Currently, solar power costs about significantly more then electricity production through hydro, coal, natural-gas and nuclear technologies. The technical limitations include:
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.
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 currently only convert about 22%, on average, 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% - but at a higher cost. 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. An even newer technology, solar sunflowers, has an incredible efficiency of around 80%.
These new technologies are extremely expensive to manufacture and the question is whether the additional cost offsets their gain in efficiency. To make higher-efficiency solar panels more accessible to the average person:
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.
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 may also make the installation costs cheaper because fewer panels will need to be installed. For example:
Fewer mechanical mounts will be required and less labor would be needed to install fewer panels, again reducing costs for the consumer.
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. Some people claim that they have been able to recondition and use old batteries, thus saving considerable expense.
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 to this point. However, we're still many years away from the point where the average homeowner can turn to solar power for a significant portion of their energy needs.