Solar Energy

- The Future of Solar Energy

The future of solar energy considers only two widely recognized technologies for converting solar energy into electricity-- photovoltaic (PV) and concentrated solar energy (CSP), sometimes referred to as solar thermal) -- for their current and plausible futures form. Since energy supply facilities typically last for decades, these categories of technologies will dominate solar power generation between now and 2050. 

As with other studies in this series, our main purpose is to inform policymakers in developed countries, especially the United States. We specialize in using grid-connected solar generators to replace traditional sources of electricity. 

For the more than 1 billion people in developing countries that lack a reliable grid, the cost of small-scale photovoltaics is often offset by the high value of electricity used to light and recharge mobile phones and radio batteries. Additionally, in some developing countries, it may be economical to use solar power to reduce reliance on imported oil, especially if the oil must be trucked to remote power generation sites. 

- Advantages of Solar Energy 

• Sustainability: The advantage of solar energy is that it is a sustainable alternative to fossil fuels. While the expiry date of fossil fuels may be imminent, the sun is likely to exist for at least billions of years. 
• Low Environmental Impact: Compared to fossil fuels, the impact of solar energy on the environment is greatly reduced. Its greenhouse gas emissions are irrelevant because the technology does not require any fuel to burn. Also, while concentrated solar thermal power plants (CSPs) are relatively inefficient with water depending on the type of technology used, the right technology can significantly improve efficiency, while photovoltaic (PV) solar cells do not require any water to generate electricity. Solar technology is emerging as a more cost-competitive alternative to fossil fuels, although it remains somewhat expensive in some markets.
• Energy Independence: As the sun shines across the globe, it makes every country a potential energy producer, allowing for greater energy independence and security. Not only does solar power promise to bring security and independence at the national level; solar panels can be installed in individual homes, providing electricity that is not dependent on being connected to a larger grid.

- Disadvantages of Solar Energy

• Intermittent: One of the biggest problems with solar technology is that energy can only be produced when the sun is shining. That means nighttime and cloudy days could disrupt supply. Shortages caused by such disruptions would not be a problem if there were low-cost ways to store energy, since sunny periods would actually create excess capacity. As the world's solar power generation capacity continues to increase, countries such as Japan and other global leaders in solar technology are working to develop enough energy storage to solve the problem.
• Use of Land: Another concern is that solar energy could take up a lot of land and lead to land degradation or loss of wildlife habitat. While solar PV systems can be anchored to existing structures, larger utility-scale PV systems may require as much as 3.5 to 10 acres per megawatt, while CSP facilities require 4 to 16.5 acres per megawatt.  However, impacts can be reduced by placing facilities in low-quality areas or along existing transport and transmission corridors.
• Material Scarcity: Certain solar technologies require rare materials in their production. However, this is primarily an issue with PV technology rather than CSP technology. Furthermore, it is not so much a lack of known reserves that current production is unable to meet future demand: many rare materials are by-products of other processes rather than the focus of targeted mining efforts. Nanotechnology advancements in recycling photovoltaic materials and improving solar cell efficiency are both helping to increase supply, but perhaps finding more abundant material alternatives could play a role. 
• Environmental Disadvantages: One environmental disadvantage of solar technology is that it contains many of the same hazardous substances as electronics. As solar energy becomes a more popular energy source, the issue of disposal of hazardous waste becomes an additional challenge. However, the reduced greenhouse gas emissions offered by solar energy make it an attractive alternative to fossil fuels, assuming the challenges of getting it right are met.

[More to come ...]