Hi, think of it this way:

• electric energy: bills you for the actual energy you individually consumed. This pays the generators in the province. Generation is very variable because it has to match what people are using. Light usage, light generation. Supper time, lots of generation. It's measured in kwhrs, which is average power used x hours used. If you use 1kw of power for an hour straight, you used 1kwhr of energy. 2kw for one hour or 1kw for 2 hours = 2kwhrs. In Alberta generation is privately owned and in a competitive market. This was done to allow "free market" mechanics drive competition and efficiency.

• electric delivery charges (distribution and transmission): bills you a fixed amount, like a mortgage, that pays for the wires, transformers, substations, power line crews, everything that connects everyone in a giant electrical grid. This is a huge amount of expensive infrastructure. It's a fixed charge, more or less, because it's financed through borrowing, and paid back like a mortgage. That cost is spread across all customers, and slightly different across regions, which reflects the costs of the local wires utility.

Speaking of the wires utilities, these are regulated monopolies. Epcor has Edmonton's service area (and they're wholly owned by the City of Edmonton, but not part of the City's administration). They make profit for financing allowed costs, which are determined through regulation. This is where the Distribution and Transmission separation comes in.

• Transmission is the really big stuff. Big high voltage towers crossing the whole province. They are fully cost of service regulated, and can have large individual costs.
• Distribution are the smaller lines, still high voltage but much less, think the wooden electric poles, and the services and meters to peoples houses. They are regulated in a financial envelope way, with incentives for maintaining metrics and service reliability.

So the mechanisms for costs to go up or down are very different in the way they are regulated.

So why are they shown the way they are on the bill? I'm not sure. I think there's a much better way to breakdown a bill for a customer. But this is where my expertise runs out.

To summarize the important part: the energy you consume is highly variable and in your control. It's like choosing to drive more or less to save gas cost. The delivery charges (D & T) are the payments on the car. You owe it no matter how much you drive or not. And because it has to be continuously renewed, it's costs remain relatively constant, and (supposed to) grow slowly in proportion to economic activity and other growth like population growth.

I hope some of this made sense. Not everything above is 100% detailed and correct, the whole thing is horrifically complex, and you're seeing just the tip of the iceberg.

Source: I'm in the industry, don't rat me out to my boss please