  Beijing is a megacity with a population of over 20 million. It has a massive
demand for water and electricity and is responsible for achieving carbon
neutrality. However, Beijing is in a highly arid region, and its local
electricity production supply is less than 30% of the demand. The city's carbon
neutrality goal also faces enormous challenges. To address these problems, this
paper proposes a plan to cover the Beijing area's surface reservoirs and water
channels with solar panels. The results show that the plan is expected to save
an average of 383 million m3 of water per year (which can meet the annual water
needs of 2.13 million households), generate 72.6 billion kWh of electricity
(which can meet the annual electricity needs of 25.23 million households),
reduce carbon dioxide emissions by 6.84 billion kg (equivalent to the annual
carbon dioxide absorption of 3.1 billion mature trees), and reduce the
concentration of one carcinogenic substance, microcystin, by 97.3%, while also
addressing the issue of bromate. The results strongly suggest the potential
social and economic value of using solar panels to cover surface reservoirs and
water channels. Field control experiments and related research should be
actively promoted.
