Module B1 Study Book - the Graduate School of the Environment

its member states' electricity grids.
d) Distributed generation
DG can provide great benefits for local distribution companies by relieving
congestion, reducing transmission losses and delivering ancillary services to
the system. Thus, DG could provide fast and longer-term reserve requirements
to the grid on a regional level as an alternative to large-scale power plants.
One of the most frequently cited DG options is combined-heat and power
(CHP) plants, which produce heat much like a conventional boiler but also
produce electricity at the same time, thus increasing the efficiency of fuel
use.
Improvements would be required in information exchange: IEA (2002:98)
notes:
"If networks are managed in a decentralised way, for example with individual
customers responding to the needs of the local network, they will require
a greatly increased flow of information to ensure smooth operation of the
system. The distribution utility of the future will need to be in a position to
provide information, and to monitor and control its own system in a more
sophisticated manner."
e) Demand Side Response (DSR)
Electricity produced at different times of the day has different values. If the
marginal peak load price is higher than the value that customers gets out of
the services at that time, they might be willing to modify or defer demand if
the grid pays them to do so.
A grid operator is indifferent between paying a power producer to supply
more output and paying the same amount to a customer to switch of his/her
electric appliances instead, as both provide the identical balancing service.
DSR makes the demand curve for electricity more elastic and thus sensitive
to price changes which, other things being equal, will reduce the need for
reserves in an electricity market.
While households would be an attractive target for DSR, their electricity bill
is often only a small fraction of total household spending which provides only
a small incentive. However, aggregation or 'consolidation' service providers
that represent a bundle of households at the wholesale market could explore
this market niche.
f) Curtailment of wind farms
Recently, with the expansion of wind farms offshore, curtailment of intermittent
technologies has become a further option to cope with system variability.
Large wind farms, with a significant number of megawatt-sized turbines can
in principle provide the same ancillary services that conventional generators
offer today. Switching off some wind turbines for operational reserve or
running them at reduced output becomes a realistic option with modern
large-scale wind farms.
98 Lecture: Britains Power System