There’s No PlaceLike a Solar Home

By Katie Lopez and Katie Bailey

Why Solar Power?

Power plants that burn coal, oil and natural gas, as well as vehicles everywhere, continue to pour millions of tons of pollutants and greenhouse gases into the atmosphere annually, threatening the planet’s well-being.

How We Can Fix This

A massive switch from coal, oil, natural gas and nuclear power plants to solar power plants could supply 69 percent of America’s electricity and 35 percent of its total energy by 2050.

Why Isn’t This Happening Now?

The federal government would have to invest more than $400 billion over the next 40 years to complete the 2050 plan.

Although the Cost is High, the Payoff is Even Greater

Solar plants consume little or no fuel, saving billions of dollars year after year.

The plan would effectively eliminate all imported oil, fundamentally cutting U.S. trade deficits and easing political tension in the Middle East and elsewhere.

Cont’d… The plan would also reduce

greenhouse gas emissions from power plants by 1.7 billion tons a year, and another 1.9 billion tons from gasoline vehicles would be displaced by plug-in hybrids refueled by the solar power grid.

In 2050, U.S. carbon dioxide emissions would be 62 percent below 2005 levels, putting a major brake on global warming.

Solar Energy Can Help

Solar energy’s potential is off the chart. The energy in sunlight striking the earth for 40 minutes is equivalent to global energy consumption for a year.

Land Available in U.S. At least 250,000 square miles of land

in the Southwest alone are suitable for constructing solar power plants

That land receives more than 4,500 quadrillion British thermal units (Btu) of solar radiation a year

Converting only 2.5 percent of that radiation into electricity would match the nation’s total energy consumption in 2006.

How to Get Solar Power Working

To convert the country to solar power, huge tracts of land would have to be covered with photovoltaic panels and solar heating troughs

Direct-current (DC) transmission backbone would also have to be erected to send that energy efficiently across the nation.

Solutions

Photovoltaic Farms

Pressurized Caverns

Hot Salt Direct Current

Photovoltaic Farms

Made up of thin films (cadmium telluride)

To provide electricity at $.06 per kWh by 2020, cadmium telluride modules would have to convert electricity with 14 percent efficiency, and systems would have to be installed at $1.20 per watt of capacity.

Cont’d…

Current modules have 10 percent efficiency and an installed system cost of about $4 per watt.

Commercial efficiencies have risen from 9 to 10 percent in the past 12 months.

As modules improve, photovoltaic cells on rooftops will be used more by homeowners, reducing demand for electricity during the day

Pressurized Caverns These allow the energy that is produced during

sunny hours to be stored during dark hours. Usually batteries are used, but these have proven

to be expensive and inefficient. Compressed-air energy storage has emerged as a

successful alternative. Electricity from photovoltaic plants compresses air and pumps it into vacant underground caverns, abandoned mines, aquifers and depleted natural gas wells.

In turn, the pressurized air can be released on demand to power a turbine, which generates electricity.

Cont’d…

The cost of compressed-air energy storage today is about half that of lead-acid batteries.

Pressurized caverns would add three or four cents per kWh to photovoltaic generation, bringing the total 2020 cost to eight or nine cents per kWh.

Hot Salt This process uses long, metallic mirrors

to focus sunlight onto a pipe filled with fluid, heating the fluid.

The hot fluid runs through a heat exchanger, producing steam which turns a turbine, in turn generating electricity.

To store energy, the pipes run into a large, insulated tank filled with molten salt. The salt retains heat efficiently and allows for heat to be extracted at night, creating steam to generate electricity.

Cont’d…

One drawback is that the molten salt cools down, so the stored energy must be used within a day.

Concentrated solar power is practical, but costly. Technology must improve before concentrated solar power becomes a feasible option.

Direct Current Currently, power plants exist in clusters

near where energy is needed. For solar power, most of the generators would need to be in the Southwest.

The existing system of alternating-current (AC) power lines is not able to carry power from solar energy centers in the Southwest to consumers across the nation. AC lines would also lose too much energy over long hauls.

A new high-voltage, direct-current (DC) would replace the old AC lines.

Cont’d… The backbone of the DC lines would

radiate from the Southwest toward the nation’s borders.

The DC lines would end at converter stations, where the power would be switched to AC and sent along existing lines that supply customers currently.

DC lines are cheaper to build and require less land area than equivalent AC lines. In addition, no new technology is required to implement the use of DC lines.

Lowered Energy Consumption Converting to solar energy would actually

lower energy consumption. Even if energy demand grows one percent

annually, the 100 quadrillion Btu consumed in 2006 could potentially fall to 93 quadrillion Btu by 2050.

Extracting and processing fossil fuels consumes a great deal of energy, as does burning them and controlling their emissions.

The energy saved from not using fossil fuels would provide an excess of energy, essentially lowering demand.

Eco-Friendly

Solar energy is much more eco-friendly than are fossil fuels because it does not pollute the environment.

How to Pay for Solar Energy The switch to solar energy would most

likely cost around $420 billion. One option to combat the price is to

implement a carbon tax, which would induce electricity generators to adopt carbon capture and storage systems to reduce carbon dioxide emissions.

Congress could also adopt a national renewable energy plan.