I have no idea what these solar panels are going to be used to power. If I had to guess, I would say that there are batteries under the seating and the power will be used to provide lighting after dark. The lower one of the two collectors in the close-up shot looks like it might have a light fitting there. And if it is light the rest of the Venetian public lighting we saw, it will be using CFL, or perhaps another low power technology (perhaps LEDs).

The first article, in Inhabitat, talked about a solution from Australian company Going Solar. Their idea combines solar panels with a sound barrier along the sides of freeways that pass through residential areas. This cuts the noise level in the houses, while at the same time supplying them with electricity.

Local Distribution
While the roadside system may not be ideal for solar, it does have the benefit of being relatively local to the places where the power is needed. Some of the larger wind and solar projects being talked about for remote areas of the US at the moment are facing the problem of getting the power from the remote location to the towns & cities where it is needed. Our aging power grids are not able to cope, so these projects find themselves being able to generate plenty of green power, but not being able to get it to the people who need it easily.

Going Solar’s roadside solution brings the power generation closer to the homes that need it, reducing the distribution problem to essentially the last mile.

Stored Heat
The other article I read about energy from roads was about using the actual asphalt. Our roads are essentially a massive network of solar energy collectors. Anybody who has walked barefoot on a road surface on a hot summer’s day knows just how hot the roads can get. Even better, that heat is retained for a long time after the sun goes down.

Worcester Polytechnic Institute scientists have been working on a plan to collect that heat energy using a heat exchanger embedded in the road surface. As roads are resurfaced, the heat exchangers could be embedded in them. The hot water flowing out of the heat exchanger can then be used to generate power, or even just as hot water!

At the moment it is still very experimental; the test surfaces the team have been using have copper pipes embedded in them which will need to be changed for a practical solution, but nonetheless it is a promising idea for reusing an existing infrastructure for another purpose. Also, removing the heat from the roads has the added benefit of helping to reduce the heat island effect of dense urban areas.

One is with High Plains Ranch II, LLC, a subsidiary of SunPower Corporation, for 250 MW of solar power. The other is with Topaz Solar Farms LLC, a subsidiary of OptiSolar, for 550 MW more.

As we commented last week, solar power is currently a very small part of the power mix for PG&E, and in fact for the state of California as a whole, contributing less than 1% today. Investments like these two will go some way to turning that around, and making better use of that environmentally sound solar energy that warms and lights the state every day.

The table below shows the projected 2008 mixes for PG&E and Alameda, alongside the 2007 mix for the whole state. As you can see, Alameda Power & Telecom is doing a pretty good job of using renewables (79% total when you include the large hydroelectric mix), whereas PG&E, one of the largest electricity utilities in the state, is still reliant on natural gas and nuclear power.

It would be nice to see solar playing a larger part in that mix too. Perhaps over the next few years, as some of the larger solar power station projects come on line, that number will increase for both companies.

How does your local utility do when it comes to the use of renewable energy sources?

Earth2Tech has a list of ten companies who have provided some eco-friendly equipment for the games. Everybody from LED lighting experts Cree, who provided LED displays for the swimming cube and the bird’s nest National Stadium, to companies like GE who are involved in all kinds of projects at the games, including wind turbines, solar lighting and even rainwater recycling.

Hong Kong
While most events will be held in Beijing, the equestrian events will be taking place in newly built facilities in Hong Kong. Horse events are not new in Hong Kong – the race track has been an important part of the city since it was created by the British.

The new facilities have been designed and constructed to respect the environment. Internal structures are use bamboo; the rubber floors are all made from recycled tyres and all the organic waste is collected and taken to a worm farm to be converted into natural fertilizer.

The reason CPV systems are interesting is that the cost of the collector is generally lower than the same area of solar cells. The catch is that the solar cell needs to be cooled (solar cells operate best when cool). Also, a CPV system is less effective on overcast days because the light striking the concentrator is diffused by the clouds.

Stirling Engine
Stirling Energy Systems is developing a similar system, but replacing the photovoltaic cell with a stirling engine. Their first project, in the Mojave Desert in southern California, is planned to generate 850MW of power, and the second (also in southern California) will reach 900MW.

Sounds a bit silly when put like that, but the part that I missed out is that there is a time delay between splitting the water and using it to generate electricity.

Storage
Solar panels on the roof of the house generate electricity while the sun shines on them during the day, but at night they’re not generating anything. Additionally, during the day many houses are using less power since their occupants are out at work. The MIT plan is to use the excess energy from the panels during the day to split water into its two constituent gases, and store those in tanks in the house.

At night, when the panels are not generating any power, the hydrogen and oxygen are fed from the storage tanks into a fuel cell, generating electricity for the house’s night time needs (and water which can be split again the next day).

This video from MIT explains it in more detail:

Click To Play

Why Not Use Batteries?
Good question. Solar installations for off-grid projects will often make use of batteries to solve this problem of time shifting the power. The reason the hydrogen fuel cell idea is interesting comes down to energy density. A lithium-ion battery has a density of around 2.5 MJ/kg; a lead-acid battery is around 0.1 MJ/kg. Hydrogen has a density of 143 MJ/kg. So, storing the energy in the form of hydrogen makes sense as long as you can generate the hydrogen efficiently; and that has been the problem until now. The real breakthrough the MIT team claims to have made is in being able to efficiently split water into hydrogen and oxygen, and to do so using materials that are plentiful.

[Via Earth2Tech]

The energy from the solar panel is collected by a small lithium-ion battery pack inside the bag, so your device can charge day or night using the energy collected from the sun.

[Via Inhabitat]

Unlike developed nations, many of the places where this technology was designed to be deployed lack electricity, so the Green Wi-Fi project designed a self-contained unit consisting of a solar panel, charge controller and battery for power, and a modified Linksys WRT54GL wireless router with a high gain external omni-directional antenna for the internet access part. These boxes form the nodes of a self-healing mesh network. Connect one or more of them to the internet somehow (often via a cellular modem) and you can share that connection across the entire mesh. Since the boxes need no external power, they can be placed on rooftops anywhere to build up the mesh.

Got Wi-Fi, Now What?
Having a solar powered Wi-Fi mesh alone doesn’t get you much, so what else is needed to make this useful? Well, the most obvious thing that is needed next is computers, and the OLPC project’s XO laptop makes a perfect device for use with the mesh Wi-Fi network. The team at Green Wi-Fi have also developed solar charging solutions for these little laptops, allowing a school to have a collection of them which can be charged using a panel mounted on the roof of the school building.

Bruce Baikie, Green Wi-Fi’s CEO, just returned from a trip to Senegal along with a group of high school volunteers from San Francisco, where they delivered 25 OLPC laptops to the village school, and installed a 60W solar charging station for them too. The US high school students also trained the village’s teachers how to use and maintain the new laptops, as well as helping to repair school rooms, desks, the village health clinic, bathrooms, roofs, and anything else they could help with. Later this year Bruce will be returning to install a Wi-Fi mesh (they currently have just a single network connection provided by a very power-hungry, and somewhat unreliable, CDMA modem).

Photos from Senegal

[Senegal photos with thanks from Bruce Baikie @ Green Wi-Fi.]

While I was out the other day I came across a couple of solutions for charging portable devices, like iPods & media players, iPhones and other mobile phones, GPS navigation units or portable gaming devices using the energy of the sun. The two models I saw in the store were the Solio Universal Hybrid Solar Charger and the Solio H1000 Hybrid Battery Charger.

Of the two, the H1000 was perhaps the most appealing to me, simply because I’m not such a big fan of the fan out operation on the other model. Both have an internal battery that is charged by the solar panel, and can then be used to charge your external device. That means you can leave the charger in a sunny place all day, and then top up your phone from it overnight. And using solar power instead of leaving the phone’s AC charger plugged in all day, reduces the phantom power drain too (unplugging that AC adapter when you’re not using will help there too).