Will Solar Power Breakthroughs Make this Alternative Energy Source More Accessible to Homeowners?

Consumers are becoming more environmentally-conscientious. The increasing interest towards "greener" technologies makes solar power an alternative energy source that's worth considering. With solar power breakthroughs on the horizon, this pollution-free energy source will be seen more in our homes and in society at large.

Currently, solar power costs about 6-10 times more then electricity production through hydro, coal, natural-gas and nuclear technologies. The technical limitations are:

• Low efficiency of the semiconductor (about 22%).
• Large amounts of land required to concentrate enough energy.
• Expensive manufacturing costs.
• Limited storage capacity of batteries.

Engineering and scientific solutions are trying to address these major problems. The goal is to make solar power production as affordable as coal-fired generation.

HIGHER EFFICIENCY SEMICONDUCTORS

Solar cells are composed of silicon doped with phosphorous and boron (See: How do solar cells work?). These elements are readily available and the electronics industry has mastered the specialized manufacturing techniques required to produce cost-effective semiconductor material.

However, solar panels only convert about 22% of the sunlight that strikes the surface into electricity. The rest is reflected or wasted as heat.

New technologies using gallium, indium, germanium and phosphorus, have provided efficiencies up to 40%. Doubling the efficiency means that only half the amount of equipment or half the amount of land is needed to produce the same amount of power.

These new semiconductors are extremely expensive to manufacture and the additional cost does not offset their gain in efficiency. To make these solar panels more accessible to the average person:

• More research is needed to bring down the cost.
• More mining is required to increase the supply of these elements.
• More manufacturing capacity is needed to bring down assembly costs.

CONCENTRATED SOLAR POWER

Focusing sunlight with a lens concentrates more energy into a small area. A solar cell can be placed at the focal point to create more energy. This technique may be more cost-effective because a large, plastic lens is less expensive than a solar panel of the same size. However, the solar cell will have to withstand the high temperature of the solar beam or else it could disintegrate or melt.

Since some of the sunlight will be wasted as heat, a reliable cooling system is required to remove the excess heat from the solar cell.

BETTER MANUFACTURING TECHNIQUES

There are two ways in which factories can reduce the cost of solar panels. First, as factories become larger and more efficient, they increase the economy-of-scale of production. If it can output 100 units every minute, the additional cost of increasing it to 101 units is minimal. The more units it outputs, the cheaper the cost, which can then be passed on to the consumer.

Second, increasing the size of the solar panels will also make the installation costs cheaper. For example:

• If a solar panel is 3’ x 4’ then a 144 square foot roof will require 12 panels (144/12 = 12).

• If a solar panel is 4’ x 4’ then the same 144 square foot roof will require only 9 panels (144/16 = 9).

Fewer mechanical mounts will be required and less labor would be needed to install fewer panels, again reducing costs for the consumer.

BATTERY STORAGE

When sunlight isn’t striking the solar panel, electricity is not being produced. Homeowners certainly wouldn't appreciate a blackout whenever a cloud goes overhead, or after sunset! Therefore, batteries are required to supply energy whenever there is an interruption.

Existing deep-cycle batteries are expensive and hold only limited charge. To provide enough power for a household, an extremely costly and heavy battery bank is required.

New research from the automotive industry is showing that batteries made from lithium and other rare earth elements can hold more energy, recharge more quickly, and perform better at low temperatures. Unfortunately, mining these elements is difficult and expensive and the supply is limited. Once researchers figure out how to tap into a larger, more stable supply, then the price of these efficient batteries could drop to a level that's more accessible to the average homeowner.

Solar power breakthroughs have made great strides in recent years to get us to this point. However, we're still years away from the point where homeowners can rely on solar power for a significant portion of their energy needs.