Page 31 - Gi_September2021

igem news – yppc

I am looking to confirm there are POWER GENERATION STATISTICS
no pressure spikes during these two
scenarios that take the pressure above
or below the allowable limits on the
upstream network. I conducted FT
analysis at peak demand and summer
night demand. Network pressures will
be at their highest during summer night
demand and therefore we need to see
if the pressure spikes above the peak
level operating pressure (PLOP) during
an emergency switch off.
As part of the FT analysis, I will
suggest a suitable main and service
size allowable for the PG site to operate
safely. The main and service design must
abide by NP14 regulations and therefore: SCADA FLOW AND PRESSURE GRAPH
“For all new services operating at
pressures not exceeding 7bar the
design gas velocity shall not exceed
15m/s… For all new mains operating at
pressures not exceeding 7bar the design
gas velocity should not exceed 40m/s”
(Wales & West Utilities, 2008)
This is then incorporated into the FT
analysis to give us the most realistic
and accurate view possible.

Power generation NexA
PG has had a major impact on our local
transmission system (LTS) storage to SCADA FLOW AND PRESSURE GRAPH CLOSE UP
the point where systems that previously
had a huge surplus in storage are now
in deficit. In response to this, where
ad-hoc storage cannot be obtained, we
have introduced peak day percentage
Network Entry Agreement (NExA) to
ensure that the site can connect and
operate normally, but only to a specified
demand level. Once that demand level
has been exceeded, then the PG site
must operate at a flat 24-hour rate to
avoid storage issues.
ANALYSIS PROCESS
Biomethane If, for example, a customer wanted
The rise and impact of biomethane to export 500scmh into our network,
WWU’s first biomethane site connected then it would not be possible.
in 2013 and since then we have Furthermore, we do not know how
connected a further 18 sites onto our the biomethane site will interact with
network with a further six accepted the other feeds into the network once
sites looking to connect. connected. Therefore, we need to
Interest level in biomethane has model this scenario and combine it
decreased since 2017, evidenced by with our supervisory control and data
the drop in enquiries we have received. acquisition (SCADA) flow data to obtain
Even with the decrease in recent years, the results we require.
we do expect biomethane uptake to our flow data to determine how much
increase again. Biomethane analysis of that flow could be supplied by the bio
“We expect biomethane to increase To ensure the bio site has the best chance site the previous year.
from 3TWh in 2018 to 22TWh in 2030… to export, the outlet pressure is set to Between the months of April and
This is in line with current run-rates the downstream maximum operating October, the site will not be able to
and stakeholder feedback.” (Navigant pressure (MOP). We can then analyse the export the full 500scmh and therefore
Europe Ltd, 2019) model at each end of the demand scale, the customer would have to accept
In an ideal world, a biomethane site noting the flows going through each a reduced export rate during those
would be able to export at a continuous feed and what percentage of the total months. This reduced amount can be
flat rate without any disruption. network flow is being supplied by the detailed within the terms of a Network
However, that is not always the case. bio site. This is then incorporated into Entry Agreement (NEA).

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