Iivalvu zetywina zoxinzelelo zenzelwe ubushushu obuphezulu kunye neenkonzo zoxinzelelo oluphezulu ikakhulu kwiplanti yamandla.Xa kuthelekiswa neevalvu zebhonethi eziboshiweyo, iivalvu ze-BVMC zokutywinwa koxinzelelo azintsonkothanga kwaye zinokubonelela ngenkonzo yokutywina egqwesileyo enokugcinwa okuncinci.