The power generated from the solar panels set on top of this building will provide electricity to the shared spaces in this building, such as the entrance hall, staircase, elevator lightings and so on.
On the other hand, the individual apartments will receive their electricity from the electric company.
ご質問ありがとうございます。
"The power generated from the solar panels set on top of this building"＝「この建物の屋上に設置されているソーラーパネルによる発電される電力」
"will provide electricity to the shared spaces in this building, such as the entrance hall, staircase, elevator lightings and so on."＝「はこの建物の共有スペースに電力を供給します。例えば玄関、階段、エレベーターの電気など。」
"On the other hand,"＝「一方、」
"the individual apartments will receive their electricity from the electric company."＝「各住居は電力会社から電気が供給されます。」
ご参考になると幸いです。
アメリカ合衆国 
