When you think of clean sources of energy? The answer is Hydroelectric, geothermal, wind. But those sources of energy have significant limits on how much energy it can produce.
The sun is capable to generate energy billions times greater than we generated today and the expected lifetime of the sun is an estimated 4-5 billion years, making the sun the next truly long-term energy solution. The Earth receives only one part in 2.3 billion of the Sun's energy and solar energy is routinely used on nearly all spacecraft today. 40 years ago a renowned scientist Doctor Peter Glaser theorized about a concept of a space-based solar power due to the energy crisis. Later, this idea was followed up by the U.S. Department of Energy, NASA, and also major aerospace companies and countries such as Japan and India.
The next studies concluded that the only barrier for this type of technology is economics due to the fact that it would be a challenge to space-based solar power (SBSP) provide electricity at a competitive price.
Even though all viable energy option must be researched, space solar power offer advantages over other energy sources. Right now, are various ideas on how to build a space-based solar collection system in order to lowered the numbers
One of those ideas is to launch and assemble with a robot identically sized modules in “geosynchronous orbit”. The basic design of the SBSP would be mirrors concentrate sunlight onto solar panels that convert the energy into electricity. Then the electricity is converted in the SBSP into low-intensity microwaves that are transmitted to large, circular receivers on the ground. Those receivers on the ground converts the microwaves back into electricity and fed the existing grid.
Specialist John Mankins is developing the idea of the space solar power plant concept in greater detail. He says that we have knowledge to make these ideas possible.
Even though there a lot of work to be done in order to bring the SBSP, they are reasonably near-term and have numerous attractive approaches. Jhon Mankins and others scientist estimate the cost of $4 to $5 billion for implementing a space-based solar power plant and represents a fraction of the $28 billion price on China’s Three Gorges Dam.
One of the Critical aspects of this type of energy is the price per kilowatt-hour in comparison with the conventional technology. In order to make these types of technology a reality the price per kilowatt-hour should be lowered to double digits or even single digits of cents per kilowatt-hour.
Specialist engineer at the Naval Research Laboratory in Washington, Paul Jaffe developed one of the critical aspect of space solar. He worked on two prototypes of the collection module and he stated that
“The weight of each individual module ultimately determines the pricing of the distributed electricity on the ground; in terms of watts per launched kilogram, the basic tile design came in at around 6 watts per kilogram. Doing even really simple things to reduce the mass gets us into the 100 watts per kilogram range, and 1,000 watts per kilogram isn’t crazy”.
Some Critics of this technology say that isn’t feasible due the converting and reconverting of the power that is required, but the space solar power:
- Doesn´t emits greenhouse gases and does not compete for or depend upon increasingly scarce fresh water resources or compete for increasingly valuable farm land or depend on natural-gas-derived fertilizer unlike bio-ethanol or bio-diesel.
- Doesn’t produce hazardous waste, which needs to be stored and guarded for hundreds of years, is available 24 hours a day in huge quantities and is not an easy target for terrorists.
- Space solar power can be exported any place in the world and it can help develop the low-cost space transportation system that is required for its deployment.
Thanks to 
• Sunday - Light
• Monday - Darkness
• Tuesday - Animal Kingdom
• Wednesday - Structures
• Thursday - Forces in Nature
• Friday - LoveBeauty Freedom
• Saturday - Agriculture
Source
http://www.nss.org/settlement/ssp/
https://www.smithsonianmag.com/innovation/whats-next-solar-energy-how-about-space-180961008/
https://www.greenmatch.co.uk/blog/2014/10/space-based-solar-power