Today, when it comes to choosing a lift truck energy solution, it is no longer as simple as ICE or electric. With multiple existing and emerging options for providing motive power to industrial lift trucks, it is important for purchasers to become aware of the alternatives and to understand the trade-offs between the competing technologies.

When choosing an energy technology, lift truck buyers will want to consider basic parameters such as cost, performance, application, operational benefits, environmental impact, regulatory compliance and the rapid rate of technological change, both as it relates to new capabilities as well as to potential obsolescence. When considering true environmental impact, it is useful to consider the total supply chain from the energy source to the point of use: the so-called “well-to-wheel” model.

Green Power: A New Mandate

With the green movement taking root, major corporations are devoting significant resources to calculating and reducing their carbon footprint through activities related to recycling, reducing waste, conserving energy and adopting cleaner energy and processes. Wal-Mart's recent announcement to develop a sustainable product index based on the total product lifecycle is a harbinger of the attention focused on energy use.

With the rising levels of awareness surrounding energy efficiency and economy, it is clear that several factors will determine the next step in the rapidly accelerating world of motive power technology. Cleaner fuels, cap and trade legislation, renewable energy, more efficient engines, fuel cells and advanced battery technologies are just a few drivers with the potential to usher in sweeping change over the next five to 10 years in the industrial lift truck industry.

While LPG, diesel and lead acid batteries still power the majority of North American lift truck fleets, the next decade will see new energy sources and storage devices joining the fleet, with some potential game changers waiting in the wings.

ROI and Carbon Impact

Choosing a lift truck power source requires weighing the relative importance of a number of key factors, some of which vary considerably from one power source to another. When considering costs, it is important to bear in mind the full lift truck lifecycle costs associated with the technology, namely costs associated with initial purchase, annual maintenance, consumable energy and support infrastructure, such as chargers and refueling stations. Initial costs of many new technologies may be high and early market penetration accordingly measured, but a thoughtful review of expected overall lifetime ownership cost implications gives a better perspective of eventual economics and ROI.

Environmental regulations are likely to increase in importance as a factor in the choice for a lift truck energy solution. ICE emissions, including hybrids, are regulated by the EPA and CARB, authorities which primarily focus on reducing pollution levels of particulate matter and NOx. Carbon footprinting considers the entire lifecycle impact on the environment, particularly the greenhouse gases resulting from energy consumption. A complete environmental analysis of motive power sources should consider both the implication of meeting engine emission requirements and the impact on carbon footprint.

Following the European model, a possible future cap and trade system in the U.S. may tie financial benefit directly to improvements in carbon impact. In assessing the environmental impact of an energy technology, consideration should be given both to emissions at the point of lift truck use as well as to emissions at the point of production and delivery of the energy. Although hydrogen consumption does not currently factor into a lift truck user's carbon footprint calculation, that may very well change as the regulatory environment evolves.

In our studies, the hydrogen carbon impact for many applications was less favorable than battery electrics due to the early stages of hydrogen infrastructure distribution. As these develop, so could a more favorable environmental model. With current infrastructures and distribution, the advanced battery technologies using the electric grid for distribution produced the lowest carbon footprint.

A Vision for the Future

The arena of energy storage and delivery is entering a period of rapid technological advancement as regulatory, market and environmental forces are driving several promising technologies down their respective development paths. These include technologies such as:

• Materials breakthroughs in battery chemistries;

• Ultracapacitors with improved energy storage capacity;

• Ultracapacitor-battery hybrids;

• Direct hydrogen combustion;

• Carbon fiber flywheel energy storage units.

Against a constantly changing landscape of volatile energy prices, new regulations and subsidies, alternative lift power sources will commercialize at varying rates. It is important for lift truck buyers to understand the trade-offs between the various existing and emerging technologies to make informed decisions. Lift truck purchasers will want to consider costs, performance, operational benefits and environmental impact/regulatory compliance.

Managing carbon footprints through the adoption of fuel- efficient technologies will be a function of both economics and environmental impact. Lift truck manufacturers, including Hyster Co., are currently researching and testing alternative and mainstream power solutions to assist their customers in making long-term, viable investments that suit the application and offer a positive return on investment.

Although it is yet unclear which emerging technologies will gain dominance for motive power, it is readily apparent that the next decade will produce exciting developments in energy storage and delivery solutions. To take advantage, it is important to monitor these developments because the coming energy innovations will not just have operational benefits for the lift truck industry. They will also enable us to reduce overall energy consumption and our dependence on volatile energy sources as well as set our industry on a path to a more sustainable future.

Darel Reed is manager of technology development for the NACCO Materials Handling Group. He has 16 years of experience in electronic materials and component development and marketing and has been heavily involved in alternative power for lift trucks the past three years. Patrick Duhaime is vice president of marketing for Hyster Co. He previously spent 15 years in product marketing with John Deere Power Systems and Cummins Engine Co.

Motive Power Alternatives: What's Around the Corner?

With the exception of bio-diesel, ethanol, direct hydrogen ICE and ICE hybrid engines, the focus on commercialized and near-term alternative power choices are nearly all electric powered, whether by hydrogen fuel cells or new energy storage technologies. Below is a brief look at each of today's major players.

Hydrogen Fuel Cells

The commercial application of hydrogen fuel cells in lift trucks is currently taking place at several sites. Unlike a battery, which must be recharged after use, a fuel cell produces electric current continuously, provided there is a constant supply of hydrogen fuel and oxygen. A short refueling time of only minutes makes a hydrogen fuel cell-powered fleet ideal for multi-shift, constantly running operations.

While fuel cells are the most widely commercialized energy source among the emerging technologies, there are some points to consider before converting a fleet to hydrogen. Hydrogen fuel cells are becoming more efficient and are 100% green at the point of use. However, in the total environmental model and calculation, it is necessary to factor in where the hydrogen originated from, the economic and environmental cost of distribution, and the overall carbon footprint.

Advantages

• Zero emissions at the point of use

• Very fast refueling time

• Potential for increased productivity

• Reduced battery inventory

• Potential to eliminate battery change equipment, space and personnel

• Voltage and truck performance remain stable over a shift

Disadvantages

• Up-front capital investments, in both on-truck and infrastructure costs

• Hydrogen fuel delivery is not readily available in all areas; delivery infrastructure is not mature

• Currently produced from fossil fuels in many cases (Commercial bulk hydrogen, for example, is usually produced by the steam reforming of natural gas.).

• Fuel cell packs are not yet available for all lift truck types, making full fleet deployment more difficult

Lithium-Ion Batteries

The most promising family of battery chemistries, in terms of improving recharge times and high energy density, is lithium ion. There are two general approaches to lithium-ion batteries: a large format approach and a smaller cell approach. The larger format approach typically includes advanced nano-based materials for improved performance and safety. The smaller cell approach combines large quantities of commodity cells using conventional chemistries but relies on sophisticated electronics to ensure safety.

While the larger format nano-based chemistries promise superior charge times, they are more expensive and further out on the development horizon. Both approaches to lithium ion cost multiples more than lead acid batteries, but longer life and zero maintenance offer the possibility of favorable total lifecycle costs.

Companies are taking a hard look at the economies involved with lithium ion and advanced battery technology. Based on advancements in other industries, it is expected that lithium ion and other advanced battery technologies will get serious play in the material handling space in the future.

Advantages

• Short recharge time

• Higher energy density (especially advantageous for Class II applications)

• Higher energy efficiency and reduced carbon footprint

• Suited to smaller fleets and a wider range of applications and truck types

Disadvantages

• High initial cost

• Significantly lighter weight affects need for lift truck counterbalance weight

• Early stage commercialization for motive power

Advanced Lead-Acid Technologies

Much research and development is focused on improving current wet cell lead-acid battery technologies. New advances include thin-plate pure lead, carbon lead and carbon-graphite foam grid technology. These batteries, with potentially shorter lead times to full commercial use in lift trucks, share the advantages of being based on existing technology.

With a size and weight comparable to normal lead-acid batteries, advanced lead-acid batteries could be used as drop-in replacements in existing electric lift trucks and should not require substantial investments in additional infrastructure or charging setups.

Advantages

• Short charging time

• Greater cycle life

• Standard dimensions, plug-and-play alternative to lead-acid batteries

• Lower cost than lithium-ion alternatives

• Shares high rate of recycling potential with existing lead-acid batteries

Disadvantages

• New technology, only now moving into motive power

Battery Hybrids

As in the auto industry, the battery to be used in combination with the ICE will likely be either nickel metal-hydride (Ni-MH) or lithium ion (Li-Ion). Compared to an ICE truck, a battery/ICE hybrid will reduce fuel consumption and engine emissions, possibly eliminating emissions during idling. These benefits will likely come at an increase in initial truck costs, which would need to be factored into the overall lifecycle cost analysis.

Considering that fully electric lift trucks are already prevalent in the market with many potential improvements in battery technology on the horizon, the benefits of battery/ICE hybrids will be limited to traditional ICE truck segments, in which they may soon compete with fully electric lift trucks.

Advantages

• Reduced energy consumption compared with ICE

• Reduced emissions compared with ICE

• Quick refuel, duty cycle similar to ICE

Disadvantages

• Higher initial cost, still likely to depend on lithium ion

Sources: Darel Reed, manager of technology development, NACCO Materials Handling Group, and Patrick Duhaime, vice president of marketing, Hyster Co.