§ 11. Quorum; powers of a commissioner. A majority of the duly appointed commissioners shall constitute a quorum and not less than a majority of such commissioners concurring may transact any business, perform any duty or exercise any power of the commission. The commission may hold meetings of the commission at any time or place within the state. Any investigation, inquiry or hearing which the commission has power to undertake or to hold may be undertaken or held by or before any commissioner or before any specially authorized officer or employee of the commission, provided that at least one commissioner shall hold at least one public hearing without delegation of authority to any specially authorized hearing officer or employee when such hearings are mandated by applications for rate increases. All investigations, inquiries, hearings and decisions of a commissioner or specially authorized officer or employee shall be and be deemed to be the investigations, inquiries, hearings and decisions of the commission and every order made by a commissioner, when approved and confirmed by the commission and ordered filed in its office, shall be and be deemed to be the order of the commission.