Renewable, sustainable, clean energy. Science is searching for a solution that can replace our dependency on fossil fuels for electricity. Solar panels are key contender to the solution in addition to other forms of clean, renewable energy such as hydropower, wave power, and wind power. While these are proven technologies that are currently used to reduce our dependency on non-renewable energy sources, they have their limitations.
“ Currently, there is no way solar and wind energy can sustainably power Earth.”Forbes.com
There are two key limiting factors to how much energy can be generated through terrestrial solar panels. Firstly, the rotation of the planet means that no solar energy can be collected during the night time. Secondly, the atmosphere helps to filter the dangerous levels of incoming solar radiation. This function of the atmosphere helps to make the planet liveable for humans and other forms of life. The remaining radiation gets reflected back into space.
“About 30% of all incoming solar radiation never makes it to ground level.”energy.gov
This is where Space-Based Solar Power comes in. The solar panels will orbit the Earth, collecting the suns rays and sending them to the Earth’s surface. There are two solar satellites concepts which have been modelled: laser solar satellites and microwave solar satellites.
Laser Solar Satellites
Laser solar satellites have a lower start up costs (around $500million to $1Billion) as they:
- Are self assembling, lowering the costs and associated risks of assembly
- Use laser technology to beam the energy from the satellite to Earth’s surface. The laser beam will have a smaller diameter than its microwave counterpart making it simpler and cheaper to implement on the ground.
The laser satellites would be cheaper, however the technology is not without its drawbacks:
- Several satellites would be required to produce a substantial amount of energy as each individual one is low powered (1-10 megawatts per satellite) when compared to Microwave Solar Satellites
- There are safety concerns with having lasers in space such as blinding and weaponisation
- The laser would have trouble beaming through heavy clouds and rain, meaning weather will still be a limiting factor to energy production.
Microwave Solar Satellites
Microwave solar satellites individually generate more energy, but are more expensive and more difficult to assemble in space.
- Each satellite can beam over 1 gigawatt of energy to a terrestrial receiver. This is enough to power a large city.
- Production and assembly costs will be in the range of tens of billions of dollars as assembly in space will be required with close to 100 launches needed In the process.
- The long distance between the satellite and Earth would make it nearly impossible to repair damages or malfunctions.
- Terrestrial receiver would have to be several kilometres in diameter, but the microwaves are safe to transmit through the air. The intensity of the microwaves will be no greater than the midday sun.
- Microwave beam will be able to reliably transmit energy through rain, clouds, and other atmospheric conditions unlike laser alternatives.
Wireless Power Transfer
This is the technology I think has the most potential for issue. The microwave beam transmission would require a kilometre wide receiver, and the laser beam transmission could be used for space war fare. The technology is currently being researched by Caltech, but the safety of the technology needs to be greatly considered before it can be implemented.
“More solar energy energy reaches the Earth in an hour than humans use in a year.”energy.gov
Advantages of Solar Based Energy
- There is no need for a large scale electricity grid. Energy can be transmitted to rural locations without them having to be connected to the larger grid.
- Abundant clean energy.
Disadvantages of Space Based Solar
- Geopolitical playing field
- Potentially high risk
- Laser Solar Satellites could be seized and used as weapons
- How reliable is the technology. What if a satellite gets hit by space debris or a asteroid? If we are reliant on this technology, what happens if it becomes damaged?
Space-based solar energy is a potential resource that can be used for a virtually limitless supply of clean energy, unaffected by weather or time of day. For as long as the sun shines and we have the technology to harness its energy, we will always have electricity.