[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: RE: OCPP: Tariff vs Price
You are doing fine with English, it is a subtle point.
Pricing may be determined any number of ways. It could be a fixed price per Newton or per kWh. It could be agreed upon in party to party negotiations. It could be computed per some sort of cost-plus agreement. It can even be the result of a tariff.
A tariff is a formal agreement on how to set pricing. It is usually set by a government entity, or perhaps approve by one. Sometime a tariff is a tax atop the
market price. In power, it is a set of fixed prices that apply to a period.
On the call, four time of day “tariffs” were described. What it actually is, is four prices that are specified in a single tariff, i.e., the approved tariff for this type of customer include 4 prices for four different times of day. The same tariff may specify additional prices, as in “when the [provider] declares a hot weather event at least 24 hours in advance, prices for period two and period three shall be 50% higher than normal”.
Rather than attempting to transmit complicated rules to a device that may be small, and potentially not understand them, it is better to convey a price. “However we computed them, these will be the prices you will see during each time period [interval] today”
With the OASIS Energy Interoperation Specification (which uses EMIX), the ability to define agreements that are dependent on the underlying prices was defined. For example, a Reserve is an asset that has an agreement in place to provide power with an agreed upon performance (time to perform) for an agreed upon interval of time. These were described using the language of financial options. “During the Interval(s), specified, the buyer has the right to buy up to [15 minutes] of power at a given rate-of-power by giving at least [2 minutes] notice. The buyer agrees to pay [a fixed price] or [a per cent premium over the prevailing market price] for this interval.
This is consistent with the mechanisms used to convey price events during DR events. A DR event can be declared by invoking existing options, or by tendering a new price to attract additional sellers into the market.
There can be some confusion over Price in English, as common parlance may fail to distinguish between unit price and total price, as was touched on in your email.
Hope this helps.
From: Robert de Leeuw [mailto:email@example.com]
Intresting issue you touched apone during the OASIS OCPP TC Call.
I'm not native English, so it is great to get input from native English people.
I always understood that Tariff is the description, describing the amount a person can expect to pay when he starts the charge.
So the information provided before using a service.
Price is is the amount a person has to pay.
But as I understand, that is not correct...
What would be the correct terms to use?