Granted every fossil fueled device ever has quoted efficiency with the Lower Heating Value, whereas the HHV is the fairest measure. The difference consists of if you should extract energy from the humidity in the exhaust, and the clear answer is yes.
For most thermal generation, however, it's Carnot-cycle limits which get you down, and that's governed by hot vs. cold side efficiency.
Coal actually has some of the higher efficiencies, in some cases, exceeding 45%, though whether that's through high temps or combined cycle I'm not sure. (I'm not defending coal, just noting efficiency numbers I've encountered.)
Update: Wikipedia's language is "possibly 62%" efficiency, FWIW: https://en.wikipedia.org/wiki/Combined_cycle_power_plant
For example, [1] achieved 63.08% efficiency at the whole-site level (ie. including inefficiencies in startup, testing, etc. over a year)
[1]: http://interfaxenergy.com/article/30230/chubu-electric-plant...
While I agree with you, it's worth noting that the server farms of our tech giants are already powered by renewable energy (Google 100%, AWS 50%, Microsoft 50%, ...).
"The 180 watt laptop
While these reports are in themselves reason for concern, they hugely underestimate the energy use of electronic equipment. To start with, electricity consumption does not equal energy consumption. In the US, utility stations have an average efficiency of about 35 percent. If a laptop is said to consume 60 watt-hours of electricity, it consumes almost three times as much energy (around 180 watt-hour, or 648 kilojoules).
So, let's start by multiplying all figures by 3 and we get a more realistic image of the energy consumption of our electronic equipment. Another thing that is too easily forgotten, is the energy use of the infrastructure that supports many technologies; most notably the mobile phone network and the internet (which consists of server farms, routers, switches, optical equipment and the like)."