In the last decades the hydrogen-solar technology gained ground more and more. The energy of the sun is transformed with PV panels to electric current, than with this direct current water is dissociated. The hydrogen disengaged from the waters dissociation can be used in many ways. The hydrogen on air is consumable and it can be used to make heat. If it is consumed on air beside the water it springs some nitrogen-oxide too, but if the catalytic ignition is ensured the quantity of the nitrogen-oxide can be negligible.

The internal-combustion engines after some smaller modifications can be used with hydrogen too. First the BMW works were who expanded their automobile with hydrogen engines. On the exhaust pipe water and some nitrogen-oxide leaves, its efficiency is far more than the benzene engines efficiency is. (The fuel can be liquid hydrogen too, but this is more expensive, that’s why is rather stored in high pressure tanks). The hydrogen’s usage reached the most efficiency in fuel cells. In these cells in a catalytic way hydrogen is oxygenated, in other words chemical energy is transformed to electric energy. There are different cells, for example: lixivious, acid, dry polimercells, moreover recently microorganical (biochemical) cells too. The enthalpy of the water produced this way is 286kJ/mol. So the chemical energy in the cells is directly transformed to electric energy; this is why the process is  often  called         ”cold burn”. The efficiency of the energy transformation is 60% which is more than the burning processes efficiency is. With a cell 1,23 Volts can be generated. The fuel cells buildup is very difficult technically so the cells are very expensive too. Their advantage is the continuous run and the minimally pollution.

In wide understanding the heat arose inside the earth and stored in rocks. In a proper understanding the energy reside in heat of the water which is under the surface. Currently the geothermic energy can be used profitable only with the help of thermal springs, because of the high water equivalent. The thrift retrieve of the geothermic energy depends on the geothermic gradient, the refilling water and the water holding capacity of the strata. The geothermic gradient means that closing to the middle of the earth every 100 meters how much the temperature grow in Celsius. The spatial scattering of the geothermic energy is graphed on a map. If a smaller area’s geothermic gradient departs from its larger environments average we speak about geothermic anomaly. The reason of the deviation could be the taper of the ground (for example: Kárpát medence), closely working Vulcan (for ex.: Island) ,and horizontal thermal water movements. Thermal waters extraction is thrift ,when the geological makings are favorable, so in a relatively small deep thermal water has high temperature. The geothermic energy nowadays is first used in the local energy supplements: for example in Island, New Zealand, Japan, Kamchatka, and in the western regions of North America. The geothermic energies utilization depends on the flaring thermal waters temperature. If its temperature is over 212,00 Fahrenheit the thermal water could be used for making electric current.
If its under 212,00 Fahrenheit it could be used for heating buildings, planthouses, than the water cooled down  to 95,00 -68,00 Fahrenheit is used in thermal baths. Although digging thermal water wells is very expensive, the geothermic energy is very thrift and it doesn’t pollute the nature.

Biomass could be: organic scrapings (for example: from vegetal or animalistic scrapings),or the plants grew for producing electric current.

It belongs to biomass:
-  Traditional cuttings from agriculture (straw, corn-stalk)

- Spoilage from forestry, woodworking (sawdust)

- Plants grew for making electric current (grasses, trees: locust tree, alder, and willow)
   Forages: (sugar beet, panic grass, rye, and rape).
- Biomass from animals (excrement)   

The advantage of the biomass is that it can be transformed to energy without increasing the atmospheres carbonic-acid gas content. While burning the biomass only springs as much carbonic acid gas as the plant used in the curse of its photosynthesis. The biomass after the coal, oil, and natural gas is the fourth biggest energy source. The biomass gives 14 % from the worlds energy produce, in developed countries it gives the produced energies 35 %.

In the USA every year almost 250 million tons of trimmings are thrown off.  Only in New York 10 tons. From this 250 million tons of trimmings can be produced as much energy as from 100 million tons of coal. The most of the trimming is buried instead of making energy from it. The half of the worlds litter is paper, the one fourth is litter from the kitchen and only the tenth is plastic. Of this litter merely one fifth is that can’t be burnt, but in general these can be recycled. There are almost 350 refuse burners mainly in Europe and in Japan, which produce electric current. For example in London a big settlement built in 1974 burns 400.000tons of trimmings every year. With the heat spawned from the burning, boil water, and with the water vapor make generators worked. So the generators make electric current.
This power station saved 1 million tons of coal in 10 year. The power station built in New York, Peekskill was built to burn 2250 tons of trimmings a day. This power station makes 60kW s of electric current (a day). This quantity of energy is enough for 70.000 people.