Renewable Energy

This is the final post in  a series by Barbara Young.

Arguments for Solar Energy:

• Heating our homes with oil or gas or using electricity from power plants running with oil and coal is a reason behind climate change and climate disruption. Solar power, on the other hand, is clean and environmentally-friendly.

• Solar hot-water heaters require little maintenance, and their initial investment could be recovered in just a relatively limited time.

• Solar hot-water heaters can work in almost any climate, even very cold ones. You just need to choose the right system for your climate: drainback, thermosyphon, batch-ICS, etc.

• Maintenance costs of solar powered systems are minimal.

• Solar systems at present are generally designed for use by a homeowner or small business, decreasing dependence on large utilities and susceptibility to energy price fluctuations.

• Financial incentives (USA, Canada, European states…) can reduce the cost of the first investment in solar technologies. The U.S. government, for example, offers tax credits for solar systems certified by by the SRCC (Solar Rating and Certification Corporation), which amount to 30 percent of the investment (2009-2016).

Challenges of Solar Energy Systems:

• The initial investment in solar hot water heaters or in photovoltaic electric systems is greater than that required by conventional electric and gas heaters systems.

• The payback period of solar PV-electric systems is high, as are those of solar space heating or solar cooling (only the solar hot water heating payback is short or relatively short).

• It can be difficult to integrate solar water heating systems with existing radiators (including baseboard radiators).

• Some solar space heating and solar cooling systems are very expensive, and others use untested technologies: solar air conditioning so far has not been a truly economical option.

• The usefulness of solar-powered systems depends on sunlight resources. In colder climates, where heating or electricity needs are higher, solar produces the least useful energy.

This is the third in a series of guest posts by Barbara Young.

Solar power can be used in a number of different ways. There are two very basic forms of solar energy:

• Solar thermal energy collects the sun’s warmth through 1 of 2 means: in water or in an anti-freeze (glycol) mixture.

• Solar photovoltaic energy converts the sun’s radiation to usable electricity.

Here are five practical and popular applications for solar power:

1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden tools. Portable units may be used for RV appliances and other applications, while single panel systems are used for traffic signs and remote monitoring stations.
2. Solar pool heating. Running water in direct circulation systems through a solar collector is a very practical method to heat water for your pool or hot tub.
3. Thermal glycol as an energy storage medium used to heat water. In this method (indirect circulation), glycol is heated by the sun’s rays and the heat is then transferred to water in a hot water tank. This method of collecting the sun’s energy has become much more practical with recent innovations. In areas as far north as Edmonton, Alberta, solar thermal to heat water has become economically viable. It can pay for itself in 3 years or less.
4. Integrating solar photovoltaic energy into your home or office power. In many areas of the planet, solar photovoltaics, or PVs, are an economically feasible means to supplement the power of your property. In Japan, photovoltaics are competitive with other forms of power. In America, incentive programs make this form of solar power practical in many states.
5. Large independent photovoltaic systems. When you have enough sun power at your site, you could possibly go off grid. You may also integrate or hybridize your solar power system with wind power or other forms of alternative energy to stay ‘off the grid.’

D.J. adds: passive and active solar air heating are also worth mentioning, as are solar “batch” preheaters and solar hot water systems.  All of these, especially when self-constructed, provide significant cost savings.  In some parts of the world, solar cookers are viable.  Even where they aren’t practical, a solar food dryer can make sense.

(Leonardo.Bonanni photo: solar oven.)

This is the second in a series of guest posts by Barbara Young.

About 15 percent of the sun’s energy which hits the planet earth is reflected back to space. Another 30 percent is used to evaporate water, which, lifted in to the atmosphere, produces rainfall. Solar power is absorbed by plants, the land, and the oceans. Theoretically, the remainder could be employed to supply our energy needs.

People have harnessed solar power for centuries. As early as the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they would cause wood to catch fire. More than 100 years ago in France, a scientist used heat from a solar collector to create steam to drive a steam engine. At beginning of this century, scientists and engineers began researching ways to use solar energy in earnest. One important development was a remarkably efficient solar boiler invented by Charles Greeley Abbott, an American astrophysicist, in 1936.

The solar water heater gained popularity at that time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing prior to The second world war. This growth lasted prior to the mid-1950s when low-cost natural gas had become the primary fuel for heating American homes.

People and world governments remained largely indifferent to the possibilities of solar energy before oil shortages of the1970s. Today, people use solar technology to heat buildings and water and also to generate electricity.

(Thai Jasmine photo.)

This is the first in a series of guest posts by Barbara Young, who writes on solar panels in her personal hobby website 12voltsolarpanels.net. Her efforts are centered on helping people to use solar energy to eliminate CO2 emissions and reduce energy dependency.

Solar energy is radiant energy that is produced by the sun. Every day the sun radiates, or sends out, an incredible quantity of energy. The sun radiates more energy in a second than human beings have used since the beginning of time!

The energy of the Sun comes from within the sun itself. Like other stars, the sun is a big ball of gases––mostly hydrogen and helium.  The hydrogen atoms in the sun’s core combine to form helium and generate energy in a process called nuclear fusion.

During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. However the helium atom contains less mass than the four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

It requires countless years for the energy in the sun’s core to make its way to the solar surface, and slightly over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the velocity of sunshine.

Only a small percentage of the power radiated from the sun into space strikes the earth, one part in two billion. Yet this quantity of energy is enormous. Every day, enough energy strikes the U.S. to provide the nation’s energy needs for one and a half years!