Now we are in the midst of The Digital Revolution where the widespread use of computers and the internet are continuously changing how we interact with other people. Yet, we haven't seen a major disruption in how we produce and use energy in a way similar to that characterized by the last two technological revolutions. That change is surely set to come, and the way that the internet has changed our relationship with each other could show the way that our relationship with energy will change.
First, a Disclaimer
It seems that some people thought from my last article that I was portraying myself as an expert in the future of EVs. Let me be completely clear that I am not an expert in that, nor in this article on the future of energy. My expertise comes solely from what I read about the subject, and my desire to wrestle with complex ideas and combine trends together to speculate about the future. If at any point it seems like I don't know what I'm talking about, that's because I don't, but quite possibly, neither do you. The future of technology is notoriously hard to predict, yet it is still great fun to do, so I like to keep an open mind.
In speculating about future technology, I try to look at general trends without looking specifically at what is possible today. Doing that may carry me past the edge of possibility, but that is where real disruptive advances in technology happen. The naysayers are always right at first, but they are only right until someone who's likely not paying attention comes along and proves them wrong. That's when the impossible becomes possible. So, here's fair warning that there is hand-waving optimism ahead. If that offends you, stop reading now, but if you enjoy dreaming about eternal possibilities, then let's have some fun.
Oil and Coal vs. Solar
The amount of solar energy that hits the Earth's surface is simply astounding. Let's do some quick and dirty calculations to get an idea of how much energy we're talking about here. Since these will be incredibly large numbers, we'll use petawatt-hours (PWh) as the energy unit of measure. That's a watt-hour with 15 zeros behind it.
We can approximate the surface of the Earth as a disc that the sun's rays hit. The area of that disc multiplied by the solar constant of 1,366 watts per square meter gives the amount of solar radiation that hits the Earth's surface in an instant. The radius of the Earth is about 6,371 km, giving a disc area of 127.5 * 10^12 square meters and an energy flux of 174 PW. Multiply this by 24 hours to get the amount of solar energy reaching Earth's surface in a day - about 4,180 PWh.
As a point of comparison, the total energy used by commercial energy sources from 1880 to 2000 is about 4,806 PWh. Let that sink in for a moment. The Earth is bathed in nearly as much energy from the sun in one day as the world used in 120 years. We might want to think about capturing some of that energy. Of course, we can't capture anywhere near all of that solar energy. Much of it is absorbed by the oceans, plants need it for photosynthesis, and the Earth needs a fair amount for warmth to support life. But the World's energy usage in 2010 was about 150 PWh, or about 0.41 PWh per day. That's rounding error compared to the amount of solar energy we're getting in a day.
If we were to capture some of this energy using solar PV panels, it's difficult to think about how much we could reasonably capture starting from all that is available, so let's come at it from the other direction of how much we need to satisfy our energy needs. Limiting things a bit further, let's look at the energy needs of the U.S. Here is a great chart of the U.S. energy usage in 2012, from Lawrence Livermore National Labs (click to enlarge):
For our purposes, we'll convert Quads to PWh, with 1 Quad equaling 0.293 PWh. That means the U.S. used 27.9 PWh of energy in 2012, mostly coming from natural gas, coal, and petroleum. But look at how much was wasted in electricity generation and transportation. Electricity generation was only 32.5% efficient and transportation was abysmal at 21% efficient. Most of that energy was expelled as heat, as well as a significant amount of wasted electricity because utilities need to generate extra supply for demand spikes.
Solar (and wind) is inherently different than fossil fuels because the energy is there regardless of whether we use it or not. Any amount of energy we can capture for useful purposes can be thought of as energy that was reclaimed from the vast amount of unused renewable energy that's available. And once solar power plants are installed, the maintenance and operating costs can be much lower than coal power plants or oil refineries because the energy source does not need to be constantly dug out of the ground and consumed by the plant; it's already freely available without any extra effort to keep generating electricity.
Because of the way that residential, commercial, and industrial sectors use electricity that already uses raw resources, as well as their relatively high efficiency compared to generation and transportation, let's ignore them and focus on the amount of energy consumed from electricity generation and transportation that does useful work. If we were to replace all of that coal and oil (and natural gas, nuclear, etc) with solar energy, we would need to generate 5.27 PWh of energy per year.
How much solar panel area would that require? From the National Renewable Energy Lab, we can estimate that on average the U.S. receives about 5.5 kWh per square meter per day, or 2.0 MWh per square meter per year, of solar energy. Solar panels are far from perfect, though. If we assume they are 20% efficient at converting solar radiation into electricity, we would need 13,200 square km of solar panels to supply the U.S. electricity and transportation needs. That's about 110 square meters, or 1,180 square feet, of solar panels for every U.S. household. It's a lot, but still doable.
On a side note, that 20% efficiency estimate is likely on the low side for the future, considering the continuous advances made in solar cell efficiency as shown in this chart from the NREL:
On the other hand, assuming that all of our transportation needs will be supplied with electricity is highly unlikely. I do believe that the energy market for transportation will become much more segmented with biofuels, hydrogen fuel cells, and electricity all competing with gas and diesel in the transportation sector for quite a long time. The point of combining our electricity and transportation needs together is to get a rough idea of what it would take to transition most of our fossil fuel use to a more sustainable form of energy.
Where to Put All of Those Panels?
If we have learned anything from the internet, it is that distributed, networked solutions can be extremely powerful. What happens if we bring some of that knowledge to our energy problem? For the first time in modern history the prospect of the average person having their own personal power plant is within reach. The cost per watt for solar cells is dropping like a rock and quickly reaching or even surpassing the cost for coal or natural gas generated electricity, as shown in the following chart from the DoE:
However, this chart is already outdated. According to recent market research, we are now at $0.50 per watt for solar cells instead of $1.00 per watt, and we're heading for $0.36 per watt by 2017. After that solar will be cheaper than coal or natural gas are today. In the mean time, those fossil fuels are getting more expensive as they get harder to recover in more remote reserves and as the quality of those resources diminishes because we're using up the highest quality reserves first.
If all of these solar panels were installed as massive projects sponsored by the government and power utility companies, it would truly be a huge undertaking, similar to the U.S. interstate highway system. But if the installation was widely distributed, it would be much more like the formation and growth of the internet, and the main issue would be the manufacturing of huge quantities of solar panels. So how could we make significant progress in covering 13,200 square km of space with solar panels?
Rooftop installations on residential, commercial, and industrial buildings: Once solar panels are cheap enough that their break-even point with traditional electricity is 3-5 years or less, every individual consumer and business is going to have a huge incentive to convert to solar. If the panels are financed, consumers and businesses will be able to reduce their monthly energy costs immediately, and then they'll have substantially reduced energy costs once the panels are paid off.
Solar canopies in parking lots: There are huge areas of parking lots across America that could be partially covered with solar panels. Businesses could have that electricity available for their employees and customers to charge electric cars, or sell the surplus electricity to utility companies.
Solar panels on cars: I brought up the idea of adding solar panels to electric cars as a way to extend the range of the car's battery, but for everyday driving they would serve equally well for charging the battery without ever having to plug it in. On a typical day I drive less than 25 miles to and from work, and my car sits in the sun for the entire day. If I could have 5 square meters of 20% efficient solar panels on my car, they would nearly replenish the battery everyday. More efficiency directly translates into more miles per day. Considering that the average American drives less than 40 miles a day, this is a significant amount of driving sourced directly from the sun, and if the battery didn't need the extra charge, the car could be plugged in so that the elecricity went back to the grid.
Solar panels on semi-trailers, buses and trains: There are 5.6 million semi-trailers registered in the U.S. with a typical roof surface area of 100 square meters. That's 560 square km of area being hauled around the country by trucks. If they were fitted with solar panels on top and a decent sized battery underneath, the extra energy could supplement hybrid semi-truck engines to increase their efficiency. Similar logic could be extended to buses and trains.
Wind turbines: As long as wind turbines stay competitive with solar panels, wind farms and consumer wind turbines can carry a lot of the necessary energy load. They're also a good compliment to solar because in a lot of places and at many times when the sun isn't shining, the wind is blowing.
Traditional power plant sized installations: There will still be a significant need for large-scale installations of solar power plants and wind farms because not everyone has the space or the desire to have their own solar panels or wind turbines.
Distributed Energy Generation Will Change Everything
Once a significant portion of the population is generating their own power, and they're connected through the grid, things will start to get very interesting. When enough people were connected through computers and the internet and barriers to self-publishing content came crashing down, things changed in completely unpredictable ways. People did not foresee the development of Wikipedia, Facebook, and Twitter and what they would do to serve as platforms for individual, freely-shared content creation.
Prior to the internet, content creation was primarily controlled and distributed by publishing and broadcasting companies. Individuals only had access to public exposure through these companies. Media was centralized in a way very similar to how electricity and oil companies are now. Individuals depend on getting their energy from these sources, but what will happen when that changes? The role of utility companies will surely change.
Those companies that cannot adapt will get left behind, like encyclopedia producers and some newspapers did when the internet changed the rules for communication. If utility companies are to survive, they'll have to figure out how to make more of a business of metering and managing power from its widely distributed sources and less from generating it themselves. Once people are both producers and consumers of energy, there will be much more of a need to keep tabs on their net energy usage. Some people will be net producers and others will be net consumers, and energy will be shared within a much more interconnected network. I'm not sure what the oil companies will do.
It is really difficult to predict what will happen when people producing their own energy is the norm. All I can think of is that energy will be cheaper and the friction inherent in the current centralized system will be eliminated. When that happened to the telecommunications industry, we saw drastic changes in our society. And every time we capture a cheaper and more abundant source of energy, like coal in the Industrial Revolution or petroleum in the Technical Revolution, we also see drastic changes in our society. We are still in the midst of the Digital Revolution, and we are likely about to see both a reduction in the cost of energy and a change from centralized to distributed energy. I honestly can't imagine what is going to happen because of that, but I can say one thing. It's going to be big.