Navigant Research Blog

Small Fuel Economy Advances Deliver Big Benefits

— September 4, 2012

Fuel economy has become one of the most important considerations for OEMs in recent years, driven by rising fuel prices and more challenging legislation on emissions and fuel economy.  Major technological advances, such as plug-in electric vehicles, tend to grab most of the attention around reducing fuel use and carbon emissions.  But often less visible, incremental changes can have equally large effects, and in shorter timeframes.

Stop-start technology is one of the systems being used to meet targets, and Pike Research will shortly release a new report on this topic.  Downsizing the engine volume along with forced induction – either turbocharging or supercharging – is another approach being used to increase efficiency.  At higher speeds, better aerodynamic design can also pay dividends.

OEMs have also been investing for some time in lowering the vehicle’s mass.  In an average car, reducing the weight by 220 pounds translates to a fuel economy improvement of about 3%.  Tires with lower rolling resistance and installing electric power assist steering also have small but measurable benefits.

Incremental improvements to existing technology have been made over many years, with little notice.  For example, a vehicle with a 1.6-liter diesel engine at Ford averaged 185 grams of CO2 emitted per kilometer (g/km) in 1998.  By 2012 that number has been reduced to 88 g/km.  Other manufacturers have accomplished similar improvements as they introduce features such as common rail fuel injection and stop-start technology.  Over the same period, a gasoline vehicle with a 1.6-L engine showed a reduction from 194 g/km to 139 g/km.  Replacing the naturally aspirated 1.6-L engine with its 1.0-L EcoBoost engine that delivers the same power rating, Ford has been able to reduce the CO2 emission to 109 g/km in 2012.

It is also important to note that stop-start may never become a standard feature on all vehicles.  On small city vehicles the extra cost, bulk, and weight may not be offset by the fuel savings.  But on larger vehicles with powerful internal combustion engines, stop-start is destined to become standard worldwide.  The drive for this will come from OEMs doing all they can to meet emissions regulations, and also from consumers and fleet buyers who recognize a feature that pays for itself.

Most OEMs will need to devote some resources to educating drivers about stop-start technology, though, first to get them to choose it when specifying a new car, and second to get the most out of it when driving.  One of the reasons for the slow launch of stop-start technology in North America is that the official EPA
test-drive cycle does not include much stationary time and so the benefits of stop-start do not show up in the comparison figures that are mandatory on a new car sticker.

While stop-start can save some fuel by not allowing the engine to idle when the vehicle is stationary, another approach is to tackle the issue of congestion and solutions that keep traffic moving.  Telematics and Smart Cities offer some new ways to tackle this problem, by helping drivers to find more efficient routes.

When considering the bigger picture, it’s important to recognize that high-volume, less noticeable technologies can have a much bigger effect on the environment than cost-intensive advanced concepts, even if the incremental benefit is smaller.


Microinverters Brighten Future of Distributed Solar

— September 4, 2012

The Achilles’ heel of solar PV has been its low efficiency.  Even the most efficient commercially available monocrystalline silicon PV panel is only 20% efficient; the majority of modules installed today range from 12% to 18%.  This compares with wind at 30% and fossil fuel generators at 80% to 95%.  However, this is only part of what determines the solar PV system’s overall output.  Shading, dirt, cabling, voltage drop, inverter efficiency, and heat also affect the overall energy harvest.  Breakthroughs in microinverters (which convert DC electricity to AC power) and DC optimizers (which provide a steady and “optimum” voltage level for the current fed to the inverter) are two of the most disruptive technologies in the solar PV sector today, as we describe in Pike Research’s recently published report Inverters for Renewable Energy Applications.  The main benefit of microinverters is an overall higher energy yield because they prevent one panel’s failure from affecting the overall system’s energy harvest (unlike solar PV installations that use string or central inverters).  At the installation site, microinverters are easily installed on the back of each panel, matching the rated capacity.

With microinverters, each panel is individually monitored, thus removing the need for DC cabling.  This architecture distributes the overall risk of failure among all the panels in the installation, and relies on information technology to identify and isolate failed panels.  By contrast, central inverters have a single point of failure, which can lead to longer periods of downtime if that inverter fails.  With maximum power point tracking (MPPT) at the panel level instead of the string level, microinverters are ideally suited for residential and small commercial systems that are likely to be shaded more often that centralized solar power plants in the desert.  Microinverter companies claim their technologies reduce the overall levelized cost of energy (LCOE) by 15% to 20% as compared to string inverters.  Individual modules can also be shut down remotely and, with AC electricity, safety is increased for installers.  Microinverter manufacturer Enphase Energy claimed to have 34% of the California residential market in 2011, based on wattage.

The downside of microinverters is that they are typically two to three times as expensive as string inverters and have lower efficiencies (although they do typically result in a better overall energy harvest).  While the distributed architecture removes the risk of a single point of failure, many more electronics are being introduced to the PV system.  Startup microinverter companies claim higher reliability than string inverters, but microinverters have not been used long enough to test this claim.  Furthermore, placing microinverters on the back of a panel and on a roof could increase the risk of heat damage to the inverter due to higher rooftop temperatures, compared to string and central inverters, which are normally housed elsewhere.

The future of microinverters could very possibly end up being with fully integrated AC panels, of the type that SolarBridge Technologies and SunPower are experimenting with.  Under this architecture, the microinverter is pre-installed on the module at the factory.  The main value-add is the reduction in installation time from not having to separately install the microinverter or AC bus cabling at the job site.

Despite the doom and gloom in the headlines, and as we describe in the recently published Renewable Distributed Energy Generation report, the future of distributed solar PV is bright. Microinverters will continue to play an increasingly important role in this future.


An Internet Protocol for Smart Cities

— August 30, 2012

The list of smart city initiatives continues to grow.  Recent examples include the new EU smart city project fund; almost 400 U.S. cities competing for $9 million in awards for city innovation as part of the Mayors Challenge launched by Bloomberg Philanthropies; a £25 million ($40 million) Future Cities Demonstrator competition for cities in the United Kingdom; and a new smart cities network formed by 24 Spanish cities.  One of the most interesting new programs was launched in Barcelona in July.  The first City Protocol workshop, co-hosted by the City of Barcelona, GDF Suez and Cisco, brought together a diverse group of stakeholders including city councils, academia, suppliers and interest groups, all committed to the development of a “more sustainable, efficient, cohesive, innovative and smart city.”  Over 30 cities from across the world were represented, as well as around 20 suppliers, including Accenture, IBM, Microsoft, Oracle, Schneider Electric, Siemens, Telefonica, and Philips.

The City Protocol aims to enable cities that are “adaptive, learning, evolving, robust, autonomous, self-repairing, and self-reproducing.” The Protocol spans the whole of the city ecosystem including water, waste, matter, energy and utilities, mobility, goods, people, and information.  Taking its inspiration from the way Internet and Web standards have been delivered, it fosters a similar process of open, transparent, and robust collaboration on an international basis.  Leadership will be provided by the City Protocol Society (CPS), which will loosely follow the model of the The Internet Society,  addressing specific issues and delivering formal agreements, recommendations, technology standards, reference projects, policies, and certification models.

Of course, there are already many collaborative efforts on city innovation that focus on developing innovative solutions to common challenges.  The danger is that the City Protocol will be just another talking-shop on the fascinating challenges of urban renewal and growth.  There are two critical areas where it could make a real difference.

‘Anything Connected to Anything’

First, a well-defined and shared process for the ratification, incorporation, and further development of technology standards that meet the needs of smart cities would be a major step forward.  The City Protocol could make a significant contribution to enabling better integration of information flows and communications networks across multiple domains such as transport, sustainability, and public safety, for example.  This would make analogies to the Internet Protocol or to concepts such as the Smart City Operating System more than just metaphors.  Vint Cerf, one of the founding fathers of the Internet, told delegates to the first City Protocol Workshop that one of the biggest insights of the Internet’s early development was that eventual applications were less important than simply creating a platform where an arbitrary collection of computers could communicate over an arbitrary collection of networks.  Tim Berners-Lee had a similar vision for the World Wide Web: “Anything being potentially connected to anything.”  If the City Protocol can help develop a similar approach to connectivity across the diversity and complexity of urban operations, then it will be a major achievement.

However, the need to address practical issues around specific application areas is where the City Protocol most clearly diverges from the Internet Protocol.  This is also where its second major contribution can be made.  Participants in the City Protocol workshop recognized the need for better cost-benefit analyses that can reduce the risk and improve the repeatability of new programs in areas such as energy efficiency.  If the public and private sector can develop models for delivering financial returns and public benefits on energy efficiency programs or better managed transportation systems, for example, then it will be much easier to implement such smart city projects at scale.


New CAFE Rules Anger Just About Everyone

— August 30, 2012

The Obama administration announced new fuel economy rules this week requiring that vehicles reach 54.5 miles per gallon by 2025.  Typical of the corporate average fuel economy (CAFE) rules, there are many credits offered for different types of vehicles based on their drivetrains, encouraging automakers to make and sell alternative drive and alternative fuel vehicles. The effort to tighten CAFE standards has been the epitome of government sausage making.  The process required not only getting Republicans and Democrats to agree on something, but also getting environmentalists and, more importantly, auto manufacturers to agree on something that no party really likes.  All of this makes for a very messy show, and it’s the biggest reason why from 1990 to 2009 fuel economy for cars remained unchanged.

Not surprisingly, automakers are not happy with the new rules.  Even less surprisingly, Republicans are eager to make that known.  Representative Darrell Issa (R-CA), who seems generally opposed to regulating the auto industry, leads the House Oversight and Government Reform Committee, which issued a report on August 10th showing that foreign automakers complained about the process.  The report quotes Toyota as claiming the rules “give preferential treatment to larger trucks [and are] ‘a second bailout for Detroit.’” There is likely some truth in here.  The credit system in the proposed rules do not provide credit for hybrid cars – Toyota and Honda’s alternative drivetrain bread and butter – but do provide credit for hybrid pickup trucks (only GM offers a hybrid pickup at the current time).  The report claims that German automakers are also unhappy, because diesels are not included for alternative drivetrain credit.  The final rules announced today did feature one change that will make Honda happy, a new credit was added for natural gas vehicles.

One big win for all the automakers in these new rules is getting California back into the national fold.  Earlier this year, California’s Air Resources Board (CARB) produced its own emissions and fuel economy standards, and a handful of other states jumped on board.  The new CAFE rules were negotiated in collaboration with CARB, which wanted a 5% annual rise fuel economy, but ultimately agreed to 3.5% increases for trucks in 2017–2021.  This brings California and the federal rules into alignment (mostly).

Upon the announcement of the new regulations, the Detroit Free Press reported that Rep. Issa issued a statement: “The rule finalized today by the Obama Administration will hurt American consumers by forcing them to drive more expensive and less safe automobiles.  I support the goal of higher fuel efficiency, but this rule will only add to the burdens American small businesses and middle class families face under the heavy hand of the Obama Administration.”

The rules do include a review period in 2021 to determine if the targets are technically feasible.  I’ve always thought this would ultimately prove to be the automakers’ way out from these requirements, and their responses to this week’s announcement seem to confirm that the review period and elimination of state-by-state regulations remain the industry’s two key objectives.  Depending on how the elections swing in November, the rules may not even make it that far before being shot down.


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