I have a table that looks like

```
ServicePointID          EndTime              Energy Usage
1                2004-01-01 06:30:00.00          6075Kwh
2                2004-01-01 06:30:00.00         14000Kwh
3                2004-01-01 06:30:00.00          1250Kwh
4                2004-01-01 06:30:00.00            40Kwh
1                2004-01-01 07:00:00.00          7106Kwh
2                2004-01-01 07:00:00.00         10000Kwh
3                2004-01-01 07:00:00.00         11000Kwh
4                2004-01-01 07:00:00.00         12000Kwh

```

...

I am trying to sum all of the values for a given timestamp, 
kinda like 

```
     EndTime              Energy Usage Total
2004-01-01 06:30:00.00          21365Kwh
2004-01-01 07:00:00.00          40106Kwh

```