Page 30 - Gi flipbook April 2019

small but mighty

enough firm capacity to meet the peak
demand of winter with an appropriate
safety margin. This is the benchmark of
a safe and secure electricity system. It
must also have the flexibility to quickly
respond to changes in supply/demand
within shorter time periods due to the
volatility generated from wind and solar.
In summary, the UK needs more
firm balancing capacity and faster
response times while decreasing the
number of hours these plants operate
in order to reduce carbon emissions.
One conservative forecast is that the
UK requires at least 4-7GWe of firm
peaking/balancing generation capacity.
Though various energy storage
technologies are in development, the
majority are currently not economical
or practical enough to meet this
challenge now. Batteries will have a
role to play for situations that require
a superfast response, though they
typically cannot operate for more
than two hours at a time and require
charging. There is a clear demand for an These engines tend to be of smaller to generate in £/MWh. This, in turn,
established technology to balance the capacities, able to ramp quickly and means that the CO₂/MWh is also higher.
system right now, while closely following combine to form total installation Data from Wales & West Utilities, in
the energy trilemma principles of capacities of 5-50MWe. These plants addition to the government’s capacity
economic power, secure energy supply operate using established spark ignition mechanism contracts, shows the growth
and low carbon generation. engine technology, as utilised in CHP of this of type of plant.
installations, with a few manufacturer So far, we’ve seen a substantial
tweaks making them more reliable, increase in firm gas engine power plant
There is a clear demand for able to ramp faster and more suited to capacity by 400MWe from 2013 to 2018.
an established technology to starting several times a day. The number of applications for network
balance the system right now, The distributed gas engine power loads currently being processed will
while closely following the energy plants have all the key criteria to be the likely take this to 1GWe by 2022.
Due to the operational pressure
optimal grid balancing solution before
trilemma principles of economic more flexible, large scale, economical required, these sites are normally
power, secure energy supply energy storage technologies are connected to a minimum of MP270, IP
and low carbon generation developed. The advantages of these and some LTS networks. At medium
plants are as follows: pressure, sufficient capacity needs to
Highly flexible operation (0-10+ hours be available, so this tends to lead to
The energy industry has been per day) connections on 180mm pipe and above.
transitioning from large, transmission- Fast ramping (typically 2-8 minutes) The smaller engines (1-2MWe) operate
connected power plants to more Flexible (multiple starts per day) at 200-300 mbar and some of the largest
numerous, smaller power plants, Low emission, including NOx engines (10MWe) operate at around 5bar.
connected to electricity and gas through emissions. No SOx, or particulates The rise of gas engine power plants
local distribution networks. Economical – viable to finance on presents a number of challenges for the
This originally started with solar 1,000 hours operation with a range distributed gas networks now and in
farms, onshore wind and CHP of commercial revenue streams the future. These include taking large
installations connected to low including capacity mechanism gas loads from the network, the strain/
voltage local networks. This range of payments, embedded benefits, market excess placed on the networks during
technologies now also incorporates gas trading and other direct arrangements peak/low demand periods and the GDN
engine power plants, batteries, diesel with National Grid such as the processes to fairly allow capacity to be
engine installations, etc. This increasing balancing mechanism, STOR contracts reserved on the network.
trend has been demonstrated clearly Lower total carbon output when
in the UK government’s capacity utilised at 1,000 hours vs a CCGT’s
mechanism auctions, in which the bulk 4,000+ hours References
of contracts were awarded to smaller, Plants can be deployed extremely 1. Chart 5.3: Shares of electricity generation, by
more flexible distributed power plants quickly (as little as six months). fuel assets.publishing.service.gov.uk/government/
– the most economical way to provide Higher efficiency (when compared to uploads/system/uploads/attachment_data/
file/736152/Ch5.pdf
this required capacity. an OCGT) 2. Chart 5.4: Generating capacity of all power
The gas engine power plants use a The main disadvantage of this producers 2000 assets.publishing.service.gov.uk/
modular array of engines combined to technology is its lower electrical efficiency government/uploads/system/uploads/attachment_
data/file/736152/Ch5.pdf
produce a larger total power output. vs CCGT, making it more expensive

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