Complex sentence: Eskilstuna Energy and Environment is certified according to ISO 14001 since 2002 and since 2013 also approved issuer of Diploma of standard Svensk Miljöbas.
Split into simpler sentences: Eskilstuna Energy and Environment is certified according to ISO 14001 since 2002. Since 2013 they are also an approved issuer of Diploma of standard Svensk Miljöbas.