Antihydrogen - a new energy source ?

The answer is: NO !

because:

there are no antimatter resources in our world
antimatter has to be created in a energy-waisting process
efficiency: 0.000 000 01 % !!!
storing antiprotons in magnetic bottles has an efficiency of 1 %
antihydrogen has to be produced and stored inside magnetic bottles
the energy in matter-antimatter annihilation has to be converted into
- electricity
- propulsion
- ...

While antihydrogen production at rest is hoped to be solved within the next years, there is no meaningful idea how to use energy set free by annihilation. StarTreks warp engine may be a clever idea, but in real life it wouldn't work.
Anyhow, the overall efficiency would be smaller than 0.000 000 000 1 % !!!
So, it's better to use the available energy 'directly', even an old steam engine has an efficiency of 10 %.

Some examples:

All antiprotons produced at CERN in one year carry an amount of energy which is capable to light a 100 W light bulb for 3 seconds
The world production of electricity converted into antiprotons would theoretically light this 100 W light bulb for 95.6 hours
All known coal, oil, gas resources would result in a number of antiprotons which would be equivalent to the energy needed to drive 10 small cars from Hamburg to Munich and back

Detailed calculations

CERN PS-Complex

10 MWyears (=3.15*10^14 J) are needed to produce 10^14 antiprotons
10^12 antiprotons would be stored in magnetic bottles
annihilation of 10^12 antiprotons would give 300 J
300 J are able to light a 100 W light bulb for 3 seconds

World electricity in 1993

10.050*10^12 kWh = 1147260 MWyears would produce 1.147*10^19 antiprotons
1.147*10^17 antiprotons would be stored in magnetic bottles
annihilation of 1.147*10^17 antiprotons would give 34.4 MJ
34.4 MJ are able to light a 100 W light bulb for 95.6 hours

The originally given value of 5.8 minutes was wrong due to an error in the encyclopedia

Known coal, oil, gas ressources

3.287*10^22 J = 1.04*10^9 MWyears would produce 1.04*10^22 antiprotons
1.04*10^20 antiprotons would be stored in magnetic bottles
annihilation of 1.04*10^20 antiprotons would give 31.34 GJ
31.34 GJ are able to drive 10 cars over 1500 km