Grid Connectivity Talk Hosted by Greencape Initiative (Cape Town)

We attended a "Grid Connectivity" talk hosted by the Greencape Initiative in the Cape Town CBD today. Our rough notes on what was covered are given below[for confirmation of the facts, refer to the Greencape Initiative website]:

FIRST, OUR COMMENTS:
It is interesting to note that at events such as this, it has become apparent that there is substantial public interest in smaller projects and home installations. The fact that getting net metering off the ground could be difficult due to the potential risk of loss of income to Municipalities is unfortunate and makes one wonder about the actual purpose of these public bodies (i.e. protecting the public's best interests v being a going concern as if a private company). We do, however, hope that the steps Eskom is taking to allow for IPPs to get RE projects off the ground in SA are going to be fruitful and we think that the Greencape Initiative is a valuable support structure to help this process get off the ground.

OUR ROUGH NOTES:
The main speaker was Riaan Smit, Chief Engineer of Network Planning at Eskom.

Riaan started by reviewing the outcome of the first bidding process for SA's tender for the procurement of renewable energy by Independant Power Producers for which applications were accepted up to 04 November 2011.

149 applications for wind power projects, 122 Solar PV, 9 CSP & 41 applications for 'other' projects were received. Wind was clearly proved the most popular (in terms of the number of applications submitted) with PV following close behind.

In terms of capacity (MW), wind power again came tops, taking roughly 75%.

Rebid progress (started 17 November 2011):
Only 53 bids have been confirmed as received.
Many applications are not meeting the necessary requirements (environmental and other)
[Note: preferred bidders to be announced by the DoE over Cop17 (Durban).]

THE GRID & DIFFERENT RENEWABLE ENERGY TECHNOLOGIES

Challenge:
Where to develop new grid. Lead times of projects etc. New grids need to be built over the next 30 years.

Different technologies - Impact on the grid:
wind - You get the older and newer concepts all with different specs in terms of: power regulation; speed; gearbox; type; inverter, and voltage. There is a need to model the various types (a, b, c and d). Types C & D favoured (DFIG & PMSG[full power electronic converters]).
Ref: africa electricity.com

CSP - discussed two types of energy storage:
steam storage vessel (e.g. Spain example) or salt storage.
Indicated that steam storage "stabilised production during cloud transient - more grid friendly".

TECHNICAL CONCERNS / AWARENESS

1.thermal loading of lines and transformers
2.voltage variations during the normal operation
3. overvoltage studies for RE projects
4. voltage recovery after faults
5. phasing out old networks [instead of fixing existing infrastructure, maybe redo on new network.

(dependant on size and location)

Took Laingsberg wind power facility as an example - expect high voltages; small voltage changes due to line outages.
power factor control characteristic - need to choose correct wind turbine technology [C or d].

Line lengths are a big factor - Longer the line, increase in losses, voltage changes, limit transfer, capacity constrained.

what to do? Thicken[?] up conductor? Ask developers to move sites?

More technical concerns/awareness:
6.reactive power control
7.focus on load modelling
8.short circuit currents. fault level.
9.limit system losses vs maximum use of thermal capacities
10.reliability required by wind, pv, csp, other developers.
11.impact on power quality aspects.
12.transmission system requirements such as voltage stability
13.dynamic studies for various technologies, including mw networks.
14.impact on sub-synchronous resonance for cape network (rotor movement in cape v rotor movement north - can cause resonance).
15.voltage sags due to breaker operation
16.cable/transformer inrush currents
17.influence on ripple control systems.

CURRENT ESKOM ACTIVITIES:
Staff went to Denmark to visit two facilities for 3 weeks to gain practical experience. Feedback is that we are not as far behind as what was anticipatied. The main focus during this visit was skills development and new documentation.

Grid access unit established - customer service interface and applications.

Distribution master plans and network development plans to cater for RE scenarios. What to expect? Which applications will be approved? How to plan for networks in future.

Distribution self build policy and guideline - expect for it to be available Dec 2011.

Transmission updating generation connection capacity assessment future scenarios - A follow up of GCCA-2012. Making some changes to this. Should be available middle next year (scenerious up to 2040) [IRP going on to 2013]. Will build different scenarios, including less nuclear scenario to see if replaced by RE how it will be.

STILL NEED TO ADDRESS requirements for small renewable energy projects (based on NRS 097-2). Smaller i.e. 1mw and bigger.

Nothing yet for smaller than 1MW. Commented that maybe get the bigger ones goings and then tackle 100kw (household). Maybe next year. NRS 097-2 - making provision for smaller project technical requirements.

Smart grid working group.
people say smart grid(s) are the answer.
For this reason, this group has been established.

LESSONS LEARNT
company "A" does not transfer cost estimate from Eskom to company "B"

Mismatch between property ownership/rights and actual servitude requirements.

Mismatch between Eskom technical solutions offered and developer documents
point of utility coupling - gaps identified

developers risk project if scope not clearly defined and agreed with Eskom mismatch between developer EIA own solutions vs Eskom practical solution - eg cannot just rebuild new line on existing servitude while supplying customers.

Clear indication of self built with time lines/lead times to be well defined.

Q&A:
1. EIA time lapse - Can use of cables make it easier? - A: If the EIA needs to improve route - then it won't make it easier.

2. Someone from the floor said that NERSA has condoned roof top - unqualified access to grid for anything below 100kw. A:Rian says that nothing has been approved. If NERSA condones then it is something still to be developed, perhaps next year.

Another response to question 2 above: Someone added that we are talking about net metering and that local authorities are working together to try and achieve this. There is no problem with it, but we just haven't worked out the regulatory environment for it. Once this is in place, Eskom has to execute it, but to get this in place will take time. NERSA does the regulating, but at the end of the day, it must be dealt with on a local authority level. To get anything through, it will have to be sent through National Treasury. Local authorities make their revenue from electricity sales and Treasury may be weary of implementing systems which may lead to having to bail out local authorities that go bust.

3. Developers are not allowed to combine (resources?). DOE issue.

4. How to handle intermittent load of RE. Example of how Germany and Netherlands have good integrated networks and why gas can play a role as it does there, in allowing for quick response. Ramp rate of solar might also help. Noted that it is said that ramp rate in Britain is not a big issue. Example of sports event or royal wedding intermission times when there is major consumption peak (use of kettles, etc) and how the grid handled it. It is a matter of conventional and reserves being properly managed. Problem in SA is that we don't have reserve to allow for this.
................