emix — archive

[Girish Ghatikar <ed@cazalet.com>]

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 > > ed@cazalet.com