all of the fuels together under the canopy, whereas it used to be that if you needed diesel you would go off to the side...it was like being treated as a second-class citizen. Today, most branded service stations have the diesel pump right there as a choice alongside all the gasoline blends. The message to consumers is that filling up with diesel is just like filling up your gasoline vehicle.
TH: What about for availability of this fuel for developing countries? Personally, I've traveled to places like Cairo, Egypt, where the air pollution is awful, in part because of all the old diesels.
AS: This is a considerable challenge. At the outset, I talked about the clean diesel system. The foundation is that what comes out the tailpipe depends on what comes in, so if you're trying to clean it up and you are working with a dirty fuel, life is going to be hard. Sure, you can find scrubbers and things, but at the end of the day, they don't work as well. So by having ultra low sulfur diesel, it's as significant from a societal view as the removal of lead from gasoline was in the 70's, that gives us today's cars that are 99% lower in emissions compared to cars 20 years ago. It's the same thing: the cleaner diesel fuel enables this new generation of advanced engine, because these catalysts and filters are very sensitive to high levels of sulfurs in the fuels. Getting sulfur down to low levels is critical. The challenge in any country is getting that system in place. Companies like Tata, which is an incredibly innovative company in India, has incredible technical expertise in producing all types of vehicles, but they have the fundamental limitation that they are dealing with a fuel that is nowhere near the quality and consistency of what we have in America. China is moving ahead, trying to do things in a rapid way for the Olympics. I don't know that the entire nation's diesel fuel supply is going to be ready in time, but they are in a similar situation: you can produce very clean cars, but they only work if you have clean fuels. The developing countries are behind on that.
TH: What's involved in making the diesel fuel clean?
AS: Sulfur occurs naturally in crude oil, and some has more in it than others. When it is naturally low in sulfur, it is known as sweet crude. The process for taking sulfur out of diesel is pretty straightforward. It's called hydro treating; basically pumping in hydrogen into the refining process extracts the sulfur out of the crude oil, allowing it to be "low sulfur." The sulfur can then be recovered and sold on the commodity chemical market.
TH: In your view, is diesel a short-term solution, or a long-term solution to climate change and other related issues such as dependence on foreign oil?
AS: I think the important perspective to have here is that there are many solutions to the idea that this country needs to reduce its reliance on imported oil and lower emissions of CO2--—and sooner rather than later, and clean diesel is one of the best here and now strategies out there. I think when you talk to people that understand where you have to go to get a fuel cell vehicle to market, beyond the demonstrations, we are talking about production of a new technology, fuel cell, safety issues, infrastructure, and its going to take longer than we like, so the question becomes, in the interim, what is better than what you're doing currently? And this is not rocket science. We need to use less of our resources, and for the foreseeable future petroleum is going to be a predominant resource, whether that means moving goods via freight (which, by the way, is almost 100% diesel), some of those applications are not going to change from diesel in our lifetime, especially when we think about the value diesel brings in being able to move things efficiently, at low cost, and now with very low emissions.
For passenger cars, it's really a moving target, and you see manufacturers responding to the higher CAFE standards under the new energy bill. There are lots of choices available to them, and the automakers are trying to figure out what consumers will buy. You need to have near-term solutions, mid-term, and there must be a long-term plan. GM, for instance, has shown their Volt, basically an electric source that can get energy from diesel, hydrogen, electricity or gasoline—a very flexible platform. Not every technology is going to make it, and there are demands from consumers for choice. Some people feel they must have a minivan, and it's a bigger vehicle, so what is the best technology to put in there? Fitting a minivan with a diesel engine would make it competitive with a hybrid, in terms of mileage. Not in every model, but we clearly see diesel fitting in as a near-term technology.
MIT believes that not until 2050 will hydrogen and fuel cells conquer 50% of the U.S. market for personal transport. We're looking to reduce reliance on foreign oil now. That's the beauty of diesel. It's a technology that has stepped up to the challenge. It's as clean as gasoline, and that wasn't the case 5 years ago, but diesel is now meeting the same EPA certification standards. Now that it has met the environmental challenge of lower emissions, we find it being able to compete in this ever-evolving future technology platform of plug-in and hybrid vehicles, ethanol, electric, and hydrogen. Diesel is going to be one of those choices, and for some applications it's going to be the better choice. We already see that for pickups. The fact is that half of Americans that buy new cars, buy big cars or trucks. Those are the kind of vehicles that would benefit form a diesel engine. Instead of 17 mpg, you'd be getting 25/27 mpg. So diesels are always going to be better suited for some vehicles.
TH: What are your thoughts on biodiesel?
AS: One of the interesting features of a diesel engine is that it can burn a lot of things in it. You can use biomass to liquids, you can do switch grass, canola, or a whole range of things that people are thinking and talking about, such as algae. So the diesel engine is not terribly specific about which kind of renewable fuel gets mixed with diesel. Lots of frontier work is being done looking at where you can source renewable, bio-based products, and as I said, the diesel engine can burn about anything. And when compared against ethanol, biodiesel looks better right from the beginning in a "wells to wheels" comparison. You can just look at the studies, everybody knows that. Biodiesel and renewables are going to be another niche add-on to more diesels coming into the U.S. You start out with an engine that is 20-40% more efficient, and if you add on to that with renewable fuels, you can sweeten the deal. Biofuels are typically more expensive, even with subsidies, and that's still something to contend with, but over time, as the market grows, prices will go down.
TH: Anything else you'd like to add?
AS: We have a great story to sell about the light duty diesel opportunity, but the story we've been talking about--the evolution to clean diesel--is a story that applies across the board to every kind of diesel engine. Highway vehicles are the first generation of that story, but off-road vehicles are starting to use a cleaner fuel as well, so this paradigm of the clean diesel system is permeating any type of application, from marine, railroad, off-road, as well as the highway vehicles. This is really about a fundamental transformation of the entire industry. More often than not, people say that diesel is a technology that is only used in trucks or buses. Or they will say that diesel is not a clean. That's a view of the past, certainly not of the future. This change is encompassing the entire industry. Consumers won't find any smoke or odor coming out of a diesel anymore.
Cleaner fuel and the emissions stuff is a great story for cars, but the challenge is, how do you deal with issues of the ports, where you have a lot of older equipment. What do you do for them? The answer is, just using cleaner fuel reduces particulate matter by 10%, and then if we incentivize retrofits for the trucks, then you can make it run 70-80% cleaner, and everyone wins. So this whole idea of a cleaner fuel as an enabler for all kind of diesel technology is where we are now.
Learn all about clean diesel at the Diesel Technology Forum.