The world energy market is roughly $6 trillion per year:
$1.8 trillion per year is invested in energy, in things like digging wells, R&D, erecting wind towers and so on.
That is the pot of money you can tap into with cold fusion. $1.8 trillion is the amount people will be willing to invest in cold fusion R&D per year, once it becomes clear that cold fusion will become a practical source of energy. $6 trillion per year is how much money you can divert from the oil, gas and coal companies earnings into your own pocket if you succeed in commercializing it. Not overnight, but in a remarkably short time. Roughly the time it took automobiles to replace most horses, which was from 1908 when the Model T was introduced, to 1928.
So, how do you make this money? Not by trying to sell energy! That is a highly regulated industry. It is a difficult and complex business. The way to make money is to sell equipment. You gradually divert the earnings of energy industry into earnings by you. Many companies are already doing this, by selling machines with improved efficiency. Suppose you make an efficient water heater. You can sell it at a premium, and make more profit. The customer is willing to pay more because it reduces the natural gas bill and saves money overall.
The average water heater costs $55 a month in gas. Suppose the customer ends up paying you $10 month more for your heater, but he saves $20 a month in gas. In effect, you are reducing the gas company's earnings by $20, and splitting the money between you and your customer.
The potential is greater with cold fusion, because you eliminate the entire cost of fuel. You and the customer spit the $55; the gas company loses the whole amount.
It is even more attractive for big ticket equipment. If an apartment complex pays $1000 a month for the gas space heating, you sell them a heater that costs about $500 a month more than a gas heater. The natural gas company loses $1000, you and the customer each make $500. After 20 years the equipment wears out and you sell a replacement. It is a steady stream of income. It is siphoned off from a $6 trillion pot of money, so there is plenty more money to grab. There is no way the energy companies can compete or under-price you.
This is not a one-time profit. It is a steady stream of income, because the equipment wears out and must be replaced.
In real life you have competition, and as you gradually wear away at gas, oil and coal company earnings, they lower their costs, and the amount left on the table decreases. But in principle, that is how it works.
This only works out well if the cold fusion apartment complex space heater costs roughly as much to manufacture as a gas-fired heater. I think it will, because it is not particularly complicated and the materials are not rare. For the most part, it consists of pumps, thermostats and whatnot that are the same as the ones in a gas-fired or electric heater. Once the technology matures, there is no reason to think it will cost more. But you can sell it for much more, with much larger profits. The customer will be happy to pay more, because it eliminates the cost of fuel. Over the life of the machine, the fuel costs more than the equipment. So you have a tremendous potential profit margin. If the customer cannot afford the up-front cost, you can arrange for leasing. As long as it ends up costing substantially less per month, the customer will be happy. As old gas-fired equipment wears out, your equipment gradually replaces gas fired heaters. Then as your equipment wears out, you keep selling cold fusion heaters.
To reiterate, the money goes from the natural gas company into your pocket, and into the customer's pocket, even though you are not selling energy per se. The amount of money waiting for you to tap into and transfer is $6 trillion per year. That is the most lucrative business opportunity in history. Every industrial company will understand that the first day it becomes generally known that cold fusion is real. They will soon be spending billions of dollars per year to develop it, just as they are now spending billions to develop self-driving cars.