January 2018 was officially the hottest month ever recorded in New Zealand. Recent events including storms, fire and ice melt are all signs that our climate is changing.
The impacts of climate change are detailed in the recently released Adapting to Climate change in New Zealand a stocktake report issued by the Climate Change Adaption Technical Working Group. Impacts include ex-tropical cyclones, more frequent extreme rainfall events, more frequent fires, higher storm surges and increased coastal erosion and more days with extreme high temperatures.
- The report is available here.
Since the Industrial revolution humans have been releasing increased amounts of greenhouse gases particularly carbon dioxide (CO2) emissions into the atmosphere which have upset the natural balance.
At present most of the world’s energy is generated by using fossil fuels such as coal, natural gas and oil which produces around two-thirds of all emissions.
Wind energy plays an important, global role in addressing climate change. Many developed nations have worked hard to reduce their carbon dioxide (CO2) emissions from electricity over the past couple of decades. Developed countries with a downward trend in CO2 per unit of electricity generated include the US, Denmark, Australia and the UK.
Unfortunately for our image and for the future, New Zealand’s trend is one of increasing emissions.
NZ’s gross emissions have increased 24.1% since 1990 to 80.2 Mt CO2-e in 2015 while over the same period CO2 emissions have increased 41.2%.
According to the Ministry for the Environment, New Zealand’s emissions intensity by population is amongst the highest for developed countries.
The Government has signed the Paris Agreement and has committed to reducing the level of carbon. The current target is to reduce emissions to 30% below 2005 levels by 2030. The Government has also advised it is to investigate ways to achieve a net zero carbon footprint by 2050.
Energy sector and electricity
Energy sector emissions are up 36.7% since 1990 to 32,455.2 kt CO2-e in 2015, representing 40.5 per cent of New Zealand’s gross GHG emissions. The largest sources of emissions in the Energy sector were Road transportation, contributing 13,282.3 kt CO2-e (40.9 per cent of the Energy sector), and Public electricity and heat production, contributing 4,041.1 kt CO2-e (12.5 per cent of the Energy sector) to energy emissions.
New Zealand’s electricity sector emissions show large inter-annual fluctuations. The fluctuations are influenced by the close inverse relationship between thermal and renewable generation. Generation is dominated by hydroelectric generation. In a dry year, where low rainfall affects the majority of New Zealand’s hydroelectric lake levels, the shortfall is made up by thermal electricity generation. New Zealand’s hydro resources have limited storage capacity; total reservoir storage is only around 10 per cent of New Zealand’s annual demand. Hence, regular rainfall throughout the year is needed to sustain a high level of hydro generation. Electricity generation in a ‘normal’ hydro year does not require significant use of natural gas and coal, while a ‘dry’ hydro year necessitates higher utilisation of natural gas and coal.
The Ministry of Business Innovation and Employment produce an annual report on Energy Sector Greenhouse Gas Emissions.
- The latest report is available here.
How does wind energy address climate change?
One way we can reduce our greenhouse gas emissions – as well as our dependency on fossil fuels – is by increasing the proportion of electricity that is generated from wind and other renewable energy resources. Wind farms don’t emit greenhouse gases as they generate electricity, whereas coal and gas stations do.
Both coal and gas generation also create a lot of waste heat that cannot be easily used for generating electricity. Over 50% of the energy used to produce electricity from gas and coal is lost through the production process, which is not the case with wind energy.
The US National Renewable Energy Laboratory recently compiled the results of all peer-reviewed publications on lifecycle emissions for different energy sources. This study shows that it takes less than six months for a wind farm to produce more energy than it will consume in its entire lifetime. The lifecycle emissions (including manufacturing of components, transport to site, construction, operation and decommissioning) from wind farms are about 1% of the emissions from thermal generation.
Another opportunity is to increase the use of electric vehicles and look to change the source of industrial heat from using fossil fuels to electricity. As long as New Zealand continues to generate most of its electricity from renewables these strategies will result in a large reduction in carbon emissions.
The Energy Efficiency and Conservation Authority (EECA) latest strategy Unlocking our energy productivity and renewable potential highlights these opportunities.
NZWEA also provides further information on climate change and the importance of renewable energy in addressing global warming.
- See our Climate Change Student Fact Sheet.