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Traditional ChineseSimplified ChineseText onlyPDARSS
Senior HK Government officials speak on topical issues 
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November 30, 2006
Renewable energy's many challenges 
Secretary for the Environment, Transport & Works Dr Sarah Liao
Dr Sarah Liao

A world-renowned professor predicted two decades ago that environmental disasters would appear as a result of excessive energy consumption by the post war baby boomers. Recently, while the same professor has proven his prediction on the level of energy consumption, he has come to the conclusion that technology has saved the day for environmental disasters, at least for now.

 

We cannot be more familiar with the problems associated with the use of fossil fuels. Surveys and polls have repeatedly showed that air pollution is a top concern for Hong Kong people. Our international friends, and competitors have made this point in the headlines of their news. The alarm of global warming has kept the international community on the alert. All these are linked to consumption of energy from fossil fuels.

 

The search for alternative energy is not without its contraints. What we need is renewable clean and portable energy supply generating little or no pollution. So, let's first turn to the renewables:

 

* Solar heat energy - The use of solar energy for purely heating has been well developed for years but in Hong Kong it is not widely employed by businesses. The use of solar energy can be made possible by a simple installation of heat exchanger with water flowing through and being kept warm. If you need abundant supply of hot water, this is a very cost-effective system with a short pay-back period.

 

Unfortunately, such a simple rudimentary technology has almost been ignored except in a few places. As far as I know, the Chinese University is perhaps the only tertiary institution making extensive use of this! Government is also an extensive user. We have solar heating systems in some prisons, a slaughtering house, and a swimming pool complex, to name a few.

 

* Solar photovoltaic panels - This technology converts solar energy into electricity and either stores it in batteries, transmits it into the electricity conveyance grid, or uses it directly. The panels are made of crystalline or amorphous silica materials. By using batteries as the electrical energy storage medium, the cost would get higher and the capital investment in these panels could hardly be recouped during the life cycle of the solar panels.

 

If the energy generated from the panels can be fed into the main electricity grid, it may present another kind of problem concerning safety, power quality and reliability, which will normally cause the grid operator to demand a significant amount of money to cater for the risks involved.

 

However, all these problems may be overcome shortly. Though the panels are still expensive, the price dropped rapidly in the last decade or so, perhaps thanks partially to the fact that China has become a large producer of these panels. With technology innovation, the efficiency of solar panels is also improving and the risk related to grid connection is decreasing.

 

Recently we have worked through a whole set of technical specifications with our Electrical & Mechanical Services Department to set out the requirements concerning connection of the solar panels onto the grid. And hopefully we have overcome this very technical problem and allow other forms of renewable energy to enter the grid. In fact, this is one of the requirements we have put in our negotiation with power companies in their new scheme of control.

 

The prospect of utilising the solar energy through these panels in an even more cost-effective manner will be better. In fact, nowadays, such panels have already become the lifeline of villages in the western part of China where the solar-power generator provides electricity for pumping water to irrigate fields, providing lighting for households, and supporting the basic needs of scattered local communities involving of a few thousand population each.

 

* Wind energy - Wind turbines are simple, mechanical setups fitted with electronic detectors to enable the rotor to follow the direction of the wind and stop turbines for protection when the wind speed exceeds a certain limit. They have worked well for Denmark which proudly claims the highest utilisation rate of wind energy in the world, up to about 20% of its electricity being supplied from wind.

 

The first or second generations of wind turbines were huge structures and were hard to maintain if the wind conditions were erratic. Moreover, such wind mills were usually built in remote areas and the transmission loss is often very significant, making the already low efficiency of the wind-power-generation process even less efficient.

 

Such setups also attracted objections if they were too close to residential areas as the noise generated by them was significant. As a result of all these constraints, it was often extremely difficult to identify a suitable location with steady, constant wind speed of around 10m/s to promote the wider use of wind power in the past.

 

However, the development of the latest generation of wind turbines have significantly removed some of these constraints, for they are a lot more efficient, quieter, and yet cheaper.

 

Small turbines could be fitted on rooftops

I am a strong supporter of renewable energy and believe more research and development should be conducted to overcome some of the critical problems relating to their application. I have recently learned that there are new wind turbines of considerably smaller sizes which could be fitted on top of buildings for supplying electricity. If the efficiency and cost effectiveness of such products can continue to improve, I am sure that HK's skyscapers will at last have some premium points!

 

Innovation is not limited to technology advancement. Innovation in deployment of existing technologies is at least as important as innovation in advancing them. A notable example is our 61-hectare wetland park in the northern part of the New Territories which has employed a geothermal heat-pump system for air-conditioning. The system has a total cooling capacity of 2500 kW. Instead of using air to carry away heat generated from the air-conditioning system, heat is dissipated through the ground which has a lower temperature. As a result, 25% of energy is saved.

 

Hydrogen energy an emerging hope

As it takes time to improve the efficiency of renewable energy to the next level which can genuinely outperform that of the fossil fuel, it is only sensible for people to develop clean energy in parallel. Hydrogen energy is an emerging hope: Hydrogen may be used as a direct fuel as it burns in air and produces energy and water vapour, which makes it the cleanest fuel thus far discovered. The fuel-cell technology is what will allow the portable use of hydrogen in daily life.

 

At present, hydrogen cars and buses have already been developed and used in North America. A new generation of hybrid cars using hydrogen are also being developed in California. In the Mainland, hydrogen buses may also feature in the Beijing Olympics.

 

How to obtain clean sources of hydrogen is an important question to overcome. Otherwise, while the use of hydrogen as fuel may be pollution-free, the generation of it may cause as much if not more pollution. A visionary idea being explored is to generate a large amount of hydrogen through electrolysis of seawater powered by large remote wind farms. The hydrogen is then compressed and shipped to other places for use, similar as we now do with liquefied natural gas.

 

Renewable energy not ready to replace fossil fuels

So have we found a solution to supply human beings' insatiable demand for more energy? Not yet. If we look at the current average power demand by human activities in the developed world, a modest guess is about 5 kW/m2. The world average efficiency of solar power is about 40 watt/m2 while wind power is only about 2 watt/m2. These figures point out the inconvenient truth that renewable energy has a long way to go before it can replace fossil fuel, as much as would we like it to.

 

In the final analysis, there is no silver bullet to improve our environment instantly and to secure energy sustainability. Technology only offers part of the solution. We have to ask ourselves that we can do and should be doing to reduce energy consumption and hence pollution.

 

Many businesses have begun to embrace environmentally responsible principles in their procurement requirements, manufacturing or operation processes and material selections.

 

I don't want to repeat here again as to what the Government has been doing to improve our environment. But the important thing is we are doing everything we can. And we need time to get the support of the community. There are dissenting voices all the time. We need to deal with them. We are not saying that we have to listen to them entirely but we cannot ignore the dissenting voices.

 

Full co-operation needed

I can assure you that with the measures that we've both implemented in Hong Kong and the Pearl River Delta, we are charting along the right path. We are measuring the results and we are seeing the reduction in the measurement that we have made. Of course most people would rely on their perception more. It is very hard to convince people with figures.

 

We do need time, there is no magic wand that will solve the air-pollution problem in a day. Only with the full cooperation with the community and our businesses, will we be able to succeed. I look forward to collaboration with all of you in our future efforts to improve the environment.

 

Secretary for the Environment, Transport & Works Dr Sarah Liao gave these remarks at the HSBC Living Business Eco Day.

 


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