Category Archives: Renewables and Energy

Make Your Own Methane to Cook With Using Your Table Scraps

Posted on April 3, 2013 | Leave a comment

Feed the Biogas Digester: Biodigesters trap the methane gas from decomposing organic waste, such as manure and table scraps, and use it for producing electricity or cooking fuel. Methane is composed of carbon and hydrogen — CH4. It has an octane rating of 110 and produces about 1,000 Btu of heat per cubic foot of gas.

About five years ago, writer and renewable energy aficionado Warren Weismann was researching ancient Greece for his novel when he stumbled across information that the Greeks had built anaerobic digesters to produce methane. He then read about similar archaeological evidence in ancient Syria and China. But it was the modern biogas boom in China that got him most excited and distracted him from his writing career: Tens of millions of home-scale biodigesters have been built in China over the last century, with the pace of construction still accelerating. Warren wanted one for himself.

After a few years of further research, including conversations with colleagues in India and Nepal, where small-scale biogas production is prevalent, Warren modified traditional designs to create a plan for his own 700-gallon biodigester. He was living at Maitreya Ecovillage, a threeblock community and green-building-oriented neighborhood near downtown Eugene, Oregon. After building his first biodigester last year, he’s become increasingly excited about the possibilities for home-scale biogas, and has established Hestia Home Biogas to build biodigesters locally and consult on biodigesters across the globe.

Disclaimer: For information and entertainment purposes only

DIY Emergency Solar Power System

Posted on March 29, 2013 | Leave a comment

How can I build a small solar power system for backup power during emergencies?

Putting together a system that provides enough solar power to run a few key appliances during a power outage is certainly possible — and it’s also a fun and educational project.

Small backup solar power systems consist of a photovoltaic (PV) panel or two to generate the electricity, a battery to store the energy, a charge controller to keep the PV panel from overcharging the battery, and an inverter that converts the battery voltage into regular 120-volt alternating-current (AC) house power. All of these parts are easy to find, and connecting them is simple and safe as long as you follow the instructions. (You can also tap into easy, DIY solar-powered lighting — read more at Easy DIY Solar Lighting.)

Many variations of DIY solar power systems are possible, but the table below will give you a starting point. The equipment brands I chose are just examples. The batteries in these systems are oversized to allow for poor sun conditions, and you should only drain the batteries to their minimum capacity if you are confident that power will be restored promptly. Some off-grid folks who are careful about power consumption live year-round on systems no larger than the “Larger system” outlined below.

One good way to find a set of components is to search online for RV or cabin PV systems. Many suppliers sell kits of compatible components in various sizes.

You should keep the system’s batteries fully charged at all times, both to keep the batteries healthy and to have as much stored power as possible at the start of an outage. You can also find packaged systems that come assembled and wired except for the battery, which you can buy locally. This saves you the job of putting the system together yourself, but the price can be quite steep. And be careful — these systems are often advertised by the size of the inverter they use. Knowing the size of the PV panel and battery is much more important, as these determine what you can power and for how long, so be sure to look at the actual size of the PV panel and battery storage that any system supports.

DIY Solar Power System Options

Total Cost

What Will It Power?

Recommended Components

Minimum system (16 hours to fully recharge; provides 800 watt-hours)

About $250

A 7-watt LED light for 114 hours; a 20-watt LCD TV for 40 hours; or both for 30 hours

• Generic 60-watt. 12-volt PV panel

• 5-amp Morningstar SunGuard charge controller

• 12-volt, 80-amp-hour Interstate SRM-24 deep-cycle battery

• 150-watt modified sine wave Tripp Lite PV150 inverter

Larger system (7 hours to fully recharge; provides 2,200 watt-hours)

About $965

A 7-watt LED light for 314 hours; a 20-watt LCD TV for 110 hours; a 50-watt fridge for 44 hours; or all three for 29 hours

• 430-watt DMSolar 145 PV panel (three 12-volt panels, 145 watts each)

• 30-amp Morningstar SunGuard charge controller

• Two 6-volt, 225-amp-hour Trojan T-105 golf cart batteries

• 1,000-watt modified sine wave Tripp Lite PV100 inverter

Disclaimer: for information and entertainment purposes only

Buffett Firm Bets Big on Solar

Posted on January 3, 2013 | Leave a comment

Warren Buffet’s energy company has placed another big bet on solar power plants, spending up to $2.5 billion to buy two facilities under development by San Jose’s SunPower Corp.

A subsidiary of Buffett’s MidAmerican Energy Holdings Co. will own the 579-megawatt Antelope Valley Solar Projects, two power plants that will straddle the line between Kern and Los Angeles counties in the Mojave Desert. SunPower will manage the plants’ engineering and construction under a deal the companies reported Wednesday.

Construction is expected to begin in the next three months and wrap up in 2015, employing about 650 workers. Once complete, the plants will sell electricity to Southern California Edison under agreements already approved by California utility regulators.