Seven new energy technologies at the US Energy Show

At an energy show held in Wisconsin, USA in 2011, the focus was on infrastructure for electric vehicles and technologies that could promote green buildings overall.

Electric vehicles were in the spotlight at the annual renewable energy event, and as gas prices continue to hover around $4 a gallon in many U.S. cities, energy conservation has never been more resonant.

There was no shortage of renewable energy and solutions on display at the Midwest Renewable Energy Association's annual show, where green building suppliers, startups and even inventors showed off everything from solar-powered charging stations for electric cars to methods for making biofuel from waste vegetable oil and compressed natural gas and -- believe it or not -- power from poop.

After GM and Nissan launched electric vehicles, Toyota finally launched a new Prius plug-in version, and its technical focus has shifted to batteries with higher energy density and the deployment of public charging infrastructure. This is also the first time that the energy exhibition has displayed a solar charging station for electric vehicles.

In fact, the trend of building electric vehicle charging infrastructure in various countries has emerged beyond the original leader California. For example, in the Midwest of the United States, emerging interstate rest stops such as Ohio and Pennsylvania are equipped with electric vehicle charging stations. Some of them even provide electrical and wireless connection services in the parking lot, allowing drivers to shut down diesel engines and connect to charging services to keep the temperature warm or cool at night.

One of the most anticipated projects at this year's Energy Show is the 2006 documentary "Who killed the Electric Car?" produced by producer Chris Paine, and the upcoming film "Revenge of the Electric Car." Pain believes that the electric vehicle industry is driving a transformation comparable to the "Industrial Revolution." He points out that almost all mainstream automakers have launched all-electric or hybrid vehicles.

One of the more eye-catching displays at the Energy Show - Chris Paine

Documentary filmmaker Chris Paine advocates for a shift toward all-electric vehicles at the 2011 Midwest Renewable Energy Show.

Meanwhile, emerging automakers such as Tesla Motors are readying their second-generation electric cars, which are expected to cost around $40,000, in line with General Motors' Chevy Volt and Nissan's Leaf.

One of the more eye-catching exhibits at the Energy Show: Chevy Volt

The Chevy Volt was the talk of the town at this year's Energy Expo—an American-made electric car that was priced within the reach of most American consumers.

However, limited driving range remains the main obstacle to the expansion of the electric vehicle market. Paine believes that for urban consumers, the ideal driving range is 100 miles. He also predicts that high oil prices in the future will make commuters who have to drive to work start to consider electric vehicles.

The development of electric vehicles has long been hampered by two factors: range and price. After comparing cars with traditional engines with electric vehicles, Paine and others noticed that it takes about 4 to 6 kilowatt-hours of electricity to refine each gallon of natural gas. This electricity would be better used to power electric vehicles. Nissan recently launched the all-electric Leaf, and the company believes that the energy consumed to refine one gallon of natural gas can allow the Leaf to travel about 30 miles.

One of the more eye-catching exhibits at the Energy Show: Charging Stations

This year's Energy Show showcased a variety of hybrid battery charging technologies, one of which was a solar-powered charging station

In other areas, such as green homes, builders are trying to go beyond current methods and promote various renewable energy technologies into homes to provide a more comprehensive approach to reducing energy consumption, which is expected to attract homebuyers who were originally skeptical of so-called green buildings. Gene Becker, a green builder from Hortonville, Wisconsin, said that traditional green building practices are like using a 4-cylinder engine to drive a 3-ton truck. The result is naturally insufficient power.

"It's wrong to want a single approach that fits all buildings," Becker said. Instead, his construction company, Lifetime Structures, tries to design all renewable energy components into its green homes. This includes many advanced construction materials, advanced insulation and solar collectors.

While selling so-called "green homes" is difficult in a depressed real estate market, the approach promoted by Becker and others portrays the concept of so-called green living as something that is moving from a pie-in-the-sky fantasy to a reality that, while still expensive, promises to provide a faster return on investment while also significantly reducing energy consumption and carbon footprint.

All the demonstrations at the event will help reduce dependence on imported oil and reduce carbon dioxide emissions. As crude oil prices rise, the emerging green economy is gradually emerging.

One of the most eye-catching technologies at the Energy Expo: power generation from feces

Yes, Even Cow Dung Can Power Electric Cars

One of the more eye-catching displays at the Energy Show: Multiple Batteries

One attendee installed a number of lead-acid batteries in a conventional car. The owner of the car joked that the extra weight improved the car's handling.

One of the more eye-catching exhibits at the Energy Show: the Prius plug-in

A more practical plug-in hybrid: the Prius plug-in

One of the more eye-catching displays at the Energy Show: Gasoline prices

Chris Paine's data shows the harsh reality: gasoline prices in the United States are soaring