when ever we think about a big machine we think about giant nuclear warhead or a engine or a manufacturing unit but the biggest machine that the mankind has built is used by all of us and is an essential part of our lives its electricity and the power plant that we have built. it is spread across 1000s of kilometers and can wrap the earth several times but there is problem in all of these we need to make electricity when we need it and till now we dont have an effective way to store it. there is where tesla comes in. it is a company founded by elon mush and they now have started to manufacture batteries which can store the excess energy at the times when there is a surpass of energy and can use be used at the peak time. it was currently installed in southern California and tesla have offered Australia (as they are recently having a lot of blackouts) to setup up tesla batteries in 100 days or they will give the setup for free. renewable energy may be the future but currently we cannot relay on them, we cant create them as we like ex we cant tel a windmill to start and stop so there can be an excess of energy which could harm the power grid. also the renewable energy are not constant so we cannot make them as we wish.
solar energy will certainly not be in the near future but it will not stop people like elon to stop trying and one day we will make this machine even greater.