The 2nd Law of Thermodynamics applies.
"The entropy of a closed system will always increase"?
Yeah, entropy is a little difficult a term to understand, but that statement can be rephrased many ways in more down-to-earth language. One way is "You can never get out of a process as much as you put into it." It's the reason that perpetual motion devices always fail. Entropy is a measure of disorder, such as energy losses in thermodynamic conversions. Bake a cake. The dough starts out neatly packaged. When you mix it, there'll be dough left over in the mixing bowl that doesn't get poured into your baking pan. You don't get as much cake as you paid for. You never can. Another example. It's very orderly to have all the electrons amassed on the negative pole of a battery, but leave that battery in your drawer for two years, and a significant amount will have leaked over internally. The battery will be dead without ever being used. Nothing can be 100% efficient. Everything is slowly wasting away.
Coal plants can generate an average of 31% of theoretical potential energy, with a practical high of 45% that depends more on input coal quality rather than actual infrastructure itself. Legislation can't change the quality of coal that is available.
Hence why we have to start moving away from coal, among other reasons.
Comparable efficiency in natural gas, at about 45% efficiency for decades, but the key point is that you can't get 100% of the theoretical energy from any source. Solar has a possible ceiling of 60% efficiency called the Shockley–Queisser limit, and it's prohibitively costly to even approach that limit. All forms of electricity generation meet practical limits far below theoretical maxima.
In Sci-fi fantasyland, we would have lossless superconductors, of course, but that isn't going to happen.
developing room-temperature superconductors, which are not lossless but are as close to lossless as is permitted by reality. Investing in researching and developing these is how we're going to get them, and is a worthwhile use of government money.
We could also put 500k tons of lead in Fort Knox and invest $1 trillion dollars into Philosopher Stone advances, claiming we'd profit by 28 times on the research outlay after we turn it all into gold. In the end, you have to target an achievable goal and have a scientist capable of discovering it. Government money has little effect on those things. That approach is called throwing money at a problem, and it's generally not effective. Room temperature superconductors are not readily achievable, if at all. I believe the best so far is 90 Kelvins or so, just 210 Kelvins short of what would be needed.
Anyway, there are plenty of other things that can be done for efficiency. The average American ends up wasting a lot of money and energy on very small things that add up over time, like phantom draws and inefficient planned obsolescence appliances. Gradually raising standards so that industry has to sell efficient appliances that don't draw power when not being used will solve this on an individual level and lead to savings on a national level.
Probably the most fruitful area for energy savings, but realistically, you'd probably cut 10% off of electricity consumption and still have a huge demand. Big-ticket items like heating and air-conditioning systems have already plucked the low-hanging efficiency fruit. It simply takes a lot of energy to do what modern humans expect of their appliances. Leakage of appliance not in use happens, true. Yet much of this leakage stuff is simpy unavoidable due to limitations on human awareness, like leaving a phone recharger connected and leaking current that way. People are going to do this.
that's 25,630 square miles of solar panels, or 23% of the land area in Nevada.
....and? The panels don't have to all be in Nevada. We can put them all over the place.
But that is the most
efficient place to put solar panel. It's 1.6 times more efficient than New York. The moderate temperatures and predictable weather also minimize wear-and-tear and replacement rates. Decentralized solar generation runs into this trouble, in particular. If every house has a solar panel array, then who cleans the solar panels? For example, cold water sprayed onto a solar panel on a hot summer day can causing cracking. Solar energy is best generated in large farms where appropriate personnel can maintain it.
No one said energy renewablity would necessarily be easy, but we need it. We need it very badly. Once a collapse starts it will be difficult to pull out of it, so we need to start and ideally finish going renewable before that has a chance to happen.
We have about 100 years of recoverable shale products under America at current consumption, and China has 300 years. Solar will have to compete on a marketplace with other cheap sources of energy for another half century, perhaps. Slowly it will cut out a larger share of the energy pie, but largely due to market forces and slow development of better technology, which government grants can certainly support over the long-term but not rush immediately to fruition.