received by the International Bureau on 24 March 2014 (24.03.2014)

1. Process for local and small-scale production of electricity (13) by combustion of renewable fuel, characterized in that the combustion takes place in a boiler (1), which has oil (2) or another heat carrying medium with higher boiling point than water as heat conducting medium, that the heated oil (2), or another heat carrying medium with higher boiling point than water, conveyed from the boiler (1) is circulated through a steam heat exchanger (3) for heating water (4) or another suitable fluid in order to generate steam (5), that the steam (5) is conveyed to pairs of membrane tanks (6, 7) or to a piston pump (8), which comprises a centrally located cylinder space (21) with piston (22), which space receives water or another fluid, and with a steam cylinder space (23, 24) with piston (25, 26) located on either side of said space (21), and with connecting piston rod (27), and where the steam (5) is exchanged into water pressure or another fluid pressure (9) and is conveyed to a pressure tank accumulator (10), that said water pressure or another fluid pressure (9) drives a turbine (11), which in its turn operates a generator (12) to produce electricity (13), that the membrane tanks (6, 7) arranged in pairs and connected in parallel are used, which are alternately emptied and filled with water etc. by means of a valve system, and that said membrane tanks (6, 7) are used connected in parallel, so that a pump function is

obtained, and that this alternating emptying and filling of water etc. is used to control said valve system. 15

2. Process according to claim 1,

characterized in that the steam (5) used to alternately empty and fill the tanks (6, 7) or the cylinder of a piston pump (8) with water is returned to a heat exchanger

(16) or to a hot water accumulator tank to generate heat

(17) .

3. Process according to anyone of the

preceding claims, characterized in that the oil (2) , or another heat carrying medium with higher boiling point than water, in the boiler (1) is heated to a temperatur below its boiling point. 4. Plant (20) for carrying through a process for local and small-scale production of electricity (13) by combustion of renewable fuel according to anyone of the preceding claims, characterized in

that a boiler (1) comprises circulation conduit for the reception of oil (2) or another heat carrying medium with higher boiling point than water, and which in its turn leads through a steam heat exchanger (3) ,

that pairs of membrane tanks (6, 7), where the respective membrane divides the associated membrane tank (6, 7) into separate spaces, or a three way linear piston pump (8), which comprises a centrally located cylinder space (21) with piston (22), which space receives water or another fluid, and with a steam cylinder space (23, 24) with piston (25, 26) located on either side of said space (21), and with connecting piston rod (27), is/are arranged to exchange the pressure of the steam (5) into water pressure or another fluid pressure (9), that 16

the water pressure or another fluid pressure (9) is accumulated in a pressure tank accumulator (10), that a turbine (11) is arranged to be driven by said water pressure or another fluid pressure (9), and which in its turn is arranged to operate a generator (12), in which electricity (13) is arranged to be produced, and that the three way linear piston pump (8), which is arranged to exchange the steam pressure (5) into water pressure (9), comprises valves to the centrally located cylinder space (21), which receives water or another fluid, on either side of the piston (22) dividing said space (21), and valves for the separate steam cylinder spaces (23, 24) on either side of the centrally located space (21), which receives water or another fluid, for the steam pressure (5) , which is conveyed to and from said separate steam cylinder spaces (23, 24), respectively, and that a common piston rod (27) supports one piston (22, 25, 26) for each of the respective spaces (21, 23, 24) . 5. Plant according to claim 4,

characterized in that a pressureless vessel (15) is arranged to receive used water (14) from the turbine (11) .

6. Plant according to anyone of the claims 4-5, characterized in that the pressure tank accumulator (10) is arranged to sequentially accumulate the water pressure (9) generated in said number of membrane tanks (6, 7) or in the three way linear piston pump (8). 7. Plant according to anyone of the claims

5-6, characterized in that one of the steam receiving spaces leads to a heat exchanger (16) or a hot water accumulator tank for generation of heat.