Mathew McBride's website

Is electricity demand rising? Maybe, maybe not?

technologyelectricitySat 27 Oct 2012 04:39:17No comments

Here is some statistics for Victoria's Electricity demand (and wholesale price) from 2008 up to the end of September, 2012.

Demand (MW) 2008 2009 2010 2011 2012 (to 1/10)
Minimum 4004.1 3882.1 3717.5 3853.5 3767.2
Maximum 9701.5 10415 9858.3 9570.3 9069.2
Mean 5956.3 5856.8 5842.9 5724 5745.2
StdDev 837.64 909.71 919.98 844.98 861.36
Price ($/MWh)
Minimum -134.09 -496.71 -817.03 -332.92 -150.18
Maximum 8766.2 10000 9998.6 9596.5 4364.1
Mean 40.232 36.485 34.443 29.368 39.148
StdDev 116.11 233.64 262.22 104.89 59.943

The sources to compile these statistics come from AEMO. This source lists demand and price every 30 minutes, but the actual market moves on five-minute dispatch intervals.

So, peak demand from the wholesale side hasn't really been growing - more skilled analysts elsewhere confirm that demand is declining. But I've also heard people on both sides of the fence - those on the retailer/consumer side suggesting there is a regulation problem, and those in the industry putting forward a case that peak demand is definitely rising with an increase in home air conditioners. In any event, I am not in the industry so am not in a good position to judge who is right.

The numbers above only show demand on the National Electricity Market. It is possible localized demand on the distribution (as opposed to transmission networks) is higher than shown here - as 'demand-side' sources such as Solar PV present to the market as 'negative demand'.

Another possibility to entertain is that after some high profile infrastructure failures (such as on Black Saturday some years back), transmission and distribution operators would rather take heat for overbuilding on reliability rather than be asked why the lights went out. And, as typical for many pieces of infrastructure that were neglected for many years, asset replacements may be catching up.

The above numbers don't factor in blackouts causing demand to drop (particularly in peak demand episodes) or other factors, such as general climate trends.

Dumps of myki short term ticket cards

technologynfcmykiTue 25 Sep 2012 11:22:39No comments

In light of a recent demonstration of a 'replay' attack on MiFare Ultralight Cards, here is some further analysis.

Some years back I had posted on the (now-defunct) myki.org forum that myki used DESFire and the STT's Ultralight C (with 3DES encryption). The STT's are actually the plain Ultralight variety. (In fact, Ultralight C was only launched shortly before myki went live)

Also, at that time, libnfc did not contain the code to differentiate between a normal Ultralight card, and the 'C' variant

The following data was generated by using the libnfc and associated libfreefare toolkits

(Read below the fold)

SELinux Policy Macros: Reference

technologylinuxselinuxSat 15 Sep 2012 18:20:27No comments
I have posted a 'cheatsheet' of SELinux Policy Macros to assist in development of SELinux Policy Modules.

Notes from PowerCor Smart Meter Rollout Presentation

technologypowersmartmeterSat 15 Sep 2012 09:05:14No comments

I was fortunate enough to attend a presentation by Mark Pilkington, Metering Standards Manager at CitiPower/PowerCor on the ongoing Smart Meter rollout in Victoria.

The story behind the Smart Meter rollout was interesting, and didn't match any of the diatribe that has been circulated in public. Indeed, he noted that Engineers need to improve the communication to the public on issues such as these.

Read below the fold for more..

SELinux add on policy repository

technologylinuxselinuxgentooSat 08 Sep 2012 09:23:12No comments

I have created a git repository for my addon SELinux polices for Gentoo at Gitorious.

Right now it includes rules for php-fpm with nginx and unix domain sockets, as previously mentioned, as well as nzbget+nzbgetweb and uwsgi

SELinux add on policy for php-fpm + nginx with sockets on Gentoo

technologyselinuxphpnginxgentooSat 25 Aug 2012 13:21:40(Last updated: Sun 26 Aug 2012 03:46:16)No comments
  1. emerge -av selinux-phpfpm to get the php-fpm policy
  2. Set "listen = /var/run/php-fpm.socket" in /etc/php/fpm-php5.X/php-fpm.conf . By default, this is set to TCP port 9000
  3. Create fpmphp.te:
    policy_module(fpmphp-c,1.0.2);
    
    require {
            type phpfpm_var_run_t;
            type phpfpm_t;
            type nginx_t;
            type var_run_t;
    }
    allow phpfpm_t phpfpm_var_run_t:sock_file {create write unlink};
    allow phpfpm_t self:unix_stream_socket listen;
    
    type_transition phpfpm_t var_run_t:sock_file phpfpm_var_run_t;
    #file_type_auto_trans(phpfpm_t, var_run_t, phpfpm_var_run_t, sock_file)
    allow phpfpm_t var_run_t:sock_file {create write};
    # allow nginx to connect to the php fpm socket
    allow nginx_t phpfpm_var_run_t:dir search;
    allow nginx_t phpfpm_var_run_t:sock_file {write};
    allow nginx_t phpfpm_t:unix_stream_socket connectto;
    
    # allow phpfpm to connect to mysql socket
    optional_policy(`
            mysql_stream_connect(phpfpm_t)
            ')
    

    If you don't know how to do this, turn back and learn more about SELinux first
  4. Create fpmphp.fc
    /var/run/php-fpm.socket -s system_u:object_r:phpfpm_var_run_t
    
  5. Compile and install the SELinux policy
  6. Use this fastcgi_pass block in nginx.conf:
    location ~ .php$ {
                            fastcgi_pass unix:///var/run/php-fpm/php-fpm.socket;
                            include fastcgi.conf;
                            # if under HTTPS
                            #fastcgi_param HTTPS on;
                    }
    

Setting up a Gentoo container under lxc - notes (Feb 2012)

technologygentoolxcMon 13 Feb 2012 10:48:31No comments

For anyone who is trying to set up a Gentoo container under lxc manually, and not having any luck:

  • Set rc_sys="lxc" in /etc/rc.conf in your container
  • Manually create /dev/pts
  • and /dev/shm

Configuring Racoon on FreeBSD to connect to a Cisco IPSec VPN

technologyfreebsdracooncisconetworkingSat 18 Jun 2011 11:46:51No comments

Traditionally the third-party client of choice for connecting to Cisco IPSec based VPNs on Unix has been vpnc. Unfortunately, while it connects successfully in my situation, there were issues with vpnc being unable to hold a stable connection. racoon is used as the Cisco VPN client on Mac OS X, which is very reliable. This document will detail configuring racoon to connect to a Cisco VPN on FreeBSD.

Recipe: 'Gentooize' an existing virtual server (VPS)

technologygentooSat 05 Feb 2011 11:02:04No comments

I was testing an OpenVZ VPS from a provider who didn't have any Gentoo installation images, so I wanted to replace the Debian installation provided with a Gentoo one. It needed to be done entirely over SSH (with the SolusVM serial console to augment it).

HOWTO: HostAP (Master) mode for Ralink rt73 USB wifi

technologywirelesslinuxSun 21 Nov 2010 11:23:17No comments

Here is how I managed to get my Ralink-based WIFI stick working in access point mode with WPA encryption.

  • Hardware used: TP-Link TL-WN321G
  • System: Gentoo

Read on for more..

Welcome to my site

Mathew McBride, telecoms hardware access engineer, programmer, gamer and all round nerd

Warning: contents of blog may not make any sense whatsoever.

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