The entire globe still heavily relies on fossil fuels instead of using solar energy, a free, environmentally friendly, and almost unlimited energy source to satisfy our energy needs. Why is that? The answer to this question is quite simple, fossil fuels are still considerably cheaper energy option compared to solar energy, and energy consumers are still not ready to pay higher prices, even if this means helping our environment and reducing climate change impact. Together with costs, fossil fuels technologies also have far better efficiency compared to currently available solar power technologies.
Solar energy industry still searches for its holy grail in form of cheap and highly efficient solar cells. There are many ongoing researches that offer some interesting solutions, but none of these solutions have the sufficient commercial component that would make it economically viable, and thus competitive with fossil fuels.
Standard solar panels installed on a house may convert only up to 15% of the sun's rays. What this means is that the large potion of available solar energy remains untapped and instead becomes waste heat. Even the most efficient solar panels available on the market today have efficiency of only around 20%.
Scientists use different approaches in their research of efficient and inexpensive solar photovoltaic panels. Some believe the key may lie in complex nanomaterials (carbon nanotubes) and semiconductors, while others focus on the process itself, not focusing only to materials used in process.
How difficult it is to improve efficiency of solar panels with currently available technologies? Many energy experts will tell you that improving efficiency of solar panels by only 5% would be a massive achievement, and this certainly answers the above question.
Photovoltaics are complicated technology, and in many cases when scientists try to improve efficiency their end result it even worse then it was in the beginning. The discovery of cheap and efficient solar panels is definitely one of the greatest scientific and technological challenges of our time.
Though fossil fuels currently have big advantages in terms of costs and efficiency compared to solar panels, fossil fuel industry still wakes up each day in fear thinking "what if today is the day when solar panels become cheaper and much more efficient?".