There will always be a need for large transmission lines, at least over the planning horizon, and probably more in specific locations. However, the advent of storage, if you project the trends over the last few years, will mean that less of it will be required than if we had continued the same technologies that we've had over the last century.
It's quite incredible. The cost of storage and the cost of, say, solar generation has been decreasing at about 20% to 25% over the last many years. There's no reason for it not to continue. The manufacturing scale is increasing, largely driven by electric vehicles. The scale of the systems is increasing. Right now, the largest battery is about 100 megawatts. It wasn't there last year. The scale is increasing every year. Manufacturers like S&C are learning how to better integrate all of these systems together, working with our utility partners. You can foresee the same kind of trend in the future. What does 20% to 25% mean? It means that, say, in three years it's going to be half.
Right now, a large-scale utility storage system is about $400 per megawatt. In three years, it's going to $200. In 10 years it's going to be about one-tenth of that, projecting linearly. You can say that seems quite incredible. Well, perhaps, except that you may have heard about Moore's law in computing, which says that every 18 months the cost of computing drops by 50%. That law has been going on for 50 years, since 1967. What we're seeing is the same kind of thing happening in solar energy and storage. For the foreseeable future, we'll see a constant decrease in price, which will make it more and more cost-effective.
Today, solar is the most cost-effective source of energy in 60 countries. It's coming down by 20% per year, so you can expect that next year there will be more than 60 countries.