Energy Department Releases Second Quadrennial Technology Review

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September 11, 2015

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(US Department of Energy) Research Opportunities Highlighted in Report Lay Out Options for America’s Clean Energy Future -- Today (September 10, 2015), the Energy Department released its second Quadrennial Technology Review (QTR), which examines the current status of clean energy technologies and identifies hundreds of clean energy research opportunities that could support the effort to modernize the power sector as a whole, while also helping Americans to power their homes, businesses, cars and trucks more efficiently. The report finds that emerging advanced energy technologies provide a rich set of options to address the nation’s economic, security, and environmental challenges, but continued improvements in cost and performance are crucial to the large-scale deployment of these technologies.

“The energy sector in the United States has changed dramatically in recent years due to advances in clean energy technologies, increased oil and gas production and the increased risk to energy infrastructure from extreme weather, cybersecurity and other factors,” said Secretary of Energy Ernest Moniz. ”The Quadrennial Technology Review is intended to serve as a blueprint for the Energy Department, its National Laboratories and the public and private sectors as we all work toward additional future technology breakthroughs that can help to mitigate the risks of climate change, modernize our energy infrastructure and enhance our energy security.”

“No challenge poses a greater threat to our future than climate change, which is primarily caused by carbon pollution from energy use,” said Dr. John Holdren, Director of the White House Office of Science and Technology Policy. “The QTR makes clear that we have the technological know-how and innovative spirit to move to a low-carbon economy. It’s up to us to carry these opportunities through and make them a reality.”

Over the course of six technology chapters – grid modernization, clean power, buildings, manufacturing, fuels, and transportation – the QTR examines the current status of energy technologies and research opportunities to advance them in addition to key enabling science and energy capabilities.

In completing the review, a number of overarching themes emerged:

Researchers found that the nation’s energy systems are becoming increasingly connected through the internet and other technologies, which may provide a game-changing new paradigm for cost and emissions reduction.
The range of options available to meet the nation’s energy needs is increasing, and this diversification creates a more dependable energy system and offers consumers new choices.
The nation has embraced energy efficiency as a way to reduce energy use and costs, but substantial efficiency opportunities remain untapped.
Breakthroughs in next generation high-tech tools including x-ray light sources and supercomputers are helping scientists find new ways to deliver cheaper, faster clean energy innovation.

The QTR also highlights the dramatic changes that have occurred in the American energy system over the past four years. The nation has increased wind energy capacity by 65 percent, increased solar capacity 9 fold, and replaced some of our oldest, least efficient power plants with cleaner, more efficient ones. At the same time, vehicle gas mileage has increased to record levels. In the four years since the first QTR was released, the United States has also become the largest producer of oil and gas combined. By pursuing the research and development opportunities, as well as the untapped opportunities for greater energy efficiency highlighted in the QTR, the U.S. can move closer to its clean energy future. READ MORE and MORE (Politico's Morning Energy) Download report

Excerpt from Politico's Morning Energy: The 2011 report laid out six strategies, including language that seemed targeted at the agency itself: “Electrification is the next greatest opportunity to dramatically reduce or eliminate oil consumption in the light-duty vehicle fleet. DOE’s most significant role in transport research is here,” it declared. “Within our transportation activities, we conclude that DOE should gradually increase its effort on vehicle efficiency and electrification relative to alternative fuels.” The 2015 report, by comparison, plays nice with everyone. READ MORE

Excerpts from report: Fuels sector: Fuels supply 99.8% of the energy currently used in the transportation sector and 70% of the energy used to generate electricity in the United States. The economy will need to balance the various strengths and shortcomings of a broad mix of fuels during the transition from a high-carbon to a low-carbon economy. This fuel mix includes the following:

 Fossil fuels: Chemical fuels, primarily derived from fossil energy resources, supply about 83% of total U.S. primary energy use.

 Bioenergy fuels: With technology improvement and a mature market, available bioenergy could provide more than fifty billion gallons of fuels per year, equivalent to about 25% of current transportation fuel demand.

 Hydrogen fuels: Technologies for producing hydrogen from large natural gas reforming plants are mature, but the costs of converting the end-to-end fuels infrastructure, including delivery, to accommodate hydrogen are high. While the near-term deployment challenge is to reduce the cost of infrastructure for fueling vehicles, in the longer term the major challenge is to reduce the cost of hydrogen production from regionally optimized renewable and low-carbon resources.

With recent growth in domestic shale gas and tight oil production, near-term concerns over fuel supply and energy security are easing. However, the economic and environmental impacts of heavy reliance on fossil fuels make their further cleanup or transition to clean alternatives imperative. The trade-offs between conventional (oil and gas) and alternative fuels (primarily biofuels and hydrogen) or substitution with electricity—i.e., cost, performance, infrastructure, security, and environmental impacts—are complex. Optimizing the benefit of fuel diversification is challenged by the varying time frames for development and deployment of fuels, production and distribution infrastructures, and end-use devices such as vehicles. The focus of Chapter 7 is Advancing Systems and Technologies to Produce Cleaner Fuels.

Transportation sector: Transportation provides essential passenger, freight, and other mobility services to individuals and the economy. It is the primary user of petroleum in the United States and a major emitter of air pollutants and GHGs. Currently, light- and heavy-duty vehicles account for approximately three-quarters of transportation energy use and emissions. Other modes in the transportation system include rail, marine, 6 Quadrennial Technology Review ES Executive Summary aircraft, and pipelines, the proportional emissions from which are likely to grow in importance as the efficiency of on-road transportation technologies improves. To greatly reduce GHG emissions, a larger share of vehicles must efficiently use fuels or power with drastically reduced life-cycle carbon emissions. The technology portfolio benefits from a set of complementary RDD&D pathways, including advanced combustion, light-weighting, battery storage, electric drivetrain, fuel cell systems, and recharging and refueling infrastructure. Addressing the transportation sector as a holistic system that encompasses more than just vehicle technologies is another important emerging research opportunity. The focus of Chapter 8 is Advancing Clean Transportation and Vehicle Systems and Technologies.

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Fuel-engine co-optimization: With bio-derived and/or other synthetic fuels there is an opportunity to optimize the end-to-end fuel-vehicle system for improved efficiency and reduced environmental impacts.

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Bioenergy can help meet the need for liquid fuel with lower emissions through production of biofuels and other bioproducts. This requires developing, producing, and collecting sustainable feedstocks, efficient conversion processes, and a competitive final fuel product that has the necessary physical and chemical properties. Properties that are required include appropriate energy content and characteristics for use, acceptable transport characteristics, ability to withstand temperature extremes, and storage suitability.

In general, bioenergy pathways consist of production and collection of feedstock supply; conversion of that feedstock through a wide variety of processes into the desired fuel; and distribution in the energy infrastructure for use (Figure 7.7). In addition, biogenic wastes (e.g., manures, biosolids [treated sewage], food wastes, and municipal solid waste) can be converted into liquid fuels and products. This section describes a variety of technologies across these generalized pathways and associated metrics used to assess the viability and desirability of these technologies.

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Bioenergy can provide options to replace oil, especially in challenging applications like aircraft fuels, diesel, and bioproducts that can substitute biomass for petroleum feedstocks (Figure 7.8). Renewable fuels are needed for reducing GHG emissions from these sectors because other approaches like electrification are not viable in the near term. A fuel that is compatible with existing infrastructure may increase the ability of the fuel to serve many needs and reduce barriers to deployment.

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Growth of biomass may also impact soil carbon or standing biomass. Challenges associated with large-scale utilization of biomass include the need for a large land area to grow biomass feedstocks, water and nutrient requirements for feedstock cultivation, and the impact of feedstock growth because of climate issues. Life-cycle assessment (LCA) is a technique used to evaluate total energy use and GHG emissions associated with biofuels and compare energy pathway performances. Pathway emissions depend on factors such as the energy needs of the feedstock, logistics energy use, fertilizer requirements, conversion efficiency and chemistry, and biorefinery energy needs. R&D can identify ways to improve the conversion efficiency for many pathways. Fuels under development can reduce the life-cycle emissions of GHGs in comparison to existing fossil-derived transportation fuels (Figure 7.10). Some topics, such as landuse change, can be challenging to include in an LCA framework and are a subject of ongoing research.

Total Bioenergy Potential The total emissions reductions and petroleum displacement potential of biofuels and hydrogen depend on factors such as the total sustainable resource, the availability of a cost-effective resource, and the efficiency of conversion technologies (Figure 7.9). More than one billion dry tons of biomass may be available sustainably for use as bioenergy by 2030 (Figure 7.10 and Table 7.3).49 With technology improvement and a mature market, this available bioenergy could provide approximately 58 billion gallons of fuels to replace gasoline, diesel, and jet fuel—produced from approximately 18 quadrillion British thermal units (Btu) of biomass feedstock by 2050.50 Capturing this total potential would require significant success in RD&D and market deployment activities.

Even in high-usage scenarios, bioenergy would not supply sufficient energy to totally replace petroleum at current use levels. However, when combined with efficiency and other strategies in transportation (Chapter 8) and industry (Chapter 6), bioenergy can represent a key part of a clean energy future, especially by meeting liquid fuel needs in uses like jet fuel that are challenging to replace. Conversion technologies need to be developed utilizing lignocellulosic feedstocks, waste materials, and algae that minimize land-use change and deforestation around the world.

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Significant improvements in engine efficiency and GHG emissions are possible through co-optimization of fuels and engines that are designed in tandem to enable maximum performance. Additional GHG reductions are possible through leveraging the lowest carbon pathways to create fuels with desired properties (discussed in detail in Chapter 7). Higher compression ratios in engines can allow higher maximum efficiency, but in SI engines, compression ratios are limited by the tendency of gasoline to autoignite, or “knock.” Increasing the octane of liquid fuels would enable design of engines with higher compression ratios without experiencing knock. A high-octane fuel from a renewable source can have the additional benefit of reducing life-cycle GHG emissions. Currently, the only renewable high-octane fuel available at large scale is ethanol, which makes up 10% of gasoline sold by volume. Increasing this percentage of ethanol can dramatically increase the octane rating of the finished gasoline/ethanol fuel blend, with most of the benefit being realized around 25%–40% ethanol by volume. Other renewable components (e.g., bio-derived isobutanol) also have high octane ratings. Higher-octane fuel would enable downsizing, downspeeding, and charge air boosting of the engine to improve the fuel economy of vehicles. Understanding what additional physical fuel properties, such as heat of vaporization, impact engine performance and how fuel with desirable properties can be produced using the lowest-carbon pathways is a key area requiring research.

Similarly, fuel properties optimal for advanced compression ignition engines (i.e., diesel engines) and advanced combustion regime engines (e.g., low temperature combustion) will be sought via renewable routes. Advanced combustion regime engines present a particular challenge because they are less well understood than conventional spark ignition and compression ignition engines. Much of the data space, including determination of desirable properties for fuels, remains to be populated. Many versions of advanced combustion exist and each has fuel property requirements associated with it that do not always match those for other versions (or current fuel specifications). As advanced combustion engines come into the market over the next few decades, we have a unique opportunity to design the performance specifications of commercially available fuels for the future to match the appetite of whatever version of advanced combustion regime engine emerges as dominant in the market.

The following technological barriers to the co-development of fuels and engines require R&D:

 A high volume of candidate fuel and an expensive and cumbersome engine-based test are currently required to compare candidate fuels to a baseline.

 The decades-old octane tests (Reasearch Octane Number and Motor Octane Number) were designed to detect auto-ignition for petroleum-derived fuels. As bio-derived feedstocks diversify the blending streams for gasoline fuels, some of the knock-resistant fuel properties are not adequately measured (such as heat of vaporization). Moving forward, it is essential to ensure that fuel standards tests measure all of the relevant fuel properties under relevant engine conditions for current and evolving combustion regimes.

 There is a lack of information on current biochemical and thermochemical routes for biofuels, as well as a need to develop a library of pathways and proposed end products, and how these relate to and can be co-optimized with engine performance.

 There is no database of fuel properties for candidate low-carbon fuels and biofuels. Because end-to-end, market-driven solutions are required to bring any new fuel to market, R&D should consider production, distribution, and dispensing of fuels into the retail market including required technology and infrastructure compatibility, topics that are discussed in detail in Chapter 7. READ MORE