I disagree. Why would green tech look any different in 20 years? The only two possible ways that could happen is a massive cost reduction of geothermal or a fusion power breaktrough. Nuclear energy is in no way competitive at all, there is no business case for nuclear energy at the slightest, since the power plants are more expensive to operate and to build and financially very risky to build compared to all alternatives. Furthermore nuclear fuel requires more and more energy to mine and refine, which means costs only rise, at the same time nuclear only becomes worse and worse for the environment since the amount of pollution for building the plants, tearing them down, maintenance and the uranium fuel pollution and energy used for the fuel just gets higher and higher. Now lets assume a fusion power breaktrough indeed does happen, it would still take another decade to build the first plants and then many more decades to replace all the existing coal, gas and nuclear power plants. Only then at the very end and only IF fusion power was very cheap, (unlikely, although its costs would decline slowly over the decades) could it possibly replace wind or solar. WInd and solar have DECLINING costs over time. And the introduction of green hydrogen into industrial production will massively accelerate this, its in fact already being accelerated from it. Since there are big syngeries to get from combining hydrogen with volatile renewable energy production. You are right that power transmission improvements are essential.. however those are already underway in large scale and really can only do so much. Fossil fuels will remain necessary for the next 100 or more years unless something drastical happens.