Summer is just around the corner, and for those who live in big cities, that means spring warmth will soon give way to searing heat. Green roofs can help regulate city temperatures, giving people, and the electrical grid, a much needed break.

Toronto is the first city in North America with a bylaw that requires roofs to be green. And we're not talking about paint. A green roof, also known as a living roof, uses various hardy plants to create a barrier between the sun's rays and the tiles or shingles of the roof. The plants love the sun, and the building (and its inhabitants) enjoy more comfortable indoor temperatures as a result.

Toronto's new legislation will require all residential, commercial and institutional buildings over 2,000 square meters to have between 20 and 60 percent living roofs. Although it's been in place since early 2010, the bylaw will apply to new industrial development as of April 30, 2012. While this is the first city-wide mandate involving green roofs, Toronto's decision follow's in the footsteps of other cities, like Chicago and New York.

Under the direction of Mayor Richard Daley the city of Chicago put a 38,800 square foot green roof on a 12 story skyscraper in 2000. Twelve years later, that building now saves $5000 annually on utility bills, and Chicago boasts 7 million square feet of green roof space. New York has followed suit, and since planting a green roof on the Con Edison Learning Centre in Queens, the buildings managers have seen a 34 percent reduction of heat loss in winter, and reduced summer heat gain by 84 percent.

But lower utility bills aren't the only benefit of planting a living roof. In addition to cooling down the city, green roofs create cleaner air, cleaner water, and provide a peaceful oasis for people, birds and insects in an otherwise polluted, concrete and asphalt-covered environment.

Image via Flickr/pnwra

Silicon Valley might have a corner on electronics, but a dark horse has been creeping up the ranks of clean tech innovation...Britain! In fact, the land of the London Fog was recently placed 10th in a new global ranking of the 38 countries providing the best conditions for clean-technology start-ups.

Here are three UK companies making quite a commotion with their creative and practical clean technologies. Keep an eye out for them!

1. Seawater Greenhouse

The Seawater Greenhouse provides enables year-round crop production in some of the world’s hottest and driest regions. This is accomplished using seawater and sunlight, which can be harnessed for a fraction of normal irrigation costs. The technology imitates natural processes, helping to restore the environment while significantly reducing the operating costs of greenhouse horticulture.

2. Naked Energy (pictured at top)

This company imagines a world in which no homeowner will ever have to choose between solar PV and solar thermal ever again. Naked Energy's Virtu vacuum tube technology is a hybrid solar module that generates both electricity and heat from the convenience of your rooftop. Performance testing of the panels is happening now Imperial College London and will be published early 2012. Early indications are that 'Virtu' produces unprecedented power output and is a step change in solar technology.

3. Zeta LED

The definition of a bright idea, the folks at Zeta Controls have created an LED bulb that looks different than any other. Offering just 13% of running cost of normal 60 watt incandescent bulb, the LifeBulb contains no mercury or harmful components and is completely recyclable. And it looks like it was plucked off the set of Star Wars.

Want to learn more about the up and coming British clean tech industry? Check out Clean and Cool Mission 2012 or stop by Cleantech Forum San Francisco over the next few days.

“I'd put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.”

“Anything that won’t sell, I don’t want to invent. Its sale is proof of utility, and utility is success.”

These might sound like quotes from individuals with opposing points of view, but they’re not. In fact, they were both uttered by the same person: Thomas Edison, father of the modern electric light bulb.

Edison embodied two things that tend to be lost in today’s discussion of energy dependence and new energy technologies: he was open to proactive change (even if it superceded his own inventions) and obsessed with practicality.

It can seem like the world is awash with ideas about our energy future, some are exciting, but decades away from being practical. To choose the right option—for consumers and for our economy—can seem daunting, but we don’t have to start from scratch. Building on Edison's research, we can begin to see that the answers have been there all along.

Eventually, Edison founded General Electric, a company that has been exploring the world of efficient energy technologies for over a century. Always with an eye to the future, GE has focused on improving existing power generation products as well as inventing new ones. From the first water wheel to harness the energy of Niagara Falls to the flexible, futuristic organic, LEDs, GE has strived to produce high quality products that make life better. In fact, GE's recently released data visualization tool aggregates all of their annual reports from the past 120 years and actually lets you track all the different energy-related products it’s developed over the decades.

Click on the word solar, and you’ll see the first mention pop up way back in 1946 when GE was first developing new ways to measure solar ray intensities. The first mention of wind power shows up in 1974 when the company worked with NASA to develop a wind generator. Fast forward a few decades, and you'll find advanced technologies for gathering both of these sources of renewable energy, like GE's thin film solar panels and high capacity wind turbines. While the potential is huge, and other countries are already taking advantage of these products, in America, the true energy generating capacity of wind and solar remains to be seen.

It's frustrating to realize the disconnect between availability and utilization of solar and wind power technologies, especially since most of the decisions are made by those with a vested interested in maintaining the status quo (Edison would be livid). The good news, however, is that the renewable energy industry continues to grow. And as GE’s new data visualization tool demonstrates, these technologies are a part of our national conversation now, more than ever. The key is to never become comfortable with what we’ve got, or afraid to push the boundaries of what’s possible.

This post was written in collaboration with GE as part of their new DataViz App available here.

Top Image Credit: Flickr - webhamster

Humans have tried to harness the power of the wind for thousands of years. We've tried every design in the book, from cloth sails to wind mills, and discovered that three blades are the most efficient design for a wind turbine. But that may be about to change.

With support from Nottingham Trent University's Future Factory project, Heath Evdemon is attempting to bring his dream of a very different type of wind turbine into reality. Instead of blades that rotate around a central axis, the Wind Harvester is based on a reciprocating motion that uses horizontal aerofoils similar to those used on aeroplanes. It is virtually noise-free and can generate electricity at a low speed, which may silence critics of wind turbines residential areas. It will also be operational at higher wind speeds than current wind turbines.

"We're looking for potential sites within the Peak District National Park at the moment and then we'll turn our attention to industry," said Evdemon, "but it's a product which could one day be rolled out to farms working towards becoming carbon neutral and homeowners looking for a cheap and sustainable source of power."

The Wind Harvester can be made in any size up to approximately 15 metres across and only needs to be approximately half a metre off the ground in prominent positions such as hills and hillsides, rock outcrops, and on domestic, farm and industrial buildings and structures. At any size, this unique turbine can be broken down into handleable pieces so installation will not require the use of heavy machinery, which is particularly relevant to environmentally sensitive areas.

Along with funding from Future Factory, Evdemon's company, Wind Power Innovations, has also received £28,000 from the Peak District National Park's Sustainable Development Fund and £3,000 from the Live & Work Rural programme. A large scale demonstrator is expected to be installed in the national park once it has been completed by the team.

Image credits: Wind Power Innovations

Not every country interested in pursuing renewable energy has vast swaths of land on which to erect solar and wind farms. That's why one Israeli start-up decided to explore a completely new terrain.

When someone mentions a solar power plant, most of us immediately envision rooftops or a vast field with no trees in site. But for smaller nations, like Israel, land is at a premium. It's hard for many to justify using huge swaths of land for solar energy production when, y'know, people could live there.

So instead of a land-based solar system, Solaris Energy decided to develop a water-based technology: a floating solar power plant.

The system concentrates a large amount of sunlight onto a small area to generate electricity by converting solar radiation into direct current electricity. It features a modular design that supports power output ranging from several kilowatts to dozens of megawatts. According to Solaris, the solution dramatically lowers the cost of energy production to a level far below national feed-in tariffs (FITs), making solar competitive and there for attractive to the government and investors.

While collecting the sun's energy, the Solaris Synergy floating concentrating photovoltaic (F-CPV) system also doubles as a water reservoir cover. Lowering exposure to the sun while enabling covered water to breathe, means that the system can significantly reduce water evaporation and eliminate organic and algae growth, while preserving water freshness and quality...all important features for a water-strapped country like Israel.

Learn more in the video clip below:

Image Credit: Flickr - via www.metaphoricalplatypus.com

After two years of development, the BioLite stove is in production, with a more compact and easy-to-use design.

We first we told you about the BioLite stove in July 2011, but just in time for the 2012 camping season, BioLite is making headlines again.

After extensive user testing and field research, the BioLite team has redesigned the camp stove unit to be smaller, easier to light and more durable. The BioLite stove burns wood or other small combustible materials. Using energy captured from the fire, the stove can power or charge small gadgets and cell phones. Currently in production, the BioLite camp stove will be available in the coming months but is ready for pre-purchase now.

In addition the BioLite camp stove, BioLite also developed a home stove for use in developing countries, to address the hazardous health issue of smoke inhalation. The BioLite home stove removes 90 percent of the dangerous smoke found in wood-burning stoves, providing clean and efficient cooking. In 2012, BioLite will be starting a large scale pilot program with the home stoves in Ghana, Uganda, India and Kenya.

To learn more about BioLite visit their website or to purchase click here.

Source: BioLite

MIT research scientist Andreas Mershin is on a mission to make solar power inexpensive and accessible to the masses, especially developing countries.

After years of research, Mershin and his team at MIT's Center for Bits and Atoms, along with University of Tennessee biochemist Barry Bruce, have worked out a process that extracts photosynthetic molecules from common agricultural waste.

How would this DIY solar kit work? Ideally, Mershin wants people to be able to gather up a pile of grass clippings, mix it with a blend of inexpensive chemicals, and paint it on your roof to begin harvesting electricity.

Mershin explains, "Leaves and plants are nature's solar panels… if we manage to somehow hijack the molecules that are responsible for photosynthesis in plants and other photosynthetic organisms, and use them to generate electricity for our own needs, this would represent a fantastic and disruptive new step in the way that we generate solar power or electricity in general."

Check out the video below to learn more:

One of the team's biggest challenges was figuring out how to preserve the light-gathering molecules they extracted from plants so that they still functioned outside of a cellular environment. Eventually, they were able to stabilize the chlorophyll-rich extract, also known as Photosystem I.

Here’s a breakdown of how the technology works: Mershin and his team have fabricated teeny tiny forest-like structures made of zinc oxide nanowires scattered with titanium dioxide "sponge” components. Then, the structures are coated with the plant extract, Photosystem I. When the coated structure is placed in direct sunlight, the harvested electricity can be stored and put to work.

Currently, the efficiency of these experimental cells is very low at 0.1%. With research groups like Mershin’s, the efficiency of biophotovoltaics is expected to rise to commercially viable levels (at least 1-2%) soon.

For more details, the team's findings are detailed in the paper Self-assembled Photosystem-I Biophotovoltaics on Nanostructured TiO2 and ZnO which is available at Nature.com.

Sources: Gizmag & MIT

Header Image: Best Design Options