Solar panels are still not cheap. According to the Center for Sustainable Energy, the average cost for solar panels is $3–$5 per watt, totaling $15,000–$20,000 for a typical 5 kilowatt (kW) system.

Solar energy is only generated while the sun is shining. That means nighttime and overcast days can interrupt the supply and there is a need for a backup energy source.

Low insolation values in many areas of the world which results in reduced solar panel efficiency.

Relatively low efficiency of solar panels. The efficiency of solar panels is currently at around 20{7bfcd0aebedba9ec56d5615176ab7cebc5409dfb82345290162ba6c44abf8bc8} meaning there is much room for improvement because lots of available energy gets wasted in the process.

Fossil fuels are cheap, reliable, and familiar, because they’ve been around for longer and our industry was built on them. 

Powerful fossil fuel lobbies such as oil lobbies. The use of fossil fuels has long history and powerful lobbies who support them and have a negative impact on solar energy development.

Solar farms require very large areas. Solar developers will require a minimum of 10 acres of usable land or 200 acres for a utility-scale project.

Solar energy storage is very expensive. Most residential solar panels are paired with lithium-ion batteries, which cost anywhere from $7,000 to $14,000 to install.

The lifespan of solar panels is around 25 years, and there is still no adequate solution for their recycling in many areas of the world.

Manufacturing solar panels can harm our environment. Some of the materials required are quite rare, and the panels are usually shipped from other countries, producing carbon emissions in the process.