Although solar power is currently a relatively small component of total US electrical power generation, contributing 144 Billion KWh of utility-scale electricity and an additional 61 Billion KWh of small-scale solar power in 2022 per the US Energy Information Administration
(EIA), for a total of approximately 5% of total generation, its share has grown rapidly since 2010 when it accounted for only approximatley 0.1%. Figure 1 shows the the increase in installed solar capacity since 2010, and Figure 2 shows the percentage of new generation capacity by technology over the past 12+ years, with solar currently accounting for approximatlely 45% of all new installations.
The major pros of solar power are:
- Clean energy requiring no combustion that emits no greenhouse gasses.
- Inexhaustible and abundant "fuel" supply wherever the sun shines. Figure 3 illustrates the electrical generation potential (in terrawatt-years) for each energy source on Earth, illustrating that solar potential dwarfs all others and could provide about 1,000 times as much energy as the entire world is projected to need in the year 2050. A single year of solar power also exceeds the total recoverable power potential from all non-renewable sources combined.
- Extremely versatile from individual rooftop systems, to distributed generation with multiple medium size systems, to large commercial scale systems.
- Technology exists today and is rapidly improving.
- Silent and no moving parts.
- Generates DC power and can be used to provide power for many uses without conversion to AC.
- Components have 25-30 year life and require minimal maintenance.
- Relatively low initial cost after significant price decreases in recent years as technology has advanced and manufacturing capability have increased. See OWOE: How much does it cost to build a new power plant?
- Relatively low operating costs.
The major cons are:
- Intermittent source that is not available at night or under clouds, although new technology such as Concentrated Solar Power plants with molen salt storage (Figure 4 - See OWOE: How can a solar power plant generate electricity at night?) as well as improving battery storage technology can help overcome this limitation.
- Requires additional hardware (inverter) to convert DC to AC current for typical power uses.
- Less available to supply heating demand (time of day and season).
- Exotic materials required in photovoltaic systems, although new technology and new materials are beginning to address this issue.
- Requires a relatively large amount of open space with associated aesthetic issue (See OWOE: How much land does a solar power plant require?).
- Relatively low efficiency (around 17-40 percent), although efficiency values have been steadily increasing with technology advancements.
- Distributed solar power (e.g. rooftop or community) will require modifications to current power generation infrastructure, which is based on large power generating plants located a long distance from the consumer.
- Limited recycling options for panels that have reached their end of life pose a potential waste disposal challenge.
With the sharp decline in the cost of solar generated power of the past few years, solar power is now the least expensive form of new energy development on a per KWh capacity basis in some markets, even when excluding various tax subsidies that are currently available. See OWOE: What is the cheapest method for generating electricity today in the US?
Of all energy sources, solar power has the greatest potential for technological advances to further reduce cost and improve efficiency.