Powering the Future Summary Report - Parsons Brinckerhoff

Powering the Future Summary Report
Powering the Future Summary Report
The second unavoidable consequence of higher levels
of intermittent generation is its interaction with the
despatch of other power plant to match the varying
daily demand for electricity. The demand pattern is
characterised by three regimes: baseload (steady
day and night), mid-merit (day-time only) and peak
(shorter periods of high demand). A high penetration
of intermittent renewable generation drastically reduces
the baseload regime, undermining the economic
case for more-efficient plant types with lower carbon
emissions. This means that the most economic power
plant will be those types with the lowest capital cost,
favouring technologies with higher carbon emissions,
such as open cycle gas turbines. But when operating
with limited, irregular and less-predictable hours, such
plant types are incompatible with the limitations of the
gas network, and would therefore need to use liquid
fuel, probably diesel or kerosene, further increasing
CO 2 emissions.
These findings indicate that a very high early
penetration of wind generation is likely to have adverse
effects on the rest of the generating fleet, undermining
the benefits of an increased contribution of renewable
electricity. They also highlight the problem faced
by the industry, as private investment in new power
plant must be guided by the appropriate economic
signals to ensure that it meets the needs of a reliable,
economic and low-carbon electricity system.
In selecting the mix of plant for each scenario,
Powering the Future takes account of the impact
of higher proportions of intermittent renewable
generation. Where there are higher penetrations,
fast-response generating plant is added to ensure that
the system operates reliably. A minimum average
utilisation of load-following plant is imposed to ensure
that there is sufficient revenue to cover the necessary
investment.
The second element of matching the power generation
model to the needs of the other sectors is to ensure
that annual electricity production covers demand and
the modest losses in transmission and distribution. To
achieve this balance of energy supply and demand for
each year to 2050, we adjusted the utilisation of loadfollowing
plant – typically CCGT plant. The resulting
contributions of the various types of generating plant
are illustrated for the reference scenario in figure13.
Connecting new generating stations to the grid
network and to consumers is a key element of adding
new capacity to the UK electrical system. Most of
the existing transmission networks were constructed
more than 40 years ago and have been progressively
uprated and reinforced since that time. Spare capacity
is limited, and connections for new generating capacity
in many areas of the country cannot be provided
in less than five years as new transmission lines
and substations must first be designed, permitted,
purchased and installed. This issue is accentuated
by the growth of coastal and offshore intermittent
renewable generating capacity which is often remote
from the main transmission network.
Although the transmission and distribution networks
face serious issues, they can be resolved by
appropriate investment. For the purpose of this
study it has been assumed that the timing and
scale of development of the electrical networks will
not constrain the benefits from the CO 2 reduction
measures.
Figure 12 Installed compared with required capacity for the reference scenario
Figure 13 Electricity production by generation technology
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