Enova Systems Announces Plug-In Hybrid School Bus Testing Shows 70 Percent Improved Fuel Economy and Significantly Reduced Emissions

TORRANCE, Calif. (April 30, 2008) -- Recent dynamometer test results conclude that IC Bus school buses using post-transmission hybrid drive systems from Enova Systems (AMEX:ENA)(AIM:ENV)(AIM:ENVS) can improve fuel efficiency by more than 70 percent compared to standard diesel-powered school buses. The Enova hybrid drive systems installed in the IC Bus school buses also significantly reduce carbon dioxide, NOx and particulate matter emissions. Advanced Energy, a resource for innovative and market-based approaches to energy issues, has facilitated the adoption of IC Bus plug-in hybrid school buses in school districts in the U.S. and Canada.

These route-specific test results, along with the recent announcement by IC Bus of their intention to reduce the price of their school buses equipped with plug-in hybrid electric systems by up to $40,000, shows that significant progress has been made in developing, engineering and deploying fuel efficient and cost competitive hybrid electric buses.

“Our unique post transmission system offers original equipment manufacturers a non-invasive solution to enter the hybrid vehicle market in either the retrofit or new vehicle segment. Being the only supplier of this technology offers us and our customers a tremendous competitive advantage,” states Mike Staran, Enova's President and CEO.

The extensive series of fuel consumption and emissions tests were conducted to simulate actual route cycles and conditions using the West Virginia University Suburban Test Cycle. The tests were conducted at an independent commercial laboratory accepted by the California Air Resources Board that is properly equipped to perform specialized tests in accordance with applicable federal and California test procedures.

Tests were conducted on the following buses equipped with the Enova plug-in hybrid electric systems:

• 2007 model year IC Bus CE Series school bus with a VT365 engine and Allison 2500 transmission
• 2008 model year IC Bus CE Series school bus with a MaxxForce 7 engine and Allison 2500 transmission

The results shown below reflect a comparison of the plug-in hybrid buses to identical IC Bus school buses with standard diesel engines and drive systems. These results are based on the route-specific conditions defined by the West Virginia University Suburban Cycle and do not necessarily reflect fuel consumption and emissions data that may be generated from other route conditions. Selecting routes with frequent stops and starts and minimal highway miles allows the bus to get the most out of the hybrid system and is a key element to obtaining similar results.

“We are very pleased with the test results, and will now focus our attention to understanding school bus routes and determining the types and duration of routes that can strongly benefit from plug-in hybrid electric systems,” says Ewan Pritchard, Hybrid Program Manager for Advanced Energy.“ This proves that significant benefits are available as long as we put these in the right place,” Pritchard states.

“We believe these results show the success of our system in obtaining fuel economy and air quality improvements without major changes to standard production engines,” said David Hillman, Marketing Director for IC Bus. “But this is only the first phase of development. IC Bus and Enova are committed to developing ‘engine off' technology to obtain additional fuel economy and emissions control improvements.”

In March 2007, the first plug-in hybrid electric school bus was delivered to Manatee County Schools in Bradenton, FL., by IC Bus, Enova Systems and Advanced Energy. Today, 19 hybrid school buses are on the road in 11 states thanks to the efforts of Advanced Energy and its partners.

Enova's unique post transmission parallel hybrid system is one in which the electric drive system is integrated behind the factory-installed transmission. The Enova Hybrid has proven to be a non-invasive system that requires little or no modification to OEM chassis, body or instrumentation. However, the hybrid systems are designed to communicate with many other electronic systems on the bus, such as engine, transmissions, emissions and ABS systems controllers. An important competitive advantage that IC Bus and Enova Systems have generated by working together is to integrate and coordinate all of these electronic systems on the bus.

About Enova Systems

Enova Systems (www.enovasystems.com) is a leading supplier of efficient, environmentally friendly digital power components and systems products. The Company is focused on the development and commercialization of power management and conversion systems for mobile applications. Enova applies proprietary enabling technologies in the areas of alternative energy propulsion systems for light and heavy-duty vehicles as well as power conditioning and management systems for distributed generation systems. The Company develops, designs and produces non-invasive drive systems and related components for electric, hybrid-electric, and fuel cell powered vehicles in both the “new” and “retrofit” vehicle sales market. For further information, contact Enova Systems directly, or visit its Web site at www.enovasystems.com.

About Advanced Energy

Advanced Energy is a Raleigh, N.C.-based non-profit committed to a future in which energy needs are met at reasonable costs and with the least negative consequences. The organization continues to work collaboratively to demonstrate that industry, government and non-profits can successfully work together to improve the environment and encourage the economy. For over 25 years, Advanced Energy has created economic, environmental and societal benefits through innovative and market-based approaches to energy issues. For more information, visit www.advancedenergy.org.

About IC Bus, LLC

IC Bus, LLC is a wholly owned affiliate of Navistar, Inc. (OTC:NAVZ). The nation's largest integrated manufacturer of school buses, IC Bus is a leader in passenger protection, chassis design, engines and ergonomics. The company is also a producer of commercial buses. All IC Bus buses are sold, serviced and supported through a renowned dealer network that offers an integrated customer program encompassing parts, training and service. Additional information is available site at www.ic-corp.com.

Additional Information

This news release contains forward-looking statements relating to Enova Systems and its products that are intended to be covered by the safe harbour for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. Forward-looking statements are statements that are not historical facts. These statements can be identified by the use of forward-looking terminology such as “believe,” “expect,” “may,” “will,” “should,” “could,” “project,” “plan,” “seek,” “intend,” or “anticipate” or the negative thereof or comparable terminology and statements about industry trends and Enova' s future performance, operations and products. These forward-looking statements are subject to and qualified by certain risks and uncertainties. These and other risks and uncertainties are detailed from time to time in Enova Systems' periodic filings with the Securities and Exchange Commission, including but not limited to Enova's annual report on Form 10-K for the year ended December 31, 2007.