Well for one, my means of exchange is energy, not power. And although we aren't cars we are bio-machines, we are subject to the same laws of energy conversion. The money is an analogue of energy, power is a function of energy and work over time. >Describe the transaction for someone who wants to buy an acre of land. You buy it with currency. You can barter for land, just as easily as you can purchase it. I'm not arguing whether we should use money or not. I'm arguing we should keep money tied to energy, not power, energy. You can have all the money in the world, but if you don't allocate it correctly you cannot accomplish anything with it. That is, if you cannot convert your energy to useful work, you have essentially no power. Petroleum has a fixed energy quantity, the distillates of petroleum have a known and immutable quantity of energy. So too does the fat in your body, and the carbohydrates and proteins also have a fixed and immutable energy content. One kilogram of dietary fat contains roughly 40 Mega Joules of energy. One KG of gasoline, has roughly the same amount, diesel fuel has slightly more. When you buy a barrel of petroleum, you are buying the potential energy stored in that 55 gallon drum. That energy powers your machines, produces your food, and maintains the infrastructure around you. That energy you buy in dollars, and converting that energy into work over time is power. I hope that clarifies things a bit. The value of land is tied to what that land can produce. Crops and things you grow on land are basically energy stores. The energy from the sun is absorbed by the plants and the fruits and things that grow from the plants are basically the result of energy harvesting. Those same crops degrade and can produce fuels and alcohols. The crops have potential energy as well. The food you eat has potential energy, your body breaks down the food and releases the energy which you live on.