... Sources of energy Advantages Disadvantages (Các nguồn lượng) (Ưu điểm) (Nhược điểm) not always available, wind abundant, safe water/ hydro clean, safe, abundant expensive renewable, abundant, expensive, ... phí safe (adj): an toàn clean (adj): dangerous (adj): nguy hiểm polluting (adj): gây ô nhiễm convenient (adj): tiện lợi available (adj): sẵn có cheap (adj): rẻ expensive (adj): đắt abundant (adj): ... clean, safe restore solar biogas renewable, abundant, safe, clean difficult to restore polluting, difficult to use nuclear renewable, clean expensive, dangerous coal, oil, natural gas cheap, abundant...