High-altitude Wind Power

Flying electric generators, sometimes called tethered rotorcraft, use wind power to keep themselves airborne and at the same time to generate electricity. Operating at altitudes above 15,000 feet, the northern and southern hemisphere jetstreams provide the ideal strong reliable wind conditions for rotorcraft.

High altitude Rotorcraft solve the visual and noise problems inherent in terrestrial wind turbine farms. High altitude rotorcraft are also less likely to strike birds and bats.

During lightening storms, rotorcraft are winched back down to earth, causing a disruption in power generation. To avoid wind turbulence, rotorcraft can be moved to a different altitude much like an airliner that selects an altitude to achieve the smoothest possible ride.

Research is required to design, develop, and test the best tether. Tethers are many miles in length, must be lightweight so that they can be supported by the rotorcraft, and must be capable of transmitting high voltage electrical current down to earth.

Rotorcraft will be primarily deployed in existing no-fly zones, outside of aircraft flight paths, and away from population centers.

Sky Wind Power in San Diego is actively developing a 240kW rotorcraft and new tether technology. Current focus is on a four rotor design where each rotor has 2 blades. The best available tether technology uses insulated aluminum conductors in a vectran carbon composite shield. A series of test flights is planned to determine the optimum altitude and proximity to the jet stream.

Capturing Waste Heat

Many processes generate heat as a by-product. Most often the heat by-product is dissapated and thus wasted. Example processes that generate waste heat include: incineration, electricity generation, water heating, manufacturing, central heating, and turning an engine.

If waste heat could be captured and stored, it could potentially power other processes at very low cost. Hi-Z has developed a number of thermoelectric modules (TM) that convert low-grade waste heat into electricity.

The TM resumbles a hot pan holder. Composed of bismuth telluride-based alloys, Hi-Z's TM requires a heat flux of approximately 8 watts per cm2 to generate electricity. At 200°C, the Hi-Z TM converts 5% of the thermal energy that passes through it into electricity, generating 14 watts. It will work without maintenance for tens of thousands of hours when properly installed. It is most effective when tightly compressed and electrically insulated between a heat source and a heat sink. A spring-loaded pressure plate that allows for thermal expansion is ideal.

The result is a TM layer in close surface contact with a heat emitter. The TM will then produce electricity whenever there is heat.

Efficient Hydrogen Generation

The World Business Council on Sustainable Development (WBCSD) publishes an amazing number of high-quality reports and E-newsletters. One of today's E-newsletters included a story about Pennsylvania researchers who have developed an efficient process for generating hydrogen from biodegradable organic material.

In a process called electrohydrogenesis, an electrical charge is applied in a microbial fuel cell. The energy in the hydrogen created is nearly 3x that of the electrical charge applied.

Here's a link to the full text article .

Surf's Up

For most of its history Float Inc has developed large pneumatically-stabilized off-shore floating platforms for various industrial and military applications. Float is now developing technology that uses the movement of ocean waves to generate electricity. Here's an excerpt from Float's web site:

Wave energy is, in effect, a stored and concentrated form of solar energy, since the winds that produce waves are caused by pressure differences in the atmosphere arising from solar radiation. Waves transmit this energy thousands of miles with minimal loss. Wave size is a function of the wind's speed, how long it blows, and fetch, which is the distance over which it blows.

The Oscillating Water Column (OWC) has been shown to work well in calm conditions and in high-surf conditions. It also has a minimal number of moving parts so it can survive in salty, wet condition for a long time. An OWC is a vertical hollow pipe or column that is partially submerged and held stationary. As the water level inside the column goes up and down with wave movement, the air in the upper end of the column enters and leaves. It is this air movement that is captured to turn a turbine.

Float Inc.'s floating platform product's perimeter is coincidentally lined with columns that attenuate the water motion and stabilize the platform. These existing columns then serve double duty as electrical generators.

Alternative Fuels

On November 8th, the California Center for Sustainable Energy (CCSE) hosted a small alternative fuels conference organized by the San Diego Regional Clean Fuels Coalition and the San Diego Regional Sustainability Partnership Transportation Committee. The morning agenda was excellent.

Joanna Underwood convincingly argued in her keynote that natural gas is the only sensible stepping stone to a hydrogen economy. She noted that natural gas is H4C, which is mostly hydrogen, and that natural gas cars will run on hydrogen when it becomes cheap and plentiful. "We went from Kitty Hawk to the moon in 50 years".

Dave Richards argued in favor of bio diesel, but, in my opinion the pollutants resulting from combustion, although mitigated, are just not worth it.

Subscribe at www.energycenter.org to receive calender alerts about other upcoming conferences and events.

Survey of San Diego CleanTech

At a recent Greenovations meeting at UCSD I met Nathan Owens, the lead author of a cleantech report commissioned by the City of San Diego. In the report, Nathan establishes clean technology criteria, and then describes 143 companies that meet his criteria. The excellent report is on the www.sandiego.gov site here .

Urban Energy Plants

San Diego Gas & Electric (SDGE) has set a goal of delivering 20% of its power from renewable sources by the year 2010. Toward this goal, SDGE has contracted with Bull Moose Energy to purchase 20 megawatts of electricity in 2008, sufficient power for 20,000 homes. Bull Moose will create the power by gasifying wood that would otherwise have been dumped in a landfill.

Bull Moose Energy was founded in 2005 to develop alternative energy power production systems. Bull Moose's first eco-friendly facility will use biomass waste products to produce electrical power. Several hundred tons of green waste per day will be gasified. The 20-acre facility will be located in Otay Mesa, a suburb of San Diego that is targeted for commercial revitalization. Additional installations are being planned for municipalities throughout the U.S.

The Bull Moose biomass energy production system reportedly burns cleaner than natural gas using fuel that is comprised primarily of green waste, such as tree trimmings.

Morgan Stanley recently committed to investing up to $60 million in Bull Moose to finance the development of next generation biomass power production plants near urban centers.

Energy Management Systems

Wikipedia defines an Energy Management Systems as, "a system to control, monitor, and optimize the generation and flow of Electric Power." Founded in 2002, San Diego-based P&E Automation is a leader in the EMS field. P&E provides consulting services for: energy audits, energy conservation engineering, feasibility studies for solar & co-generation power production, LEED certification, measurement & verification, and systems integration. Past P&E projects include energy use analysis, designing conservation systems, integration, installation, commissioning, and marketing campaigns for energy management technologies.

P&E has also created a web-based EMS Suite focused on facility Intelligence. Their most recent product is EnergyConsole, an end-to-end hosted EMS that provides building automation, optimization, energy accounting, and equipment diagnostics for commercial, industrial, and government facilities. EnergyConsole will also aggregate and summarize information for geographically dispersed facilities.

An Auto Automobile

This 3-seater autonomous vehicle from French car maker Venturi requires no gas, no hydrogen, and no wall socket. It charges itself via solar panels on the roof and/or via a deployable wind turbine. Its called the Eclectic.

Falling into the category of vehicles known as Neighborhood Electric Vehicles, the Eclectic NEV has a range of 50KM (31 miles) on a full charge and an maximum speed of 50KMH. During a full day of sunlight, roof-mounted solar panel will generate and store sufficient power to propel the vehicle 7KM (4.4 miles). The external wind turbine will generate and store sufficient power to propel the vehicle 15KM. If you need more range than that, you can plug it in to give the NiMH batteries a full charge. The vehicle weighs 880 pounds and will cost € 24,000 plus VAT when the first 200 go on sale in March, 2008.