Back about 1981 one of my fellow engineers and I got the urge to try to get a little 'free' energy from the sun. He found a source of glass panes at a good price, so together we purchased about 2 1/2 tons of glass panes. At the time I owned a brick Cape Cod in Maryland. It faced a little west of south with minimal shading on the front side, so I built a removable set of large glass panels that basically covered the front of the house. I could remove them in the summer months and enjoy some free solar energy in the winter. I learned later that my abode became known locally as the 'glass house'.
When the sun was shining in the winter the panels gave me a 'low tech' solar collector of about 250 square feet, with the brick walls acting as the absorber. The temperature behind the panels would climb into the 70s even for outside temps in the 20s, which meant that about 30% of my exterior walls thought it was summer. In fact, if I was home I would open the windows behind the panels and enjoy the warm air heating the front rooms.
Of course, even though I got an encouraging return on my fairly low cost investment, I only gained when the sun was shining. To be useful as a primary source of heat, it would be necessary to store the energy for retrieval during nights and cloudy days. So before expanding my system, I did a little research on energy storage systems.
My crude low cost system used the low tech approach of storing the energy in the thermal mass of the masonry walls of the house. If the sun was not shining some of the energy from a sunny day was still warming the front wall, but most was lost. To make such a system a primary heat source it is necessary to transfer the energy during sunshine to a large thermal mass such as a basement full of rocks or a large water tank. This is usually not too practical an approach because of the amount of material needed as the thermal mass.
The next better idea is to use a material that has a phase change (solid to liquid, usually) to store a much higher amount of energy for the same mass. Water has a great latent heat of the water to ice phase change, but it occurs at much too low a temperature. Fortunately some salts have a solid to liquid phase change at temps of about 70 degrees, so a basement full of salt would work better than a basement full of rocks. But you still have to get the energy in and out. When melted salt solidifies in the basement, the heat would warm the house from below, but transferring the energy from the solar panels to melt the salt is a challenge.
The best way to store energy (short of nuclear processes) is in chemical bonds. This is why fossil fuels are such a great source of energy. So I wondered what would be a good way to store the solar energy in chemical bonds to be retrieved later. It dawned on me that the simplest way to do that is to grow trees. You don't even have to build solar panels. Just cut down the trees and burn them in a stove.
At this point I lost interest in the whole affair. I realized that I had re-invented the wood stove.
Although growing trees for low cost - low tech solar energy collection may be a more reasonable alternative to high cost - high tech solar collection, there are other reasons why tree farms are to be preferred over large areas of solar panels. Trees not only efficiently harvest sunshine, but also absorb the dreaded carbon dioxide gas that climate change doomsayers fear will destroy the planet. In addition, in the process of cleaning the atmosphere of carbon dioxide, trees produce the oxygen that we air-breathing critters need to function. Cheap fuel, carbon dioxide removal and oxygen to breath - what's not to like about that. And growing trees is minimal effort farming - just plant seedlings and forget about them for a few decades.
There is at least one more important reason to grow more trees. Whether forests are clear cut for roads, parking lots, or other building development including solar panel farms, the solar energy falling on such cleared areas is absorbed during the day and heats the atmosphere before finally being radiated to space. If you fly a small plane over West Virginia where I live, the fact that the majority of the area of the state is wooded means that there are few thermal updrafts and your flight is smooth. Over urban areas, desert areas, and even to a lesser degree agricultural land, there are significant thermals in sunny weather and a low level flight gets very bumpy. Furthermore, such thermal atmospheric activity creates violent storms such as thunderstorms and tornadoes. The relatively tree-barren midwest is a hot bed of tornado activity, but they rarely maintain their organization into West Virginia. The fact that West Virginia is so wooded is the main reason why tornadoes and t-storms tend to dissipate over the state. The trees absorb almost all the solar energy and there is little left to fuel the storms.
