This query will union the data by data center name,
calculate the total energy consumption for each data center using the union
from 3 data center and print out max value
select max(consumption), date ,location from (
select top 1 *
row_number () over( order by consumption desc) as rn
from eu_energy
union
select top 1 *
row_number () over( order by consumption desc) as rn
from na_energy
union
select top 1 *
row_number () over( order by consumption desc) as rn
from as_energy
) temp
group by date, location