by John A. Herbert
GHG inventory emissions rising
Since 2000 Hong Kong installed approximately 9000 (wet) cooling towers according to EMSD, these provide heat rejection for comfort air conditioning, it follows the HKSAR Government policy to reduce energy consumption by 1,360 million kWh, and resultant greenhouse gas emissions by 950,000 tonnes annually.
The HKSAR Government must be disappointed, the latest carbon emission data for 2013  released on 22 June 2016, records a total increased to 44.4 million tonnes CO²E  the highest recorded since 1990, and from the chart electricity and total GHG emissions have rising steadily since 2000, when the policy to permit cooling towers was initiated, it doesn’t add up.
Electricity generation being the largest, accounting for 68.29% of the total GHG inventory.
and that includes the windfall between 2000-2013, from converting air cooled air conditioning systems to water-based cooling towers.
So are we witnessing city-wide rebound effect? The rebound effect postulates that after energy saving features are installed, users waste energy because they know the energy consumption and costs will be lower. For example, switch from 100w incandescent lamp to 8w LED lamp, the energy consumption, and costs will be significantly reduced, now the user knows the running cost will be “cheap” so the 8w LED lamp is operated 24/7.
It seems Government and industry is still seeking that elusive Silver Bullet to tackle energy and GHG reduction, sadly I must inform you there is no silver bullet, the conversion to water based cooling towers has done little to stem climbing energy consumption (as the chart shows) over the last 20 years consumption has increased, a new multifaceted approach is needed.
The core issue, electricity mainly used in buildings, accounts for nearly 70% of the total GHG inventory, the other sectors, transport, agriculture, waste, etc. are insignificant compared to electricity.
Egregious waste, lighting the walkway during a bright summer day is just one of the issues that must be addressed. People are not stupid, when they see the MTR wasting money they learn by example, and rapidly lose interest in energy saving.
- Territory-wide Implementation Study for Water-cooled Air Conditioning Systems in Hong Kong http://www.legco.gov.hk/yr02-03/english/panels/ea/papers/ea0722cb1-2231-3-e.pdf