A lot. This milestone of ignition is an important one - the energy released by the initial fusion was of sufficient quantity and sufficiently contained that it

A lot. This milestone of ignition is an important one - the energy released by the initial fusion was of sufficient quantity and sufficiently contained that it could in turn cause more fusion, which in turn could cause more fusion. It is analogous to holding a lighter to a piece of wood and getting the wood to continue burning after you take the lighter away. Hence the term ignition. That said, while our fuel was alight for a little bit, it still extinguished itself pretty quickly. The energy released by the burning fuel was more than what the fuel recieved, but it was still only a fraction of the power output by the lasers (the lighter), which in turn is only a tiny fraction of the power it takes to make those lasers fire. This reactor can do one of these shots every couple of months. A reactor of this type producing useful amounts of power would need to produce about 41,000 times as much energy per shot, and fire shots at about a 14,000 times higher rate to generate 300 MW of continuous thermal power, which could be converted to about 100 MW of electrical power. To go further and make it practical, you need to do all that while also decreasing the price tag by about 90% and solving various technical hurdles such as fuel production and reactor maintenance. On a scale from 1 to 10 where 1 is "might be physically possible" and 10 is "we are ready to build a bunch of these", the technology is approximately a 3.