Allow agents to compete for demand

[alexdewar]

Agents currently serve a fixed portion of demand for different commodities, which is unrealistic. Instead, they could be allowed to compete for a share of the demand. This is necessary for trade (#509), but could also apply to some non-traded commodites.

See #509 for Adam's proposed scheme. I think we will need more guidance when we come to this, so I'm marking as "on hold".

[alexdewar]

From Adam:

Problem: At the moment demand is considered to be captive to an agent, but multiple process types can serve the demand as chosen by investment appraisal tools. But in reality often agents compete in a market without a pre-determined amount of demand to serve, or agents consider all processes at once when trying to serve a captive demand.
Possible Solution: Introduce a distinction between commodity types – those where agents compete to serve demand and those where an agent is assigned a captive demand and must serve it. Current investment appraisal tools are just about (see LCOX point below) adequate for the CAPTIVE case, but the COMPETE case requires some changes – though a simple version might not be difficult (e.g. competition on LCOX, lowest one wins with capacity installed up to the agent’s capex limit or capacity addition limit or demand limit – whichever is smallest).

[alexdewar]

@ahawkes is going to take another look at this and get back to us

[ahawkes]

I'm still interested in this CAPTIVE versus COMPETE idea.

But I can't recall why it's necessary for a basic implementation of trade.

Instead, perhaps it's possible to specify the trade groups similar to described in #509, and then when solving appraisal we do all the demand profiles in each region in the trade group at once (not added together, but treated separately).

The assets that produce the tradeable CoI in the other region/s would be included in appraisal (in addition to the assets in the current region). We'd calculate all our investment metrics, and still invest in the best one first (which could be an asset in any region, and could serve demand in any region where trade is allowed to and/or trade capacity exists).

This would require a change to investment appraisal, so that it can deal with lots of separate demand profiles instead of just one.

We would also want a trade price and trade capacity upper bound (an activity cost and a capacity variable for getting commodity X from region A to region B) which will require further input data. The capacity upper bound could be allowed to increase by a certain amount per year. (I'm trying to avoid having fully-fledged processes for trade here, but if people think that would work better, happy to entertain the idea). Dispatch would also need to be altered to include these prices and trade capacity constraints.

Can anyone think of reasons why this won't work?

[alexdewar]

@ahawkes I think I'm missing something here.

Imagine you have an agent in Germany responsible for meeting electricity demand in Germany and there is trade between Germany and France for electricity. Under the current approach, agents attempt to meet their portion of demand, but in this case, our German agent isn't responsible for any of the demand in France, so the French demand profile can't be factored into its decision-making in the same way the German one is... right? It sounds like it's not just a case of including multiple demand profiles in the appraisal, but will also involve using these demand profiles differently.