Ed,
These are some good use cases. I suggest few simple interaction diagrams
indicating the communication flow between the actors involved.
Thanks,
Rish
Ed Cazalet wrote:
>
> Made a minor correction in use case 4.
>
> David,
>
> You posed several use cases, but let me start with the use case you
> highlighted which was green energy provided by a retail service provider.
>
> The retail service provider provides you with green energy from one of
> several portfolios or from combinations of these portfolio. The green
> portfolios could be as follows:
>
> 1. Consider a set of local solar and wind resources on a micro grid
> connected to you and other customers. The retailer contracts with you
> to provide energy only from these sources at a dynamic price that
> depends on supply vs. demand or he provides you a formula allocation
> of actual generation at a price. Price, quantity and delivery interval
> and delivery location as well as a contract reference would give the
> customer, the retailer and the generators all the information they
> need given the contracts the retailer had signed. The retailer
> includes in his price to customers the price paid to the generator,
> the price of the distribution, cost of distribution losses, markup,
> and perhaps taxes. The retailer would have to have access to the
> generators' meter data in real time to inform the customers of actual
> energy delivery. Customers would automatically turn smart devices on
> and off depending or price or supply. Toby's green fountain would work
> with this. The delivery intervals for the transactions could be
> seconds or shorter. If this micro grid is not connected to the main
> grid and the only generators on the micro grid are wind and solar and
> are all contracted with the retailer a customers is assured he is
> getting only wind or solar energy. The retailer could also own
> batteries or contract for battery services to reshape the green
> deliveries accounting for the losses in storage and the cost of the
> battery storage in the price of green energy to the customer.
> Alternatively the customer could own or contract for battery storage
> to shape energy to his needs. No need for certificates here as the
> retailer has only wind and solar energy to serve you and he can only
> sell what he has on a closed microgrid.
>
> 2. Same as case one but the green generation is remotely located on
> the transmission grid. Assume the retailer has a direct contractual
> relationship the a set of green generators to take all of a wind or
> solar generator output. Then the only difference is that the retailer
> must pay for the transmission charges and losses. On an ISO controlled
> grid such as PJM or the California ISO. The retailer will be pay a
> grid access charge, a marginal congestion charge and incur marginal
> losses. Prices for these services are readily available in these ISOs.
> However the traceability of the electrons is lost. As long as the
> retailer has access to the meter data from the generators he can
> assure that he did not take out of the grid more wind and solar energy
> than this contracted generators put in. However, it could be that
> congestion on the grid would require that the green electrons be
> delivered somewhere else and a coal plant be dispatched to actually
> deliver electrons to the customers even though the customers are only
> getting energy when the wind and solar generators are producing. Again
> no green certificates are needed.
>
> 3. Same as 2 except the retailer is dealing with many green generators
> and customers. A third party or the ISO could host an exchange to take
> the wind and solar generator meter readings and allocate the
> generation among the retailers perhaps based on a sharing rule or a
> price based auction. Again no need for certificates. Intervals for
> this exchange could be as short as desired. Storage can still be used.
> The exchange operator might offer to sell excess wind and solar into
> the rest of the grid and buy an equal amount back at a later time
> using the grid like a storage battery. However he may be displacing
> hydro energy when he sells it and buying back coal energy which an
> obvious non green result but it provides greater reliability of
> service to customers.
>
> 4. Same as 3 except the a third party creates bank accounts of green
> kwh for each generator and each customer. A separate set of accounts
> is created for each delivery interval. A generator's account would be
> credited for each kwh generator in an interval. A customer's account
> would be debited for each kwh consumed in an interval. The retailer
> would buy kwh from the generator accounts and deposit them in the
> customer accounts. No kwh could be sold twice. The retailer could
> deliver energy from the main grid whenever he has a matching kwh in
> the customer account.
>
> 5 Same as 4 except there is one account per year for each customer and
> generator. There is no need for the retailer to buy energy directly
> from any wind or solar generator. Wind and solar generators continue
> to be credited with deposits in their an annual accounts. The retailer
> will contract with the green generators to buy only deposits in his
> account and the generators will sell their actual generation to anyone
> on the grid. Customers accounts will be debited a kwh of wind solar in
> their accounts and for each kwh used. To facilitate commerce each bank
> can create a */certificate/* for a kwh of green energy ( which is a
> form of currency) that can be freely traded. Since the generators are
> getting one stream of revenue for the energy to the grid and a second
> stream of revenue for the certificates, the price of the certificates
> will not include the price of the energy. With annual kwh certificates
> there will be more market liquidity than if certificates were set up
> on very short intervals. However with annual accounts we are
> essentially using the grid as a storage battery and there can be
> environmental consequences as described above.
>
> Case 5 is essentially how environmental registry services support
> green energy today with registered environmental certificates that can
> be moved among many parties and registries. In this later case emix
> can describe the energy and the certificates as price, quantity,
> delivery interval and location records with a reference to the
> contract, market or certificate authority.
>
> Probably some diagrams and editing would improve these uses cases if
> they are helpful.
>
> Ed
>
> Edward G. Cazalet, Ph.D.
>
> 101 First Street, Suite 552
>
> Los
Altos, CA 94022
>
> 650-949-5274
>
> cell: 408-621-2772
>
>
