Electronics > Power/Renewable Energy/EV's

It's happening, the power grid is changing.

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DenzilPenberthy:
An interesting thing here I stumbled across yesterday:  The National Grid in the UK are inviting tenders for projects which can supply between 1 and 50 MW into the grid in sub 1s response times.  It is interesting to see this becoming a thing now as we reduce the amount of large steam driven rotating machinery for generation.

I wonder if this reduction in system inertia is also from the demand side? i.e. fewer directly connected large synchronous motors, instead most stuff nowadays is inverter driven so presumably wouldn't contribute to the general rotating mass of the system in the same way?

http://www2.nationalgrid.com/Enhanced-Frequency-Response.aspx

Copied and pasted:

Background
The changing generation mix in GB is reducing the contribution that synchronous generation makes
to the energy market, which in turn is reducing the level of system inertia, particularly on low demand
days. Lower system inertia affects the ability of the System Operator (SO) to manage the system
frequency within normal operating limits. This in turn will drive the procurement of larger volumes of
the existing frequency response products. NGET is therefore investigating alternative solutions, one
of which is the creation of an enhanced frequency response service. The aim of this service will be to
improve management of system frequency pre-fault, i.e. to maintain the system frequency closer to
50Hz under normal operation, however performance in post-fault conditions is also of interest.
NGET believes that the most appropriate way to develop this new service is to run a tender for four
year contracts for enhanced frequency response capability. This will give NGET experience in
integrating enhanced frequency response into the suite of system management options, as well as
providing a competitive route to market for new technologies. Whilst a number of the energy storage
solutions currently available have the ability to provide frequency response in these enhanced
timescales, NGET welcomes the participation of any technology types which can meet the required
parameters. Provision of additional services such as reactive power will also be taken into
consideration.
Ultimately, it is NGET’s aim to create a sustainable tendered market for the provision of enhanced
frequency response services from all technologies, work which is being progressed through the

SMART Frequency Control project1
. This would ensure that there is a route to market for both
existing and new providers, regardless of technology type, and also would realise the benefits of
competition in the procurement of these services.

tggzzz:
Oh, that is interesting.

The sub-second response time means that hydro won't be sufficient; IIRC that takes 20s to reach full power.

Is there any indication how long this has supply power? If only 20s, then I suspect flywheels or compressed gas might work.

DenzilPenberthy:
"Our initial analysis indicated that a battery with a 45 minute duration (minimum operational state of
charge to maximum operational state of charge) based on current frequency data and possibly one
that minimizes or at least meets the 95% availability. However, this is currently under review, and
we will be giving more guidance on the minimum duration required shortly. The maximum duration
that we would value from an EFR service is 30 minutes, any ability of the assets to deliver energy
beyond this timeframe has no additional value to NGET, however it is up to Applicants to size the
energy capacity of their assets (where necessary)."

So maximum 30 mins. They've stated battery here but elsewhere in the documentation they are very keen to stress they are completely agnostic about what technology is used.  In fact I read just now that they've received tenders so far from 68 projects, 60 of which have qualified to tender of 1.3GW in total, of which 880MW is battery based. It doesn't say what other ideas people have come up with.

 As you've stated, they already have frequency response arrangements in place with things like pumped hydro and diesels that can pick up in high 10's of seconds to low number minutes.

DenzilPenberthy:
It is also interesting to think that once there is a decent install base of electric vehicles, this service could be provided by a vehicle fleet operator if the chargers were bi-directional and say 10% of the battery charge was made available to use.

coppice:

--- Quote from: DenzilPenberthy on April 20, 2016, 01:16:44 pm ---So maximum 30 mins. They've stated battery here but elsewhere in the documentation they are very keen to stress they are completely agnostic about what technology is used.  In fact I read just now that they've received tenders so far from 68 projects, 60 of which have qualified to tender of 1.3GW in total, of which 880MW is battery based. It doesn't say what other ideas people have come up with.

--- End quote ---
Battery based might mean nothing more than having a minute or two of battery capacity while they get something else on line. UPSes are often described as battery based when they have a few minutes of battery, and a diesel generating set.

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