4: Evaluation Criteria contd.
Secure, sustainable low carbon electricity - CLASS accelerates the creation of a secure and sustainable low
carbon electricity sector in the two ways: firstly the CLASS Solution utilises reliable and proven technology/
assets in a novel way to improve network efficiency whilst maintaining the security of supply to DNO
customers; and secondly CLASS facilitates the connection of low carbon generation whilst deferring the
financial/carbon costs currently required to reinforce the network in providing such additional capacity.
Reform of the electricity grid - The increase in electricity generation and the change in the generation mix
will make system control more complex and demanding. The CLASS Project accelerates the reform of the
electricity networks in two ways: firstly the flexible demand management technique trialled, facilitates the
quick connection of low carbon generation and demand; and secondly the voltage regulation techniques
trialled in CLASS will demonstrate how distribution networks can help transmission system stability by
providing a demand response for frequency control and reactive power for voltage control. Through CLASS,
research and analysis will determine whether distribution network operators can contribute to maintaining
an economic and secure electricity system; through the provision of these lower cost and lower carbon
How a roll out of the Method across GB will deliver carbon benefits more quickly
Traditional reinforcement involves the construction of carbon intensive assets, particularly new switchgear
and transformers. Significant time is currently required in the scoping, design, approval, construction and
commissioning of a new Primary substation. This is increasingly likely to become a bottle-neck, as electricity
demand and generation is expected to grow. In contrast, the CLASS Method is quick-win which provides a
window of opportunity for the network operator to make the appropriate investment decision, whether
traditional reinforcement or the procurement of demand response directly from customers or via an
aggregator. Additional capacity can be released for use in one week simply by installation of a new voltage
controller at a Primary substation, compared with a typical reinforcement timescale for a Primary substation
of 57 weeks. This quicker delivery of capacity will prevent delays in the connection of low carbon generation
and demand to the network, and impact customers' carbon emissions.
CLASS will demonstrate how distribution networks can help transmission system stability by providing a
demand response for frequency control and reactive power for voltage control. The capability to generate
the demand response and reactive power is available at a Primary substation in one week and within one
year across the whole of Electricity North West compared with several years for the installation of new
generation assets or reactive power compensation equipment.
The potential for replication across GB
CLASS will trial the voltage regulation techniques on 60 Primary substations on it's distribution network, this
represents 17% of our Primary substation assets and 1.5% of GB's Primary distribution network. The
University of Manchester's review of CLASS identified that the Electricity North West network represents
7.4% of GB's distribution networks at system peak demand. This indicates that the CLASS Method could be
scaled up to the GB level via a scaling factor of about 13.5; this facto will be refined during our Project.
With reactive power absorption, the scaling factor is slightly lower due to the necessity of two transformers
at each Primary substation and The University of Manchester report indicates a factor of about 11; again ,
this factor will be refined during our Project.
Quantifying the potential carbon contribution of a roll out of CLASS across GB
The Tyndall Centre assessed the carbon impact for the CLASS Project, for an Electricity North West roll-out
and a GB roll-out. No carbon savings have been assumed for deferring the reinforcement of Primary
substation assets as potentially these assets may be required in the future. However, in the CLASS Project
the installation of the Voltage Controllers is marginal at 1.4 tCO
eq, the roll-out across Electricity North West
totals 8.7 tCO
eq, and a GB roll-out totals 113 tCO
eq. Whilst the deferral of carbon could potentially be as
high as 289 tCO
eq in the CLASS Project, 1 736 tCO
eq in an Electricity North West roll-out and 22 571
eq in a GB roll-out, assuming the building of each new Primary substation is deferred for three years.
These figures exclude the potential carbon impact of reducing losses from the reduction in demand. During
the Trials the carbon impact will be determined.
The carbon savings are potentially very large for the provision of demand response for frequency reserve
and the provision of reactive power for voltage control. The Tyndall Centre considered the two markets of
Fast Reserve and the Firm Frequency Response to estimate the potential lower and upper carbon savings
range. For the CLASS Project the carbon savings are potentially up to 360 tCO
eq per annum assuming the
demand response is provided one hour per week. This scales up to 2 288 tCO
eq per annum for an
Electricity North West roll-out and to 29 750 tCO
eq per annum for a GB wide roll-out. In RIIO-ED1 this
technique could conservatively save 5 100 tCO
eq in an Electricity North West roll-out and 66 306 tCO
a GB wide roll-out (See Figure 6).