A=(((((1+r/100))^(40 ))*r/100)/((((1+r))^(40 ))-1));

a10=(((((1+r/100))^(10 ))*r/100)/((((1+r/100))^(10 ))-1));
a20=(((((1+r/100))^(20 ))*r/100)/((((1+r/100))^(20 ))-1));

CenaAC=(3901.61*vt+1370.58*nt+3600+min1);

rcf=40000*a10+10000*a20+16000*A+2000;
vt=0.25*el1;
nt=el1-vt;
el1=7.3;

min1=Min[15621.12, (el1)*598.95];

18904.32/598.95;
(((3901.61*vt+1370.58*nt+3600+(el1)*598.95)+rcf)/(el1*1000));

d1=Plot[{(((3901.61*vt+1370.58*nt+3600+(el1)*598.95)+rcf)/(el1*1000))},{r,0,10}, AxesOrigin->{0,0}, Filling->None, PlotStyle->{Magenta} , GridLines->Automatic, PlotRange->{0,7},AxesLabel->{"Diskont [%]","Cena [Kč/kWh]"},PlotLabel->"Závislost ceny 1 kWh na diskontu"]

r=0.05

A=(((((1+r))^(40 ))*r)/((((1+r))^(40 ))-1));

a10=(((((1+r))^(10 ))*r)/((((1+r))^(10 ))-1));
a20=(((((1+r))^(20 ))*r)/((((1+r))^(20 ))-1));

CenaAC=(3901.61*vt+1370.58*nt+3600+min1);

rcf=40000*a10+10000*a20+16000*A+2000;
vt=0.25*el1;
nt=el1-vt;

min1=Min[15621.12, (el1)*598.95];

18904.32/598.95;
(((3901.61*vt+1370.58*nt+3600+(el1)*598.95)+rcf)/(el1*1000));

d1=Plot[{(((3901.61*vt+1370.58*nt+3600+(el1)*598.95)+rcf)/(el1*1000))},{el1,0,18904.32/598}, AxesOrigin->{0,0}, Filling->None, PlotStyle->{Magenta} , GridLines->Automatic, PlotRange->{0,20},AxesLabel->{"Dodaná energie [MWh]","Náklad na 1 kWh [Kč/kWh]"},PlotLabel->"Závislost nákladu na 1 kWh na dodané energii AC nabíječkou"];

d2=Plot[{(((3901.61*vt+1370.58*nt+3600+15621.12)+rcf)/(el1*1000))+0.1},{el1,18904.32/598.95,40}, AxesOrigin->{0,0}, Filling->None, PlotStyle->{Blue}, AxesLabel->{"Dodaná energie [MWh]","Náklad na 1 kWh [Kč/kWh]"}, PlotLabel->"Závislost nákladu na 1 kWh na dodané energii AC nabíječkou", GridLines->Automatic, PlotRange->{0,20}];

Show[d1,d2, PlotRange->{0,20}]